CN121127300A

CN121127300A - Method for producing deacidified fluid streams and apparatus for deacidifying fluid streams

Info

Publication number: CN121127300A
Application number: CN202480032733.5A
Authority: CN
Inventors: J·F·豪斯; A·施罗德; L·迈尔; G·西德尔; M·莱茵富尔特; I·克劳森
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2023-05-16
Filing date: 2024-05-07
Publication date: 2025-12-12
Also published as: AU2024271426A1; KR20260009367A; KR20260009369A; AU2024270685A1; KR20260009368A; WO2024235736A1; CN121175109A; KR20260009370A; WO2024235737A1; WO2024235739A1; AU2024273005A1; AU2024272398A1; CN121127299A; CN121219058A; WO2024235740A1

Abstract

This invention relates to a method for producing a deacidified fluid stream, the method comprising a direct contact cooler and one or more heat pumps. The invention further relates to an apparatus for deacidifying a fluid stream, the apparatus comprising a direct contact cooler and one or more heat pumps.

Description

Method for producing deacidified fluid streams and apparatus for deacidifying fluid streams

The present invention relates to a method for producing a deacidified fluid stream comprising a combination of a heat pump and a Direct Contact Cooler (DCC) to transfer energy from a heat source to a regeneration step.

In a second aspect, the present invention is directed to an apparatus for producing a deacidified fluid stream, the apparatus comprising a heat pump and a Direct Contact Cooler (DCC).

In view of the increasing signs of imminent climate change and its severe impact on the global population, the united nations sustainable development goal has determined that it is necessary to take "climate action" as one of 17 sustainable development goals. One of these 17 goals is not to integrate climate change measures into national policies, strategies and plans. The european union has issued a complete set of climate change policy initiatives with the goal of climate neutral in 2050. A more direct effect is that greenhouse gas emissions reduction targets are increased to about 50% compared to 1990 levels, and the goal is to achieve net zero greenhouse gas emissions by 2050. Other governments around the world have taken similar actions and incentives for climate protection measures.

Carbon dioxide is one of the most abundant greenhouse gases in the atmosphere. Greenhouse gases are gases that absorb and emit infrared radiation in the wavelength range emitted by the earth and thus contribute to global warming. The level of CO ₂ in the atmosphere has increased from about 280 ppm in the industrialized age around 1750 to about 421 ppm in 2022. About two-thirds of all carbon dioxide emissions originate from the combustion of fossil fuels.

Most climate action measures require a huge capital investment and are implemented for up to years or even decades.

Carbon Capture and Storage (CCS) or Carbon Capture Utilization and Storage (CCUS) are readily available and developed technologies that can be implemented on a large scale in a shorter time frame and thus can have a more direct impact on climate change. Carbon dioxide may be captured directly from industrial sources such as cement production, natural gas processing, and ammonia and hydrogen production, or from fossil or biomass fuel powered power plants. Carbon capture rates of 80% to 95% are currently achievable from flue gas from carbon-based fuels.

The captured carbon dioxide may be removed from the atmosphere by carbon sequestration or carbon storage in suitable geological formations such as depleted hydrocarbon reservoirs, mines and salt or other formations. Carbon dioxide is typically compressed to a high pressure of about 100 bar before it is transported to its final storage location and injected into the ground. Other uses of captured carbon dioxide are enhanced oil recovery or conversion to fuels, cements, minerals, or chemicals.

Currently, amine gas treatment is one of the most sophisticated methods for carbon capture. Amine gas treatment refers to a process in which acid gases (acid gases), such as carbon dioxide or hydrogen sulfide, are removed from a feed gas stream by absorption in an amine solvent. A typical Acid Gas Removal Unit (AGRU) includes an absorber and a regenerator and ancillary equipment. In the absorber, the downflowing amine absorbs the acidic components of the feed gas to obtain a sweetened gas or sweet gas stream and a partially acidic component-loaded amine solution ("rich amine"). The rich amine solution is then fed to a regenerator or stripper where it is heated to strip or flash the desorbed acid gas to the top and produce a regenerated amine solution ("lean amine"), which may be recycled to the absorber. The stripped CO ₂ is then compressed, dried, and optionally refrigerated and transported to its storage destination.

Amine gas treatment is a relatively energy intensive process. It is estimated that up to 40% of the energy produced by a power plant is consumed by carbon capture and sequestration. This energy loss value is assigned to about 60% of the amine gas treatment process and 30% of the carbon dioxide compression. The high energy consumption (energy extensive) of the amine gas treatment is partly the stripping of the captured carbon dioxide in the stripper. The temperature in the absorber is typically about 30 to 70 ℃, whereas the temperature necessary to strip the carbon dioxide is typically in the range of 100 to 150 ℃. The energy required to heat the rich amine is typically supplied by transferring heat from the hot process steam to the rich amine in the regenerator.

Process steam may be generated in a combined cycle gas power plant. In such cases, steam production from electricity production may be integrated into the amine gas treatment process. However, for all AGRU, steam integration with existing steam sources is not always possible and then the required steam needs to be provided by a separate process steam production process such as a steam boiler.

Thus, many activities address the need to reduce the energy consumption of amine gas treatment units. One possible strategy to reduce the energy consumption is to try to improve the circulation capacity of the amine solvent and reduce the energy required to regenerate the amine solvent. However, solvent development is quite expensive and time consuming and often requires the use of specialized high-priced solvent systems, resulting in higher operating costs.

Another strategy for reducing the energy consumption of an amine gas treatment unit is to transfer heat from a source with a higher temperature within the gas treatment unit to a location with a lower temperature.

The most prominent example of such heat transfer measures is the so-called cross-flow heat exchanger between the regenerator and the absorber, wherein the hot lean amine leaving the regenerator heats the cold rich amine from the absorber before feeding the rich amine to the regenerator. However, the indirect heat exchange by the cross-flow heat exchanger is generally insufficient to supply the majority of the energy required to operate the stripper. US3823222 teaches the use of the energy contained in the hot feed gas to be deacidified in AGRU to produce steam in a separate boiler, which steam can be used for steam stripping in the regenerator to heat the reboiler of the regenerator.

US3101996 also teaches the use of a hot fluid stream such as synthesis gas or hydrogen obtained in a water shift reaction to produce steam in a separate boiler that can be used to heat the amine stripper.

WO200712143 discloses two separate cooling stages for cooling hot flue gas from a steam turbine prior to amine gas treatment. In the initial stage, the flue gas is cooled in a heat exchanger by indirect heat exchange with a fluid used to heat the stripper. In the second stage, the flue gas is cooled by transferring thermal energy to a heat pump system for heating the stripper. The heat pump system may be supplemented by heat regenerated in other heat sources such as a CO ₂ compression stage.

The use of a heat pump to transfer energy from a process unit having a higher thermal energy level to a process unit having a lower thermal energy level is not limited to just a hot feed gas. Almost every heat source in an amine gas treatment process is proposed for use with heat pumps.

WO 2010097047 and WO 2011122525 use the heat of absorption in the absorber as a heat source for a heat pump to heat the rich amine solution.

JP2015131735 uses an intercooler circuit in the absorber as a heat source for a heat pump to heat the stripper. WO200781214 and CN114405258 disclose the use of condensation energy generated in the condenser of a stripper as a heat source.

WO201258558 describes the use of the thermal energy of the stripper gas in the overhead condenser as a heat source for a heat pump. The disclosure is limited to the removal of SO ₂ from gaseous mixtures, but theoretically the principle can be transferred to CO ₂ removal.

JP2010088982 discloses the use of heat of compression generated in one or more compressors for compressing carbon dioxide to high pressure to heat a rich amine solution.

JP2015131736 essentially teaches replacing a conventional cross-flow heat exchanger with a heat pump for transferring heat from the hot lean amine solution leaving the stripper to the rich amine solution entering the stripper.

FR2968574 discloses the use of multiple heat sources for a heat pump, such as the overhead condenser of a stripper, lean amine solution leaving an absorber, and the overhead condenser of an absorber, for removing water vapor from sweetened gas.

Also CN10289584 mentions the use of lean amine solution leaving the regenerator stripper and stripper overhead condenser as heat source for heat pump.

Heat sources outside of the amine gas treatment process may also be used.

CN112126477 discloses the use of blast furnace slag rinse water as a heat source for heating a stripper with a heat pump.

The energy contained in the various heat sources disclosed is typically insufficient to provide the full energy required in the stripping step. Therefore, multiple heat sources need to be tapped, which requires the use of more than one heat pump. The use of several heat pumps increases the capital cost of the amine gas treatment unit.

While much of the disclosure focuses on heat integration in gas processing, there remains a need for a heat integration solution that can supply most or all of the energy required in the regenerator and that does not result in a dramatic increase in capital costs.

The problem underlying the present invention is therefore to provide a method for reducing the energy requirements of a gas treatment unit using a liquid absorbent while reasonably limiting the additional investment in plant infrastructure. A potential additional problem with the present invention is the reduction of corrosion and fouling in equipment in contact with fluid streams. Another problem underlying the present invention is avoiding the need for expensive equipment required to transport the gaseous stream. In addition, it is an object of the present invention to electrified the steam production required for regeneration of rich absorbent solutions and potentially separate the steam production from the electricity production in a power plant or the need to provide a separate steam production facility. It is a further object of the present invention to reduce the energy requirements of the steam production required in the regeneration step. It is yet another object of the present invention to provide a method for gas treatment that is flexible and can accommodate fluctuations in the load of the feed gas stream supplied to the gas treatment unit. This problem becomes more and more important as more and more energy from renewable resources is introduced into the energy network affected by fluctuations caused by the available wind and solar energy. Such fluctuations in energy supply need to be balanced by carbon-fuel based power plants that are used to compensate for energy shortages and thus themselves produce varying flue gas streams that need to be treated by acid gas removal processes.

Aspect 1-method for producing deacidified fluid streams by a heat transfer process comprising two or more heat pumps

In a first aspect, the invention relates to a method for producing a deacidified fluid stream, the method comprising:

a) A thermal energy transfer step, wherein thermal energy is transferred from the fluid stream FS1 comprising at least one acid gas to the regeneration step c) to obtain a fluid stream FS2 having reduced thermal energy compared to the fluid stream FS 1;

b) An absorption step, wherein the cooled fluid stream FS2 is contacted with an absorbent A1 in an absorber to obtain an absorbent A2 loaded with acid gas and an at least partially deacidified fluid stream;

c) A regeneration step, wherein at least a portion of the loaded absorbent A2 obtained from step b) is regenerated in a regenerator, obtaining an at least partially regenerated absorbent A3 and a gaseous stream GS comprising at least one acid gas;

d) A recycling step, wherein at least one substream of the regenerated absorbent A3 from step c) is recycled to the absorption step b);

Wherein the thermal energy transfer step a) comprises a combination of a direct contact cooler DCC and one or more heat pumps.

Thermal energy transfer step a):

The method of the present invention comprises a thermal energy transfer step a) wherein thermal energy is transferred from a fluid stream FS1 comprising at least one acid gas to a regeneration step c) to obtain a fluid stream FS2 having reduced thermal energy compared to the fluid stream FS 1.

Fluid flow FS1

The fluid stream FS1 from which thermal energy is transferred to the regeneration step c) may be any fluid stream comprising at least one acid gas.

Preferably, fluid stream FS1 comprises CO ₂. In addition to CO ₂, other acid gases, such as H ₂S、CS₂ or COS, may also be present. In addition, oxides of sulfur and nitrogen, SO _x and NO _x, may be present.

The acid gas content in the fluid stream FS1 is typically 0.01% to 40% by volume, preferably 2% to 30% by volume and more preferably 3% to 25% by volume.

The fluid stream FS1 introduced into the process of the invention may comprise water. The water content in the fluid stream is typically in the range of > 0% by volume up to a content corresponding to the saturation concentration of water in the fluid stream under the existing pressure and temperature conditions.

The pressure of the fluid stream FS1 generally depends on the source of the fluid stream FS1, as further outlined below. Preferably, the fluid stream FS1 is flue gas.

The flue gas is preferably obtained by combustion of carbon-based fuels, such as fossil fuels like coal, natural gas and oil, or biomass feedstock from plants, algae or animals.

Such combustion processes may occur in a power plant or power station. Preferably, the source of flue gas is combustion of biomass from coal, natural gas, petroleum, biofuels such as bioethanol or biodiesel, or from forestry, agricultural or aquaculture.

Preferably, the fluid stream FS1 is flue gas leaving a steam turbine of a steam power plant in which the generator is driven by steam obtained from the combustion of a carbon-based fuel.

Most preferably, the fluid stream FS1 is flue gas leaving a steam turbine of a gas power plant designed as a simple cycle gas turbine or a combined cycle power plant.

Before being used in the method of the present invention, the flue gas stream FS1 is optionally treated to remove particulate matter by filtration or electrostatic precipitation.

In a preferred embodiment, flue gas stream FS1 is desulfurized by removal of sulfur dioxide. An overview of Flue gas desulfurization processes can be found in the wikipedia article "fluid-gas desulfurization [ Flue gas desulfurization ]" (https:// en. Wikipe-dia. Org/wiki/fluid-gas desulfurization).

The fluid flue gas stream FS1 preferably comprises:

CO ₂:1 to 25 vol%, preferably 5 to 20 vol%;

h ₂ O3 to 50 vol%, preferably 5 to 30 vol%, and

O ₂:0.1 to 16 vol-%, preferably 1 to 10 vol-%.

In addition, even after the flue gas desulfurization step, the flue gas contains small amounts of other gases, in particular nitrogen oxides (NO _x) and sulfur oxides (SO _x).

The flue gas also contains an amount of nitrogen such that the sum of the volume fractions of each component present in the flue gas amounts to a value of 1 (or 100 vol. -%). Typically, the nitrogen content is in the range of 40 to 95 vol. -%.

The fluid stream FS1 is preferably in a gaseous state. Depending on the temperature and water content, fluid stream FS1 may also contain condensed water and acid.

When the fluid stream is flue gas, the pressure of the fluid stream FS1 entering the cooling step is typically at atmospheric pressure, preferably in the range of 0.7 to 1.5 bar, more preferably 0.8 to 1.3 bar and more preferably 0.9 to 1.2 bar.

The temperature of the fluid flue gas stream FS 1 is preferably in the range of 50 ℃ to 300 ℃, preferably 60 ℃ to 250 ℃ and most preferably 60 ℃ to 200 ℃.

The fluid stream FS1 may also be an exhaust stream, where CO ₂ is emitted in an industrial process that releases CO ₂ from a chemical reaction. Such industrial process streams include CO ₂ emissions from the thermal decomposition of limestone and dolomite in cement production, CO ₂ emissions from the use of carbon as a reducing agent in the commercial production of metals from ores (e.g., the production of iron in a blast furnace), or CO ₂ emissions from biomass fermentation (e.g., the conversion of sugar to alcohol).

In a preferred embodiment, the fluid stream FS1 is a stream combining flue gas from a carbon fuel combustion process with CO ₂ emissions from an industrial process that produces CO ₂, such as cement production, metal production, or fermentation processes.

In a further preferred embodiment, the fluid stream FS1 is a flue gas stream from a furnace of a cracker, in which hydrocarbons (such as petroleum fractions, naphtha, natural gas liquids such as methane, ethane and propane) are thermally or catalytically cracked to obtain shorter chain molecules or recombinant molecules having different structures. Preferably, the fluid stream FS1 is the flue gas of a steam cracker.

The fluid stream FS1 may alternatively be a raw synthesis gas. Such synthesis gas (or "syngas") may be obtained from gasification of coal or mineral oil, steam reforming of mineral oil distillates, steam reforming of methane, or autothermal reforming of natural gas. Synthesis gas typically comprises at least hydrogen, carbon monoxide and some carbon dioxide and water.

The preferred fluid stream FS1 is the fluid stream leaving the water shift reactor in the production of synthesis gas. The water shift reaction is preferably carried out as a High Temperature Shift Conversion (HTSC) at a temperature of about 300 ℃ to 450 ℃, as a Medium Temperature Shift Conversion (MTSC) at a temperature of about 150 ℃ to 350 ℃, as a Low Temperature Shift Conversion (LTSC) at a temperature of about 150 ℃ to 250 ℃, or as an acid gas shift conversion (SGS) at a temperature of about 200 ℃ to 300 ℃.

When the fluid stream is synthesis gas, the total pressure is typically in the range of 5 to 120 bar, preferably 10 to 100 bar and more preferably 10 to 60 bar.

According to the invention, the thermal energy transfer step comprises a combination of a direct contact cooler DCC and a heat pump HP 1.

Direct Contact Cooler (DCC)

In step a), thermal energy from the fluid stream FS1 is transferred to the regeneration step c) in a configuration comprising a direct contact cooler.

The term "direct contact" in a direct contact cooler means that the stream FS1 and the stream acting as a stream of cooling medium or heat transfer material are not spatially separated by a partition, but are in direct physical contact with each other (direct heat exchange).

The advantage of direct heat exchange is that the exchange area between the two fluids increases, which reduces the thermal resistance and maximizes the thermal efficiency. In addition, direct heat exchangers generally have lower operating and capital costs than indirect heat exchangers due to the high heat transfer rate per volume and because fouling and corrosion are generally not an issue. In the case of residual sulfur oxides (SO _x) in the fluid stream FS1, corrosion is a non-negligible problem in indirect heat exchangers, which can cause dew point corrosion if the temperature of any metal in contact with FS1 is below the dew point of sulfuric acid, which is typically in the range of 110 ℃ to 170 ℃. Furthermore, the pressure loss in the direct contact cooler is lower compared to an indirect gas-liquid heat exchanger. Thus, the size of or even avoiding expensive equipment, such as fans or blowers, required to compensate for the pressure loss and transport the fluid stream FS2 to the absorber can be reduced.

The direct contact preferably occurs in a Direct Contact Cooler (DCC) in which heat is transferred from the fluid stream FS1 to the liquid cooling medium stream CMS1 to obtain a cooling medium stream CMS2 having a higher thermal energy than the cooling medium stream CMS2 and a cooled fluid stream FS2. Within the present invention, the terms "direct contact condenser" and "direct contact cooler" are used synonymously, as the degree of condensation occurring in DCC depends on the water content of the feed gas.

Direct contact cooling may be achieved with a) spray towers, b) baffle towers, c) sieve plate towers or bubble cap towers, d) packed towers, e) pipe contactors, and f) mechanical agitation contactors.

Additional details concerning the design of Direct Contact coolers can be found in the Madejski et al review article （Madejski, P.; Kus, T.; Michalak, P.; Karch, M.; Subramanian, N. Direct Contact Condensers: A Comprehensive Review of Experimental and Numerical Investigations on Direct-Contact Condensation [ Direct Contact condenser, general reviews of experiments and numerical studies of Direct Contact condensation, energies [ energy source ] 2022, 15, 9312, https:// doi.org/10.3390/en 15249312) and Kreith, frank & Boehm, robert (1987), direct-Contact HEAT TRANSFER [ Direct Contact heat transfer ], 10.1615/atoz.d. dircon heatra, chapter 19, pages 1359 to 1399.

Preferably, the direct contact cooler operates in a counter-flow mode, meaning that the heat stream FS1 typically enters at an inlet opposite to the inlet of the cooling medium stream CMS1 or the heat transfer material stream HTMS 1. However, it is also possible to operate the direct contact cooler in parallel flow mode, wherein CMS1 or HTMS and FS1 enter the heat exchanger from the same direction. A parallel flow mode direct contact cooler is described in US 9034081.

The most preferred direct contact coolers are spray towers, baffle towers, sieve-plate towers or bubble-cap towers and packed towers. More preferably, the cooler operates in a countercurrent flow mode.

In a direct contact cooler, the heat stream FS1 is preferably in direct contact with a cooling medium stream CMS1 or a heat transfer material stream HTM1, and thermal energy is transferred from the heat stream FS1 to obtain a cooled fluid stream FS2 and a heated cooling medium stream CMS2 or a heated heat transfer material stream HTMS or HTMS a (see below).

The cooling medium flows CMS1 and CMS2 are flows of the cooling medium CM. The cooling medium CM is preferably one or more cooling media selected from the group consisting of ethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol and their corresponding polyglycols, such as diethylene glycol, triethylene glycol, 1, 2-dipropylene glycol, 1, 2-tripropylene glycol, 1, 3-dipropylene glycol and 1, 3-tripropylene glycol, their corresponding methyl or dimethyl ether, and water. Preferably, the cooling medium CM is glycol or water, or

A mixture of ethylene glycol and water. Most preferably, the cooling medium CM consists essentially of water. The advantage of using pure water is that no additional separation step is required. When the cooling medium stream CMS1 contains other components than water, an additional separation step is preferred, because the water contained in the hot stream FS1 results in dilution of the concentration of the other non-aqueous components. To restore the original concentration, an additional separation step is preferred to separate the water introduced into the cooling medium stream CMS1 or CMS2 from the hot stream FS 1.

The direct contact cooler is preferably designed in such a way that the following requirements are fulfilled:

The temperature T _CMS1 is in the range of 25 ℃ to 100 ℃, preferably 25 ℃ to 70 ℃ and more preferably 30 ℃ to 50 ℃.

The temperature T _CMS2 is about 5K to 100K, preferably 10K to 80K and more preferably 15K to 50K higher than T _CMS1.

The temperature T _FS2 is preferably in the range of 20 ℃ to 80 ℃, more preferably 25 ℃ to 70 ℃ and most preferably in the range of 30 ℃ to 60 ℃.

The direct contact cooler is also typically operated such that the cooling medium flow CMS2 remains in a liquid state so that it can thus be easily separated from the gaseous fluid flow FS 2.

If additional moisture is contained in the fluid stream FS1, a portion of the cooling medium stream CMS2 may be purged from the cooling medium stream circulation. The amount of the purged cooling medium flow is selected in such a way that the cooling medium flow rate remains substantially constant.

In a preferred embodiment, the direct contact cooler is designed in such a way that more energy is transferred than is required to be supplied to the regeneration step. In such a case, excess energy may be preferred for providing excess steam, which may be transferred to a site steam network for distribution to other processes or process steps in the site that may require such energy.

Alternatively, the direct contact cooler may also be designed in such a way that less energy is transferred than is required in the regeneration step. In this case, it is preferable to provide additional energy, preferably steam, to the regeneration step from an additional source (e.g., an on-site steam network that distributes steam from other steam generating sources).

The direct contact cooler is preferably designed in such a way that the thermal energy transferred is just sufficient to provide the thermal energy required in the regeneration step c). If the heat energy or heat contained in the heat stream FS1 is more than necessary to be transferred by the heat pump to the regeneration step c), only the energy required in the regeneration step c) is transferred in the direct contact cooler. If after transferring the heat or thermal energy required for the regeneration step C) the fluid stream FS2 will be too hot to enter the absorber, it is preferred to cool the fluid stream FS2 leaving the direct contact cooler in one or more additional heat exchangers before entering the absorber such that the fluid stream FS2 has a temperature at the inlet of the absorber in the range of 20 to 80 ℃, more preferably 25 to 70 ℃ and most preferably 30 to 60 ℃. Such additional heat exchangers are air coolers or water coolers, such as cooling towers. An overview of Cooling towers that may be used to further cool fluid stream FS2 may be found in Wikipedia article "Cooling towers [ Cooling towers ]" (https:// en. Wikipedia. Org/wiki/cooling_tower#). An advantage of this embodiment is that the temperature of the fluid stream FS2 at the absorber inlet can be adjusted independently of the operation of the heat pump HP1, as will be described below.

Heat pump

According to the invention, the transfer of thermal energy from the thermal stream FS1 to the regeneration step c)) also comprises one or more heat pumps.

Within the meaning of the invention, a heat pump is a device for transferring heat from a heat source at one temperature to a heat sink at a higher temperature.

The heat pump may be a conventional heat pump employed in the method according to embodiment a described below, or two or more conventional heat pumps connected in series and operable according to embodiment B described below. The heat pump may also be a so-called modified heat pump operating according to the method described in embodiment C below. The so-called improved heat pump differs from conventional heat pumps in that the evaporator of the heat pump is replaced by a heat exchanger in which the working medium does not undergo a phase change, followed by a separate evaporation device for evaporating the heat transfer material. In other words, the heat transfer and evaporation achieved in the evaporator of a conventional heat pump is performed in two different process steps as described in example C below.

Conventional heat pump

The conventional heat pump preferably includes:

a heat exchanger HE1 for transferring heat energy from the cooling medium flow CMS2 to the heat transfer medium flow HTMS1 of the heat pump HP1 to obtain a heat transfer material flow HTMS2 having increased heat energy compared to the heat transfer medium flow HTMS,

One or more compressors for compressing the heat transfer material stream HTMS in one or more compression steps to obtain a heat transfer material stream HTMS3 having an increased pressure compared to the heat transfer material stream HTMS,

A heat exchanger HE-R for transferring thermal energy from the heat transfer material stream HTMS to the regeneration step,

-A heat transfer material HTM1.

The heat transfer step a) comprising a combination of a direct contact cooler and a conventional heat pump is further described in example a below.

Heat pump connected in series

By serially connected heat pumps is meant that the compressed heat transfer medium of heat pump HP1 acts as a heat source for the heat transfer medium flow of heat pump HP2, the heat pump HP2 acts as a heat sink for heat pump HP1, and the heat transfer medium flow of heat energy from heat pump HP1 heat transfer medium flow HTMS to heat pump HP2 is effected by a common heat exchanger HE 2. In other words, the heat exchanger HE2 serves as a condenser of the heat transfer material HTM1 of the heat pump HP1 and as an evaporator of the heat transfer material HTM2 of the heat pump HP 2. Thus, the heat pump connected in series comprises

A heat exchanger HE2 for transferring heat energy from the heat transfer material flow HTMS to the second heat transfer medium flow SHTMS1 of the heat pump HP2 to obtain a second heat transfer material flow SHTMS having increased heat energy compared to the heat transfer medium flow SHTMS1,

One or more compressors for compressing the second heat transfer material stream SHTMS in one or more compression steps to obtain a heat transfer material stream SHTMS having an increased pressure compared to the heat transfer material stream SHTMS,

A heat exchanger HE-R for transferring thermal energy from the heat transfer material flow HTMS of the first heat pump HP1 to the regeneration step,

-A heat transfer material HTM1 and a heat transfer material HTM2.

The advantage of using two heat pumps connected in series is that the thermal energy from the hot stream HS1 can be raised to a level that can effectively generate steam in the heat pump HP2, which steam can be used to transfer heat to the regeneration step c). Thus, the stream generated in the heat pump HP2 can effectively replace the process steam normally required as a heat source in the regeneration step c). Thus, the use of two heat pumps in series can replace the need to install separate process steam production processes at the site of the acid gas removal unit or the need for steam turbines, such as back pressure turbines or vented condensing turbines, which produce process steam to be decarbonized at the power plant. Thus, the present invention is particularly useful in situations where process steam is not readily available on site in an acid gas removal unit. Moreover, the method according to the invention can be used as an alternative method of producing process steam in the field where process steam is readily available, as it allows the use of potentially limited process steam resources for other uses or allows the reduction of power losses of a power plant associated with the production of process steam. In addition, the method of the present invention is an interesting alternative in the design of new power plants incorporating acid gas removal units for carbon capture, as the need for transferring energy for steam production to power the recycling step can be reduced. In addition, the process of the present invention is a useful method of electrifying steam production so that the steam required in the amine gas treatment process can be provided by "green" power from renewable resources.

The heat transfer step a) comprising a combination of a direct contact cooler and a heat pump connected in series is further described in example B below.

Improved heat pump

The heat pump of the present invention may also be designed as an improved heat pump.

In the improved heat pump, the heat exchanger HE1 is not an evaporator but is a heat exchanger in which substantially no phase transfer occurs from the liquid heat transfer material stream HTMS to the gaseous heat transfer material stream HTMS, but rather the heat exchanger is configured to obtain the liquid heat transfer material stream HTMS a and to phase change from the liquid heat transfer material stream HTMS a to obtain the gaseous heat transfer material stream HTMS b by feeding the heat transfer material stream HTMS a to the evaporation device. The evaporation means is typically a combination of an expansion valve and an expansion vessel. Expansion is preferably performed as a heat transfer material stream HTMS a by expansion or flash evaporation through a throttle valve into a vessel having a pressure below p _HTMS2a. Thus, in the improved heat pump, the steps of heat transfer and evaporation are performed as separate process steps. The improved heat pump thus includes a heat exchanger HE1 and means for additional expansion or evaporation of the liquid heat transfer material stream HTMS a.

An advantage of using an improved heat pump in which the heat transfer step and the evaporation step are two different steps is also that the thermal energy from the hot stream HS1, in particular FS1, can be raised to a level that can be used to generate steam in the heat pump HP1 that can be used to transfer heat to the regeneration step c). This embodiment has similar advantages as a series connected heat pump.

The heat transfer step a) comprising a combination of a direct contact cooler and a modified heat pump is further described in example C below.

Heat transfer material

Heat pumps typically include a heat transfer material.

The heat transfer material HTM1 is a working fluid used in the heat pump HP 1.

The heat transfer material HTM2 is the working fluid used in the second series heat pump HP 2.

If more than two heat pumps are connected, additional heat transfer materials HTM3 to x may be used in the heat pumps HP3 to HPx.

The heat transfer material HTM1 is a working fluid used in the heat pump HP1 to transfer thermal energy from the heat exchanger HE1 to the heat exchanger HE2 or HE-R, depending on the embodiment and design of the heat pump HP 1. Preferably, the heat transfer material HTM1 may undergo at least a partial phase change from liquid to gaseous in the heat exchanger HE1 (in the case of a conventional heat pump) or in the heat exchanger HE1 and the subsequent expansion step (in the case of a modified heat pump) when transferring thermal energy.

Preferably, the heat transfer material HTM1 may also undergo at least a partial phase change from gas to liquid when transferring thermal energy in heat exchanger HE2 (in the case of a heat pump connected in series) or heat exchanger HE-R (in the case of a single conventional heat pump or a single modified heat pump).

Thus, the heat transfer material HTM1 is preferably selected from the group of refrigerants consisting of ammonia, butane, R1233zd (e), R1224yd (z), air, CO ₂, water, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, hydrofluoroolefins, hydrochlorofluoroolefins, hydrocarbons, perfluoro (2-methyl-3-pentanone), and mixtures of two or more thereof. Suitable refrigerants are known to the skilled person and are disclosed, for example, in c. Arpagaus et al (c. Arpagaus et al, energy [ Energy ] 152 (2018), pages 985 to 1010).

In the case of a single conventional heat pump or a single modified heat pump, the heat transfer material HTM1 is most preferably water. If the heat transfer material HTM1 is water, the heat transfer material HTM1 may be used directly for the steam production required in regeneration step c), in particular in reboiler HE-R or in other plants of the integrated site (Ver-bund-site). In addition, water is an environmentally friendly heat transfer material that can be dispersed into the environment either directly or after being sent to a wastewater purification plant. Water is also readily available in many plants or facilities and can be provided in the required amount even without the need to recycle the water. An additional advantage of water is that if the regeneration step requires more steam than is produced using a heat pump, the steam can potentially be replenished from other sources, or in the event that excess steam is produced, the steam can be distributed to other consuming entities, such as an onsite steam network. This makes the method of the invention very flexible.

Likewise, the second heat transfer material HTM2 of the heat pump HP of the two serially connected heat pumps HP1 and HP2 is most preferably also water. This choice of water as the preferred heat transfer material is generally applicable to the last heat pump in a series of connected heat pumps.

In the case of two serially connected heat pumps, the HTM1 of the heat pump HP1 is typically a heat transfer material having a lower boiling point than water under the conditions of the condenser of the heat pump HP, and most preferably ammonia, butane, R1233zd (e), R1224yd (z), air, CO ₂, water, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, hydrofluoroolefins, hydrochlorofluoroolefins, hydrocarbons, perfluoro (2-methyl-3-pentanone) and mixtures of two or more thereof. The use of a heat transfer material HTM1 with a lower point in the first heat pump HP1 allows a higher heat flow from the fluid flow FS1, especially if the temperature of the fluid flow FS1 or the cooling material CMS2 is not high enough to directly generate steam. In the case of heat pumps connected in series, the heat transfer material HTM1 of the heat pump HP1 is preferably ammonia or butane, most preferably ammonia.

Open loop and closed loop heat pump

Conventional or series connected heat pumps (as described above) may be designed as open loop or closed loop heat pumps.

Open loop heat pumps generally comprise the steps of:

the heat energy is transferred from the heat source to the heat transfer material, typically by means of a heat exchanger, which is typically designed as an evaporator for at least a part of the heat transfer material of the heat pump.

Compressing the partially vaporized heat transfer material in one or more compression steps, typically comprising one or more compressors, to raise the temperature of the heat transfer material, and

The heat energy is transferred from the compressed heat transfer material to the radiator, typically by means of a further heat exchanger, which serves as a condenser for the at least partly gaseous heat transfer material of the heat pump.

An advantage of an open loop heat pump is that it can utilize media from a variety of sources, particularly water that is typically already present in amine gas treatment processes.

A closed loop heat pump typically includes a heat transfer medium between a heat source and a radiator in a closed loop. This is typically carried out by an additional recirculation step of the heat transfer medium, as further described below for the recirculation step R1 or R2 of the heat pump HP1 or HP 2.

The improved heat pump described above is preferably designed as an open loop heat pump. An advantage of an open loop heat pump is that it can utilize media from a variety of sources, particularly water that is typically already present in amine gas treatment processes. In addition, open loop heat pumps do not require recirculation of heat transfer material, which allows for simplifying the heat pump design and potentially making it more cost effective.

An embodiment configured to include heat integration of a direct contact cooler and a heat pump in the energy transfer step a):

the combination of a direct contact cooler and a heat pump allows an efficient and flexible method for removing acid gases and utilizing the fluid stream FS1 as a heat source to provide heat to the regeneration step c).

Fluid stream FS1 typically has a low temperature that is not suitable for direct steam generation. Moreover, the fluid flow FS1 may cause corrosion in downstream equipment.

The large fluid flows (e.g., FS 1) are often difficult to handle and transport and result in significant pressure losses in the plant, which need to be overcome by additional pumps or fans for transporting the high volume gas flows. The advantage of using a direct contact cooler is that the above drawbacks can be reduced, making it feasible to use the fluid vapor FS1 as a heat source.

The advantage of a direct contact cooler is that the exchange area between the fluid stream FS1 and the cooling medium stream CMS1 is large, which reduces the thermal resistance and maximizes the thermal efficiency. In addition, direct contact coolers typically have lower operating and capital costs than indirect heat exchangers due to the high heat transfer rate per volume and because fouling and corrosion are not generally an issue. In the case of residual sulfur oxides (SO _x) in the fluid stream FS1, corrosion is a non-negligible problem in indirect heat exchangers, which can cause dew point corrosion if the temperature of any metal in contact with FS1 is below the dew point of sulfuric acid, which is typically in the range of 110 ℃ to 170 ℃. Furthermore, the pressure loss in the direct contact cooler is lower compared to an indirect gas-liquid heat exchanger. Thus, the size of or even avoiding expensive equipment, such as fans or blowers, required to compensate for the pressure loss and transport the fluid stream FS2 to the absorber can be reduced.

The combined use of a heat pump and a direct contact cooler enables the heat contained in the fluid stream FS1 to reach the level required in the regeneration step using electricity. In particular, if the heat transfer material (e.g. HTM1 or HTM 2) of the (last) heat pump is water, the steam required in the regeneration step c) can be directly generated with a relatively low energy input.

The heat integration including DCC and heat pump allows transfer of thermal energy from fluid stream FS1 having a relatively low temperature. Moreover, the thermal integration of the present invention results in a process with significantly reduced corrosion. Thus, the process of the present invention allows for improved heat integration in acid gas treatment. The operating and capital expenditures for operating and constructing the method according to the invention are advantageous and the method of the invention is very flexible and can compensate for load fluctuations of the fluid stream FS 1.

The integration of the direct contact cooler and heat pump of the present invention can be demonstrated in heat transfer step a) by one of the embodiments A, B and C described later.

Embodiment a illustrates the integration of a direct contact cooler and a conventional heat pump.

Example B shows the integration of a direct contact cooler and two heat pumps connected in series.

Embodiment C shows the integration of a direct contact cooler and a so-called improved heat pump.

The embodiments of the present invention are not intended to be exhaustive and should not be construed as limited to the disclosed embodiments. Rather, the embodiments are chosen and described to demonstrate the principles and practice of the present invention.

Example A conventional Heat Pump

The transfer of thermal energy from the fluid stream FS1 of step a) to the regeneration step c) preferably involves a combination of a direct contact cooler and a so-called conventional heat pump.

The transfer step a) of embodiment a preferably comprises the steps of:

(i) Transferring thermal energy from the fluid stream FS1 to the cooling material stream CMS1 in a direct contact cooler to obtain a cooling material stream CMS2 and a fluid stream FS2 having reduced thermal energy compared to the fluid stream FS 1;

(ii) Transferring heat energy from the cooling material stream CMS2 to the heat transfer material stream HTMS1 in the heat exchanger HE1 to obtain a heat transfer material stream HTMS2 having higher heat energy than the heat transfer material stream HTMS 1;

(iii) Compressing the heat transfer material stream HTMS2 in one or more compression steps to obtain a gaseous heat transfer material stream HTMS3 having a higher pressure than the heat transfer material stream HTMS2, and

(Iv) Transferring thermal energy from the heat transfer material stream HTMS to the regenerating step c) to obtain a heat transfer material stream HTMS;

fig. 1 shows a process configuration according to embodiment a.

Step i)

In step i) of embodiment a, thermal energy from the fluid stream FS1 is transferred to the cooling material stream CMS1 in a direct contact cooler to obtain a cooling material stream CMS2 and a cooled fluid stream FS2.

The principle and design of the direct contact cooler of step i) is described in the corresponding section "direct contact cooler" above.

Step ii)

In step ii) of embodiment a, the heat energy from the cooling material stream CMS2 is transferred to the heat transfer material stream HTMS, preferably in a heat exchanger HE1, to obtain a gaseous heat transfer material stream HTMS having a higher heat energy than the heat transfer material stream HTMS1 and a cooling medium stream CMS3 having a lower heat energy than the cooling medium stream CMS 2.

The heat exchanger HE1 preferably comprises:

An inlet for a cooling medium flow CMS2, at the entry of which the cooling medium flow has a pressure p _CMS2 and a temperature T _CMS2;

an outlet for a cooling medium flow CMS3, at the exit of which the cooling medium flow has a pressure p _CMS3 and a temperature T _CMS3;

An inlet for a flow HTMS of heat transfer material, at the inlet of which the flow is at a pressure p _HTMS1 and a temperature T _HTMS1, and

An outlet for the heat transfer medium flow HTMS, at the exit of which the heat transfer medium flow has a pressure p _HTMS2 and a temperature T _HTMS2.

The heat exchanger HE1 is preferably an indirect heat exchanger, such as an evaporator, in particular HE1 is preferably a tube heat exchanger, preferably a shell-and-tube heat exchanger, a double tube heat exchanger and a drop tube heat exchanger, or a plate heat exchanger. Most preferably, the heat exchanger HE1 is a shell-and-tube heat exchanger or a plate heat exchanger.

In the case of indirect heat transfer via an intermediate cooling circuit, the heat exchanger HE1 is preferably designed in such a way that the following requirements are fulfilled:

the temperature T _CMS2 is in the range 25 ℃ to 120 ℃, preferably 30 ℃ to 100 ℃ and more preferably 40 ℃ to 70 ℃.

The temperature T _HTMS2 is about 0.1K to 50K, preferably 0.5K to 25K and more preferably 1K to 10K higher than T _HTMS1.

The heat transfer material HTM1 in the heat transfer material flow HTMS1 undergoes at least a partial phase change from liquid to gaseous.

Step ii) of example a produces a substantially gaseous heat transfer material stream HTMS and a cooled cooling medium stream CMS3, which is preferably recycled as cooling medium stream CMS1 to step i). In order to impart the properties of the cooling medium flow CMS1 to the cooling medium flow CMS3, an additional cooling step may preferably be carried out, for example by cooling the cooling medium CMS3 in a heat exchanger HE-CMS, preferably a cooler, more preferably an air or water cooler. Preferably, cooling medium stream CMS3 is cooled to a temperature at which cooling medium stream CMS1 is introduced into direct contact cooler HE-C.

Step iii)

After heat energy has been transferred to the heat transfer medium flow HTMS, it is preferred to further transfer heat energy in step iii) of embodiment a by compressing the heat transfer medium flow HTMS in the heat pump HP1 to obtain a heat transfer medium flow HTMS3 having a higher pressure than the heat transfer medium flow HTMS.

Compression is preferably effected in a compressor.

A compressor is a device for increasing the pressure of at least a portion of a gaseous fluid.

The compressor is typically a positive displacement compressor or a dynamic compressor. Positive displacement compressors include reciprocating compressors that use pistons driven by a crankshaft to deliver fluid at higher pressures. The reciprocating compressor may be single stage or multi-stage. The positive displacement compressors also include rotary screw compressors, conical screw compressors, rotary vane compressors, rolling piston compressors or scroll compressors.

The compressor may also be a dynamic compressor, such as a centrifugal compressor or an axial compressor.

Preferably, the compressor is a rotary screw compressor, a centrifugal compressor, a piston compressor or an axial compressor.

The compression may be performed in one compressor or a series of compressors, depending on the desired pressure increase of the heat transfer material HTM 1.

The heat transfer material HTM1 enters the compression step as a heat transfer material stream HTMS at a pressure p _HTMS2 and a temperature T _HTSM2 and exits the compression step as a heat transfer material HTMS3 at a pressure p _HTMS3 and a temperature T _HTMS3.

The pressure increase Δp (p _HTMS3-p_HTMS2) in the compression step is typically selected such that the temperature of the heat transfer medium stream HTMS is raised to the temperature required in the regeneration step c), as described below.

In a preferred embodiment, the compression step is performed in a series of two or more compressors and the heat transfer material HTM1 is water. In this embodiment, an additional stream of heat transfer material HTM1 is additionally fed after each of the compressors in series to increase the amount of gaseous heat transfer material HTM1 produced, at the cost of reducing the temperature of the stream. In this way, the opportunity to generate sufficient steam for regeneration step c) can be obtained. In addition, the addition of a further heat transfer material HTM1 is energetically advantageous compared to a scenario in which the same amount of gaseous heat transfer material HMT1 is generated (wherein no additional heat transfer material HTM1 is introduced after the compression step). Preferably, saturated steam is produced and used for heating in reboiler HE-R. The superheating of the steam is aided by injecting water between the compressor sections. In addition, the injection of additional heat transfer material HTM1 results in a reduced volumetric flow rate and in a reduced power demand of the subsequent compressors in the successive compression stages.

Step iii) of example a produces a compressed heat transfer material stream HTMS.

Step iv)

In embodiment a, thermal energy is transferred to the regeneration step c) in step iv) by transferring thermal energy from the heat transfer medium stream HTMS to the regeneration step c) to obtain a heat transfer medium stream HTMS having a reduced thermal energy content compared to HTMS 3.

The transfer of thermal energy from the heat transfer material stream HTMS to the regeneration step c) may occur indirectly or directly, as described below.

Indirect heat transfer to regeneration step c)

In a preferred variant of step iv), the transfer of thermal energy from the heat transfer material stream HTMS to the regeneration step c) takes place in a heat exchanger HE-R, wherein the loaded absorbent A2 obtained in step b) is heated before entering the regeneration step c).

The heat exchanger HE-R may be used instead of or in addition to the cross-flow heat exchanger for transferring heat from the regenerated absorbent A3 to the loaded absorbent A2 before entering the regeneration step c).

The heat exchanger HE-R is preferably an indirect heat exchanger.

When the heat exchanger HE-R is an indirect heat exchanger, HE-R preferably includes:

-an inlet for the loaded absorbent A2;

An outlet of the loaded absorbent A2, the loaded absorbent A2 having increased thermal energy compared to the loaded absorbent A2 at the inlet of the heat exchanger HE-R;

An inlet for a second flow HTMS of heat transfer medium, at the inlet of which the second flow of heat transfer medium has a pressure p _SHTMS1 and a temperature T _SHTMS1, and

An outlet for the second heat transfer medium flow HTMS, at the exit of which the second heat transfer medium flow has a pressure p _SHTMS2 and a temperature T _SHTMS2.

More preferably, the heat exchanger HE-R is a shell-and-tube exchanger or a plate exchanger.

This embodiment may be particularly useful in case the fluid stream FS1 is flue gas and when an intermediate evaporation or flash step (see below) is performed after the cross-flow heat exchanger HE-CF. In this case, at least part of the loaded absorbent stream A2 may be reheated before entering the regenerator.

Direct heat transfer to regeneration step c)

In the most preferred embodiment of step iv) the thermal energy is transferred directly by transferring thermal energy from the heat transfer medium stream HTMS to the absorbent stream AS1 withdrawn from the regenerator in step c) in a heat exchanger HE-R to obtain an absorbent stream AS2 with increased thermal energy compared to the absorbent stream AS1 and feeding AS2 to the regenerator in step c).

More preferably, the transfer of thermal energy is effected by means of a heat exchanger HE-R connected to the bottom of the regenerator, in which heat exchange takes place indirectly. Most preferably, the indirect heat exchanger HE-R is a reboiler.

The reboiler typically comprises an inlet connected to the bottom of the regenerator, from which inlet the absorbent stream AS1 enters the reboiler, and an outlet connected to the inlet at the bottom of the regenerator, through which outlet the absorbent stream AS2 exits the reboiler and re-enters the regenerator.

The reboiler also includes an inlet through which the second heat transfer material stream HTMS enters the reboiler, and an outlet through which the second heat transfer material stream HTMS exits the reboiler.

HE-R is preferably a reboiler selected from the group consisting of a kettle reboiler, a thermosiphon reboiler, and a forced circulation reboiler.

By heating the absorbent stream AS2, the acid gas (in particular CO ₂) is typically desorbed and the water contained in the absorbent is at least partially evaporated into a stream to propagate the stripping effect, resulting in further release of the acid gas from the loaded absorbent.

Further details concerning the regeneration step c) and the recirculation step d) are indicated in the later part of the present description.

Recycle of

In a preferred embodiment, embodiment a comprises an additional recycling step R1), wherein the heat transfer material stream HTMS obtained in step iv) is expanded to obtain a heat transfer medium stream HTMS, which has a reduced pressure compared to the heat transfer material stream HTMS4 and is at least partly recycled as heat transfer material stream HTMS to step i).

Expansion is preferably accomplished by reducing the pressure p _HTMS4 of the heat transfer medium stream HTMS to the pressure p _HTMS5 of the heat transfer medium stream HTMS.

Expansion is preferably achieved by a thermal expansion valve. The Thermal expansion valve that can be used in the recycling step R1) is described in Wikipedia article "Thermal Expansion Valve [ Thermal expansion valve ]" on https:// en.wikipe-dia. The pressure decrease Δp from p _HTMS4 to p _HTMS5 typically results in adiabatic flashing of a portion of the heat transfer medium stream HTMS and the auto-refrigeration effect of this adiabatic flashing reduces the temperature of the heat transfer medium stream HTMS 4.

The expansion valve is preferably operated and designed in such a way that p _HTMS5 is equal to p _HTMS1 and T _HTMS5 is equal to T _HTMS1 so that the heat transfer material stream HTMS5 can be recycled to step 1, preferably as heat transfer material stream HTMS 1.

An advantage of performing the additional recycling step R1) is that the heat transfer material HTM1 can be reused in a closed loop heat pump to save material costs and resources or to prevent environmental pollution that would be associated with the loss of heat transfer material HTM1 if an environmentally detrimental heat transfer material HTM1 were selected.

If the heat transfer material HTM1 is water/steam, it is not necessary to forcibly expand the heat transfer material stream HHTM to recycle the water, as the water can be discarded to the environment or used to transfer heat to other processes. In one embodiment of the invention, it is therefore preferable not to recycle the heat transfer material stream HTMS4 directly to the heat exchanger HE1.

Heat transfer material

In embodiment a, the heat transfer material HTM1 may be any of the heat transfer materials described above. Most preferably, the heat transfer material HTM used in embodiment a is water.

In embodiment a, the heat transfer material flows HTMS to HTMS are flows of heat transfer material 1 in different stages of the heat pump HP1, wherein:

-the heat transfer material stream HTMS1 is a stream of heat transfer material HTM1 entering step i);

-the heat transfer material stream HTMS is a stream of heat transfer material HTM1 leaving step 1) and entering the compression step ii);

-the heat transfer material stream HTMS is a stream of heat transfer material HTM1 leaving the compression step 2) and entering step iii);

-the heat transfer material stream HTMS is a stream of heat transfer material HTM1 leaving step iv) and optionally entering the recycling step R1);

The heat transfer material flow HTMS is the flow of heat transfer material HTM1 leaving the recirculation step R1).

Example B series Heat Pump

In a preferred embodiment B, the transfer of thermal energy from the fluid stream FS1 to the regeneration step c) is performed in two or more heat pumps connected in series.

The heat transfer step a) according to embodiment B preferably comprises the steps of:

i) Transferring heat energy from the heat stream HS1 to the heat transfer medium stream HTMS1 of the heat transfer material HTM1 in the heat exchanger HE1 of the first heat pump HP1 to obtain a heat transfer medium stream HTMS having increased heat energy compared to the heat transfer medium stream HTMS 1;

ii) compressing the heat transfer medium flow HTMS2 in the first heat pump HP1 to obtain a heat transfer medium flow HTMS3 having a higher pressure than the heat transfer medium flow HTMS 2;

iii) Transferring heat energy from the heat transfer medium stream HTMS of the first heat pump HP1 to the second heat transfer medium stream SHTMS of the second heat transfer material HTM2 in the heat exchanger HE2 of the second heat pump HP2 to obtain a second heat transfer medium stream SHTMS having increased heat energy compared to the second heat transfer medium stream SHTMS1 and a heat transfer medium stream HTMS4 having reduced heat energy content compared to the heat transfer medium stream HTMS 3;

iv) compressing the second heat transfer medium stream SHTMS in the second heat pump HP2 to obtain a second heat transfer medium stream SHTMS3 having a higher pressure than the second heat transfer medium stream SHTMS 2;

v) transferring thermal energy from the second heat transfer medium stream SHTMS of the second heat pump HP2 to the regeneration step c) to obtain a second heat transfer medium stream SHTMS having a reduced thermal energy content compared to SHTMS 3.

Fig. 2 shows a process configuration of embodiment B.

Step i)

Step i) of example B is preferably performed in substantially the same manner as step i) in example a.

Step ii)

Step ii) of example B is preferably carried out in substantially the same way as step ii) in example B.

Step iii)

After increasing the pressure to obtain the heat transfer material flow HTMS, heat energy is further transferred from the heat pump HP1 to the heat pump HP2 in step iii) by transferring heat energy from the heat transfer medium flow HTMS of the first heat pump HP1 to the second heat transfer medium flow SHTMS of the second heat pump HP2 to obtain the second heat transfer medium flow SHTMS2 having increased heat energy compared to the second heat transfer medium flow SHTMS1 and the heat transfer medium flow HTMS having reduced heat energy content compared to the heat transfer medium flow HTMS 3.

The transfer of heat from the heat transfer material stream HTMS to the second heat transfer material stream HTMS1 is preferably accomplished by heat exchanger HE 2.

The heat exchanger HE2 is a device for transferring thermal energy in the form of heat between the heat transfer material stream HTMS and the second heat transfer medium stream SHTMS to obtain a second heat transfer medium stream SHTMS2 having increased thermal energy compared to the heat transfer medium SHTMS1 and a heat transfer material stream HTMS having reduced thermal energy compared to the heat transfer material stream HTMS 3.

The heat exchanger HE2 is preferably an indirect heat exchanger.

When heat exchanger HE2 is an indirect heat exchanger, HE2 preferably comprises:

An inlet for a flow HTMS of heat transfer medium, at the inlet, the flow of heat transfer medium having a pressure p _HTMS3 and a temperature T _HTMS3;

An outlet for a flow HTMS of heat transfer medium, at the exit of which the flow of heat transfer medium has a pressure p _HTMS3 and a temperature T _HTMS3;

An inlet for a second flow SHTMS of heat transfer medium, at the inlet of which the second flow of heat transfer medium has a pressure p _SHTMS1 and a temperature T _SHTMS1, and

An outlet for the second heat transfer medium flow SHTMS, at the exit of which the second heat transfer medium flow has a pressure p _SHTMS2 and a temperature T _SHTMS2.

More preferably, the heat exchanger HE2 is a shell-and-tube or a plate exchanger.

The heat exchanger HE2 is preferably designed in such a way that the following requirements are fulfilled:

the temperature T _HTMS3 is significantly higher than the boiling point of the heat transfer material HTM2 in the heat pump HP2 at the regulated pressure, preferably 5K to 200K or more, preferably 5K to 50K or more, and most preferably 5K to 25K or more, than the boiling point of the heat transfer material SHTM1 at the pressure p _SHTMS1.

The temperature T _SHTMS2 is about 0.1K to 50K, preferably 0.3K to 15K and more preferably 1K to 5K higher than T _SHTMS1.

The heat transfer material HTM2 in the second heat transfer material flow SHTMS in the heat pump HP2 undergoes at least a partial phase change from liquid to gaseous.

The pressure p _SHTMS1 is preferably in the range of about 1 bar. It is possible that the pressure p _SHTMS1 is below atmospheric pressure, such as 0.1 to 1 bar, but in a preferred embodiment the pressure p _SHTMS1 on the side of the second heat transfer material HTM2 is at atmospheric pressure or higher, preferably in the range of 0.7 to 2 bar, more preferably 0.8 to 1.5 bar and more preferably 0.9 to 1,2 bar.

Step iv)

In a preferred embodiment, the transfer of heat from the heat pump HP1 to the heat pump HP2, in particular to the second heat transfer material flow SHTMS, is preferably followed by a compression step iv), wherein the second heat transfer medium flow SHTMS2 in the second heat pump HP2 is compressed to obtain a second heat transfer medium flow SHTMS having a higher pressure than the second heat transfer medium flow SHTMS 2.

Compression is preferably effected in a compressor.

The compression may be performed in one compressor or a series of compressors, depending on the desired pressure increase of the heat transfer material HTM 2.

The heat transfer material HTM2 enters the compression step as heat transfer material stream SHTMS at pressure p _SHTMS2 and temperature T _SHTSM2, and exits the compression step as heat transfer material stream SHTMS3 at pressure p _SHTMS3 and temperature T _SHTMS3.

The pressure increase Δp (p _SHTMS3-p_SHTMS2) in the compression step is typically 1 to 20 bar, preferably 1.2 to 10 bar and more preferably 1.5 to 3 bar, and the concomitant temperature increase is preferably 20K to 2000K, more preferably 25K to 6K and most preferably 30K to 50K.

In a preferred embodiment, the compression step is performed in a series of two or more compressors and the heat transfer material HTM2 is water. In this embodiment, an additional stream of heat transfer material HTM2 is additionally fed after each of the compressors in series to increase the amount of gaseous heat transfer material HTM2 produced, at the cost of reducing the temperature of the stream. In this way, the opportunity to generate sufficient steam for regeneration step c) can be obtained. In addition, the addition of a further heat transfer material HTM2 is energetically advantageous compared to a scenario in which the same amount of gaseous heat transfer material HMT2 is produced, wherein no additional heat transfer material HTM2 is introduced after the compression step. Preferably, saturated steam is produced and used for heating in reboiler HE-R. The superheating of the steam is aided by injecting water between the compressor sections.

In addition, injection of additional heat transfer material HTM2 results in a decrease in volumetric flow rate and in a decrease in power demand of subsequent compressors in successive compression stages.

Step v) transfer of thermal energy from SHTSM to regeneration step c)

According to a preferred embodiment of the invention, the thermal energy is transferred to the regeneration step c) in step v) by transferring the thermal energy from the second heat transfer medium flow SHTMS of the second heat pump HP2 to the regeneration step c) to obtain a second heat transfer medium flow SHTMS having a reduced thermal energy content compared to SHTMS.

The transfer of thermal energy from the second heat transfer material stream SHTMS to the regeneration step c) may take place indirectly or directly in substantially the same way as the transfer of thermal energy from the heat transfer material stream HTMS3 to the regeneration step c) takes place in step iv) of example a.

Open loop heat pump

In a preferred embodiment of embodiment B, the last heat pump of the series connected heat pumps is designed as an open loop heat pump, wherein the heat transfer material stream leaving heat exchanger HE-R is not recycled to heat exchanger HE-2. This is even more preferred if the heat transfer material used in the last of the series connected heat pumps is water. The open loop heat pump has the advantages previously described.

Recycle step

In a further preferred embodiment, embodiment B comprises an additional recycling step R1), wherein the heat transfer material stream HTMS obtained in step iii) of embodiment B is expanded to obtain a heat transfer medium stream HTMS, which has a reduced pressure compared to the heat transfer material stream HTMS4 and is at least partly recycled as heat transfer material stream HTMS to step i) of embodiment a.

The recycling step R1 is basically performed in the same manner as the recycling step R1 performed in example a.

In a further preferred embodiment, embodiment B comprises an additional recycling step R2), wherein the second heat transfer material stream SHTMS obtained in step v) of embodiment B is expanded to obtain a second heat transfer medium stream SHTMS, which has a reduced pressure compared to the second heat transfer material stream SHTMS, and is at least partially recycled as second heat transfer material stream SHTMS1 to step 3).

Expansion is preferably accomplished by reducing the pressure p _SHTMS4 of the heat transfer medium stream SHTMS4 to the pressure p _SHTMS1 of the heat transfer medium stream SHTMS 1.

Expansion is preferably achieved by a thermal expansion valve. The Thermal expansion valve that can be used in step 4) is described in Wikipedia article "Thermal Expansion Valve [ Thermal expansion valve ]" on https:// en.

The pressure decrease Δp from p _SHTMS4 to p _SHTMS5 results in adiabatic flashing of a portion of the heat transfer medium stream SHTMS and the auto-refrigeration effect of this adiabatic flashing reduces the temperature of the heat transfer medium stream SHTMS 4.

The expansion valve is preferably operated and designed in such a way that p _SHTMS5 is equal to p _SHTMS1 and T _SHTMS5 is equal to T _SHTMS1.

The heat transfer medium stream SHTMS is preferably recycled as heat transfer material stream SHTMS1 to step 1 of the evaporation process).

An advantage of performing at least one of the additional recycling steps R1 and R2 in embodiment B is that the heat transfer materials HTM1 and HTM2 can be reused in a closed-loop heat pump in order to save material costs or to prevent environmental pollution that would be associated with the loss of the heat transfer material HTM1 or HTM2 if the heat transfer material HTM1 or HTM2 were selected to be harmful to the environment.

If the heat transfer material HTM2 is water/steam, it is not necessary to forcibly expand the second heat transfer material stream SHTM to recycle the water, as the water may be discarded to the environment or used to transfer heat to other processes. Preferably, however, if the heat transfer material HTM2 is water or another heat transfer material HTM2 (which is particularly preferred in areas where water is a scarce resource), the method of the present invention further comprises a recycling step R2.

Heat transfer material

The heat transfer material HTM2 is the working fluid used in embodiment B of the heat pump HP2 to transfer thermal energy from the heat exchanger HE2 to the heat exchanger HE-R.

Preferably, the heat transfer material HTM2 may undergo at least a partial phase change from liquid to gaseous when transferring thermal energy in the heat exchanger HE 2.

Preferably, the heat transfer material HTM2 may also undergo at least a partial phase change from gaseous to liquid when transferring thermal energy in the heat exchanger HE-R.

The heat transfer material HTM2 is preferably a substance whose boiling point at p _SHTMS1 is lower than T _HTMS3 at p _HTMS3 and lower than the temperature at which the regenerator is operated.

Thus, in addition to water, any other material having a boiling point below 150 ℃, preferably 140 ℃ and more preferably below 130 ℃ at a pressure p _SHTMS1 is preferred.

The most preferred heat transfer material HTM2 is water, as water may undergo a phase change to steam at least partially in the heat exchanger HE 2.

The heat transfer material HTM1 used in the heat pump HP1 of embodiment B preferably has a lower boiling point than the heat transfer material HTM2 under the conditions of the heat pump HP 1. Preferably, HTM1 may be selected from the group consisting of ammonia, butane, R123zd (e), R1224yd (z), air, CO ₂, water, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, hydro fluoro-olefins, hydrochlorofluoro-olefins, hydrocarbons, perfluoro (2-methyl-3-pentanone).

In example B, a combination of one of ammonia or butane for the heat transfer material HTM1 with water for the heat transfer material HTM2 is preferred.

In embodiment B, the heat transfer material flows HTMS to HTMS are flows of heat transfer material 1 in different stages of the heat pump HP1, wherein:

the heat transfer material flow HTMS is the flow of heat transfer material HTM1 leaving the recirculation step R1)

The second heat transfer material flow SHTMS1 is a flow of heat transfer material HTM2 entering step 3);

The second heat transfer material stream SHTMS is the stream of heat transfer material HTM2 leaving step 3) and entering the compression step 4);

The second heat transfer material stream SHTMS is the stream of heat transfer material HTM2 leaving the compression step 4) and entering step 5);

The second heat transfer material stream SHTMS is a stream of heat transfer material HTM2 leaving step 5) and optionally entering the recycling step R2);

second heat transfer material stream SHTMS is a stream of heat transfer material HTM2 that exits the recycling step R2) and may be recycled as second heat transfer material stream SHTMS1 to step 3).

Example C) improved Heat Pump

Embodiment C utilizes a so-called modified heat pump in which heat transfer from the fluid stream FS1 to the heat transfer medium stream HTMS is effected in the heat exchanger HE1 to obtain the liquid heat transfer material stream HTMS a, and evaporation of HTMS a is performed by a separate evaporation device as described below.

An advantage of embodiment C is that steam can also be generated directly from the fluid stream FS 1. This allows for thermal integration of streams from which steam cannot be directly generated. In addition, the process including the improved heat pump may be designed in such a way that the operating and capital costs are relatively low.

The heat transfer step a) of embodiment C preferably comprises the steps of:

(i) Transferring heat energy from the fluid stream FS1 to the liquid heat transfer material stream HTMS1 of the heat transfer material HTM1 in the direct contact cooler to obtain a liquid heat transfer material stream HTMS a;

(ii) Expanding the heat transfer medium stream HTMS a in one or more expansion steps to obtain a gaseous heat transfer material stream HTMS b (g) having a lower pressure than the heat transfer material stream HTMS a;

(iii) Compressing the heat transfer material stream HTMS b (g) in one or more compression steps to obtain a gaseous heat transfer material stream HTMS having a higher pressure than the heat transfer material stream HTMS b (g), and

(Iv) Heat energy is transferred from the heat transfer material stream HTMS to the regeneration step c) to obtain a heat transfer material stream HTMS.

Step i)

In step i) of embodiment C, the transfer of thermal energy from the fluid stream FS1 to the heat transfer material stream HTMS1 in the modified heat pump may be performed directly or indirectly.

Fig. 3 shows a process configuration of example C, in which heat transfer from fluid stream FS1 to the heat transfer material stream is performed directly.

Fig. 4 shows a process configuration of example C with indirect heat transfer via a cooling medium circuit comprising cooling medium streams CMS1, CMS2 and CMS3.

The direct heat transfer can be performed in essentially the same way as step i) in example a is performed, provided that the cooling material CM1 used in the direct contact cooler is the heat transfer material HTM1 of the improved heat pump.

Thus, direct contact cooling includes transferring thermal energy from fluid stream FS1 to heat transfer material stream HTMS1 to produce heat transfer material stream HTMS a having higher thermal energy than heat transfer material stream HTMS 1. Thus, heat transfer material flows HTMS and HTMS a correspond to cooling medium flows CMS1 and CMS2 in step i) of embodiment a.

Heat transfer from fluid stream FS1 may also be indirect. The indirect heat transfer may be performed in substantially the same manner as steps i) and ii) in example a, provided that the phase change of the heat transfer material HTM1 in the heat exchanger HE1 does not occur in step i) and a liquid heat transfer material stream HTMS a is obtained.

Step i) of example C produces a liquid heat transfer material stream HTMS a.

Step ii)

After thermal energy has been transferred to the heat transfer material stream HTMS a, the liquid heat transfer material stream HTMS a is expanded in one or more expansion steps to obtain a gaseous heat transfer material stream HTMS b (g) having a lower pressure than the heat transfer material stream HTMS a.

The expansion step is preferably carried out by means suitable for achieving such expansion. Expansion is preferably performed as a heat transfer material stream HTMS a by expansion or flash evaporation through a throttle valve into a vessel having a pressure below p _HTMS2a. The container preferably has a liquid outlet and a vapor outlet. More preferably, the vessel is a flash drum. The heat transfer material stream HTMS a (HTMS a (I)) which remains in liquid form after evaporation is preferably recycled as heat transfer material stream HTMS1 to step I), as described further below.

The pressure in evaporation step ii) is preferably reduced to a value of 10 to 900 mbar, preferably a value of 30 to 700 mbar and more preferably a value of 50 to 300 mbar.

The pressure drop may be achieved in one evaporation step or in two or more evaporation steps.

The decrease in pressure generally results in a temperature drop of preferably 2K to 30K, more preferably 3K to 20K, and most preferably 5K to 15K, and partial evaporation of the heat transfer material stream HTMS a to obtain a gaseous heat transfer material stream HTMS b (g), while another portion of the heat transfer material stream HTMS a remains in a liquid state to obtain a liquid heat transfer material stream HTMS b (I). By pressure reduction, the original mass of the heat transfer material stream HTMS a will typically undergo a phase change to the gaseous state of about 0.5 to 10 weight percent, preferably 1 to 8 weight percent and more preferably 2 to 5 weight percent. The liquid portion of heat transfer material stream HTMS b (I) is preferably recycled as heat transfer material stream HTMS1 to heat exchanger HE1 in step I) or ia), respectively. In order to impart the properties of heat transfer material stream HTMS1 to the liquid portion of heat transfer material stream HTMS b (I), it may be necessary to perform one or more compression and or cooling steps. Preferably, the heat transfer material stream HTMS b (I) is cooled in a heat exchanger HE-RS, which is preferably a water or air cooler.

Step iii)

After expanding the heat transfer medium stream HTMS a to obtain the heat transfer material stream HTMS b (g), heat energy is preferably further transferred in step iii) by compressing the heat transfer medium stream HTMS b (g) in the heat pump HP1 to obtain the heat transfer medium stream HTMS3 having a higher pressure than the heat transfer medium stream HTMS b (g).

Compression is preferably effected in a compressor.

The heat transfer material HTM1 enters the compression step as a heat transfer material stream HTMS b (g) at a pressure p _HTMS2b and a temperature T _HTSM2b and exits the compression step as a heat transfer material HTMS3 at a pressure p _HTMS3 and a temperature T _HTMS3.

The pressure increase Δp (p _HTMS3-p_HTMS2b) in the compression step is typically selected such that the temperature of the heat transfer medium stream is raised to the temperature required in the regeneration step b). Preferably, the pressure increase Δp is selected to achieve a temperature of 100 ℃ to 150 ℃, preferably 105 ℃ to 140 ℃ and most preferably 110 ℃ to 130 ℃ in heat exchanger HE-R, which is preferably the reboiler of the regenerator in step b).

In a preferred embodiment, the compression step iii) is performed in a series of two or more compressors and the heat transfer material HTM1 is water. In this embodiment, an additional stream of heat transfer material HTM1 is additionally fed after each of the compressors in series to increase the amount of gaseous heat transfer material HTM1 produced, at the cost of reducing the temperature of the stream. In this way, the opportunity to generate sufficient steam for regeneration step c) can be obtained. In addition, the addition of a further heat transfer material HTM1 is energetically advantageous compared to a scenario in which the same amount of gaseous heat transfer material HMT1 is generated (wherein no additional heat transfer material HTM1 is introduced after the compression step). Preferably, saturated steam is produced and used for heating in reboiler HE-R. The superheating of the steam is aided by injecting water between the compressor sections. In addition, the injection of additional heat transfer material HTM1 results in a reduced volumetric flow rate and in a reduced power demand of the subsequent compressors in the successive compression stages.

Step iv):

In embodiment C, thermal energy is transferred to the regeneration step C) in step iv) by transferring thermal energy from the heat transfer medium stream HTMS to the regeneration step C) to obtain a heat transfer medium stream HTMS having a reduced thermal energy content compared to HTMS 3.

The transfer of thermal energy from the heat transfer material stream HTMS to the regeneration step c) may take place indirectly or directly as described under step iv) of example a.

Open loop heat pump

In a preferred embodiment of embodiment C, the improved heat pump is designed as an open loop heat pump, wherein the heat transfer material flow HTM4 leaving the heat exchanger HE-R is not recycled to the heat exchanger HE1. This is even more preferred if the heat transfer material used in the last of the series connected heat pumps is water. The open loop heat pump has the advantages previously described.

Use of HTMS4

The heat transfer material HTM4 in embodiment C may also be recycled or used to provide heat to other parts of the process or other heat consuming bodies.

The recirculation may require an additional cooling step to cool the heat transfer material stream HTMS obtained at the outlet of heat exchanger HE-R, which is then recirculated as heat transfer material stream HTMS1 or cooling medium stream CMS 1. The cooling step preferably includes heat transfer to a portion of the process requiring additional heat. For example, the heat transfer material stream HTMS4 may additionally be used to heat the loaded absorbent stream A2 before it is introduced into the regeneration step c).

Alternatively, the heat transfer material stream HTMS4 may be used in an AGRU or other process on site of other heat-consuming bodies to provide heat.

In a further preferred embodiment, heat transfer material stream HTMS a may be mixed with heat transfer material stream HTMS b. In this case, the heat transfer material flow HTMS or the cooling medium flow CMS1 may need to be replenished with fresh heat transfer material HTM1 or fresh cooling medium CM 1.

Heat transfer material HTM1

The heat transfer material HTM1 used in the improved heat pump is preferably water, especially when the cooling medium CM1 directly contacting the cooler is also the heat transfer material HTM1 of the improved heat pump HP 1. In this case, steam can be generated directly from the cooling medium flow CMS1 by steps ii) and iii) of example C. This embodiment requires relatively low investment and can be easily implemented.

Acid gas absorption process-absorption step b)

According to the invention, the fluid stream FS2 obtained in the energy transfer step a) is deacidified in an absorption step b), wherein the cooled fluid stream FS2 is contacted with an absorbent A1 in an absorber to obtain an absorbent A2 loaded with acid gas and an at least partially deacidified fluid stream.

An absorbent:

the absorbent comprises at least one amine.

The following amines are preferred:

i) An amine having the formula I:

NR¹(R²)₂(I)

Wherein R ¹ is selected from the group consisting of C ₂-C₆ -hydroxyalkyl, C ₁-C₆ -alkoxy-C ₂-C₆ -alkyl, hydroxy-C ₁-C₆ -alkoxy-C ₂-C₆ -alkyl and 1-piperazinyl-C ₂-C₆ -alkyl, and R ² is independently selected from the group consisting of H, C ₁-C₆ -alkyl and C ₂-C₆ -hydroxyalkyl;

II) an amine having the formula II:

R³R⁴N-X-NR⁵R⁶(II)

Wherein R ³、R⁴、R⁵ and R ⁶ are independently selected from H, C ₁-C₆ -alkyl, C ₂-C₆ -hydroxyalkyl, C ₁-C₆ -alkoxy-C ₂-C₆ -alkyl and C ₂-C₆ -aminoalkyl, and X is C ₂-C₆ -alkylene, -X ¹-NR⁷-X² -or-X ¹-O-X² -, wherein X ¹ and X ² are independently C ₂-C₆ -alkylene, and R ⁷ is H, C ₁-C₆ -alkyl, C ₂-C₆ -hydroxyalkyl or C ₂-C₆ -aminoalkyl;

iii) A 5-to 7-membered saturated heterocyclic ring which has at least one nitrogen atom in the ring and may contain one or two further heteroatoms selected from nitrogen and oxygen in the ring, and

Iv) mixtures thereof.

Specific examples of amines that are preferably useful are:

i) 2-aminoethanol (monoethanolamine), 2- (methylamino) ethanol, 2- (ethylamino) ethanol, 2- (N-butylamino) ethanol, 2-amino-2-methylpropanol, N- (2-aminoethyl) piperazine, methyldiethanolamine, ethyldiethanolamine, dimethylaminopropanol, t-butylaminoethoxyethanol (TBAEE), 2-amino-2-methylpropanol, diisopropanolamine (DIPA);

ii) 3-methylaminopropylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, 2-dimethyl-1, 3-diaminopropane, hexamethylenediamine, 1, 4-diaminobutane, 3-iminodipropylamine, tris (2-aminoethyl) amine, bis (3-dimethylaminopropyl) amine, tetramethyl hexamethylenediamine;

iii) Piperazine, 2-methylpiperazine, N-methylpiperazine, 1-hydroxyethylpiperazine, 1, 4-dihydroxyethylpiperazine, 4-hydroxyethylpiperidine, homopiperazine, piperidine, 2-hydroxyethylpiperidine, triethylenediamine (TEDA) and morpholine, and

Iv) mixtures thereof.

In a preferred embodiment, the absorbent comprises at least one of Monoethanolamine (MEA), methylaminopropylamine (MAPA), piperazine (PIP), diethanolamine (DEA), triethanolamine (TEA), diethylethanolamine (DEEA), diisopropanolamine (DIPA), aminoethoxyethanol (AEE), t-butylaminoethoxyethanol (TBAEE), dimethylaminopropanol (DIMAP) and Methyldiethanolamine (MDEA), triethylenediamine (TEDA) or mixtures thereof.

Additional amines that can be introduced into the process are t-butylaminopropane, t-butylaminoethoxyethylmorpholine, t-butylaminoethyl morpholine, methoxyethoxyethoxyethyl-t-butylamine, t-butylaminoethyl pyrrolidone.

The amine is preferably a sterically hindered amine or a tertiary amine. Sterically hindered amines are secondary amines in which the amine nitrogen is bonded to at least one secondary carbon atom and/or at least one tertiary carbon atom, or primary amines in which the amine nitrogen is bonded to a tertiary carbon atom. A preferred sterically hindered amine is t-butylaminoethoxyethanol. Preferred tertiary amines are methyl diethanolamine and Triethylenediamine (TEDA).

If the objective is to completely or almost completely remove CO ₂ present in the fluid stream, the absorbent preferably additionally comprises an activator when the amine present in the absorbent is a sterically hindered amine or tertiary amine. The activator is typically a sterically unhindered primary or secondary amine. In these sterically unhindered amines, the amine nitrogen of at least one amino group is bonded only to the primary carbon atom and the hydrogen atom. If the objective is to remove only a portion of these gases present in the fluid stream, e.g., to selectively remove H ₂ S from a fluid stream comprising H ₂ S and CO ₂, the absorbent preferably does not comprise any activator. Sterically unhindered primary or secondary amines which can be used as activators are selected from, for example, alkanolamines, such as Monoethanolamine (MEA), diethanolamine (DEA), ethylaminoethanol, 1-amino-2-methyl-propan-2-ol, 2-amino-1-butanol, 2- (2-aminoethoxy) ethanol and 2- (2-aminoethoxy) ethylamine, polyamines, such as hexamethylenediamine, 1, 4-diaminobutane, 1, 3-diaminopropane, 3- (methylamino) propylamine (MAPA), N- (2-hydroxyethyl) ethylenediamine, 3- (dimethylamino) propylamine (DMAPA), 3- (diethylamino) propylamine, N' -bis (2-hydroxy-ethyl) ethylenediamine, 5-, 6-or 7-membered saturated heterocycles having at least one NH group in the ring, which may contain one or two further heteroatoms selected from nitrogen and oxygen, such as piperazine, 2-methylpiperazine, N-ethylpiperazine, N- (2-hydroxyethyl) piperazine, N- (2-aminoethyl) piperazine, homopiperazine and piperazine.

Particularly preferred are 5-, 6-or 7-membered saturated heterocycles having at least one NH group in the ring and which may contain one or two further heteroatoms selected from nitrogen and oxygen in the ring. Very particular preference is given to piperazine.

The molar ratio of activator to sterically hindered amine or tertiary amine is preferably in the range of 0.05 to 1.0, more preferably in the range of 0.05 to 0.7.

The absorbent typically comprises 10% to 60% by weight of amine.

In one embodiment, the absorbent comprises the tertiary amine methyldiethanolamine and the activator piperazine.

In a preferred embodiment, the absorbent comprises

A) At least one cyclic amine compound having only tertiary amine groups, and

B) At least one cyclic amine compound having at least one sterically hindered secondary amine group, wherein the total concentration of a) +b) is from 10 to 60% by weight.

Such absorbents are disclosed in EP 2391435. Most preferably, amine a) is Triethylenediamine (TEDA) and activator amine B) is piperazine.

The absorbent may additionally comprise a physical solvent. Suitable physical solvents are, for example, N-methylpyrrolidone, tetramethylene sulfone, oligomeric ethylene glycol dialkyl ethers such as oligomeric ethylene glycol methyl isopropyl ether (SEPASOLV MPE), oligomeric ethylene glycol dimethyl ether (SELEXOL). The physical solvent is generally present in the absorbent in an amount of from 1% to 60% by weight, preferably from 10% to 50% by weight, in particular from 20% to 40% by weight.

In a preferred embodiment, the absorbent comprises less than 10% by weight, for example less than 5% by weight, in particular less than 2% by weight, of inorganic basic salts, such as for example potassium carbonate.

The absorbent may also contain additives such as corrosion inhibitors, antioxidants, enzymes, defoamers, and the like. Typically, the amount of such additives is in the range of about 0.01% to 3% by weight of the absorbent.

The absorber may be supplied with fresh absorbent, or the absorber may be supplied with absorbent regenerated in the recycling step c). The provision of fresh absorbent means that the components of the absorbent have not passed steps b) to d). The provision of regenerated absorbent requires that at least a portion of the components of the absorbent have passed steps b) to d).

The absorbent is preferably aqueous. This means that the various different components of the absorbent, such as amine, methanol, physical solvents, additives, can be mixed with water in the amounts described above.

An absorber:

the fluid stream FS2 is preferably contacted with absorbent in the absorber in step b).

The absorber is preferably an absorption tower (absorption column), such as a tower or tray tower with random or structured packing.

The absorber generally comprises an absorption zone and optionally a re-wash zone.

The absorption zone is considered to be the section of the absorption column in which the fluid stream is in mass transfer contact with the absorbent.

The fluid stream is preferably contacted counter-currently with the absorbent in the absorption zone.

To improve contact with the absorbent and provide a large mass transfer interface, the absorption zone typically includes internals such as random packing, structured packing and/or trays, such as valve trays, bubble cap trays, soman trays or sieve trays.

If the absorption zone comprises random or structured packing, the height of the random/structured packing in the absorption zone is preferably in the range of 5 to 20m, more preferably in the range of 6 to 15m and most preferably in the range of 8 to 14 m.

If the absorption zone comprises trays, the number of trays in the absorption zone is preferably in the range of from 8 to 30, more preferably from 12 to 25 and most preferably from 15 to 23 trays.

In the case of columns with random or structured packing, the absorption zone may be divided into one or more sections, preferably from 2 to 4 sections. The loading and holding trays and/or distributor trays can be disposed between the individual sections of the absorption zone and these trays improve the distribution of the absorbent over the entire cross section of the column.

Temperature of absorbent introduced into absorption zone

Typically about 0 ℃ to 60 ℃, preferably 10 ℃ to 50 ℃ and more preferably 25 ℃ to 50 ℃.

The pressure in the absorber depends on the pressure and type of fluid stream FS2 entering the absorber.

When the fluid stream FS2 is synthesis gas, the pressure in the absorber is typically in the range of 5 to 120 bar, more preferably 10 to 100 bar and most preferably 10 to 60 bar.

When the fluid stream FS2 is flue gas, the pressure in the absorber is typically preferably in the range of 0.7 to 1.5 bar, more preferably 0.8 to 1.3 bar and more preferably 0.9 to 1.2 bar. Most preferably, when the fluid stream FS2 is flue gas, the absorber operates at atmospheric pressure.

The feed point of the incoming fluid stream is preferably below or in the lower region of the absorption zone. The feed is preferably distributed uniformly over the cross section of the absorber via a gas distributor.

The absorber may include one or more feed points for the incoming absorbent. For example, the absorber may include a feed point for fresh absorber A1 and a feed point for regenerated absorber A3. The fresh absorbent and regenerated absorbent may alternatively be fed together into the absorber via one feed point. The one or more feed points are preferably above or in the upper region of the absorption zone. The individual components of the absorbent, such as make-up water, may also be fed via the feed point of the fresh absorbent.

If the absorber has an optional re-wash zone, the feed is preferably between the absorber zone and the re-wash zone.

Contact of the fluid stream with the absorbent in the absorption zone provides an at least partially deacidified fluid stream FS3 and absorbent loaded with acid gas.

In the upper region of the absorber there is typically a withdrawal point for deacidified fluid stream FS 3. A mist eliminator can be installed in the region of the extraction point in order to separate any liquid residue of absorbent or detergent from the exiting fluid stream.

In the lower region of the absorber, preferably at the bottom, there is generally a withdrawal point for the loaded absorbent FS 2.

The at least partially deacidified fluid stream FS3 may optionally be contacted with a wash liquid in one or more re-wash zones (collectively, "re-wash zones").

The washing liquid is more preferably an aqueous liquid. The washing liquid may be a liquid inherent to the process, i.e. an aqueous liquid obtained elsewhere in the process, or an aqueous liquid supplied from the outside. Preferably, the wash liquor comprises condensate (referred to as absorber overhead condensate) and/or fresh water formed in a downstream cooling operation on the deacidified fluid stream.

The re-wash zone is typically the section of the absorber above the feed point of the absorbent.

The re-wash zone preferably has random packing, structured packing, and/or trays to enhance contact between the fluid stream and the wash liquid. The re-washing zone has, in particular, trays, in particular valve trays, bubble cap trays, soman trays or sieve trays.

The re-wash zone comprises a packing height (random packing/structured packing) of preferably 1 to 7, more preferably 2 to 6 and most preferably 3 to 5 trays, or preferably 1 to 6 m, more preferably 2 to 5m and most preferably 2 to 3 m.

The wash liquid is typically introduced above or into the upper region of the re-wash zone. The washing liquid used may be the washing liquid described above.

The wash liquor may be recycled via the re-wash zone. This is achieved by collecting the washing liquid below the re-washing zone, for example by means of a suitable collecting tray, and pumping it to the upper end of the re-washing zone by means of a pump. The recycled washing liquid may be cooled, preferably to a temperature of 20 ℃ to 70 ℃, in particular 30 ℃ to 60 ℃. This is advantageously achieved by circulating the washing liquid through a cooler. In order to avoid any accumulation of the washed absorbent component in the washing liquid, it is preferred to drain a substream of the washing liquid from the re-washing zone.

By contacting the at least partially deacidified fluid stream FS3 with a wash liquid, entrained absorbent components, such as amines, may be washed out. When more water is discharged via the exit stream than is introduced via the entry stream, contact with the aqueous wash liquor may additionally improve the water balance of the process.

As mentioned above, the deacidified fluid stream FS3 is preferably withdrawn via a withdrawal point at the upper portion of the absorber.

Alternatively, the deacidified fluid stream FS3 may be directed through a condenser.

The condensers used may be, for example, condensers with cooling coils or coils, plate heat exchangers, jacketed tubular condensers and shell-and-tube heat exchangers.

The condenser is typically operated at a temperature in the range of 10 ℃ to 60 ℃, preferably 20 ℃ to 50 ℃, more preferably 20 ℃ to 30 ℃.

The water content of the deacidified fluid stream is typically 80% to 100% of the saturation concentration of water in the fluid stream at the prevailing temperature and pressure conditions.

Step b) provides an absorbent A2 at least partially loaded with acid gas.

The loaded absorbent A2 may be fed directly to the regeneration step c).

An expansion step (optional):

In a particular embodiment of the process according to the invention, the loaded absorbent A2 is first subjected to an expansion step before it is introduced into the regeneration step c).

In the expansion step, the loaded adsorbent A2 is typically directed into one or more expansion vessels.

If the pressure in the absorber is higher than the pressure in the regenerator, the loaded absorbent can be expanded through a throttle valve into an expansion vessel.

If the fluid stream FS2 is synthesis gas, the loaded adsorbent is preferably expanded to a pressure of 3 to 15 bar, preferably 4 to 12 bar and more preferably 5 to 10 bar.

The expansion generally results in so-called desorption of the flash gas. The flash gas may be directed back into absorption by means of a compressor or burned to produce energy or burned in situ.

If the fluid stream FS2 is flue gas, the loaded absorbent is preferably pumped to an expansion vessel that is located downstream of the cross-flow heat exchanger HE-CF. In this case. In this case, the pump typically increases the pressure of the fluid stream FS2 by about 2 to 8 bar gauge, so it can be expanded into an expansion vessel, which is preferably operated slightly above the pressure of the regenerator. The effect of the expansion step is typically enhanced by the temperature increase of the fluid stream FS2 as it passes through the cross-flow heat exchanger HE-CF. The advantage of performing the additional expansion step is that at least a portion of the oxygen contained in the fluid stream FS2 may be flashed off, which has a negative impact on the desired purity of the CO ₂.

The flash vessel is typically a vessel that does not contain any particular internals. The flash vessel is preferably a so-called flash drum. Alternative flash vessels include columns with internals such as random packing, structured packing or trays.

In the upper region of the flash vessel there is typically a gas withdrawal port for converting the gas into the gas phase. The demister may preferably be further arranged in the region of the gas outlet. If desired, the acid gas present may be separated from the flash gas in a further absorber. Typically, a substream of the regeneration solvent is supplied to an additional absorption column for this purpose.

At the bottom of the flash vessel, typically, at least part of the absorbent A2 loaded with acid gases that have not been converted into the gas phase is withdrawn and typically led to a regeneration step c).

Regeneration step c):

According to the invention, at least part of the adsorbent A2 loaded with acid gas is fed into a regeneration step C), wherein at least part of the loaded adsorbent A2 obtained from step b) is regenerated in a regenerator to obtain at least part of the regenerated adsorbent A3 and a gaseous stream GS comprising at least one acid gas.

The gaseous stream GS may contain residual amounts of water which have not been separated off in the re-washing zone.

At least part of the adsorbent A2 loaded with acid gas is preferably led through a cross-flow heat exchanger HE-CF before being introduced into the regeneration step c).

In the cross-flow heat exchanger HE-CF, the absorbent A2 at least partially loaded with the acid gas is preferably heated to a temperature in the range of 50 to 150 ℃, more preferably 70 to 130 ℃ and most preferably 80 to 110 ℃. In a particular embodiment, the regenerated absorbent A3 withdrawn from the bottom of the regenerator is used as heating medium in the heat exchanger HE-CF. An advantage of this embodiment is that the thermal energy from the regenerated absorbent A3 of stage c) can be used to heat the loaded absorbent A2 from step b) in a heat exchanger HE-CF. In this way, the energy costs of the overall process and the energy requirements in the reboiler of regeneration step c) can be further reduced.

In a further preferred embodiment-as described in more detail above-, the second heat transfer material stream SHTMS is used as a heating medium in a heat exchanger HE-R, which is in addition to or instead of a cross-flow heat exchanger HE-CF.

A regenerator:

according to the invention, the regeneration step is carried out in a regenerator.

The regenerator is typically configured as a stripper.

The regenerator preferably comprises a regeneration zone and a reboiler.

The regenerator is preferably operated at a top pressure in the range of 0.5 to 5 bar, preferably 0.7 to 4 bar and more preferably 0.9 to 2.5 bar.

At the bottom of the regenerator, a liquid withdrawal port for regenerated absorbent A3 is typically provided.

At the top of the regenerator there is typically a gas withdrawal outlet for the gaseous stream GS. The demister is preferably installed in the region of the gas outlet.

The regenerator typically has a regeneration zone disposed above the bottom and below the re-wash zone. In this context, a regeneration zone is considered to be the area of the regenerator that contacts the loaded absorbent with steam generated in the reboiler.

To improve and provide a large mass transfer interface, the regeneration zone typically includes internals such as random packing, structured packing and/or trays, such as valve trays, bubble cap trays, soman trays or sieve trays.

If the regeneration zone comprises structured packing or random packing, the height of structured packing/random packing in the regeneration zone is preferably in the range of 5 to 15m, more preferably in the range of 6 to 12 m and most preferably in the range of 8 to 12 m.

If the regeneration zone comprises trays, the number of trays in the regeneration zone is preferably in the range of from 10 to 30, more preferably from 15 to 25, and most preferably from 17 to 23 trays.

In the case of columns with random or structured packing, the regeneration zone may in turn be divided into a plurality of sections, preferably from 2 to 4 sections. The loading and holding trays and/or distributor trays may be disposed between the sections of the regeneration zone and these trays improve the distribution of liquid across the cross section of the regenerator.

In general, it is preferred to introduce the loaded absorbent A2 into the regenerator in the upper zone or above the regeneration zone and below the re-washing zone.

In the regeneration zone, the vapor produced in the evaporator typically operates counter-current to the absorbent flowing down through the regeneration zone.

The zone of the regenerator below the regeneration zone is commonly referred to as the bottom.

In this zone, the absorbent is typically collected and (i) fed via piping to reboiler HE-R AS absorbent stream AS1 via a liquid withdrawal port in the lower zone of the regenerator, and/or (ii) partially recycled to the absorber AS regenerated absorbent A3.

The bottom can be separated by a collecting tray arranged between the bottom outlet and the feed point of the steam generated in the evaporator.

Typically, at least a portion of the regenerated absorbent A3 is directed AS absorbent stream AS1 from the bottom draw of the regenerator to the reboiler.

Preferably, the bottom draw from the regenerator is directed entirely into the reboiler AS absorbent stream AS 1.

Reboiler HE-R is typically a kettle reboiler, a natural circulation reboiler, or a thermosiphon reboiler, or a forced circulation reboiler.

The reboiler HE-R of the regenerator is preferably arranged outside the regenerator and connected to the bottom withdrawal outlet via a pipe.

The reboiler HE-R is typically operated at a temperature in the range of 100 ℃ to 150 ℃, preferably 105 ℃ to 140 ℃ and most preferably 110 ℃ to 130 ℃.

In reboiler HE-R, typically, at least a portion of the bottom draw is vaporized and returned to the regenerator AS absorbent stream AS 2. The absorbent stream AS2 is preferably fed to the regenerator below the regeneration zone, preferably to the bottom of the regenerator.

If an additional collecting tray is provided at the bottom, the steam generated in the reboiler is preferably fed below the collecting tray.

Rewashing zone:

In a preferred embodiment, the regenerator has a re-washing zone above the regeneration zone, particularly preferably above the feed point of the loaded absorbent A2.

The re-wash zone typically takes the form of a section of the regenerator disposed above the regeneration zone. The re-wash zone preferably has internals, especially random packing, structured packing and/or trays, to enhance contact between the fluid stream and the wash liquid. Particularly preferably, the washing section has trays, in particular valve trays or bubble cap trays.

In a preferred embodiment, the internals are random packing and/or structured packing. The packing height (random packing/structured packing) is preferably in the range of 1 to 10m, more preferably 2 to 8m and most preferably 3 to 6 m.

In a very particularly preferred embodiment, the re-washing zone has trays, in particular valve trays or bubble cap trays, the number of trays preferably being in the range from 2 to 10, more preferably from 2 to 8 and most preferably from 2 to 6 trays.

The wash liquid may be introduced into the upper region of the re-wash zone or above the re-wash zone. The washing liquid used is generally an aqueous or slightly acidic aqueous solution, in particular water. The temperature of the washing liquid is typically in the range of 10 ℃ to 60 ℃, preferably in the range of 20 ℃ to 55 ℃ and more preferably in the range of 30 ℃ to 40 ℃.

In the re-wash zone, entrained residual amounts of amine can be washed out of the absorbent such that the acid off-gas GS exiting the regenerator is substantially free of amine. In the re-wash zone, the water content of the gas stream obtained at the top of the regenerator may be additionally reduced, as contact with cooler detergent may result in condensation of a portion of the vapor water.

And (3) condensing:

in a preferred embodiment of the invention, the acid gas stream GS from the regenerator is introduced into the condensing step.

In the condensation step, a condensate comprising water is condensed out of the gaseous stream (condensate outlet). The uncondensed vapor phase is preferably vented to a compression step, as described further below. The condensation step is preferably carried out in such a way that the gaseous stream GS from stage c) is led through one or more condensers (regenerator overhead condenser). The top condenser typically comprises a heat exchanger and a vessel in which the liquid phase can be separated from the gas phase (phase separation vessel). However, the heat exchanger and the vessel may also be integrated in one component.

The regenerator overhead condenser is typically operated in such a way that the water will condense while the acid gas remains predominantly in the gas phase.

The regenerator top condensers used may be, for example, condensers with cooling coils or coils, jacketed tubular condensers, and shell-and-tube heat exchangers.

The regenerator overhead condenser is typically operated at a temperature in the range of 10 ℃ to 60 ℃, preferably 20 ℃ to 55 ℃, more preferably 30 ℃ to 40 ℃.

In a preferred embodiment, the gaseous stream GS from stage c) is led through a regenerator overhead condenser. Optionally, a wash liquid as described above may be additionally introduced into the regenerator together with the condensate from the condensing step. The introduction may be achieved via the same feed point. The washing liquid may alternatively be introduced via a separate feed point.

Compression and/or liquefaction step:

the fluid stream GS preferably comprises CO ₂.

To prevent this release of CO ₂ to the atmosphere, it is preferable to enclose CO ₂ in a suitable storage location.

Sequestration typically requires that the gaseous CO ₂ stream GS be compressed and optionally cooled into a fluid that can be transported through a pipeline to its destination or can be transported as a chemical to its destination where it is used for other purposes. Typical pressures of CO ₂ in the pipeline for transport are 70 to 200 bar, preferably 90 to 150 bar. Typical pressures for CO ₂ for transport by ship, truck or train are 5 to 50 bar, preferably 6 to 40 bar and more preferably 7 to 35 bar.

Compression is typically achieved in one or more compressors. The compressor is generally configured to receive a gaseous stream GS comprising CO ₂ and compress the gaseous stream to produce a compressed fluid stream CFS. The compressor is typically a positive displacement compressor or a dynamic compressor. Positive displacement compressors include reciprocating compressors that use pistons driven by a crankshaft to deliver fluid at higher pressures. The reciprocating compressor may be single stage or multi-stage. The positive displacement compressors also include rotary screw compressors, conical screw compressors, rotary vane compressors, rolling piston compressors or scroll compressors.

The compressor may also be a dynamic compressor, such as a centrifugal compressor or an axial compressor. Preferably, the compressor is a rotary screw compressor, a centrifugal compressor, a piston compressor or an axial compressor.

After compression or after each compression step in the compressor, the fluid stream CFS is preferably passed through one or more heat exchangers to dissipate heat from the compressed fluid or to utilize the heat of compression as a heat source to heat other processes or other steps of the gas treatment process.

Alternatively, the compression may be supplemented with liquefied CO ₂ by one or more additional refrigeration steps. The CO ₂ may be cooled in a heat exchanger, which is an evaporator of a heat transfer material, preferably liquid ammonia. The vaporized heat transfer material is then compressed, cooled and expanded in a conventional refrigeration circuit. It is also possible to combine two or more refrigeration circuits in series, which reduces the energy consumption of refrigeration.

In addition, CO ₂ may be compressed and cooled by external water and expanded to the transport temperature and then compressed. The non-liquefied CO ₂ is preferably separated and recycled to the compression step. The energy consumption can be reduced by performing compression and decompression (evaporation) in several steps.

Drying and other purification steps

It is generally preferred to dry the stream GS containing CO ₂. Drying may occur before, after, or after one or more of the compression or cooling steps.

Drying is preferably carried out in the form of Pressure Swing Adsorption (PSA) and more preferably in the form of Temperature Swing Adsorption (TSA) or in the form of a glycol drying operation.

PSA or TSA can be performed by methods known to those skilled in the art. Standard variant procedures are described, for example, in Nag, ashis, "Distillation and Hydrocarbon Processing Practices [ distillation and hydrocarbon processing practice ]", pan Weier publication group (PennWell) 2016, ISBN 978-1-59370-343-1 or a. Terrigeol, GPA Europe, annual Conference [ european GPA annual meeting ], berlin, 2012, 5, 23, 25, （https://www.cecachemicals.com/export/sites/ceca/.content/medias/downloads/products/dtm/molecular-sieves-con-taminants-effects-consequences-and-mitigation.pdf）.

In PSA or TSA, it is preferred to use zeolite, activated carbon or molecular sieves.

It is preferred to use molecular sieves as solid adsorbents in PSA or TSA.

In the ethylene glycol drying operation, it is preferable to use a liquid adsorbent such as monoethylene glycol (MEG), diethylene glycol (DEG), triethylene glycol (TEG) or tetraethylene glycol (TREG). TEG is particularly preferably used as the liquid adsorbent.

The ethylene glycol drying operation may be performed by process variants known to those skilled in the art. Examples of ethylene glycol drying are likewise found, for example, in Nag, ashis, "Distillation and Hydrocarbon Processing Practices [ distillation and hydrocarbon processing practice ]", pan Weier publication group (PennWell) 2016, ISBN 978-1-59370-343-1.

Also, other components such as carbonyl sulfide (COS) and hydrogen sulfide may be removed by installing additional filters and adsorbers.

Transportation and storage and utilization:

The fluid stream CFS is preferably transported to its storage location or where it is ultimately utilized. The CO ₂ may be transported via pipeline or by means of transportation such as trucks, trains, and ships.

Suitable storage sites are suitable geological formations such as depleted hydrocarbon reservoirs, mines and salt or other formations.

CO ₂ can also be used by the food industry, petroleum industry and chemical industry.

A preferred use of CO ₂ in the food industry is carbonization of beverages.

Other uses of captured carbon dioxide are in enhanced oil recovery or conversion to fuels, cements, minerals or chemicals, or as a material for fire extinguishers, as a solvent, as an inert gas or as a refrigerant.

Recycling step d):

According to the invention, the regenerated absorbent A3 obtained at the bottom of the regenerator from step c) is returned to the absorption step b).

The regenerated absorbent is preferably recycled in one of the feed points of the absorber for regenerated absorbent as described above.

Summarizing:

The method of the invention allows to utilize the thermal energy inherent in the hot stream HS1, in particular in the stream FS1, to power the high-energy regeneration step c).

The advantage of using two heat pumps connected in series is that the thermal energy from the heat stream HS1, in particular FS1, can be raised to a level where steam can be generated in the heat pump HP2, which steam can be used to transfer heat to the regeneration step c). Thus, the stream generated in the heat pump HP2 can effectively replace the process steam normally required as a heat source in the regeneration step c). Thus, the use of two heat pumps in series can replace the need to install a separate process steam production process at the site of the acid gas removal unit or the need for a steam turbine, such as a back pressure turbine or an exhaust condensing turbine, to produce process steam. Thus, the present invention is particularly useful in situations where process steam is not readily available on site in an acid gas removal unit. Moreover, the method according to the invention can be used as an alternative method of producing process steam in the field where the process steam is readily available, so that it allows the use of potentially limited process steam resources for other uses or allows the reduction of power losses of the power plant associated with the production of process steam. In addition, the method of the present invention is an interesting alternative in the design of new power plants incorporating acid gas removal units for carbon capture, as the need for transferring energy for steam production to power the recycling step can be reduced. In addition, the process of the present invention is a useful method of electrifying steam production so that the steam required in the amine gas treatment process can be provided by "green" power from renewable resources. In a preferred embodiment of the invention, thermal energy from the gaseous heat stream HS1, in particular the fluid stream FS1, is transferred to the regeneration step via an intermediate cooling circuit comprising a direct contact cooler DCC and a cooling material CM. The advantage of direct heat exchange is that the exchange area between the two fluid streams HS1 and CMS1 increases, which reduces the thermal resistance and maximizes the thermal efficiency. In addition, direct heat exchangers generally have lower operating and capital costs than indirect heat exchangers due to the high heat transfer rate per volume and because fouling and corrosion are generally not an issue. In addition, expensive equipment such as blowers or fans, etc., required to transport fluid streams FS1 and FS2 in the indirect gas-liquid heat exchanger may be reduced or even eliminated in the direct heat exchanger because of the lower pressure drop in the direct heat exchanger compared to the indirect heat exchanger.

The method of the present invention is particularly effective in the following cases:

using water as cooling medium in the cooling medium flows CMS1 and CMS2,

Use of ammonia or butane or R1233zd (e) as heat transfer material HTM1, and

-Using water as heat transfer material HTM2.

When such a combination of cooling medium and heat transfer material is used, particularly high values of the coefficient of performance of the heat pump can be achieved.

In a preferred embodiment of the invention, the method of the invention may be combined with additional heat pumps designed to transfer thermal energy from other heat sources present in the gas treatment process. Such other heat sources include, but are not limited to, heat sources HS set forth above, including, but not limited to:

the absorption heat occurring in the absorber, which can be utilized in the charge air cooler or by integrating a heat exchanger into the absorber,

If the re-washing zone is equipped with a pump and a cooler, the heat of absorption in the re-washing zone at the top of the absorber,

The heat of condensation of the condensate at the head of the absorber or regenerator,

Compression heat in the compression step, which is generated when the gaseous stream GS is compressed into a supercritical fluid.

The use of these additional measures may help reduce the energy requirements for carbon capture and storage, even further resulting in reduced power transfer from the power plant to the gas treatment unit.

Aspect 2-apparatus for producing deacidified fluid streams

In a second aspect, the invention relates to an apparatus for deacidifying a fluid stream.

Fig. 1 shows an apparatus for deacidifying a fluid stream useful in practicing a method according to embodiment a of the present invention, the apparatus comprising:

a) A direct contact cooler, the direct contact cooler comprising

A. an inlet for fluid stream FS 1;

b. an outlet for fluid stream FS 2;

c. an inlet for a cooling medium flow CMS1, and

D. outlet for a cooling medium flow CMS2

B) An absorber, the absorber having

A. the inlet of the fluid stream FS2,

B. an outlet for deacidified fluid stream FS 3;

c. the inlet of the absorbent stream A1,

D. An inlet for a regenerated absorbent stream A3, and

E. outlet of the loaded absorbent stream A2

C) A regenerator having

A. an inlet for the loaded absorbent stream A2;

b. an outlet for regenerated absorbent stream A3 and/or AS 1;

c. an inlet for the absorbent stream AS 2;

d. An outlet for the acid gas stream GS;

d) A heat pump HP1 comprising

A. heat exchanger HE1, which has

I. an inlet for a flow HTMS of heat transfer material, and

An outlet for the heat transfer material stream HTMS;

b. One or more compressors in series, wherein the first compressor in the series has an inlet for heat transfer material stream HTMS and the last compressor in the series has an outlet for heat transfer material stream HTMS;

c. a heat exchanger HE-R comprising

I. an inlet for a flow HTMS of heat transfer material;

An outlet for a flow HTMS of heat transfer material;

a second inlet for the absorbent stream AS1, and

A second outlet for the absorbent stream AS 2.

FIG. 2 shows an apparatus for deacidifying a fluid stream that may be used to implement a method according to embodiment B of the present invention, the apparatus additionally comprising

E) A heat pump HP2 comprising

A. heat exchanger HE2, which has

I. The inlet of the heat transfer material stream SHTMS,

An outlet for the heat transfer material stream SHTMS;

An inlet for a flow HTMS of heat transfer material, and

Outlet for heat transfer material stream HTMS4

B. One or more compressors in series, wherein the first compressor in the series has an inlet for heat transfer material stream SHTMS and the last compressor in the series has an outlet for heat transfer material stream SHTMS;

c. a heat exchanger HE-R in place of the heat exchanger HE-R as claimed in claim 16, the heat exchanger comprising

I. An inlet for a flow SHTMS of heat transfer material;

an outlet for a flow SHTMS of heat transfer material;

a second inlet for the absorbent stream AS1, and

A second outlet for the absorbent stream AS 2.

FIG. 3 shows an apparatus which can be used to carry out the method according to embodiment C of the invention in step i) by direct heat transfer, the apparatus comprising

A) An absorber, the absorber having

A. the inlet of the fluid stream FS2,

B. an outlet for deacidified fluid stream FS 3;

c. the inlet of the absorbent stream A1,

D. An inlet for a regenerated absorbent stream A3, and

E. outlet of the loaded absorbent stream A2

B) A regenerator having

A. an inlet for the loaded absorbent stream A2;

b. an outlet for regenerated absorbent stream A3 and/or AS 1;

c. an inlet for the absorbent stream AS 2;

d. An outlet for the acid gas stream GS;

c) A heat pump HP1 comprising

A. Heat exchanger HE1, which is a direct contact cooler with

I. an inlet for a flow HTMS of heat transfer material, and

An outlet for the heat transfer material stream HTMS a;

b. One or more evaporation devices for expanding the heat transfer material HTMS a, the evaporation device having

I. an inlet for a flow HTMS a of heat transfer material, and

An outlet for the heat transfer material stream HTMS b (g);

c. one or more compressors in series, wherein the first compressor in the series has an inlet for heat transfer material stream HTMS b (g) and the last compressor in the series has an outlet for heat transfer material stream HTMS;

d. a heat exchanger HE-R comprising

I. an inlet for a flow HTMS of heat transfer material;

An outlet for a flow HTMS of heat transfer material;

a second inlet for the absorbent stream AS1, and

A second outlet for the absorbent stream AS 2.

Fig. 4 shows an apparatus useful for implementing the method according to embodiment C of the invention in step i) by indirect heat transfer, the apparatus comprising:

a) A direct contact cooler, the direct contact cooler comprising

A. an inlet for fluid stream FS 1;

b. an outlet for fluid stream FS 2;

c. an inlet for a cooling medium flow CMS1, and

D. outlet for a cooling medium flow CMS2

B) An absorber, the absorber having

A. the inlet of the fluid stream FS2,

B. an outlet for deacidified fluid stream FS 3;

c. the inlet of the absorbent stream A1,

D. An inlet for a regenerated absorbent stream A3, and

E. outlet of the loaded absorbent stream A2

C) A regenerator having

A. an inlet for the loaded absorbent stream A2;

b. an outlet for regenerated absorbent stream A3 and/or AS 1;

c. an inlet for the absorbent stream AS 2;

d. An outlet for the acid gas stream GS;

d) A heat pump HP1 comprising

A. heat exchanger HE1, which has

I. an inlet for a flow HTMS of heat transfer material, and

An outlet for the heat transfer material stream HTMS a;

I. an inlet for a flow HTMS a of heat transfer material, and

An outlet for the heat transfer material stream HTMS b (g);

d. a heat exchanger HE-R comprising

I. an inlet for a flow HTMS of heat transfer material;

An outlet for a flow HTMS of heat transfer material;

a second inlet for the absorbent stream AS1, and

A second outlet for the absorbent stream AS 2.

In all the figures, the absorber is configured as an absorber column.

The absorber preferably has an absorption zone. In the context of the present invention, an absorption zone is considered to be a section of an absorption column in which a fluid stream is in mass transfer contact with an absorbent. In order to improve contact and provide a large mass transfer interface, the absorption zone preferably comprises internals, preferably random packing, structured packing and/or trays.

In columns with random packing or structured packing, the absorption zone is preferably divided into two to four packing sections arranged one above the other, which are separated from one another by support and retention trays and/or distributor trays.

If the absorption zone comprises random or structured packing, the height of structured packing/random packing in the absorption zone is preferably in the range of 5 to 20m, more preferably in the range of 6 to 15m and most preferably in the range of 8 to 14 m.

Preferably, below or in the lower region of the absorption zone, there is an inlet for the fluid stream FS2 to be deacidified.

Fresh absorbent A1 may be fed via an inlet in the upper zone or above the absorption zone. The supply of fresh absorbent may also include a supply of individual components of the absorbent such as makeup water.

Regenerated absorbent A3 may be fed via the same inlet or an inlet also in the upper zone or above the absorption zone.

Preferably above the absorption zone, preferably at the top of the absorption column, there is an outlet for the deacidified fluid stream FS 3.

A mist eliminator (not shown) is preferably installed in the region of the withdrawal point of the deacidified fluid stream.

In a particularly preferred embodiment, a feed point (not shown) for the detergent is present in the upper zone or above the absorption zone.

In very specific embodiments, the absorber includes an additional re-wash zone (not shown) above the absorption zone. The re-wash zone is typically configured as a section of the absorber in the form of a rectification section that is disposed above the feed point of the absorbent. The re-wash zone preferably has random packing, structured packing, and/or trays to enhance contact between the fluid stream and the wash liquid. The re-washing zone has, in particular, trays, in particular valve trays, bubble cap trays, soman trays or sieve trays.

Preferably, there is a feed point (not shown) for the detergent above the re-washing zone. The re-wash zone comprises a packing height (random packing or structured packing) of preferably 1 to 7, more preferably 2 to 6 and most preferably 3 to 5 trays, or preferably 1 to 6m, more preferably 2 to 5m and most preferably 2 to 3 m.

A collecting tray (not shown) may be provided below the re-washing zone, on which the washing liquid may be collected and recycled. Recirculation is usually effected here by means of a pump (not shown) which pumps the scrubbing liquid from the collecting tray to the feed point. In the case of recirculation, the washing liquid can be cooled by means of a heat exchanger (not shown).

Preferably, in the lower region of the absorber, there is preferably a liquid withdrawal port carrying the absorbent A2.

In a preferred embodiment, a heat exchanger HE-CF is present between the absorbent-loaded liquid withdrawal port in the absorber and the absorbent-loaded feed port in the regenerator. The heating medium for this heat exchanger is preferably a recycle stream of regenerated absorbent A3 from the bottom of the regenerator to the absorber. In this preferred embodiment, the energy requirements of the overall process can be reduced.

The heat exchanger HE-CF may be configured as a plate heat exchanger or a shell and tube heat exchanger. The heating medium used in the heat exchanger is preferably a bottom stream from the regenerator.

In the figure, the outlet of the loaded absorbent A2 from the absorber is preferably connected to the regenerator via a conduit via a heat exchanger.

The regenerator in all figures preferably comprises a regeneration zone, an evaporator, a feed inlet for the loaded absorbent A2, a liquid withdrawal outlet (outlet) for the at least partially regenerated absorbent A3 at the bottom of the regenerator, a re-washing zone (not shown) and an outlet for withdrawing the acid gas stream GS in the top zone of the regenerator. In this context, a regeneration zone is considered to be the zone of the regenerator where the loaded absorbent is contacted with steam produced by the reboiler.

In order to improve contact and provide a large mass transfer interface, the regeneration zone preferably comprises internals, preferably random packing, structured packing and/or trays.

In columns with random or structured packing, the regeneration zone is preferably divided into two to four packing sections arranged one above the other, which are separated from one another by support and retention trays and/or distributor trays.

If the regeneration zone comprises random or structured packing, the height of random/structured packing in the regeneration zone is preferably in the range of 5 to 15m, more preferably in the range of 6 to 12 m and most preferably in the range of 8 to 12 m.

The feed inlet for the loaded absorbent A2 is preferably above or in the upper region of the regeneration zone.

The regenerator in fig. 1 and 2 additionally comprises a reboiler HE-R.

The reboiler is preferably a kettle reboiler, a natural circulation evaporator or a forced circulation evaporator.

The reboiler HE-R is preferably connected via a conduit to a liquid withdrawal at the bottom of the regenerator to introduce the absorbent stream AS1 into the reboiler HE-R. The bottom generally refers to the area below the regeneration zone.

The absorbent stream AS2, which is typically a vapor-liquid mixture produced in a reboiler, is preferably introduced into the lower zone of the regenerator via a feed point above the liquid withdrawal at the bottom but below the regeneration zone.

In a further preferred embodiment, the bottom of the regenerator is separated by a collecting tray (not shown). The absorbent collected therein is supplied to a cross-flow heat exchanger HE-CF. Stream AS2 is preferably recycled to the regenerator below the collecting tray.

The regenerators in all the figures preferably comprise the withdrawal point of the gaseous stream GS formed during regeneration. The withdrawal point of the gaseous stream GS formed in the regeneration is preferably arranged in the top region of the regenerator. Preferably, there is a demister (not shown) in the region of the extraction point.

The regenerator in the drawings preferably includes a re-wash zone (not shown) with internals. The internals present in the re-washing zone are preferably structured or random packing, wherein the packing height (random packing/structured packing) is preferably in the range of from 1 to 10m, more preferably in the range of from 2 to 8m and most preferably in the range of from 3 to 6 m. Alternatively, the internals present in the re-washing zone are trays. More particularly, the number of trays is preferably in the range of 3 to 20, more preferably 4 to 16, and preferably 6 to 12. The trays in the washing section may be, for example, valve trays, bubble cap trays, soman trays or sieve trays.

In the figures, there may be a separate feed (not shown) of washing liquid above or in the upper region of the re-washing zone. If a washing liquid such as fresh water is additionally supplied, it is preferred that this washing liquid is led into the regenerator at the top of the regenerator together with condensate from the additional condensation step. Preferably, the withdrawal point of the gaseous stream GS formed in the regenerator is connected to a top condenser (not shown). The top condenser preferably comprises a heat exchanger, a vessel for phase separation (phase separation vessel), a gas withdrawal outlet and a condensate outlet. The condensers used may be, for example, condensers with cooling coils or coils, jacketed tubular condensers and shell-and-tube heat exchangers.

The invention is illustrated by the following examples:

Example 1 is based on calculations performed using a simulation model. The phase equilibrium of the carbon capture moiety is described using model Pitzer (K.S. Pitzer, activity Coefficients in Electrolyte Solutions [ coefficient of activity in electrolyte solution ] 2 nd edition, CRC Press, 1991, chapter 3, ion Interaction Approach: theory [ ion interaction method: theory ]). The simulation of the absorption process is described by means of mass transfer-based methods, the details of which are given in the non-equilibrium rate-based simulation of Asprion（Asprion, N.: Nonequilibrium Rate-Based Simulation of Reactive Systems: Simulation Model, Heat Transfer, and Influence of Film Discretization [ reaction systems, simulation models, heat transfer and the effect of film discretization, ind. Eng. Chem. Res. [ Industrial and engineering chemistry research ] (2006) 45 (6), 2054-2069).

Separately, for heat pumps, the required thermodynamic data is provided by PC-SAFT (NH 3) (Gross, J.; sadowksi, G.: industrial & ENGINEERING CHEMISTRY RESEARCH [ Industrial & engineering chemical research ], 2002, 41 (22) 5510), and for water, the required thermodynamic data is provided by NBS Table (L. Haar et al, NBS/NCR Steam Tables [ NBS/NCR Steam Table ], new York: hemisphere publishing (HEMISPHERE PUBLISHING), 1984).

Example 2 is based on calculations using the thermodynamic software package REFPROP (https:// REFPROP-docs. Readthes. Io/en/last/DLL/index. Html) using an additional simulation tool called EBSILON °professional (www.ebsilon.com). The tool is typically suitable for simulation of a power plant, but is generally applicable to any type of thermodynamic cycle.

Example 1 use of a coolant flow CMS2 from a Direct Contact Cooler (DCC) as the heat flow HS1 for a series heat pump

Example 1 is based on the process scheme represented in fig. 2, comprising a combination of a direct contact cooler and two heat pumps HP1 and HP2 connected in series, wherein the heat pump HP2 is configured as an open loop heat pump, some variants of which are described further below:

1389 t/h of a fluid stream FS1 having the composition depicted in table a below and a temperature of 70 ℃ and a pressure of 1.01 bar is fed to the bottom of a heat exchanger HE-C configured as a Direct Contact Cooler (DCC). In HE-C, FS1 is brought into countercurrent contact with water as cooling medium flow CMS1 to obtain a fluid flow FS2 having a flow rate of 124.1 t/h at a temperature of 35℃and a pressure of 0.99 bar, which is slightly compressed to a pressure of 1.07 bar and a temperature of 43.4℃and then introduced into absorption step b). CMS1 was introduced at the top of the HE-C with a flow rate of 3233.3 t/h at a temperature of 40℃and a pressure of 2.25 bar. Heat energy is transferred from fluid stream FS1 to cooling medium stream CMS1 to obtain cooling medium stream CMS2 at the bottom of HE-C. A small portion of CMS2 (150.7 t/h) was purged from the process. CMS2 with a temperature of 61.4 ℃ and a pressure of 1.01 bar at 3275 t/h was used as the heat stream HS1 for a series heat pump comprising a first heat pump HP1 with ammonia as heat transfer material HTM1 and a second heat pump HP2 with water as heat transfer material HTM 2. The heat pump HP1 is designed as a closed loop heat pump comprising a regeneration step. The heat pump HP2 is designed as an open loop heat pump. The thermal energy from the heat stream HS1 (CMS 2) is transferred through the evaporator HE1 of the heat pump HP1 to the heat transfer material stream HTMS1 having a flow rate of 408.19 t/h at a temperature of 37.7 ℃ and a pressure of 14.54 bar to obtain a gaseous heat transfer material stream HTMS2 having a flow rate of 408.19 t/h and a temperature of 37.6 ℃ and a pressure of 14.49 bar. Furthermore, a cooled cooling medium flow CMS3 is obtained, which is further cooled in an additional cooler to a temperature of 32 ℃ and pumped to the heat exchanger HE-C at a pressure of 4.5 bar. The heat transfer material stream HTMS is compressed in a compressor to obtain a heat transfer material stream HTMS3 at a pressure of 75.48 bar and a temperature of 197.6 ℃. the heat transfer material stream HTMS is fed to a heat exchanger HE2, which is the condenser of heat pump HP1 and the evaporator of heat pump HP2, to obtain a cooled liquid heat transfer material stream HTMS having a temperature of 109.6 ℃ and a pressure of 75.43 bar. To close the loop and recycle the heat transfer material stream HTMS to heat exchanger HE1, the heat transfer material stream HTMS is expanded to obtain a cooled heat transfer material stream HTMS5 having a temperature of 37.7 ℃ at a pressure of 14.54 bar, which is partially liquid (246, 8 t/h) and gaseous (161.4 t/h) and which is recycled to heat exchanger HE1 as heat transfer material stream HTMS 1. in heat exchanger HE2, heat energy is transferred from heat transfer material stream HTMS to second heat transfer material stream SHTMS1 having a flow rate of 174.3 t/h at a pressure of 5 bar and a temperature of 99.6 ℃ to obtain second heat transfer material stream SHTMS2 having a flow rate of 174.3 t/h at a pressure of 1 bar and a temperature of 99.6 ℃. The second heat transfer material stream SHTMS is compressed in three stages, each stage comprising a compressor. In the first compressor, the pressure was raised to 1.5 bar and the temperature was raised to 146.1 ℃. After the first compressor, an additional water stream is added at a flow rate of 3.8 t/h and a temperature of 99.6 ℃ and a pressure of 5 bar to obtain a second heat transfer material stream SHTSM3 having a temperature of 121.4 ℃ at a flow rate of 178.1 t/h at a pressure of 1.5 bar . In the second compressor, a second heat transfer material stream STMS3Further compressed to a pressure of 2.3 bar and a temperature of 134.1 ℃. Another water stream having a temperature of 99.6 ℃ and a pressure of 5 bar was added at a flow rate of 5.8 t/h to obtain a second heat transfer material stream SHTM3 having a temperature of 134.1 ℃ and a pressure of 2.3 bar at a flow rate of 183.9 t/h . In the third compressor, the second heat transfer material stream SHTMS is still further compressed To obtain a second heat transfer material stream SHTMS having a pressure of 3.4 bar and a temperature of 184.3 deg.c . A still further water stream having a temperature of 99.6 ℃, a pressure of 5 bar and a flow rate of 6.1 t/h is added to the second heat transfer material stream SHTMS To obtain a second heat transfer material flow SHTMS having a temperature of 147.8 ℃ and a pressure of 3.4 bar and a flow rate of 190.0 t/h. The heat energy from the second heat transfer material stream SHTMS is transferred to the reboiler of the absorber to maintain a temperature of 127.3 ℃ at the bottom of the absorber. A cooler second heat transfer material stream SHTMS4 having a temperature of 137.3 ℃ and a pressure of 3.34 bar is obtained.

The coefficient of performance (COP), which is a measure of the performance of the heat pump system, is 2.34.

The heat pump HP2 operates as an open loop heat pump, i.e., the second heat transfer material stream SHTMS4 is not recycled to the heat exchanger HE2. Alternatively, it would be possible for the heat pump HP2 to operate as a closed loop heat pump and for at least a portion of the second heat transfer material stream SHTMS to be recycled to the heat exchanger HE2, for example as stream SHTMS1, or to the compression step as an additional stream of heat transfer material HTM2, ultimately to be recycled to the respective input stream after adjusting the pressure and temperature by an additional expansion, cooling or compression step to adjust the characteristics of stream HTMS.

This example shows that the energy contained in the cryogenic fluid stream FS1 can be effectively used to heat the regeneration step c).

To achieve this in a conventional heat pump, it would be necessary to find a heat transfer material that will undergo a phase change at the temperature and pressure of the heat exchanger HE1 and that can be compressed to obtain the high temperatures required in the regeneration step c), in particular in the reboiler. Ammonia is not suitable as it will need to be compressed to a pressure at which it becomes supercritical in heat exchanger HE 2.

In example 1, only the amount of steam required in regeneration step c) is produced. Since the method of the present invention generates steam, the steam may be supplemented by other steam sources, or excess steam may be provided to other consuming bodies. Alternatively, excess steam may be dispersed into the environment.

TABLE 1 composition of fluid stream FS1

Example 2:

example 2 is based on the process scheme depicted in fig. 4, which includes a combination of a direct contact cooler and a modified heat pump, some of which variants are described below.

After heat transfer from the fluid gas stream FS2 to the cooling medium stream CMS1 in a direct contact cooler (DCC or HE-C), a cooling medium stream CMS2 having a flow rate of 5500 t/h, a pressure of 1.2 bar and a temperature of 62 ℃ is obtained. The cooling medium stream CMS2 is fed to the heat exchanger HE1 of the modified heat pump HP1 to obtain a cooled cooling medium stream CMS3 having a temperature of 50 ℃ and a pressure of 1.2 bar. Stream CMS3 is additionally cooled in a water cooler to obtain a cooling medium stream CMS4 having a temperature of 42 ℃, which is recycled as cooling medium stream CMS1 to the direct contact cooler. In heat exchanger HE1, heat is transferred from cooling medium stream CMS1 to heat transfer material stream HTMS1 having a flow rate of 5500 t/h, a pressure of 1.2 bar and a temperature of 46 ℃ to obtain heat transfer material stream HTMS2 having a temperature of 57 ℃ and a pressure of 1.15 bar. The heat transfer material streams HTMS and HTMS a are streams of heat transfer material HTM1 (which is water). The heat transfer material stream HTMS a is expanded at a pressure of 0.1 bar to obtain a heat transfer material stream HTMS b having a temperature of 46 ℃ and a pressure of 0.1 bar. The heat transfer material stream HTMS b consists of a liquid stream HTMS a (I) having a flow rate of 5500 t/h and a gaseous stream HTMS a (g) having a flow rate of 113.6 t/h. After compression to a pressure of 1.2 bar, liquid heat transfer material stream HTMS b (I) was recycled as heat transfer material stream HTMS to heat exchanger HE1 to produce a heat transfer material stream having a flow rate of 5500 t/h at a pressure of 1.2 bar and a temperature of 45.8 ℃. Gaseous heat transfer material stream HTMS b (g) is fed to the compression step. Prior to expansion, an additional stream of heat transfer material HTM1 is added to heat transfer material stream HTMS a at a pressure of 1.15 bar and a temperature of 75 ℃ and at a flow rate of 113.6 t/h to compensate for the gaseous portion of heat transfer material stream HTMS b fed to the compression step and maintain the mass balance of the recirculation loop involving liquid streams HTMS1 and HTMS2 a.

The compression step to obtain the heat transfer material stream HTMS involves five compression stages, each stage comprising a compressor.

As previously described, the gaseous portion of the heat transfer material stream HTMS b having a flow rate of 113.6 t/h and a temperature of 45.8 ℃ and a pressure of 0.1 bar is fed to the first compression stage to obtain a heat transfer material stream HTMS3 having a pressure of 0.2 bar and a temperature of 114.61 ℃. At the split stream HTMS3An additional stream of heat transfer material HTM1 having a temperature of 75 ℃ and a pressure of 5 bar was added to stream HTMS at a flow rate of 3.7 t/h before feeding to the second compression stageTo obtain a flow HTMS3 of heat transfer material with a flow rate of 117.3 t/h, a pressure of 0.2 bar and a temperature of 75 ℃。

Flow HTMS of heat transfer materialIs fed to a second compression stage to obtain a heat transfer material stream HTMS3 having a pressure of 0.4 bar and a temperature of 149.6 °c . At the split stream HTMS3 An additional stream of heat transfer material HTM1 having a temperature of 75 ℃ and a pressure of 5 bar was added to stream HTMS at a flow rate of 6.3 t/h before feeding to the third compression stage To obtain a flow HTMS3 of heat transfer material with a flow rate of 123.62 t/h, a pressure of 0.4 bar and a temperature of 85 DEG C 。

Flow HTMS of heat transfer material Is fed to a third compression stage to obtain a heat transfer material stream HTMS3 having a pressure of 0.8 bar and a temperature of 161.1 °c . At the split stream HTMS3 An additional stream of heat transfer material HTM1 having a temperature of 75 ℃ and a pressure of 5 bar was added to stream HTMS at a flow rate of 6.0 t/h before feeding to the fourth compression stage To obtain a flow HTMS3 of heat transfer material with a flow rate of 129.6 t/h, a pressure of 0.8 bar and a temperature of 103 ℃ 。

Flow HTMS of heat transfer material Is fed to a fourth compression stage to obtain a heat transfer material stream HTMS3 having a pressure of 1.6 bar and a temperature of 182.1 °c . At the split stream HTMS3 An additional stream of heat transfer material HTM1 having a temperature of 75 ℃ and a pressure of 5 bar was added to stream HTMS3 at a flow rate of 6.5 t/h before feeding to the fifth and final compression stages To obtain a flow HTMS3 of heat transfer material having a flow rate of 136.1 t/h, a pressure of 1.6 bar and a temperature of 123 ℃ 。

Flow HTMS of heat transfer material Is fed to a fifth compression stage to obtain a heat transfer material stream HTMS having a pressure of 3.2 bar and a temperature of 205.2 ℃. Before stream HTMS is fed to heat exchanger HE-R to transfer heat to regeneration step C), an additional stream of heat transfer material HTM1 having a temperature of 75 ℃ and a pressure of 5 bar is added to stream HTMS3 at a flow rate of 7.4 t/h to obtain a heat transfer material stream HTMS3 having a pressure of 3.2 bar and a temperature of 143 ℃ at a flow rate of 143.5 t/h.

Heat is transferred from the heat transfer material stream HTMS to the regeneration step C) in the reboiler of the regenerator to maintain a temperature of 127 ℃ at the bottom of the regenerator.

The coefficient of performance of the heat pump was 3.57.

The heat pump operates as an open loop heat pump without recirculating the heat transfer material water to the evaporation step. However, at least a portion of the heat transfer material stream HTMS4 may be recycled, for example, to the evaporation step or to the compression step, and ultimately to a corresponding input stream, such as heat transfer material stream HTMS1 or HTMS a, after pressure and temperature are adjusted by additional expansion, cooling, or compression steps to adjust the characteristics of stream HTMS.

Claims

1. A method for producing a deacidification fluid stream from a fluid stream containing at least one acidic gas, the method comprising:

a) A heat transfer step, wherein heat energy is transferred from a fluid flow FS1 containing at least one acidic gas to a regeneration step c) to obtain a fluid flow FS2 having reduced heat energy compared to the fluid flow FS1;

b) Absorption step, wherein the cooled fluid stream FS2 is contacted with absorbent A1 in the absorber to obtain absorbent A2 loaded with acidic gas and a fluid stream at least partially deacidified;

c) A regeneration step, wherein at least a portion of the loaded absorbent A2 obtained from step b) is regenerated in a regenerator to obtain at least partially regenerated absorbent A3 and a gaseous stream GS containing at least one acidic gas.

d) A recycling step, wherein at least one sub-stream of the regenerated absorbent A3 from step c) is recycled to the absorption step b);

The heat transfer step a) includes a combination of a direct contact cooler (DCC) and one or more heat pumps.

2. The method according to claim 1, wherein the heat transfer step a) comprises:

(i) In a direct contact cooler, thermal energy is transferred from fluid flow FS1 to cooling material flow CMS1 to obtain cooling material flow CMS2 and fluid flow FS2 with reduced thermal energy compared to fluid flow FS1.

(ii) In heat exchanger HE1, thermal energy is transferred from cooling material flow CMS2 to heat transfer material flow HTMS1 to obtain heat transfer material flow HTMS2 with higher thermal energy than heat transfer material flow HTMS1.

(iii) Compressing the heat transfer material stream HTMS2 in one or more compression steps to obtain a heat transfer material stream HTMS3 having a higher pressure than the heat transfer material stream HTMS2; and

(iv) Transfer heat energy from the heat transfer material stream HTMS3 to the regeneration step (c) to obtain the heat transfer material stream HTMS4.

3. The method according to claim 1, wherein the heat transfer step a) comprises:

(i) In a direct contact cooler, thermal energy is transferred from fluid flow FS1 to liquid heat transfer material flow HTMS1 of heat transfer material HTM1 to obtain liquid heat transfer material flow HTMS2a.

(ii) In one or more expansion steps, the heat transfer medium flow HTMS2a is expanded to obtain a gaseous heat transfer material flow HTMS2b (g) with a lower pressure than the heat transfer material flow HTMS2a.

(iii) Compressing the heat transfer material stream HTMS2b(g) in one or more compression steps to obtain a gaseous heat transfer material stream HTMS3 having a higher pressure than the heat transfer material stream HTMS2b(g); and

4. The method according to any one of claims 2 or 3, the method comprising an additional recycling step R1), wherein the heat transfer material flow HTMS4 obtained in step iv) is recycled to step i) or step (ii).

5. The method according to claim 2 or 3, wherein the heat transfer material stream HTMS4 is not recycled to the heat exchanger HE1.

6. The method according to claim 1, wherein the heat transfer step comprises:

i) In the heat exchanger HE1 of the first heat pump HP1, heat energy is transferred from heat flow HS1 to heat transfer medium flow HTMS1 of heat transfer material HTM1 to obtain heat transfer medium flow HTMS2 with increased heat energy compared with heat transfer medium flow HTMS1.

ii) Compress the heat transfer medium flow HTMS2 in the first heat pump HP1 to obtain a heat transfer medium flow HTMS3 with a higher pressure than the heat transfer medium flow HTMS2.

iii) In the heat exchanger HE2 of the second heat pump HP2, heat energy is transferred from the heat transfer medium flow HTMS3 of the first heat pump HP1 to the second heat transfer medium flow SHTMS1 of the second heat transfer material HTM2, so as to obtain a second heat transfer medium flow SHTMS2 with increased heat energy compared with the second heat transfer medium flow SHTMS1 and a heat transfer medium flow HTMS4 with reduced heat energy content compared with the heat transfer medium flow HTMS3.

iv) Compress the second heat transfer medium flow SHTMS2 in the second heat pump HP2 to obtain a second heat transfer medium flow SHTMS3 with a higher pressure than the second heat transfer medium flow SHTMS2.

v) Transfer heat energy from the second heat transfer medium flow SHTMS3 of the second heat pump HP2 to the regeneration step c) to obtain a second heat transfer medium flow SHTMS4 with a reduced heat energy content compared to SHTMS3.

7. The method according to claim 2, 3 or 6, wherein step iv) of claim 2 or 3 or step v) of claim 6 is performed by transferring thermal energy from the second heat transfer medium stream SHTMS4 in the heat exchanger HE-R to the absorbent stream AS1 drawn from the regenerator in step c) to obtain an absorbent stream AS2 with increased thermal energy compared to the absorbent stream AS1, and feeding AS2 into the regenerator in step c).

8. The method according to claim 7, wherein the heat exchanger HE-R is the reboiler of the regenerator.

9. The method according to any one of claims 6 to 8, the method comprising:

- An additional recirculation step R1), wherein the heat transfer material flow HTMS4 obtained in step 3) is expanded to obtain a reduced pressure compared to the heat transfer material flow HTMS4 and is at least partially recirculated as heat transfer material flow HTMS1 to the heat transfer medium flow HTMS5 of step 1), and/or

- An additional recirculation step R2), wherein the second heat transfer material stream SHTMS4 obtained in step 5) is expanded to obtain a reduced pressure compared to the second heat transfer material stream SHTMS4 and is at least partially recirculated as the second heat transfer material stream SHTMS1 to the second heat transfer medium stream SHTMS5 in step 3), or the method according to any one of claims 6 to 8, wherein the second heat transfer material stream SHTMS4 is not recirculated to the heat exchanger HE2.

10. The method according to any one of claims 6 to 9, wherein the heat transfer material HTM1 is selected from the group consisting of ammonia, butane and RZ123zd(e), and wherein the second heat transfer material HTM2 is water; or the method according to any one of claims 2 to 5, wherein the heat transfer material streams HTMS 1 to 4 are streams of heat transfer material HTM1, and wherein the heat transfer material HTM1 is selected from the group consisting of: ammonia, butane, R1233zd(e), R1224yd(z), air, _CO2 , water, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, hydrofluoroolefins, hydrochlorofluoroolefins, hydrocarbons, perfluorinated (2-methyl-3-pentanone) and mixtures of two or more thereof.

11. An apparatus comprising:

a) A direct contact cooler, which includes

a. The inlet of fluid flow FS1;

b. The outlet of fluid flow FS2;

c. The inlet of the cooling medium flow CMS1; and

d. The outlet of the cooling medium flowing through CMS2

b) An absorber having

a. The inlet of fluid flow FS2,

b. The outlet of the deacidification fluid flow FS3;

c. Inlet of absorbent stream A1

d. The inlet of the regenerated absorbent stream A3; and

e. Outlet of the loaded absorbent stream A2

c) A regenerator, which has

a. Inlet of the loaded absorbent stream A2;

b. The outlets of the regenerated absorbent streams A3 and/or AS1;

c. Inlet of absorbent stream AS2;

d. The outlet of the acidic gas stream GS;

d) Heat pump HP1, which includes

a. Heat exchanger HE1, which has

i. The inlet of the heat transfer material flow HTMS1; and

ii. The outlet of the heat transfer material flow HTMS2;

b. One or more compressors connected in series, wherein the first compressor connected in series has an inlet for the heat transfer material flow HTMS2, and the last compressor connected in series has an outlet for the heat transfer material flow HTMS3;

c. Heat exchanger HE-R, which includes

i. Inlet of the heat transfer material HTMS3;

ii. The outlet of the heat transfer material flow HTMS4;

iii. The second inlet of the absorbent flow AS1; and

iv. The second outlet of the absorbent stream AS2.

12. The device of claim 11, further comprising:

e) Heat pump HP2, which includes

a. Heat exchanger HE2, which has

i. Inlet of heat transfer material flow SHTMS1,

ii. The outlet of the heat transfer material flow SHTMS2;

iii. The inlet of the heat transfer material flow HTMS3; and

iv. Outlet of heat transfer material HTMS4

b. One or more compressors connected in series, wherein the first compressor connected in series has an inlet for the heat transfer material flow SHTMS2, and the last compressor connected in series has an outlet for the heat transfer material flow SHTMS3.

c. A heat exchanger HE-R that replaces the heat exchanger HE-R as described in claim 11, the heat exchanger comprising

i. Inlet of the heat transfer material flow SHTMS3;

ii. The outlet of the heat transfer material flow SHTMS4;

iii. The second inlet of the absorbent flow AS1; and

iv. The second outlet of the absorbent stream AS2.

13. An apparatus comprising:

a) An absorber having

a. The inlet of fluid flow FS2,

b. The outlet of the deacidification fluid flow FS3;

c. Inlet of absorbent stream A1

d. The inlet of the regenerated absorbent stream A3; and

e. Outlet of the loaded absorbent stream A2

b) A regenerator, which has

a. Inlet of the loaded absorbent stream A2;

b. The outlets of the regenerated absorbent streams A3 and/or AS1;

c. Inlet of absorbent stream AS2;

d. The outlet of the acidic gas stream GS;

c) Heat pump HP1, which includes

a. Heat exchanger HE1, which is a direct contact cooler, the direct contact cooler having

i. The inlet of the heat transfer material flow HTMS1; and

ii. The outlet of the heat transfer material flow HTMS2a;

b. One or more evaporation devices for expanding the heat transfer material HTMS2a, the evaporation device having

i. The inlet for the heat transfer material flow HTMS2a; and

ii. The outlet of the heat transfer material flow HTMS2b;

c. One or more compressors connected in series, wherein the first compressor connected in series has an inlet for the heat transfer material flow HTMS2b, and the last compressor connected in series has an outlet for the heat transfer material flow HTMS3;

d. Heat exchanger HE-R, which includes

i. Inlet of the heat transfer material HTMS3;

ii. The outlet of the heat transfer material HTMS4;

iii. The second inlet of the absorbent flow AS1; and

iv. The second outlet of the absorbent stream AS2.

14. An apparatus comprising:

a) A direct contact cooler, which includes

a. The inlet of fluid flow FS1;

b. The outlet of fluid flow FS2;

c. The inlet of the cooling medium flow CMS1; and

d. The outlet of the cooling medium flowing through CMS2

b) An absorber having

a. The inlet of fluid flow FS2,

b. The outlet of the deacidification fluid flow FS3;

c. Inlet of absorbent stream A1

d. The inlet of the regenerated absorbent stream A3; and

e. Outlet of the loaded absorbent stream A2

c) A regenerator, which has

a. Inlet of the loaded absorbent stream A2;

b. The outlets of the regenerated absorbent streams A3 and/or AS1;

c. Inlet of absorbent stream AS2;

d. The outlet of the acidic gas stream GS;

d) Heat pump HP1, which includes

a. Heat exchanger HE1, which has

i. The inlet of the heat transfer material flow HTMS1; and

ii. The outlet of the heat transfer material flow HTMS2a;

i. The inlet for the heat transfer material flow HTMS2a; and

ii. The outlet of the heat transfer material flow HTMS2b;

d. Heat exchanger HE-R, which includes

i. Inlet of the heat transfer material HTMS3;

ii. The outlet of the heat transfer material HTMS4;

iii. The second inlet of the absorbent flow AS1; and

iv. The second outlet of the absorbent stream AS2.

15. The method according to any one of claims 1 to 10, wherein the fluid stream containing at least one acidic gas is flue gas containing _CO2 , and wherein the absorbent contains at least one amine and water.