JP2026009079A - Hydrocarbon compound manufacturing method, hydrocarbon compound manufacturing apparatus, and hydrocarbon compound manufacturing system - Google Patents

Abstract

The present invention provides a method for producing a hydrocarbon compound, an apparatus for producing a hydrocarbon compound, and a system for producing a hydrocarbon compound, which are capable of producing a hydrocarbon compound efficiently.
[Solution] According to one aspect of the present invention, there is provided a method for producing hydrocarbon compounds, comprising: a separation step of separating hydrogen from a gas containing at least carbon monoxide and hydrogen; an alcohol production step of producing alcohol from the gas from which hydrogen has been separated using a microorganism; an alkene production step of producing an alkene having three or fewer carbon atoms from the alcohol using a first catalyst; and a hydrocarbon compound production step of producing a hydrocarbon compound having four or more carbon atoms from the alkene and hydrogen using a second catalyst.
[Selected Figure] Figure 1

Description

The present invention relates to a method for producing hydrocarbon compounds, an apparatus for producing hydrocarbon compounds, and a system for producing hydrocarbon compounds.

In recent years, the mass consumption of oils and alcohol produced from petroleum has led to concerns about the depletion of fossil fuel resources and global environmental problems such as an increase in atmospheric carbon dioxide. In order to address these issues, methods of producing organic substances using raw materials other than petroleum, such as the production of bioethanol from edible materials such as corn through sugar fermentation, have been attracting attention.

Such sugar fermentation methods using edible raw materials could lead to a rise in food prices, as they require limited agricultural land to be used for non-food production. For this reason, methods are being considered for producing organic substances that were previously produced from petroleum using non-edible raw materials that would otherwise be discarded.

For example, Patent Document 1 discloses a method for producing organic substances by supplying a gas with a higher carbon dioxide content than air, partially oxidizing a carbon source to produce a synthesis gas containing carbon monoxide, and then fermenting this synthesis gas with microorganisms. However, further technological improvements are needed to produce more valuable organic substances (e.g., hydrocarbon compounds).

JP 2015-077120 A

In view of the above circumstances, the present invention provides a hydrocarbon compound production method, hydrocarbon compound production apparatus, and hydrocarbon compound production system that can efficiently produce hydrocarbon compounds.

One aspect of the present invention provides a method for producing hydrocarbon compounds, comprising: a separation step for separating hydrogen from a gas containing at least carbon monoxide and hydrogen; an alcohol production step for producing alcohol from the gas from which hydrogen has been separated using a microorganism; an alkene production step for producing an alkene having three or fewer carbon atoms from the alcohol using a first catalyst; and a hydrocarbon compound production step for producing a hydrocarbon compound having four or more carbon atoms from the alkene and hydrogen using a second catalyst.

This embodiment allows for efficient production of hydrocarbon compounds.

1 is a schematic diagram showing the configuration of a first embodiment of a system for producing a hydrocarbon compound. FIG. 2 is a schematic diagram showing the configuration of a second embodiment of a system for producing a hydrocarbon compound. FIG. 10 is a schematic diagram showing the configuration of a third embodiment of a system for producing a hydrocarbon compound.

Hereinafter, a method for producing a hydrocarbon compound, an apparatus for producing a hydrocarbon compound, and a system for producing a hydrocarbon compound will be described in detail based on preferred embodiments shown in the accompanying drawings.
First Embodiment
First, a first embodiment of a hydrocarbon compound production system that can be used in a hydrocarbon compound production method will be described.
FIG. 1 is a schematic diagram showing the configuration of a first embodiment of a system for producing hydrocarbon compounds.
The hydrocarbon compound production system 100 (hereinafter also simply referred to as "production system 100") shown in Figure 1 includes a gasification furnace (gas production section that produces gas) 10, and a hydrocarbon compound production apparatus 1 (hereinafter also simply referred to as "production apparatus 1") connected to the gasification furnace 10. In this specification, the upstream side with respect to the flow direction of gas and liquid will also be referred to simply as the "upstream side", and the downstream side will also be referred to simply as the "downstream side".

In this embodiment, the gasifier 10 is not particularly limited, but examples thereof include a fluidized bed furnace, a kiln furnace, a shaft furnace, etc. In addition to the gasifier 10, the gas generation unit may be a COX emission source in at least one facility selected from a combustion furnace (incinerator), a paper mill, a cement factory, a thermal power plant, an oil refinery, an _ethylene cracker, a refinery, a chemical plant, and a blast furnace, a converter, or an electric furnace (electric furnace) in a steelworks.
In each furnace, gas containing at least carbon monoxide and hydrogen (hereinafter also referred to as "raw material gas") is produced (generated) during combustion, melting, refining, etc. of the contents.

In the case of a combustion furnace or gasification furnace 10 at a waste incineration plant, the contents (waste) include, for example, plastic waste, food waste, municipal solid waste (MSW), industrial waste, discarded tires, biomass waste, household waste (futons, paper), building materials, etc. Note that these wastes may contain one type alone or two or more types.
In addition, in the case of a blast furnace, converter, or electric furnace in a steelworks, for example, a raw material gas is generated (or produced) when iron ore is heated together with coke, limestone, etc. In the case of a chemical plant, for example, a raw material gas is generated (or produced) when methane is steam reformed.

Carbon in a raw material gas derived from waste or the like has a different abundance ratio of carbon isotopes such as ^14C and ^13C (for example, values of ^δ14C and ^δ13C ) than carbon in petroleum. Therefore, the abundance ratio of carbon isotopes contained in hydrocarbon compounds produced from such raw material gas by the production system 100 also differs from hydrocarbon compounds derived from petroleum. Therefore, even if a hydrocarbon compound produced by the production system 100 is converted into another compound and used, it can be determined (traced) that it originated from a hydrocarbon compound produced by the production system 100 using a method with a low environmental impact.

The raw material gas typically contains, in addition to carbon monoxide and hydrogen, other gas components such as carbon dioxide, nitrogen, oxygen, water vapor, methane, etc. The raw material gas may further contain, as other components, soot, tar, nitrogen compounds, sulfur compounds, phosphorus-based compounds, aromatic compounds, etc.
The raw material gas may be generated as a gas containing 10% by volume or more of carbon monoxide by subjecting the contents (carbon source) to a heat treatment (commonly known as gasification) in which the contents are incompletely combusted (i.e., the carbon source is partially oxidized).
If hydrocarbon compounds are produced using such a raw material gas, carbon dioxide, which has conventionally been emitted into the atmosphere, can be effectively utilized, thereby reducing the burden on the environment. From the viewpoint of carbon circulation, it is preferable to use exhaust gas generated in a combustion furnace or a smelter as the raw material gas.

The gasifier 10 may also have an oxygen generator that generates the oxygen required for combustion. Examples of oxygen generators include cryogenic separation systems that compress, cool, and liquefy atmospheric air to extract liquefied oxygen, liquefied nitrogen, and the like. The heat absorbed when the resulting liquefied nitrogen evaporates can be used to cool parts of the production system 100 that require cooling (for example, the hydrogen liquefaction operation described below). Furthermore, the nitrogen gas obtained by evaporating the liquefied nitrogen can be suitably used as a purge gas for various parts of the production system 100.

The gasifier 10 may also have a reforming area inside or outside thereof for reforming the raw material gas.
In the reforming area, for example, the raw material gas is retained at a high temperature to convert hydrocarbons contained in the raw material gas (methane, ethane, char, tar, dioxins, etc.) into carbon monoxide and hydrogen. At this time, a combustion-supporting gas such as oxygen or air may be supplied to raise the temperature.
Furthermore, a portion of the carbon monoxide may be converted to carbon dioxide by reacting with oxygen. The temperature is preferably 1000°C or higher, and more preferably 1100°C or higher and 1400°C or lower.

In the reforming area, a method may be adopted in which hydrocarbons such as methane contained in the raw gas are reacted with steam at high temperatures in the presence of a catalyst to convert them into carbon monoxide and hydrogen. At this time, part of the carbon monoxide may be further converted into carbon dioxide and hydrogen by reacting with the steam.
The reaction temperature is preferably 500° C. or higher and 1200° C. or lower. Examples of the catalyst include metal catalysts, such as nickel catalysts, nickel oxide catalysts, ruthenium catalysts, rhodium catalysts, palladium catalysts, and platinum catalysts.

Here, it is known that the stable carbon isotope ratio δ ¹³ C tends to have a high value under high-temperature combustion conditions and a low value under incomplete combustion. Therefore, by providing a reforming area, the feedstock gas can have a unique δ ¹³ C value that corresponds to the combustion conditions. Therefore, even if the hydrocarbon compounds produced by the production system 100 are converted into other compounds and used, it is possible to determine (trace) that they originate from hydrocarbon compounds produced by the production system 100 using a method with a low environmental impact.

The feed gas (synthesis gas) generated by the gasifier 10 is at a high temperature. The heat of this high-temperature feed gas may be used to generate steam from water. For example, a tank storing water may be provided in the gas line GL1 connected downstream of the gasifier 10, and steam may be generated by heat exchange between the feed gas and the water. Alternatively, steam may be generated by heat exchange with the feed gas using a heat recovery device (e.g., an economizer, a heat pump, etc.) that is more suitable for recovering high-temperature heat and provided near the gas line GL1 near the outlet of the gasifier 10. In this way, by efficiently recovering the heat of the feed gas and utilizing it without waste, the environmental impact during the production of hydrocarbon compounds can be further reduced. The heat of the feed gas may be used for various purposes, not limited to the above purposes.
Furthermore, heat may be recovered from the gas discharged from the reforming area. When a scrubber is used for cooling, the heat recovery method may utilize the thermal energy recovered through the scrubber. As described above, the recovered thermal energy may be used to heat the hydrogen gas used in producing hydrocarbon compounds having 4 or more carbon atoms. By heating the hydrogen gas as described above, it becomes easier to maintain a constant temperature for obtaining hydrocarbon compounds having 4 or more carbon atoms. This is because many of the processes for obtaining hydrocarbon compounds having 4 or more carbon atoms are heating processes.

A production apparatus 1 is connected to the gasification furnace 10. The production apparatus 1 includes a culture tank (alcohol production section) 2, an alkene producer 6, a gas line GL1 connecting the gasification furnace 10 and the culture tank 2, and a liquid line LL connecting the culture tank 2 and the alkene producer 6.
In the culture tank 2, alcohol is produced from the supplied raw material gas using microorganisms (particularly, gas-utilizing bacteria). That is, in the culture tank 2, alcohol is produced by microbial fermentation of the raw material gas.
The alcohol may be, for example, at least one of methanol, ethanol, and the like.

Here, the alcohol produced in the culture tank 2 is produced using carbon derived from the feedstock gas, and therefore has a different abundance ratio of carbon isotopes such as ^14C and ^13C (for example, values of ^δ14C and ^δ13C ) from that of valuable materials derived from petroleum. Therefore, even if this alcohol is converted into a product such as another compound and used, it can be determined (traced) that it is derived from alcohol produced by a method with low environmental impact using the production system 100.

Examples of gas-utilizing bacteria include Butyribacterium methylotrophicum, Clostridium autoethanogenum, Clostridium carboxydivorans, Clostridium ljungdahlii, Clostridium ragsdalei, Moorella, and Carboxydothermus.

When a microorganism such as a gas-assimilating bacterium is used, the abundance ratio of carbon isotopes such as ^14C and ^13C in the alcohol (for example, the values of ^δ14C and ^δ13C ) can be made to deviate more greatly from the values of petroleum-derived alcohol. Therefore, even if the produced alcohol is converted into another compound for use, it can be more easily identified (traced) as being derived from alcohol produced by a method with a low environmental impact using the production system 100.

The medium (culture solution) used for culturing gas-assimilating bacteria is not particularly limited as long as it has an appropriate composition depending on the type of bacteria. For example, when Clostridium bacteria are used as gas-assimilating bacteria, the medium can be determined by referring to, for example, paragraphs 0097 to 0098 of U.S. Patent Application Publication No. 2017/260552.
The culture tank 2 can be, for example, a culture reactor of a type that stirs the culture solution with a stirring plate, a culture reactor of a type that stirs the culture solution by circulating the culture solution itself, or a culture reactor of a type that stirs the culture solution by a water flow accompanied by a bubble flow generated by aeration of the supplied exhaust gas.

The production apparatus 1 includes a pre-treatment section (separation section) 5 provided midway along the gas line GL1 (i.e., between the gasification furnace 10 and the culture tank 2).
This pretreatment section (separation section) 5 separates hydrogen from the raw material gas (gas containing at least carbon monoxide and hydrogen). In this embodiment, the raw material gas further contains carbon dioxide, and the pretreatment section (separation section) 5 also separates the carbon dioxide from the raw material gas.
Specifically, the pretreatment section 5 has a PSA unit 51 and a dehydrogenation unit 52 arranged downstream of the PSA unit 51 .

The PSA unit 51 is a pressure swing adsorption type separator, and is used to separate (remove) BTEX, carbon dioxide, nitrogen, and the like, for example.
For example, porous materials such as activated carbon, zeolite, silica gel, and molecular sieves, or aqueous solutions such as amine solutions, can be used as adsorbents in the PSA unit 51. Activated carbon or zeolite is preferably used in the PSA unit 51. By setting the type of porous material and the pore size, it is possible to select compounds that can be separated.
When separating two or more compounds in the PSA apparatus 51, multiple separators each filled with porous materials of different types or pore sizes may be used, or a single separator filled with porous materials of different types or pore sizes may be used.

A method for utilizing the carbon dioxide separated by the PSA unit 51 will be described in detail later. The separated carbon dioxide may be reacted with hydrogen using a catalyst or the like and stored as formic acid. Storing it as formic acid in this manner makes it possible to simultaneously store a carbon dioxide source and a hydrogen source in a small volume. Methods for generating carbon dioxide and hydrogen from formic acid are not particularly limited, but a method using an iridium complex or the like is known. The hydrogen and carbon dioxide generated by such a method may be used as substitute gases for the raw material gas when the gasifier 10 is shut down.
In addition, the nitrogen separated in the PSA unit 51 may be filled into the culture tank 2 when culturing microorganisms (gas-utilizing bacteria), or may be filled for cleaning the PSA unit 51 and/or the TSA unit (if used).
Nitrogen may be filled into only one of the above-mentioned devices, or into two or more of them.
In this way, by removing nitrogen from the raw material gas, the volume of the raw material gas to be processed downstream can be reduced, thereby making it possible to reduce the size of the pre-treatment unit 5 located downstream.

The dehydrogenation device 52 is mainly used to separate (remove) hydrogen from the raw material gas from which carbon dioxide and nitrogen have been separated (removed). Note that hydrogen separation may be performed on the raw material gas containing carbon dioxide and hydrogen after carbon monoxide has been separated and introduced into the culture tank 2.
The dehydrogenation device 52 can be preferably configured as a separator containing a separation membrane that selectively permeates and separates hydrogen. Examples of materials that can be used for the separation membrane include metal materials, ceramic materials, and resin materials.
Examples of the metal material include Pd--Cu alloy, Pd--Ag alloy, vanadium alloy, and amorphous alloy such as La--Ni--Mg alloy.
Examples of ceramic materials include titanium nitride, zeolite, silica (glass), alumina, and composite materials containing one or more of these (for example, alumina carbon-based materials).
Examples of the resin material include polyamide, polyimide, and polysulfone.

The separation membrane is preferably made of a porous body having continuous pores (pores penetrating the cylindrical wall) in which adjacent pores are connected to each other. A separation membrane with such a configuration can separate hydrogen more smoothly and reliably.
The porosity of the separation membrane is not particularly limited, but is preferably 10% to 90%, and more preferably 20% to 60%, which allows the separation membrane to maintain a sufficiently high hydrogen permeability while preventing an extreme decrease in mechanical strength.
The shape of the separation membrane is not particularly limited, and examples thereof include cylindrical, rectangular, hexagonal and other rectangular tubular shapes.
The average pore size of the separation membrane is preferably 500 pm or less, and more preferably 300 pm to 400 pm, which can further improve the hydrogen separation efficiency.

The pretreatment unit 5 may include, for example, a deoxidizer, a deacetylenizer, a TSA unit, a PTSA unit, etc. in addition to the PSA unit 51 and the dehydrogenation unit 52. These units may be used alone or in any combination, and the order in which they are arranged may also be arbitrary.
The deoxidizer is used to remove oxygen and can be configured as a reactor filled with metal particles such as copper (Cu), platinum (Pt), nickel (Ni), etc. as an oxygen removal catalyst. The oxygen removal catalyst is preferably heated to, for example, 150°C or higher and 400°C or lower.
The deacetyleneizer is used to remove acetylene, and can be configured with a reactor filled with particles of a noble metal such as palladium (Pd) or platinum (Pt) as an acetylene removal catalyst.
By removing acetylene prior to deoxidation, there is an advantage that the adverse effect of acetylene on the oxygen removal catalyst can be suitably prevented or reduced.

The TSA unit is a temperature swing adsorption type separator, and is used, for example, to remove aromatic compounds other than BTEX.
The PTSA unit is a pressure and temperature swing adsorption type separator, and is used, for example, to collectively remove the components removed by the PSA unit 51 and the TSA unit.
The types of adsorbents and constituent materials used in the TSA and PTSA devices may be the same as those described for the PSA device 51 .

The raw material gas treated in the pretreatment unit 5 is supplied to the culture tank 2 .
The concentration of carbon dioxide contained in the raw material gas supplied to the culture tank 2 is preferably 0.1% by volume or more and 30% by volume or less, more preferably 0.3% by volume or more and 25% by volume or less, even more preferably 0.5% by volume or more and 20% by volume or less, particularly preferably 0.8% by volume or more and 15% by volume or less, and most preferably 1% by volume or more and 10% by volume or less.

The concentration of carbon monoxide contained in the raw material gas supplied to the culture tank 2 is preferably 10% by volume or more and 90% by volume or less, more preferably 15% by volume or more and 70% by volume or less, and even more preferably 20% by volume or more and 45% by volume or less.
Furthermore, the concentration of hydrogen contained in the raw material gas supplied to the culture tank 2 is preferably 0.4 times or less, more preferably 0.35 times or less, and even more preferably 0.3 times or less, the concentration of hydrogen contained in the raw material gas generated in the gasification furnace (gas generation unit) 10. Specifically, the concentration of hydrogen contained in the raw material gas supplied to the culture tank 2 is preferably 1% by volume or more and 45% by volume or less, more preferably 5% by volume or more and 35% by volume or less, and even more preferably 5% by volume or more and 30% by volume or less. If the content of hydrogen and carbon dioxide in the raw material gas is reduced via a separation membrane or the like, it can also be expected to have the effect of suppressing variation over time in the overall composition of the treated raw material gas.
Furthermore, when the raw material gas contains water vapor, the water vapor may be removed in a step immediately before the raw material gas is introduced into the culture tank 2. Methods for removing water vapor include, for example, cooling the raw material gas to reduce the amount of saturated water vapor, or absorbing the water vapor into a moisture absorbent or the like. The moisture absorbent used is not particularly limited, but examples include silica gel, zeolite, activated carbon, and molecular sieves. Such moisture absorbents are preferred because they can be reused after undergoing a drying process or the like.

Furthermore, the concentration of nitrogen contained in the raw material gas supplied to the culture tank 2 is preferably 30% by volume or less, more preferably 1% by volume or more and 25% by volume or less, and even more preferably 5% by volume or more and 20% by volume or less.
According to the above configuration, a raw material gas with a low concentration of hydrogen is supplied to the culture tank 2, so that hydrogen is less likely to reduce the activity of microorganisms (gas-assimilating bacteria). In other words, hydrogen can be supplied at a concentration suitable for use by microorganisms, allowing the microorganisms to be active. Furthermore, since the raw material gas has an increased carbon monoxide concentration as a result of separation (removal) of mainly carbon dioxide and nitrogen in the PSA unit 51, the first valuable resource can be produced more efficiently in the culture tank 2.
Furthermore, since the volume of the raw material gas as a whole is reduced, the size of the pretreatment unit 5 and/or the piping, pumps, containers, etc. arranged downstream thereof can also be reduced.

In the culture tank 2, alcohol, specifically an alcohol-containing liquid containing alcohol, is produced using microorganisms (gas-assimilating bacteria) from the raw material gas from which carbon dioxide and hydrogen have been separated. When acetic acid is produced as a by-product during the production of the alcohol-containing liquid, the acetic acid may be further utilized.
An alkene producer (alkene production unit) 6 is connected to the culture tank 2 via a liquid line LL. This alkene producer 6 is a device that produces an alkene (organic substance) from an alcohol-containing liquid using a first catalyst. In the alkene producer 6, the alcohol-containing liquid may be vaporized (gasified) prior to the production (synthesis) of the alkene. Alternatively, the alcohol-containing liquid discharged from the culture tank 2 may be vaporized and then supplied to the alkene producer 6.

Here, the alkene is a compound having 3 or less carbon atoms, and examples thereof include ethylene, propylene, etc. These alkenes may be a single type or a mixture of two or more types.
Examples of the first catalyst include inorganic acids such as sulfuric acid (H ₂ SO ₄ ) and phosphoric acid (H ₃ PO ₄ ), oxide catalysts such as alumina (Al ₂ O ₃ ), and silica with nickel supported in its pores (Ni-MCM-41).
When an alkene is produced from an alcohol in this way, water is produced as a by-product. Therefore, it is possible to remove the water. This makes it difficult for the reverse reaction to occur, making it easier to obtain the alkene efficiently.

A hydrocarbon compound generator (hydrocarbon compound generator) 9 is connected to the alkene generator (alkene generator) 6 via a gas line GL6. This hydrocarbon compound generator 9 is a device that generates a hydrocarbon compound (organic substance) from an alkene and hydrogen using a second catalyst. Here, the hydrocarbon compound may be a compound having 4 or more carbon atoms, but a compound having 6 to 20 carbon atoms is preferred, a compound having 8 to 18 carbon atoms is more preferred, and a compound having 9 to 16 carbon atoms is even more preferred. The hydrocarbon compound may contain only one type of these compounds, or may contain two or more types. It is preferable that the hydrocarbon compound does not contain an aromatic compound.
Such hydrocarbon compounds are suitable for use as, for example, jet fuel, butadiene raw material, automotive fuel raw material, etc. The hydrocarbon may be, for example, a saturated hydrocarbon.

Examples of the second catalyst include an acidic zeolite catalyst, a metal or alloy catalyst containing nickel, etc. These second catalysts may be used alone or in combination of two or more.
The hydrogen used in the hydrocarbon compound production device 9 may be hydrogen separated in the dehydrogenation device 52 (pretreatment device 5), hydrogen separately generated by electrolysis of water, hydrogen generated during the production of caustic soda, sodium nitrate, nitric acid, or ammonia, hydrogen generated in steelmaking or petrochemicals, or a mixed gas of these. Utilizing the hydrogen separated in the dehydrogenation device 52 (pretreatment device 5), hydrogen generated during the production of caustic soda, sodium nitrate, nitric acid, or ammonia, or hydrogen generated in steelmaking or petrochemicals is preferable because it allows hydrogen to be obtained without wasting energy.
From the viewpoint of utilizing hydrogen, it is more preferable to include hydrogen separated in the above-mentioned process, i.e., hydrogen separated in the dehydrogenation device 52 (pre-treatment device 5). In particular, if hydrogen separated in the dehydrogenation device 52 (pre-treatment device 5) is used, hydrogen can be effectively utilized. In this case, transportation of hydrogen is not an essential component, and therefore energy for transportation is not required, which is even more preferable. As a result, the production efficiency of hydrocarbon compounds can be further improved. The dehydrogenation device 52 may be a hydrogen separation membrane.

The production apparatus 1 also includes a synthesis section (valuable material production section) 7 connected to the PSA apparatus 51 via a gas line GL2 and to the dehydrogenation apparatus 52 via a gas line GL3.
In the synthesis unit 7, at least the carbon dioxide separated in the PSA unit 51 and a portion of the hydrogen separated in the dehydrogenation unit 52 are reacted using a third catalyst to produce at least one selected from the group consisting of alkenes and alcohols. When an alkene is produced from an alcohol, water is produced as a by-product, so the process may further include a step of removing the by-product water. The inclusion of a step of removing water makes it difficult for a reverse reaction to occur, making it easier to efficiently obtain alkenes.
Examples of catalysts capable of producing alkenes include metal or alloy catalysts containing iron, copper, cobalt, ruthenium, rhodium, etc., and mineral catalysts containing minerals such as zeolites.

Examples of catalysts capable of producing alcohol include metal or alloy catalysts containing copper, silver, nickel, zinc, zirconium, or the like; oxide catalysts containing zinc oxide, titanium oxide, or the like; composite catalysts containing any combination of the above metal or alloy catalysts and the above oxide catalysts; carbon-supported catalysts in which metal nanoparticles are supported on a carbon material; and metal complex catalysts containing iridium, or the like.
Among these, a palladium-molybdenum intermetallic compound catalyst is suitable as a catalyst capable of producing methanol as an alcohol, as this catalyst can produce methanol from carbon dioxide and hydrogen at extremely low temperatures (room temperature).

Further, a removal unit 8 may be provided midway along each of the gas lines GL2 and GL3. The removal unit 8 has a function of removing impurities contained in the gas separated (recovered) from the PSA unit 51 or the dehydrogenation unit 52, which impair the reactivity of the catalyst.
If the separation selectivity of hydrogen and carbon dioxide is high and the separated carbon dioxide and separated hydrogen can be obtained with high purity, the removal unit 8 does not need to be provided.
Such impurities include, but are not limited to, sulfur or sulfur compounds, chlorine or chlorine compounds, cyanide compounds, etc. Among these, it is preferable to remove sulfur compounds, particularly hydrogen sulfide, as impurities. Removal of hydrogen sulfide can suitably prevent the reactivity of the catalysts (the second catalyst and the third catalyst) from being extremely reduced or from being deactivated.

The removal section 8 can be configured, for example, by a reactor filled with a desulfurizing agent. Examples of the desulfurizing agent include an iron oxide-based desulfurizing agent, an activated carbon-based desulfurizing agent, a copper-zinc-based desulfurizing agent, a copper-zinc-aluminum-based desulfurizing agent, and a lime-based desulfurizing agent.
If an iron oxide-based desulfurizing agent is used, the iron sulfide produced by the reaction with hydrogen sulfide can react with oxygen, so that oxygen can also be removed from the gas passing through the gas lines GL2 and GL3.
After the gas line GL2 and the gas line GL3 are joined, the removal unit 8 may be provided midway along the joined gas line.

Furthermore, the synthesis section 7 is connected to the hydrocarbon compound generator 9 via gas lines GL5a and GL4, and is also connected to the alkene generator 6 via a gas line GL5b as required.
The alkene synthesized in the synthesis unit 7 is supplied to the hydrocarbon compound production unit 9, where a hydrocarbon compound is produced. Furthermore, when an alcohol is synthesized in the synthesis unit 7, this alcohol is supplied to the alkene production unit 6, where an alkene is produced. Note that, when both an alkene and an alcohol are synthesized in the synthesis unit 7, an alkene/alcohol separation unit is disposed at the branch point of the gas line GL5a and the gas line GL5b.
In the synthesis unit 7, only alkenes may be synthesized without synthesizing alcohols, or vice versa.

Next, a method of using the production system 100 of the first embodiment (a method of producing a hydrocarbon compound) will be described.
[1] First, the raw material gas (gas containing carbon monoxide, hydrogen, carbon dioxide and other gas components) discharged from the gasification furnace 10 is supplied to the pretreatment section 5 .
In the pretreatment unit 5, BTEX, carbon dioxide, nitrogen, etc. are removed (separated) from the raw material gas by a PSA unit 51, and then hydrogen is removed (separated) by a dehydrogenation unit 52 (separation step). That is, the raw material gas supplied to this step [1] (separation step) further contains carbon dioxide, and in this step [1], carbon dioxide is also separated in addition to hydrogen. In this embodiment, in this step [1] (separation step), hydrogen is preferably separated from the raw material gas using a separation membrane as described above.
Furthermore, in the pretreatment section 5, for example, water-soluble substances, soot, fine particles smaller than soot, oxygen, acetylene, aromatic compounds other than BTEX, etc. may be removed from the raw material gas.
Phase transition materials such as naphthalene and naphthol may be further removed from the source gas.

Excess hydrogen in this step [1] may be, for example, stored (stored). Furthermore, if the amount of hydrogen separated (removed) becomes excessive and the amount of hydrogen introduced into the culture tank 2 is insufficient, the removed hydrogen may be introduced into the culture tank 2. Similarly, carbon dioxide may be stored or introduced into the culture tank 2.
Furthermore, the system may include a step of liquefying the hydrogen separated in step [1] (separation step) by pressurizing and cooling it, or supporting it on a carrier to create a hydrogen carrier. In this case, the surplus hydrogen described above can be stored until needed. Also, the hydrogen can be transferred to a system 100 other than the present system 100 and used. This prevents hydrogen from being wasted.
Examples of hydrogen carriers (carriers that support hydrogen) include magnesium hydride (MgH ₂ ), alkali metal alanates such as lithium alanate (LiAlH ₄ ) and sodium alanate (NaAlH ₄ ), metal amides such as lithium amide (LiNH ₂ ), boron hydride compounds containing alkali metals, alkaline earth metals, etc., formic acid, ammonia, and methylcyclohexane.

[2] Next, the raw material gas that has passed through the pretreatment unit 5 is supplied to the culture tank 2. In the culture tank 2, alcohol, specifically an alcohol-containing liquid containing alcohol, is produced from the raw material gas from which carbon dioxide and hydrogen have been separated using microorganisms (by the action of gas-assimilating bacteria) (alcohol production step).
Here, the temperature at which the alcohol-containing liquid is produced in the culture tank (alcohol production section) 2 is preferably 25°C or higher and 50°C or lower, more preferably 30°C or higher and 45°C or lower, and even more preferably 35°C or higher and 40°C or lower.
When producing an alcohol-containing liquid in the culture tank 2, the nitrogen removed (separated) by the PSA device 51 may be filled into the culture tank 2. In this case, the concentration of oxygen contained in the space within the culture tank 2 can be relatively reduced, and adverse effects of oxygen on microorganisms (gas-assimilating bacteria) can be prevented or reduced.

[3] Next, the alcohol-containing liquid produced in the culture tank 2 is supplied to the alkene producer 6 via the liquid line LL. In the alkene producer 6, an alkene having 3 or less carbon atoms is produced from the alcohol contained in the alcohol-containing liquid using a first catalyst (alkene production step).
When the reaction in step [3] requires heating, the reaction may be carried out using the heat generated during the combustion in step [1]. In this case, the heat generated by the combustion can be effectively utilized without being wasted.

[4] Meanwhile, the gas containing carbon dioxide and the like separated in the PSA unit 51 is supplied to the synthesis unit 7 via a gas line GL2. In addition, the gas mainly containing hydrogen separated in the dehydrogenation unit 52 is supplied to the synthesis unit 7 via a gas line GL3.
At this time, the gas flowing through the gas lines GL2 and GL3 passes through the removal section 8, thereby removing sulfur compounds (especially hydrogen sulfide), thereby preventing or suppressing a decrease in the activity of the third catalyst in the synthesis section 7.

In the synthesis section (valuable product generation section) 7, at least the separated carbon dioxide and a portion of the separated hydrogen are reacted using a third catalyst to generate at least one selected from the group consisting of alkenes and alcohols (valuable product generation process).
If heating is required for the reaction in step [4], the reaction may be carried out using the heat generated during the combustion in step [1]. In this case, the heat generated by the combustion can be effectively utilized without being wasted. For example, the gas lines GL2 and GL3 may be arranged close to the gas line GL1 near the outlet of the gasifier 10, and heat exchange may be performed between the high-temperature raw material gas discharged from the gasifier 10 and the gas flowing through the gas lines GL2 and GL3.

[5] Next, the alkenes produced in the alkene producer 6 are supplied to the hydrocarbon compound producer 9 via a gas line GL6. In the hydrocarbon compound producer 9, hydrocarbon compounds having four or more carbon atoms are produced from the alkenes and hydrogen using a second catalyst (hydrocarbon compound production step).
The hydrogen used in this step [5] (hydrocarbon compound production step) preferably contains the hydrogen separated in the above step [1] (separation step). Specifically, a portion of the hydrogen separated in the dehydrogenation device 52 is supplied to the hydrocarbon compound production device 9 via the gas line GL4. This allows for effective use of hydrogen and further improves the production efficiency of hydrocarbon compounds.

The amount of hydrogen used in this step [5] (hydrocarbon compound production step) is preferably greater than the amount of alkene. That is, it is preferable to use hydrogen in an excess amount relative to the alkene. This makes it possible to suitably prevent or suppress the conversion of hydrocarbon compounds to alkenes (reverse reaction). In this case, if the hydrogen separated in the above step [1] is used as the hydrogen, an increase in costs can be prevented.
Furthermore, if the unnecessary hydrogen separated in the above step [1] of the cycle preceding this cycle is liquefied or stored as a hydrogen carrier, it is possible to stably secure an excess amount of hydrogen to be used in this step [5].

When the amount of hydrogen used in step [5] (hydrocarbon compound production step) is X [mol] and the amount of alkene is Y [mol], X/Y is preferably 1.1 or more, more preferably 1.15 to 4, and even more preferably 1.2 to 2. By using hydrogen and alkene in such a quantitative ratio, hydrocarbon compounds can be produced in a higher yield without wasting hydrogen and alkene. Note that a step of separating excess hydrogen from the product containing hydrocarbon compounds may be included, and the separated hydrogen may be supplied again to the hydrocarbon compound production step. Furthermore, the flow rate of the hydrogen may be adjusted by a pressure control unit.
In the production of hydrocarbon compounds, it is advisable to keep the amount of oxygen in the entire production section to less than 1% by volume.

Second Embodiment
Next, a second embodiment of the hydrocarbon compound production system will be described.
The hydrocarbon compound production system of the second embodiment will be described below, focusing on the differences from the hydrocarbon compound production system of the first embodiment, and omitting a description of similar points.
FIG. 2 is a schematic diagram showing the configuration of a second embodiment of a system for producing hydrocarbon compounds.

The manufacturing system 100 of the second embodiment is similar to the manufacturing system 100 of the first embodiment except for the configuration of the pre-processing unit 5 .
The pretreatment unit 5 shown in FIG. 2 has a carbon dioxide removal unit 53 provided upstream of the PSA unit 51 (between the PSA unit 51 and the gasification furnace 10).
By providing the carbon dioxide removal device 53 upstream of the PSA device 51, it is possible to further reduce the concentration of carbon dioxide contained in the raw material gas supplied to the culture tank 2. As a result, it is possible to further increase the alcohol production efficiency.

This carbon dioxide removal device 53 can be configured as a device having a configuration similar to the above-mentioned PSA device 51 or TSA device, or, for example, a PTSA device (a pressure and temperature swing adsorption type separator), a low-temperature separation type (cryogenic type) separator, a membrane separation type separator, an amine absorption type separator, an amine adsorption type separator, etc.
A commercially available example of the carbon dioxide removal device 53 is a reduced pressure steam swing type CO ₂ recovery device (manufactured by JCCL Corporation, "VPSA1").
Among these, a membrane separation type separator is preferred for the carbon dioxide removal device 53. In this case, both carbon dioxide and hydrogen are separated from the raw material gas using a separation membrane in the raw material gas treatment process (separation process) in the pretreatment section 5. Devices using separation membranes are preferred because they are relatively inexpensive and can prevent or suppress increases in size and complexity. Devices using separation membranes are also preferred because they have a simple structure and are easy to maintain.

According to the manufacturing system 100 of the second embodiment, the same actions and effects as those of the manufacturing system 100 of the first embodiment can be obtained.
In particular, in the second embodiment, since the carbon dioxide removal device 53 is separately provided, the concentration of carbon dioxide contained in the raw material gas can be reduced, thereby increasing the efficiency of alcohol production. Furthermore, the concentration of carbon dioxide contained in the separated (recovered) gas can be increased, thereby increasing the efficiency of alkene and/or alcohol production in the synthesis unit 7. As a result, the production efficiency of hydrocarbon compounds can be increased in the entire production system 100.
In the second embodiment, the synthesis unit 7 is connected to the carbon dioxide removal device 53 via a gas line GL2.

Third Embodiment
Next, a third embodiment of the hydrocarbon compound production system will be described.
The hydrocarbon compound production system of the third embodiment will be described below, focusing on the differences from the hydrocarbon compound production systems of the first and second embodiments, and omitting explanations of similar points.
FIG. 3 is a schematic diagram showing the configuration of a third embodiment of a system for producing hydrocarbon compounds.

The manufacturing system 100 of the third embodiment is similar to the manufacturing system 100 of the first embodiment except for the configuration of the pre-processing unit 5 .
The pretreatment unit 5 shown in FIG. 3 has a dust removal unit 54 provided upstream of the PSA unit 51 (between the PSA unit 51 and the gasification furnace 10).
By providing the dust removal device 54 upstream of the PSA unit 51, that is, by providing a step of removing soot generated during combustion in the gasification furnace 10 from the raw material gas prior to the above step [1] (separation step), the amount of dust brought into the PSA unit 51 and the dehydrogenation unit 52 can be reduced, thereby reducing the number of maintenance operations for the PSA unit 51 and the dehydrogenation unit 52. Furthermore, since the amount of dust contained in the raw material gas supplied to the culture tank 2 can be reduced, it is less likely to adversely affect the microorganisms, and the alcohol production efficiency can also be improved.

The dust removal device 54 can be configured, for example, by a wet washing tower, a filter, or the like.
A wet scrubber is a so-called scrubber, and is used to remove contaminants contained in exhaust gas (for example, soot and compounds having a benzene ring (e.g., naphthalene)), water-soluble substances, etc. In a wet scrubber, removal is carried out by bringing a cleaning liquid into contact with the object to be removed (wet cleaning method). An example of a wet cleaning method is a cleaning method using a water curtain. Examples of cleaning liquids include water, acidic solutions, and alkaline solutions. Among these, water is preferred as the cleaning liquid. The temperature of the cleaning liquid is usually 40°C or lower, preferably 30°C or lower, more preferably 25°C or lower, and even more preferably 15°C or lower.

The filter is used to remove particles smaller than the size of soot, and may be, for example, a bag filter.
Other dust removal methods include a cyclone method that uses centrifugal force to separate particles, and an electrostatic precipitator method that applies high voltage to charge particles and then adsorbs them to an electrode.
According to the manufacturing system 100 of the third embodiment, the same actions and effects as those of the manufacturing system 100 of the first embodiment can be obtained.
In particular, in the third embodiment, a separate dust removal device 54 is provided, thereby reducing the amount of dust contained in the raw material gas, making it less likely that adverse effects will occur on each part of the production system 100, and improving the production efficiency of hydrocarbon compounds.
Furthermore, it may be provided in the following aspects.

(1) A method for producing hydrocarbon compounds, comprising: a separation step of separating hydrogen from a gas containing at least carbon monoxide and hydrogen; an alcohol production step of producing alcohol from the gas from which the hydrogen has been separated using a microorganism; an alkene production step of producing an alkene having three or fewer carbon atoms from the alcohol using a first catalyst; and a hydrocarbon compound production step of producing a hydrocarbon compound having four or more carbon atoms from the alkene and hydrogen using a second catalyst.

(2) In the method for producing a hydrocarbon compound described in (1) above, the hydrogen used in the hydrocarbon compound production step includes the hydrogen separated in the separation step.

(3) The method for producing a hydrocarbon compound according to (1) or (2) above, wherein in the separation step, the hydrogen is separated from the gas using a separation membrane.

(4) The method for producing a hydrocarbon compound according to any one of (1) to (3) above, wherein the amount of hydrogen used in the hydrocarbon compound production step is greater than the amount of the alkene.

(5) In the method for producing a hydrocarbon compound described in any one of (1) to (4) above, when the amount of hydrogen used in the hydrocarbon compound production step is X [moles] and the amount of the alkene is Y [moles], X/Y is 1.1 or more.

(6) The method for producing a hydrocarbon compound described in any one of (1) to (5) above, further comprising a step of liquefying the hydrogen separated in the separation step or supporting the hydrogen on a carrier to produce a hydrogen carrier.

(7) In the method for producing a hydrocarbon compound described in any one of (1) to (6) above, the gas supplied to the separation step further contains carbon dioxide, and the carbon dioxide is also separated from the gas in the separation step.

(8) The method for producing a hydrocarbon compound described in (7) above, further comprising a step of reacting at least the separated carbon dioxide and a portion of the separated hydrogen using a third catalyst to produce at least one species selected from the group consisting of alkenes and alcohols.

(9) An apparatus for producing hydrocarbon compounds, comprising: a separation unit that separates hydrogen from a gas containing at least carbon monoxide and hydrogen; an alcohol production unit that uses microorganisms to produce alcohol from the gas from which the hydrogen has been separated; an alkene production unit that produces an alkene having three or fewer carbon atoms from the alcohol using a first catalyst; and a hydrocarbon compound production unit that produces a hydrocarbon compound having four or more carbon atoms from the alkene and hydrogen using a second catalyst.

(10) The hydrocarbon compound production apparatus described in (9) above, wherein the hydrogen used in the hydrocarbon compound production section includes the hydrogen separated in the separation section.

(11) A hydrocarbon compound production system comprising a gas generation unit that generates a gas containing at least carbon monoxide and hydrogen, and the hydrocarbon compound production apparatus described in (9) or (10) above.
Of course, this is not the case.

As stated above, various embodiments of the present invention have been described, but these are presented as examples and do not limit the scope of the invention in any way. These novel embodiments may be embodied in a variety of other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their variations are within the scope and spirit of the invention, and are also within the scope of the invention and its equivalents as set forth in the claims.

For example, the hydrocarbon compound production system and the hydrocarbon compound production apparatus may each have any other additional configuration compared to the above embodiments, may be replaced with any configuration that performs a similar function, or may have some configurations omitted.
Furthermore, the hydrocarbon compound production systems and hydrocarbon compound production devices of the first to third embodiments may be combined in any desired configuration.
Furthermore, in the first to third embodiments, carbon dioxide and hydrogen are separated from the raw material gas in different devices, but carbon dioxide and hydrogen may be separated from the raw material gas in the same device.

100: Hydrocarbon compound production system 10: Gasification furnace 1: Hydrocarbon compound production apparatus 2: Culture tank 5: Pretreatment unit 51: PSA apparatus 52: Dehydrogenation apparatus 53: Carbon dioxide removal apparatus 54: Dust removal apparatus 6: Alkene production apparatus 7: Synthesis unit 8: Removal unit 9: Hydrocarbon compound production apparatus GL1: Gas line GL2: Gas line GL3: Gas line GL4: Gas line GL5a: Gas line GL5b: Gas line GL6: Gas line LL: Liquid line

Claims (11)

A method for producing a hydrocarbon compound, comprising:
a separation step of separating hydrogen from a gas containing at least carbon monoxide and hydrogen;
an alcohol production step of producing alcohol using a microorganism from the gas from which the hydrogen has been separated;
an alkene production step of producing an alkene having 3 or less carbon atoms from the alcohol using a first catalyst;
and a hydrocarbon compound production step of producing a hydrocarbon compound having 4 or more carbon atoms from the alkene and hydrogen using a second catalyst. The method for producing a hydrocarbon compound according to claim 1,
The method for producing a hydrocarbon compound, wherein the hydrogen used in the hydrocarbon compound production step contains the hydrogen separated in the separation step. The method for producing a hydrocarbon compound according to claim 1,
The method for producing a hydrocarbon compound, wherein in the separation step, the hydrogen is separated from the gas using a separation membrane. The method for producing a hydrocarbon compound according to claim 1,
The method for producing a hydrocarbon compound, wherein the amount of hydrogen used in the hydrocarbon compound production step is greater than the amount of the alkene. The method for producing a hydrocarbon compound according to claim 1,
wherein X/Y is 1.1 or more, where X is the amount of hydrogen used in the hydrocarbon compound production step and Y is the amount of alkene used in the hydrocarbon compound production step. The method for producing a hydrocarbon compound according to claim 1,
The method for producing a hydrocarbon compound further comprises a step of liquefying the hydrogen separated in the separation step or supporting the hydrogen on a carrier to form a hydrogen carrier. The method for producing a hydrocarbon compound according to claim 1,
The gas subjected to the separation step further contains carbon dioxide,
The method for producing a hydrocarbon compound, wherein the carbon dioxide is also separated from the gas in the separation step. The method for producing a hydrocarbon compound according to claim 7,
The method for producing a hydrocarbon compound further comprises a step of reacting at least the separated carbon dioxide and a portion of the separated hydrogen using a third catalyst to produce at least one selected from the group consisting of an alkene and an alcohol. An apparatus for producing a hydrocarbon compound,
a separation unit that separates hydrogen from a gas containing at least carbon monoxide and hydrogen;
an alcohol production unit that produces alcohol using microorganisms from the gas from which the hydrogen has been separated;
an alkene producing section that produces an alkene having 3 or less carbon atoms from the alcohol using a first catalyst;
a hydrocarbon compound production unit that produces a hydrocarbon compound having 4 or more carbon atoms from the alkene and hydrogen using a second catalyst. The hydrocarbon compound production apparatus according to claim 9,
The hydrocarbon compound production apparatus, wherein the hydrogen used in the hydrocarbon compound production section includes the hydrogen separated in the separation section. A system for producing a hydrocarbon compound, comprising:
a gas generating unit that generates a gas containing at least carbon monoxide and hydrogen;
A hydrocarbon compound production system comprising the hydrocarbon compound production apparatus according to claim 9.