CN116036829A - A system and working method for reducing carbon dioxide by using peak shaving and abandoning electricity to produce hydrogen and reduce carbon dioxide - Google Patents

Abstract

The invention discloses a system for reducing carbon dioxide by utilizing peak regulation and power-off hydrogen production and a working method thereof, belonging to the technical field of preparing methanol/methane by reducing carbon dioxide by hydrogen. The SCR denitration reactor is arranged in a tail flue of a boiler of the thermal power generation system and is connected with the carbon dioxide hydraulic device through the dust removal device and the desulfurizing tower in sequence, the carbon dioxide hydraulic device is connected with the carbon dioxide analysis device, and the carbon dioxide analysis device is connected with a carbon dioxide inlet of the gas mixing device; the hydrogen outlet of the water electrolysis hydrogen production device is connected with the hydrogen inlet of the gas mixing device; and a mixed gas outlet of the gas mixing device is connected with the hydrogen reduction carbon dioxide reactor. The invention utilizes waste electric energy and reduces the carbon emission of traditional energy sources, simultaneously produces hydrogen on site into products, reduces the risk of storage and transportation, and generates considerable economic benefit.

Description

A system and working method for reducing carbon dioxide by using peak shaving and abandoning electricity to produce hydrogen and reduce carbon dioxide

technical field

The invention belongs to the technical field of producing methanol/methane by reducing carbon dioxide with hydrogen, and specifically relates to a system and a working method for producing hydrogen and reducing carbon dioxide by utilizing peak regulation and discarding electricity.

Background technique

Electrolyzed water hydrogen production technologies mainly include alkaline water electrolysis, proton exchange membrane water electrolysis and solid oxide water electrolysis. At present, the electrolysis of water hydrogen production technology is relatively mature, its production cost is relatively low, and the gas production of a single unit is relatively large. It has been commercialized on a large scale and is the green hydrogen energy supply method with the most development potential in the future. However, there are still technical bottlenecks in the storage and transportation of hydrogen, which limits the development of the hydrogen energy industry chain.

In addition, various energy and power industries have successively proposed corresponding carbon emission reduction plans. Coal-fired power plants are an important source of carbon dioxide emissions. Every 1 ton of coal burned produces about 2.5 tons of carbon dioxide. Taking a 300MW unit as an example, it can produce 1.2 million tons of carbon dioxide per year. CO ₂ , the carbon reduction task is severe. Existing carbon dioxide capture and purification technologies in coal-fired power plants mainly use chemical absorption, and organic amines are often used as absorbents. However, this technology has the problems of high energy consumption and high cost for absorbent regeneration, and its application prospects are poor.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide a system and its working method for reducing carbon dioxide by using peak shaving and abandoning electricity to produce hydrogen, which utilizes waste electric energy and reduces carbon emissions of traditional energy sources, and at the same time produces hydrogen in situ Finished products, reducing storage and transportation risks.

The present invention is achieved through the following technical solutions:

The invention discloses a system for producing hydrogen and reducing carbon dioxide by using peak regulation and abandoning electricity, including a carbon dioxide hydraulic device, a carbon dioxide analysis device, an electrolyzed water hydrogen production device, a gas mixing device, a hydrogen reduction carbon dioxide reactor, an SCR denitrification reactor, and a dust removal device and scrubbers;

The SCR denitrification reactor is installed in the tail flue of the boiler of the thermal power generation system. The SCR denitrification reactor is connected to the dust removal device, the dust removal device is connected to the desulfurization tower, the desulfurization tower is connected to the inlet of the carbon dioxide hydraulic device, and the carbon dioxide hydraulic device is connected to normal temperature desalted water. The water inlet pipe and the compressed decarbonization flue gas exhaust pipe, the mixed liquid outlet of the carbon dioxide hydraulic device are connected to the inlet of the carbon dioxide analysis device; the gaseous carbon dioxide outlet of the carbon dioxide analysis device is connected to the carbon dioxide inlet of the gas mixing device; the decarbonization mixing of the carbon dioxide analysis device The liquid outlet is connected to the electrolyte inlet of the electrolyzed water hydrogen production device; the electrolyzed water hydrogen production device is powered by peak shaving and power abandonment, and the oxygen outlet of the electrolytic water hydrogen production device is connected to the burner in the combustion area of the boiler, and the electrolytic water hydrogen production device The hydrogen outlet of the gas mixing device is connected to the hydrogen inlet of the gas mixing device; the mixed gas outlet of the gas mixing device is connected to the hydrogen reduction carbon dioxide reactor.

Preferably, the peak shaving power abandonment comes from a generator of a renewable energy power generation system or a thermal power generation system.

Further preferably, the water electrolysis hydrogen production device is connected with a transformer, the transformer is respectively connected with a generator and an inverter, the inverter is connected with a rectifier, and the rectifier is connected with a renewable energy power generation system.

Preferably, a carbon dioxide storage device is provided on the connecting pipeline between the carbon dioxide analysis device and the carbon dioxide inlet of the gas mixing device; device.

Further preferably, the carbon dioxide storage device and the hydrogen storage device are respectively provided with a safety valve, a barometer and a thermometer.

Preferably, the electrolyzed water hydrogen production device is a proton exchange membrane electrolyzer, an alkaline electrolyzer or a solid oxide electrolyzer.

Preferably, both the carbon dioxide inlet and the hydrogen inlet of the gas mixing device are provided with drying devices.

Preferably, the inner cavity of the gas mixing device includes a first diverging section, a second diverging section, a mixing section, a horizontal section and a third diverging section; the first diverging section is connected to the carbon dioxide inlet, and the second diverging section is connected to the carbon dioxide inlet. The hydrogen inlet is connected, the ends of the first diverging section and the second diverging section are connected to the mixing section, the mixing section is connected to the horizontal section, the horizontal section is connected to the third diverging section, and the third diverging section is connected to the mixed gas outlet .

Further preferably, the array in the horizontal section is provided with several disturbing moving columns.

The working method of the above-mentioned system for producing hydrogen and reducing carbon dioxide by using peak shaving and abandoning electricity disclosed by the present invention includes:

When the thermal power generation system participates in deep peak shaving and the peak shaving depth is lower than the minimum load of the generating set itself, the excess power generated by the thermal power generation system is sent to the electrolysis water hydrogen production device; Electrolyzed water hydrogen production device; the electrolyzed water hydrogen production device uses waste electricity to electrolyze water to produce hydrogen, and the _O2 produced is sent to the boiler through the burner in the boiler combustion zone for oxygen-enriched combustion with coal powder to increase the concentration of carbon dioxide in the flue gas; Use the flue gas hydraulic device to compress the tail flue gas after the denitrification-dust removal-desulfurization treatment of the SCR denitrification reactor, dust removal device and desulfurization tower to above 10MPa, so that the carbon dioxide in the flue gas is dissolved and then liquefied by desalinated water. The mixture of liquid carbon dioxide, desalted water and carbohydrates is decompressed and heated by the carbon dioxide analysis device, so that carbon dioxide is separated from the mixed liquid and then sent to the gas mixing device, mixed with the hydrogen generated by the electrolytic water hydrogen production device, and then sent to hydrogen to reduce carbon dioxide The reactor synthesizes methanol/methane.

Compared with the prior art, the present invention has the following beneficial technical effects:

The invention discloses a system for reducing carbon dioxide by using peak-shaving and abandoning electricity to produce hydrogen to reduce carbon dioxide. It utilizes renewable energy and abandoning electricity/coal-fired power plants to produce hydrogen by electrolyzing water for peak-shaving and abandoning electricity. Oxygen-enriched combustion increases the concentration of carbon dioxide in the flue gas, and the flue gas with a high concentration of carbon dioxide is compressed into a liquid carbon dioxide-carbohydrate mixture by a flue gas hydraulic device, and then the carbon dioxide decompression device releases pressure and heats up to decompose the carbon dioxide in the liquid phase out, so as to achieve the purpose of flue gas carbon dioxide capture. The captured carbon dioxide enters the hydrogen reduction carbon dioxide reactor, and under the action of the catalyst, it can be reduced to methane by the hydrogen generated by the electrolysis water hydrogen production device and sent to the heat pipe network or reduced to methanol to be sent to the chemical plant to manufacture ethylene and other chemical products. The volatility and instability of new energy, as well as the regional and temporal imbalance of energy structure and demand, have led to serious abandonment of wind and light in some areas. Through the above process, the present invention realizes the recovery and utilization of the abandoned power of renewable energy/peak-shaving power plant of coal-fired power plants, improves the flexibility of the coal-fired unit, and realizes efficient and clean combustion of the thermal power unit. In addition, the captured carbon dioxide and hydrogen can be used to synthesize industrial products such as methane/methanol, which can be transported through pipelines or tankers, solving the technical bottleneck of hydrogen energy storage and transportation, and realizing the effective use of carbon dioxide. At the same time, in the carbon dioxide hydraulic process, the electricity used for water pumps and electrolyzed water for hydrogen production can use cheap renewable energy and abandon electricity/coal-fired power plants for peak regulation and abandon electricity; the carbon dioxide hydraulic process uses normal temperature desalted water widely available in power plants , and after carbon removal, it can be directly sent to the hydrogen production system by electrolysis of water as the electrolyte for hydrogen production by electrolysis of water, realizing secondary utilization, reducing the cost of producing industrial products such as methane/methanol, and has considerable economic benefits.

Furthermore, a carbon dioxide storage device and a hydrogen storage device are respectively arranged in front of the gas mixing device, which can control the reaction process of the system.

Furthermore, the carbon dioxide storage device and the hydrogen storage device are equipped with safety valves, barometers and thermometers respectively, which can monitor the carbon dioxide storage device and the hydrogen storage device to ensure the safety and stability of the system.

Furthermore, both the carbon dioxide inlet and the hydrogen inlet of the gas mixing device are equipped with drying devices, which can remove the water vapor carried by the carbon dioxide and hydrogen.

Further, the structure of the gas mixing device can fully mix the carbon dioxide inlet and the hydrogen.

Furthermore, the array in the horizontal section is provided with a disturbing moving column, which can improve the mixing degree of the carbon dioxide inlet and the hydrogen in the subsequent third diverging section.

The working method of the above-mentioned system for producing hydrogen and reducing carbon dioxide by using peak regulation and abandoning electricity disclosed by the present invention has a high degree of automation, rationally utilizes energy, reduces operating costs, and produces economic products at the same time, with considerable economic benefits.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the present invention;

Figure 2 is a schematic structural view of the gas mixing device.

In the figure: 1- boiler; 2- high temperature heating surface; 3- steam turbine; 4- generator; 5- carbon dioxide hydraulic device; 6- burner; 7- carbon dioxide analysis device; 8- electrolysis water hydrogen production device; 9- mixing Gas device, 9-1-carbon dioxide inlet, 9-2-hydrogen inlet, 9-3-mixed gas outlet, 9-4-first diverging section, 9-5-second diverging section, 9-6-mixing Section, 9-7-horizontal section, 9-8-third gradual expansion section; 10-hydrogen reduction carbon dioxide reactor; 11-wind power generation system; 12-photovoltaic power generation system; 13-SCR denitrification reactor; 14-dust removal device ; 15 - desulfurization tower; 16 - water pump.

Detailed ways

The present invention will be described in further detail below in conjunction with accompanying drawing, and its content is explanation of the present invention rather than limitation:

As shown in Fig. 1, it is a system for reducing carbon dioxide by using peak shaving and abandoning electricity to produce hydrogen to reduce carbon dioxide according to the present invention, including

Including carbon dioxide hydraulic device 5, carbon dioxide analysis device 7, electrolytic water hydrogen production device 8, gas mixing device 9, hydrogen reduction carbon dioxide reactor 10, SCR denitrification reactor 13, dust removal device 14 and desulfurization tower 15;

The SCR denitrification reactor 13 is located in the tail flue of the boiler 1 of the thermal power generation system, the SCR denitrification reactor 13 is connected with the dust removal device 14, the dust removal device 14 is connected with the desulfurization tower 15, and the desulfurization tower 15 is connected with the inlet of the carbon dioxide hydraulic device 5, The top of the carbon dioxide hydraulic device 5 is connected with a normal temperature desalted water inlet pipe and a compressed decarbonized flue gas exhaust pipe, and a water pump 16 is provided on the normal temperature desalted water inlet pipe; the bottom of the carbon dioxide hydraulic device 5 is provided with a The outlet of the mixed solution of the compound is connected with the inlet of the carbon dioxide analysis device 7 bottom; the gaseous carbon dioxide outlet at the top of the carbon dioxide analysis device 7 is connected with the carbon dioxide inlet 9-1 of the gas mixing device 9; The electrolyte inlet at the bottom of the water hydrogen production device 8 is connected; the electrolytic water hydrogen production device 8 supplies power through peak regulation and power abandonment, and the oxygen outlet of the electrolytic water hydrogen production device 8 is connected to the burner 6 located in the combustion area of the boiler 1, and the electrolytic water production The hydrogen outlet of the hydrogen device 8 is connected to the hydrogen inlet 9-2 of the gas mixing device 9; the mixed gas outlet 9-3 of the gas mixing device 9 is connected to the hydrogen reduction carbon dioxide reactor 10.

In a preferred embodiment of the present invention, the carbon dioxide hydraulic device 5 uses normal temperature desalted water from the power plant to compress the flue gas, and sets the number of compression stages and the volume of the compression tank according to the volume of the flue gas. The compression tank is made of 316L stainless steel and other corrosion-resistant Material.

In a preferred embodiment of the present invention, the peak-shaving power abandonment comes from the generator 4 of the renewable energy power generation system or the thermal power generation system. Preferably, the water electrolysis hydrogen production device 8 is connected with a transformer, the transformer is connected with the generator 4 and the inverter respectively, the inverter is connected with a rectifier, and the rectifier is connected with the renewable energy power generation system.

In a preferred embodiment of the present invention, a carbon dioxide storage device is provided on the connecting pipeline between the carbon dioxide analysis device 7 and the carbon dioxide inlet 9-1 of the gas mixing device 9; A hydrogen storage device is arranged on the connection pipeline between the hydrogen inlet 9-2 of the gas device 9 . Preferably, the carbon dioxide storage device and the hydrogen storage device are respectively provided with a safety valve, a barometer and a thermometer.

In a preferred embodiment of the present invention, the electrolyzed water hydrogen production device 8 is a proton exchange membrane electrolyzer, an alkaline electrolyzer or a solid oxide electrolyzer.

In a preferred embodiment of the present invention, both the carbon dioxide inlet 9-1 and the hydrogen inlet 9-2 of the gas mixing device 9 are provided with drying devices.

As shown in Fig. 2, in a preferred embodiment of the present invention, the inner cavity of gas mixing device 9 includes first diverging section 9-4, second diverging section 9-5, mixing section 9-6, horizontal section 9-7 and the third gradual expansion section 9-8; the first gradual expansion section 9-4 is connected with the carbon dioxide inlet 9-1, the second gradual expansion section 9-5 is connected with the hydrogen inlet 9-2, and the first gradual expansion section 9-4 and the end of the second diverging section 9-5 are connected to the mixing section 9-6, the mixing section 9-6 is connected to the horizontal section 9-7, and the horizontal section 9-7 is connected to the third diverging section 9-8 Connection, the third diverging section 9-8 is connected with the mixed gas outlet 9-3. Preferably, the array in the horizontal section 9-7 is provided with several disturbing moving columns.

The working method of the above-mentioned system for reducing carbon dioxide by using peak shaving and abandoning electricity to produce hydrogen includes:

When the thermal power generation system participates in deep peak shaving and the peak shaving depth is lower than the minimum load of the generating set itself, the more power generated by the thermal power generation system is sent to the electrolysis water hydrogen production device 8; into the electrolyzed water hydrogen production device 8; the electrolyzed water hydrogen production device 8 uses discarded electricity to electrolyze water to produce hydrogen, and the O2 produced is sent to the boiler ₁ through the burner 6 in the combustion zone of the boiler 1 for oxygen-enriched combustion with pulverized coal to improve the smoke The concentration of carbon dioxide in the gas, the water vapor generated by the high-temperature heating surface 2 enters the steam turbine 3 to do work, and drives the generator 4 to generate electricity. After denitrification-dust removal-desulfurization by SCR denitrification reactor 13, dedusting device 14 and desulfurization tower 15, it is sent to the flue gas hydraulic device 5, and the normal temperature desalinated water widely existing in power plants is used to cool the first flue gas in sequence (the temperature drops to 31.1 ℃) and isothermal compression, compressed to above 10MPa, and finally compressed into liquid carbon dioxide, uncompressed O ₂ , N ₂ and other gases are discharged into the atmosphere. The liquid carbon dioxide-carbohydrate mixture in the liquid phase is decompressed and heated by the carbon dioxide analysis device 7 to gasify and release the carbon dioxide, thereby achieving the purpose of capturing and purifying carbon dioxide in the flue gas. Capture and purify the carbon dioxide and reuse the carbon dioxide hydraulic device 5 at the tail of the boiler 1 to recover the carbon dioxide in the flue gas, and then send it to the gas mixing device 9 after being purified by the carbon dioxide analysis device 7, and mix it with the hydrogen generated by the electrolytic water hydrogen production device 8, Send it to the hydrogen reduction carbon dioxide reactor 10, synthesize methane under the action of Ni-based catalyst, or synthesize methanol under the action of Cu catalyst, noble metal catalyst, etc., and transport the synthesized methane/methanol to users through pipelines/tank trucks.

Hydrogen reduction of carbon dioxide to methanol uses Cu catalysts, noble metal catalysts, and other main group metal catalysts. The reaction formula is: CO ₂ +3H ₂ →CH ₃ OH+H ₂ O; Over 95% _CO2 conversion and close to 100% methane selectivity can be achieved by Ni-based catalysts at relatively low temperature and pressure. Its reaction formula is: CO ₂ +4H ₂ →CH ₄ +2H ₂ O.

The above description is only part of the embodiments of the present invention. Although some terms are used in the present invention, the possibility of using other terms is not excluded. These terms are used only for the convenience of describing and explaining the essence of the present invention, and it is against the spirit of the present invention to interpret them as any additional limitation. The above descriptions only use examples to further illustrate the content of the present invention for easier understanding, but it does not mean that the implementation of the present invention is limited to this, and any technical extension or re-creation done according to the present invention is subject to protection of.

Claims (10)

1. A system for reducing carbon dioxide by using peak shaving and abandoning electricity to produce hydrogen, characterized in that it includes a carbon dioxide hydraulic device (5), a carbon dioxide analysis device (7), an electrolyzed water hydrogen production device (8), and a gas mixing device (9) , hydrogen reduction carbon dioxide reactor (10), SCR denitrification reactor (13), dust removal device (14) and desulfurization tower (15); The SCR denitration reactor (13) is arranged in the tail flue of the boiler (1) of the thermal power generation system, the SCR denitration reactor (13) is connected with the dedusting device (14), and the dedusting device (14) is connected with the desulfurization tower (15), The desulfurization tower (15) is connected to the inlet of the carbon dioxide hydraulic device (5). The carbon dioxide hydraulic device (5) is connected with a normal temperature desalted water inlet pipe and a compressed decarbonized flue gas exhaust pipe. The mixed liquid outlet of the carbon dioxide hydraulic device (5) is connected to the The inlet of the carbon dioxide analysis device (7) is connected; the gaseous carbon dioxide outlet of the carbon dioxide analysis device (7) is connected with the carbon dioxide inlet (9-1) of the gas mixing device (9); the decarburization mixed liquid outlet of the carbon dioxide analysis device (7) is connected with the The electrolyte inlet of the electrolytic water hydrogen production device (8) is connected; the electrolytic water hydrogen production device (8) is powered by peak regulation and power abandonment, and the oxygen outlet of the electrolytic water hydrogen production device (8) is connected to the boiler (1) combustion zone. The burner (6) is connected, and the hydrogen outlet of the electrolytic water hydrogen production device (8) is connected with the hydrogen inlet (9-2) of the gas mixing device (9); the mixed gas outlet (9-3) of the gas mixing device (9) Connect with the hydrogen reduction carbon dioxide reactor (10). 2. The system according to claim 1, wherein the system for producing hydrogen and reducing carbon dioxide by using peak shaving and discarding electricity is characterized in that the peak shaving and discarding electricity comes from a generator (4) of a renewable energy power generation system or a thermal power generation system. 3. The system according to claim 2, characterized in that the electrolyzed water hydrogen production device (8) is connected with a transformer, and the transformer is connected with the generator (4) and the inverter respectively , the inverter is connected with a rectifier, and the rectifier is connected with the renewable energy generation system. 4. The system according to claim 1, characterized in that the carbon dioxide analysis device (7) is connected to the carbon dioxide inlet (9-1) of the gas mixing device (9). A carbon dioxide storage device is provided on the pipeline; a hydrogen storage device is provided on the connecting pipeline between the hydrogen gas outlet of the electrolyzed water hydrogen production device (8) and the hydrogen gas inlet (9-2) of the gas mixing device (9). 5. The system according to claim 4, characterized in that the carbon dioxide storage device and the hydrogen storage device are respectively provided with a safety valve, a barometer and a thermometer. 6. The system according to claim 1, characterized in that the electrolyzed water hydrogen production device (8) is a proton exchange membrane electrolyzer, an alkaline electrolyzer or a solid oxide electrolyzer . 7. The system according to claim 1, characterized in that the carbon dioxide inlet (9-1) and the hydrogen inlet (9-2) of the gas mixing device (9) are equipped with Drying device. 8. The system according to claim 1, characterized in that the inner cavity of the gas mixing device (9) includes a first gradual expansion section (9-4), a second gradual expansion section Section (9-5), mixing section (9-6), horizontal section (9-7) and the third diverging section (9-8); the first diverging section (9-4) and carbon dioxide inlet (9- 1) connection, the second diverging section (9-5) is connected to the hydrogen inlet (9-2), and the ends of the first diverging section (9-4) and the second diverging section (9-5) are connected to The mixing section (9-6), the mixing section (9-6) is connected with the horizontal section (9-7), the horizontal section (9-7) is connected with the third gradual expansion section (9-8), and the third gradual expansion section (9-8) is connected with the mixed gas outlet (9-3). 9. The system according to claim 8, characterized in that, the horizontal section (9-7) is provided with several disturbing moving columns in the array. 10. According to any one of claims 1 to 9, the working method of the system for producing hydrogen and reducing carbon dioxide by using peak shaving and abandoning electricity, is characterized in that it includes: When the thermal power generation system participates in deep peak shaving and the peak shaving depth is lower than the minimum load of the generating set itself, the excess power generated by the thermal power generation system is sent to the electrolyzed water hydrogen production device (8); The electricity is fed into the electrolyzed water hydrogen production device (8); the electrolyzed water hydrogen production device (8) uses the discarded electricity to electrolyze water to produce hydrogen, and the _O2 produced is sent to the boiler (1) through the burner (6) in the combustion zone of the boiler (1) ) with pulverized coal to carry out oxygen-enriched combustion to increase the concentration of carbon dioxide in the flue gas; using the flue gas hydraulic device (5), the denitrification- After dedusting and desulfurization treatment, the flue gas at the tail is compressed to above 10MPa, so that the carbon dioxide in the flue gas is dissolved and then liquefied by the desalinated water, and the hydraulically formed mixture of liquid carbon dioxide, desalted water and carbohydrates is depressurized by the carbon dioxide analysis device (7). Raise the temperature to separate the carbon dioxide from the mixed liquid and then send it to the gas mixing device (9), mix it with the hydrogen generated by the electrolyzed water hydrogen production device (8), and send it to the hydrogen reduction carbon dioxide reactor (10) to synthesize methanol/methane.

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