A system for hydrogen production by using peak shaving and curtailed power to reduce carbon dioxide and its working method

Abstract

A system and its working method for hydrogen production by using peak shaving and curtailed power to reduce carbon dioxide, which are disclosed by the present invention, belong to the technical field of hydrogen reduction of carbon dioxide to produce methanol / methane. The SCR denitration reactor is arranged in the tail flue of the boiler of the thermal power generation system, and is sequentially connected to the carbon dioxide hydraulic device through a dust removal device and a desulfurization tower. The carbon dioxide hydraulic device is connected to the carbon dioxide analysis device, and the carbon dioxide analysis device is connected to the carbon dioxide inlet of the gas mixing device; the electrolytic water hydrogen production device is powered by peak shaving and curtailed power. The oxygen outlet of the electrolytic water hydrogen production device is connected to the burner arranged in the boiler combustion area, and the hydrogen outlet of the electrolytic water hydrogen production 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. The present invention utilizes waste electric energy and reduces the carbon emissions of traditional energy. At the same time, the hydrogen produced is made into products locally, reducing the risks of storage and transportation, and generating considerable economic benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen reduction of carbon dioxide to methanol / methane, and specifically relates to a system for using peak - shaving and curtailed power to produce hydrogen for reducing carbon dioxide and its working method. Background Technique

[0002] The technologies for hydrogen production by electrolyzing water mainly include alkaline water electrolysis, proton exchange membrane water electrolysis, and solid oxide water electrolysis. At present, the technology for hydrogen production by electrolyzing water has been relatively mature, with low production costs, large gas production per unit, and has been widely commercialized. It is the most promising green hydrogen energy supply method in the future. However, there are still technical bottlenecks in the storage and transportation of hydrogen, which limit the development of the hydrogen energy industry chain.

[0003] In addition, each energy and power industry has successively proposed corresponding carbon emission reduction plans. Coal - fired power plants are important sources of carbon dioxide emissions. For every 1t of coal burned, about 2.5t of carbon dioxide is produced. Taking a 300MW unit as an example, 1.2 million tons of CO2 can be produced annually, and the carbon reduction task is severe. The existing carbon dioxide capture and purification technology for coal - fired power plants mainly uses chemical absorption method, and the absorbent commonly used is organic amine. However, this technology has problems such as high energy consumption and high cost for absorbent regeneration, and its application prospect is poor. Summary of the Invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a system for using peak - shaving and curtailed power to produce hydrogen for reducing carbon dioxide and its working method, which utilizes waste electric energy, reduces carbon emissions of traditional energy, and at the same time produces hydrogen locally into products, reducing storage and transportation risks.

[0005] The present invention is realized through the following technical solutions:

[0006] The present invention discloses a system for using peak - shaving and curtailed power to produce hydrogen for reducing carbon dioxide, including a carbon dioxide hydraulic device, a carbon dioxide desorption device, a hydrogen production device by electrolyzing water, a gas mixing device, a hydrogen reduction carbon dioxide reactor, an SCR denitration reactor, a dust removal device, and a desulfurization tower;

[0007] The SCR denitration reactor is installed in the tail flue of the boiler in the thermal power generation system. The SCR denitration 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. The carbon dioxide hydraulic device is connected with a normal temperature demineralized water inlet pipe and a compressed decarbonized flue gas exhaust pipe. The mixed liquid outlet of the carbon dioxide hydraulic device is 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 decarbonized mixed liquid outlet of the carbon dioxide analysis device is connected to the electrolyte inlet of the electrolytic water hydrogen production device; the electrolytic water hydrogen production device is powered by peak shaving and abandoned electricity. The oxygen outlet of the electrolytic water hydrogen production device is connected to the burner installed in the boiler combustion area, and the hydrogen outlet of the electrolytic water hydrogen production 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.

[0008] Preferably, the peak shaving and abandoned electricity comes from the generator of the renewable energy power generation system or the thermal power generation system.

[0009] Further preferably, the electrolytic water hydrogen production device is connected with a transformer, the transformer is respectively connected to the generator and the inverter, the inverter is connected with a rectifier, and the rectifier is connected to the renewable energy power generation system.

[0010] 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; a hydrogen storage device is provided on the connecting pipeline between the hydrogen outlet of the electrolytic water hydrogen production device and the hydrogen inlet of the gas mixing device.

[0011] Further preferably, safety valves, barometers and thermometers are respectively provided on both the carbon dioxide storage device and the hydrogen storage device.

[0012] Preferably, the electrolytic water hydrogen production device is a proton exchange membrane electrolytic cell, an alkaline electrolytic cell or a solid oxide electrolytic cell.

[0013] Preferably, drying devices are provided at both the carbon dioxide inlet and the hydrogen inlet of the gas mixing device.

[0014] Preferably, the inner cavity of the gas mixing device includes a first gradually expanding section, a second gradually expanding section, a mixing section, a horizontal section and a third gradually expanding section; the first gradually expanding section is connected to the carbon dioxide inlet, the second gradually expanding section is connected to the hydrogen inlet, the ends of the first gradually expanding section and the second gradually expanding section are both connected to the mixing section, the mixing section is connected to the horizontal section, the horizontal section is connected to the third gradually expanding section, and the third gradually expanding section is connected to the mixed gas outlet.

[0015] Further preferably, a number of disturbing columns are arranged in an array in the horizontal section.

[0016] The working method of the system for producing hydrogen by using peak shaving and abandoned electricity to reduce carbon dioxide disclosed by the present invention includes:

[0017] When the thermal power generation system participates in deep peak shaving and the peak shaving depth is lower than the minimum load of the generator set itself, the excess power generated by the thermal power generation system is sent to the water electrolysis hydrogen production device; or when there is curtailment of renewable energy, the curtailed power is sent to the water electrolysis hydrogen production device; the water electrolysis hydrogen production device uses the curtailed power to electrolyze water to produce hydrogen, and the generated O2 is sent into the boiler through the burner in the boiler combustion zone to carry out oxy-fuel combustion with pulverized coal, increasing the concentration of carbon dioxide in the flue gas; using the flue gas hydraulic device, the tail flue gas after denitrification by the SCR denitrification reactor, dust removal by the dust removal device and desulfurization by the desulfurization tower (denitrification-dust removal-desulfurization) is compressed to more than 10 MPa, so that the carbon dioxide in the flue gas is dissolved by the demineralized water and then liquefied. The mixture of the liquefied carbon dioxide, demineralized water and carbohydrates is depressurized and heated by the carbon dioxide analysis device, so that the carbon dioxide is separated from the mixed liquid and then sent into the gas mixing device, and after being mixed with the hydrogen generated by the water electrolysis hydrogen production device, it is sent into the hydrogen reduction carbon dioxide reactor to synthesize methanol / methane.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] A system for producing hydrogen by using peak shaving and curtailed power to reduce carbon dioxide disclosed by the present invention uses the curtailed power of renewable energy / peak shaving curtailed power of coal-fired power plants to electrolyze water to produce hydrogen. The produced oxygen is sent into the coal-fired boiler to carry out oxy-fuel combustion with pulverized coal, increasing the concentration of carbon dioxide in the flue gas. The flue gas carrying high-concentration carbon dioxide is compressed into a liquid carbon dioxide-carbohydrate mixture by the flue gas hydraulic device, and then depressurized and heated by the carbon dioxide analysis device to analyze the carbon dioxide in the liquid phase, 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 a catalyst, it can be reduced by the hydrogen generated by the water electrolysis hydrogen production device into methane and sent into the heat pipe network or reduced into methanol and sent into a chemical plant to manufacture chemical products such as ethylene. The volatility and instability of new energy and the imbalance of energy structure and demand in terms of region and time lead to serious phenomena of wind curtailment and light curtailment in some areas. The present invention realizes the recycling of the curtailed power of renewable energy / peak shaving curtailed power of coal-fired power plants through the above process, improves the flexibility of coal-fired units, and realizes the efficient and clean combustion of thermal power units. In addition, the captured carbon dioxide and hydrogen can be synthesized into industrial products such as methane / methanol, which can be transported through pipelines or tank trucks, solving the technical bottlenecks of hydrogen energy storage and transportation, and realizing the effective utilization of carbon dioxide. At the same time, the electricity consumption of the water pump in the carbon dioxide hydraulic process and the electricity consumption for water electrolysis hydrogen production can both use the low-cost curtailed power of renewable energy / peak shaving curtailed power of coal-fired power plants; the carbon dioxide hydraulic process uses the widely existing demineralized water at normal temperature in the power plant, and after carbon removal, it can be directly sent into the water electrolysis hydrogen production system as the electrolyte for water electrolysis hydrogen production, realizing secondary utilization and reducing the cost of producing industrial products such as methane / methanol, with considerable economic benefits.

[0020] Further, a carbon dioxide storage device and a hydrogen storage device are respectively provided in front of the gas mixing device, which can control the reaction process of the system.

[0021] Furthermore, safety valves, barometers and thermometers are respectively provided on both the carbon dioxide storage device and the hydrogen storage device, which can monitor the carbon dioxide storage device and the hydrogen storage device to ensure the safety and stability of the system.

[0022] Further, drying devices are provided at both the carbon dioxide inlet and the hydrogen inlet of the gas mixing device, which can remove the water vapor carried by carbon dioxide and hydrogen.

[0023] Further, the structure of the gas mixing device can enable the full mixing of the carbon dioxide inlet and hydrogen.

[0024] Furthermore, a number of disturbance columns are arranged in an array in the horizontal section, which can improve the mixing degree of the carbon dioxide inlet and hydrogen in the subsequent third gradually expanding section.

[0025] The working method of the system for hydrogen production by peak shaving and curtailed power to reduce carbon dioxide disclosed by the present invention has a high degree of automation, reasonably utilizes energy, reduces operating costs, and at the same time produces economic products, having considerable economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 is a schematic diagram of the structure of the gas mixing device.

[0028] 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 - electrolytic water hydrogen production device; 9 - gas mixing device, 9-1 - carbon dioxide inlet, 9-2 - hydrogen inlet, 9-3 - mixed gas outlet, 9-4 - first gradually expanding section, 9-5 - second gradually expanding section, 9-6 - mixing section, 9-7 - horizontal section, 9-8 - third gradually expanding section; 10 - hydrogen reduction carbon dioxide reactor; 11 - wind power generation system; 12 - photovoltaic power generation system; 13 - SCR denitration reactor; 14 - dust removal device; 15 - desulfurization tower; 16 - water pump. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following further describes the present invention in detail with reference to the drawings, and the content is an explanation rather than a limitation of the present invention:

[0030] As Figure 1 , the system for hydrogen production by peak shaving and curtailed power to reduce carbon dioxide of the present invention includes

[0031] It includes a carbon dioxide hydraulic device 5, a carbon dioxide desorption device 7, a water electrolysis hydrogen production device 8, a gas mixing device 9, a hydrogen reduction carbon dioxide reactor 10, an SCR denitration reactor 13, a dust removal device 14 and a desulfurization tower 15;

[0032] 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 to the dust removal device 14, the dust removal device 14 is connected to the desulfurization tower 15, and the desulfurization tower 15 is connected to the inlet of the carbon dioxide hydraulic device 5. The top of the carbon dioxide hydraulic device 5 is connected with a normal temperature demineralized water inlet pipe and a compressed decarbonized flue gas exhaust pipe. A water pump 16 is provided on the normal temperature demineralized water inlet pipe; at the bottom of the carbon dioxide hydraulic device 5, a mixed liquid outlet containing liquid carbon dioxide, demineralized water and carbohydrates is connected to the inlet at the lower part of the carbon dioxide desorption device 7; the gaseous carbon dioxide outlet at the top of the carbon dioxide desorption device 7 is connected to the carbon dioxide inlet 9-1 of the gas mixing device 9; the decarbonized mixed liquid outlet at the bottom of the carbon dioxide desorption device 7 is connected to the electrolyte inlet at the bottom of the water electrolysis hydrogen production device 8; the water electrolysis hydrogen production device 8 is powered by peak shaving curtailed power, the oxygen outlet of the water electrolysis hydrogen production device 8 is connected to the burner 6 arranged in the combustion area of the boiler 1, and the hydrogen outlet of the water electrolysis hydrogen production 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.

[0033] In a preferred embodiment of the present invention, the carbon dioxide hydraulic device 5 compresses the flue gas with normal temperature demineralized water from the power plant, sets the compression stage number and the volume of the compression tank according to the flue gas volume, and the compression tank is made of corrosion-resistant materials such as 316L stainless steel.

[0034] In a preferred embodiment of the present invention, the peak shaving curtailed power comes from a renewable energy power generation system or the generator 4 of the thermal power generation system. Preferably, the water electrolysis hydrogen production device 8 is connected with a transformer, the transformer is respectively connected with the generator 4 and an inverter, the inverter is connected with a rectifier, and the rectifier is connected with the renewable energy power generation system.

[0035] In a preferred embodiment of the present invention, a carbon dioxide storage device is provided on the connecting pipeline between the carbon dioxide desorption device 7 and the carbon dioxide inlet 9-1 of the gas mixing device 9; a hydrogen storage device is provided on the connecting pipeline between the hydrogen outlet of the water electrolysis hydrogen production device 8 and the hydrogen inlet 9-2 of the gas mixing device 9. Preferably, safety valves, pressure gauges and thermometers are respectively provided on the carbon dioxide storage device and the hydrogen storage device.

[0036] In a preferred embodiment of the present invention, the water electrolysis hydrogen production device 8 is a proton exchange membrane electrolytic cell, an alkaline electrolytic cell or a solid oxide electrolytic cell.

[0037] In a preferred embodiment of the present invention, drying devices are provided at both the carbon dioxide inlet 9-1 and the hydrogen inlet 9-2 of the gas mixing device 9.

[0038] As Figure 2 , in a preferred embodiment of the present invention, the inner cavity of the gas mixing device 9 includes a first gradually expanding section 9-4, a second gradually expanding section 9-5, a mixing section 9-6, a horizontal section 9-7, and a third gradually expanding section 9-8; the first gradually expanding section 9-4 is connected to the carbon dioxide inlet 9-1, the second gradually expanding section 9-5 is connected to the hydrogen inlet 9-2, the ends of the first gradually expanding section 9-4 and the second gradually expanding section 9-5 are both connected to the mixing section 9-6, the mixing section 9-6 is connected to the horizontal section 9-7, the horizontal section 9-7 is connected to the third gradually expanding section 9-8, and the third gradually expanding section 9-8 is connected to the mixed gas outlet 9-3. Preferably, a number of disturbing columns are arranged in an array in the horizontal section 9-7.

[0039] The working method of the above system for hydrogen production by peak shaving and curtailed power and reducing carbon dioxide includes:

[0040] When the thermal power generation system participates in deep peak shaving and the peak shaving depth is lower than the minimum load of the generator set itself, the excess power generated by the thermal power generation system is sent to the electrolytic water hydrogen production device 8; or when there is curtailed power generated by renewable energy, the curtailed power is sent to the electrolytic water hydrogen production device 8; the electrolytic water hydrogen production device 8 uses the curtailed power to electrolyze water to produce hydrogen, and the generated O2 is sent into the boiler 1 through the burner 6 in the combustion zone of the boiler 1 to perform oxygen-enriched combustion with pulverized coal, increasing the concentration of carbon dioxide in the flue gas. The water vapor generated by the high-temperature heating surface 2 enters the steam turbine 3 to do work, driving the generator 4 to generate electricity. The generated electricity can be used for electrolyzing water to produce hydrogen and oxygen, or for power generation and feeding into the grid; the flue gas at the tail of the boiler is subjected to denitrification-dust removal-desulfurization by the SCR denitrification reactor 13, the dust removal device 14, and the desulfurization tower 15, and then sent to the flue gas hydraulic device 5. The widely existing normal-temperature demineralized water in the power plant is used to cool down the flue gas (the temperature is reduced to below 31.1 °C) and isothermally compressed in sequence, compressed to above 10 MPa, and finally compressed into liquid carbon dioxide. The uncompressed gases such as O2 and N2 are discharged into the atmosphere. The liquid-phase liquid carbon dioxide-water mixture is depressurized and heated by the carbon dioxide analysis device 7 to gasify and release carbon dioxide, thereby achieving the purpose of capturing and purifying carbon dioxide in the flue gas. The captured and purified carbon dioxide is recycled by the carbon dioxide hydraulic device 5 at the tail of the boiler 1, purified by the carbon dioxide analysis device 7, sent to the gas mixing device 9, mixed with the hydrogen generated by the electrolytic water hydrogen production device 8, and then sent to the hydrogen reduction carbon dioxide reactor 10 to synthesize methane under the action of a Ni-based catalyst, or synthesize methanol under the action of a Cu catalyst, a noble metal catalyst, etc. The synthesized methane / methanol is transported to users through pipelines / tank trucks.

[0041] The hydrogen reduction of carbon dioxide to methanol uses Cu catalysts, noble metal catalysts, and other main group metal catalysts, etc. The reaction equation is: CO2 + 3H2 → CH3OH + H2O; the hydrogen reduction of carbon dioxide to methane is mainly completed through gas-solid heterogeneous catalytic reactions, and more than 95% CO2 conversion and nearly 100% methane selectivity can be achieved by Ni-based catalysts at relatively low temperatures and pressures. The reaction equation is: CO2 + 4H2 → CH4 + 2H2O.

[0042] As described above, it is only a 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 only used for convenient description and explanation of the essence of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention. The above is only described by examples to further illustrate the content of the present invention for easier understanding, but it does not mean that the embodiments of the present invention are limited to this. Any technical extension or re-creation based on the present invention is protected by the present invention.

Claims

1. A system for hydrogen production by using peak shaving and curtailed power to reduce carbon dioxide, characterized in that, It includes a carbon dioxide hydraulic device (5), a carbon dioxide desorption device (7), an electrolytic water hydrogen production device (8), a gas mixing device (9), a hydrogen reduction carbon dioxide reactor (10), an SCR denitration reactor (13), a dust removal device (14) and a 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 to the dust removal device (14), the dust removal device (14) is connected to 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 inlet of the carbon dioxide desorption device (7); The gaseous carbon dioxide outlet of the carbon dioxide desorption device (7) is connected to the carbon dioxide inlet (9-1) of the gas mixing device (9); The decarbonized mixed liquid outlet of the carbon dioxide desorption device (7) is connected to the electrolyte inlet of the electrolytic water hydrogen production device (8); The electrolytic water hydrogen production device (8) is powered by peak shaving and curtailed power. The oxygen outlet of the electrolytic water hydrogen production device (8) is connected to the burner (6) arranged in the combustion zone of the boiler (1), and the hydrogen outlet of the electrolytic water hydrogen production 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); The normal temperature desalted water is the normal temperature desalted water of the power plant. The carbon dioxide hydraulic device (5) is used to compress the tail flue gas after denitration-dust removal-desulfurization treatment by the SCR denitration reactor (13), the dust removal device (14) and the desulfurization tower (15) to more than 10 MPa, so that the carbon dioxide in the flue gas is dissolved and liquefied by the normal temperature desalted water; The carbon dioxide desorption device (7) is used to relieve pressure and raise the temperature of the mixture of hydraulic liquid carbon dioxide, desalted water and carbohydrates, so that carbon dioxide is separated from the mixed liquid, and the decarbonized mixed liquid is sent to the electrolytic water hydrogen production device (8) as the electrolyte for electrolytic water hydrogen production; The peak shaving and curtailed power comes from the renewable energy power generation system or the generator (4) of the thermal power generation system.

2. The system for hydrogen production by using peak shaving and curtailed power to reduce carbon dioxide according to claim 1, wherein The electrolytic water hydrogen production device (8) is connected with a transformer, the transformer is respectively connected with the generator (4) and an inverter, and the inverter is connected with a rectifier, and the rectifier is connected with the renewable energy power generation system.

3. The system for hydrogen production by using peak shaving and curtailed power to reduce carbon dioxide according to claim 1, wherein A carbon dioxide storage device is arranged on the connecting pipeline between the carbon dioxide desorption device (7) and the carbon dioxide inlet (9-1) of the gas mixing device (9); A hydrogen storage device is arranged on the connecting pipeline between the hydrogen outlet of the electrolytic water hydrogen production device (8) and the hydrogen inlet (9-2) of the gas mixing device (9).

4. The system for hydrogen production by using peak shaving and curtailed power to reduce carbon dioxide according to claim 3, characterized in that, Safety valves, barometers and thermometers are respectively arranged on the carbon dioxide storage device and the hydrogen storage device.

5. The system for hydrogen production by using peak - shaving curtailed electricity to reduce carbon dioxide according to claim 1, characterized in that, The electrolytic water hydrogen production device (8) is a proton exchange membrane electrolytic cell, an alkaline electrolytic cell or a solid oxide electrolytic cell.

6. The system for hydrogen production by using peak shaving and curtailed power to reduce carbon dioxide according to claim 1, characterized in that, Drying devices are arranged at both the carbon dioxide inlet (9-1) and the hydrogen inlet (9-2) of the gas mixing device (9).

7. The system for hydrogen production by using peak shaving and curtailed power to reduce carbon dioxide according to claim 1, characterized in that, The inner cavity of the gas mixing device (9) includes a first divergent section (9-4), a second divergent section (9-5), a mixing section (9-6), a horizontal section (9-7) and a third divergent section (9-8); the first divergent section (9-4) is connected to the carbon dioxide inlet (9-1), the second divergent section (9-5) is connected to the hydrogen inlet (9-2), the ends of the first divergent section (9-4) and the second divergent section (9-5) are both connected to the mixing section (9-6), the mixing section (9-6) is connected to the horizontal section (9-7), the horizontal section (9-7) is connected to the third divergent section (9-8), and the third divergent section (9-8) is connected to the mixed gas outlet (9-3).

8. The system for reducing carbon dioxide by using peak shaving and curtailed power to produce hydrogen according to claim 7, wherein A number of disturbance columns are arranged in an array in the horizontal section (9-7).

9. The working method of the system for hydrogen production by using peak shaving and curtailed power to reduce carbon dioxide according to any one of claims 1 to 8, characterized in that, Including: When the thermal power generation system participates in deep peak shaving and the peak shaving depth is lower than the minimum load of the generator set itself, the excess power generated by the thermal power generation system is sent to the water electrolysis hydrogen production device (8); or when there is curtailment of renewable energy, the curtailed power is sent to the water electrolysis hydrogen production device (8); the water electrolysis hydrogen production device (8) uses the curtailed power to electrolyze water to produce hydrogen, and the generated O2 is sent into the boiler (1) through the burner (6) in the combustion zone of the boiler (1) to carry out oxygen-enriched combustion with pulverized coal to increase the concentration of carbon dioxide in the flue gas; using the carbon dioxide hydraulic device (5), the tail flue gas after denitrification-dust removal-desulfurization treatment by the SCR denitrification reactor (13), the dust removal device (14) and the desulfurization tower (15) is compressed to more than 10 MPa, so that the carbon dioxide in the flue gas is dissolved in the desalted water and then liquefied. The liquefied carbon dioxide, desalted water and carbohydrate mixture after hydraulic pressure are depressurized and heated by the carbon dioxide analysis device (7) to separate the carbon dioxide from the mixed liquid and then sent to the gas mixing device (9), where it is mixed with the hydrogen generated by the water electrolysis hydrogen production device (8) and then sent to the hydrogen reduction carbon dioxide reactor (10) to synthesize methanol / methane.

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