Underground gasification and electrolysis water coupling zero-carbon hydrogen production system and resource comprehensive utilization method

Abstract

The application provides an underground gasification and electrolysis water coupling zero-carbon hydrogen production system and a resource comprehensive utilization method, which can effectively reduce the production cost of electrolytic hydrogen production, make full use of oxygen generated by electrolysis while providing suitable water sources, and make hydrogen energy more widely and practically applied; carbon monoxide produced by underground coal gasification and separated and purified is used as a circulating medium in the process of electrolytic hydrogen production, which can reduce a part of hydrogen production power consumption, and carbon dioxide and oxygen generated by the anode of the electrolytic cell can be used as a gasification agent in the gasification process or a combustion-supporting agent in the power generation process, and the carbon dioxide produced by the power generation device can also be injected into the underground gasification furnace as a gasification agent; while reducing the cost of high-purity gasification agent preparation and transportation, the condensate water of the synthesis gas after treatment can be reasonably utilized, and then the underground coal gasification technology and the existing electrolytic water hydrogen production process are combined to create a new zero-carbon hydrogen production system with a fusion of technical systems and efficient utilization of resources.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of underground coal gasification, and particularly relates to an underground gasification and water electrolysis coupling zero-carbon hydrogen production system and a resource comprehensive utilization method. BACKGROUND

[0002] Hydrogen energy is an indispensable secondary energy in the world at present, and has the characteristics of high heat value, high efficiency, zero pollution, etc., and plays an extremely important substitution role in promoting global economic decarbonization, especially in the fields of energy chemical industry, transportation, steel smelting, etc.

[0003] As one of the important paths of energy transformation, water electrolysis hydrogen production is playing an increasingly important role in the field of process hydrogen production. However, compared with traditional fossil fuel hydrogen production, water electrolysis hydrogen production is to provide energy to water by electricity to break the hydrogen-oxygen bond of water molecules to produce hydrogen, so the cost of hydrogen production is higher, and a suitable water source is also needed. In addition, water electrolysis hydrogen production itself belongs to the category of zero-carbon hydrogen production, and no other carbon-containing pollutants are generated in the hydrogen production process, but the electricity required is not all from zero-carbon power generation, and the zero-carbon power generation of solar energy and wind energy and other clean energy is also extremely unstable and is greatly affected by external environmental factors, which cannot continuously provide electricity for water electrolysis hydrogen production. Finally, a large amount of oxygen generated in the process of water electrolysis hydrogen production is usually directly discharged as a byproduct, which also causes waste of resources.

[0004] As a second generation of coal mining method, underground coal gasification is a new comprehensive energy production technology integrating multiple disciplines, which aims to control the combustion of coal and then convert underground coal resources into combustible gas through thermal and chemical action. In general, the heat value of underground coal gasification is not stable and cannot be directly used for combustion power generation for large-scale electricity users such as civil and industrial users. In addition, in the gasification process, high-purity carbon dioxide or oxygen as a gasification agent can effectively improve the heat value and reaction rate of synthesis gas, but the preparation and transportation cost of high-purity gasification agent is high. Moreover, the pyrolysis section of underground coal gasification inevitably produces pollutants, which will accompany the synthesis gas to the ground and form synthesis gas condensate water after passing through the water cooling spray system. The condensate water is directly discharged after treatment, and has not been well utilized as a resource.

[0005] Therefore, how to effectively reduce the production cost of electrolytic water hydrogen production, achieve sustainable "zero carbon" power supply, and fully utilize the oxygen generated by electrolysis while providing suitable water sources, so that hydrogen energy can be more widely and practically applied; how to expand the input and output paths of underground coal gasification, reduce the cost of high-purity gasifying agent production and transportation, and reasonably utilize the produced synthesis gas and treated synthesis gas condensate; how to combine the underground coal gasification technology with the existing electrolytic water hydrogen production process to create a new zero-carbon hydrogen production system with integrated technology and efficient resource utilization is a problem to be solved at present. SUMMARY

[0006] The present application aims to solve the above problems in the prior art by providing an underground gasification and electrolytic water coupled zero-carbon hydrogen production system and resource comprehensive utilization method, which can effectively reduce the production cost of electrolytic hydrogen production, and fully utilize the oxygen generated by electrolysis while providing suitable water sources, so that hydrogen energy can be more widely and practically applied; can reasonably utilize the treated synthesis gas condensate while reducing the cost of high-purity gasifying agent production and transportation, and further combine the underground coal gasification technology with the existing electrolytic water hydrogen production process to create a new zero-carbon hydrogen production system with integrated technology and efficient resource utilization.

[0007] To achieve the above-mentioned purpose, the first invention point of the technical solution provided by the present application is: an underground gasification and electrolytic water coupled zero-carbon hydrogen production system, comprising: an underground gasification furnace, a first input end at the top connected to a first output end of an electrolytic water hydrogen production device through an O2 and CO2 gasifying agent delivery pipe, a second input end at the top connected to a third output end of the electrolytic water hydrogen production device through an O2 gasifying agent delivery pipe, and a bottom input end connected to an output end of a power generation device through a CO2 gasifying agent delivery pipe;

[0008] A water cooling and spraying device, an input end connected to an output end of the underground gasification furnace through a synthesis gas delivery pipe, and a first output end connected to a first input end of a sewage treatment device through a synthesis gas condensate delivery pipe;

[0009] A synthesis gas pretreatment device, an input end communicated with a second output end of the water cooling and spraying device through a gas delivery pipe, for adsorbing impurities, compressing synthesis gas and removing acid gas and CO2 in the synthesis gas;

[0010] A gas separation device, an input end communicated with an output end of the synthesis gas pretreatment device through a gas output pipe, a first output end communicated with a hydrogen storage device I through an H2 delivery pipe, and a second output end connected to a first input end of a power generation device through a CO fuel gas delivery pipe;

[0011] The electrolytic water hydrogen production device is connected with the output end of the sewage treatment device through an electrolytic water delivery pipe at a first input end, and is connected with the second input end of the power generation device through an O2 and CO2 combustion-supporting agent delivery pipe at a second output end.

[0012] The power generation device is in communication with the syngas pretreatment device, the sewage treatment device and the electrolytic water hydrogen production device through power delivery lines.

[0013] Preferably, a third output end of the gas separation device is connected with the electrolytic water hydrogen production device through a CO circulating medium delivery pipe, for delivering the circulating medium CO of the anode of the electrolytic cell in the electrolytic water hydrogen production device, so as to reduce the power consumption of hydrogen production.

[0014] Preferably, the syngas pretreatment device comprises, in sequence, a coke adsorption device, a syngas compression device, an acid gas removal device and a CO2 desorption device, wherein the coke adsorption device is in communication with the second output end of the water cooling spray device through a gas delivery pipe at an input end, the input end of the syngas compression device is in communication with the output end of the coke adsorption device through a first gas delivery pipe, the input end of the acid gas removal device is in communication with the output end of the syngas compression device through a second gas delivery pipe, the input end of the CO2 desorption device is in communication with the output end of the acid gas removal device through a third gas delivery pipe, and the output end of the CO2 desorption device is in communication with the input end of the gas separation device through a gas output pipe.

[0015] Preferably, the electrolytic water hydrogen production device comprises an electrolytic cell, a separator I, a cooler I, a droplet catcher I, a separator II, a cooler II, a droplet catcher II and a hydrogen storage device II, the first input end of the separator I is in communication with the anode of the electrolytic cell through an O2 and CO2 delivery pipe, the second input end of the separator I is in communication with the anode of the electrolytic cell through an O2 delivery pipe, the first output end of the separator I is connected with the first input end of the top of the underground gasification furnace through an O2 and CO2 gasification agent delivery pipe, the second output end of the separator I is connected with the second input end of the power generation device through an O2 and CO2 combustion-supporting agent delivery pipe, the third output end of the separator I is in communication with the input end of the cooler I through a first delivery pipe, the output end of the cooler I is in communication with the input end of the droplet catcher I through a second delivery pipe, the first output end of the droplet catcher I is connected with the second input end of the top of the underground gasification furnace through an O2 gasification agent delivery pipe, the input end of the separator II is in communication with the cathode of the electrolytic cell through an H2 output pipe, the first output end of the separator II is connected with the input end of the cooler II through a third delivery pipe, the output end of the cooler II is in communication with the input end of the droplet catcher II through a fourth delivery pipe, and the output end of the droplet catcher II is in communication with the hydrogen storage device II through an H2 delivery pipe.

[0016] Preferably, the second output end of the droplet catcher I is communicated with the input end of the ozone generator through an O2 delivery pipe, and the output end of the ozone generator is communicated with the sewage treatment device through an oxidant O3 delivery pipe.

[0017] Preferably, the fourth output end of the separator I is communicated with the electrolytic cell through a first drainage pipe, and the second output end of the separator II is communicated with the electrolytic cell through a second drainage pipe.

[0018] Preferably, the power generation device is further communicated with the energy storage device through a power delivery line.

[0019] The second invention point of the technical solution provided in the present application is a resource comprehensive utilization method of the underground gasification and electrolysis water coupled zero-carbon hydrogen production system, comprising the following steps:

[0020] Step S1, coal underground gasification: the crude synthesis gas produced by the underground gasification furnace is cooled and sprayed by a water cooling spraying device, so as to condense oil, dust, organic impurities and part of water vapor in the crude synthesis gas, thereby forming synthesis gas condensate water, the synthesis gas condensate water is sent into the sewage treatment device through a synthesis gas condensate water delivery pipe, the synthesis gas from which oil, dust, organic impurities and part of water vapor are removed is sent into the coke adsorption device through a gas delivery pipe, so as to adsorb organic and inorganic pollutants remaining in the coal gas, the synthesis gas after being adsorbed by the coke adsorption device is sent into a synthesis gas compression device through a first gas delivery pipe for gas compression, the compressed synthesis gas is sent into an acid gas removal device through a second gas delivery pipe for removal of acid gas, the synthesis gas after removal of acid gas is sent into a CO2 desorption device for removal of CO2, the synthesis gas after removal of CO2 is sent into a gas separation device through a gas output pipe for separation of CO and H2, the H2 separated by the gas separation device is sent into a hydrogen storage device I, and can be stored and transported as industrial fuel gas and chemical synthesis raw material gas;

[0021] Step S2, combustion power generation: the CO separated by the gas separation device can be used as fuel gas of the power generation device, the power generation device not only can provide electric energy for the electrolysis water hydrogen production device, the sewage treatment device and the synthesis gas pretreatment device, but also can send the surplus electric power into the energy storage device as standby electricity for storage, and the high-concentration CO2 produced thereby can be injected into the underground gasification furnace as a gasification agent to participate in the reaction;

[0022] Step S3, sewage treatment: the crude synthesis gas produced by the underground gasification furnace is sprayed by a water cooling spraying device, so as to condense oil, dust, organic impurities and part of water vapor in the crude synthesis gas, thereby forming synthesis gas condensate water, the synthesis gas condensate water is sent into the sewage treatment device through a synthesis gas condensate water delivery pipe, and the wastewater treated by the sewage treatment device is used as electrolysis water.

[0023] Step S4, hydrogen production by electrolysis of water: another part of the CO separated by the gas separation device is used as the circulating medium of the anode of the electrolytic cell in the hydrogen production by electrolysis of water device, thereby reducing the power consumption of hydrogen production, and the wastewater treated by the wastewater treatment device is used as the electrolysis water for electrolysis of hydrogen in the electrolytic cell of the hydrogen production by electrolysis of water device, O2 and CO2 produced by the anode of the electrolytic cell are separated by separator I, a part of O2 and CO2 is used as a combustion aid to participate in power generation, and another part of O2 and CO2 is used as a gasification agent to participate in the gasification reaction of the underground gasification furnace, the separated O2 is cooled by cooler I, and then water droplets are collected by droplet catcher I, a part of O2 is used as a gasification agent to participate in the gasification reaction of the underground gasification furnace, and another part of O2 is used to prepare O3 in the ozone generator, which is used as an oxidizing agent to oxidize and degrade organic pollutants in the wastewater treatment device, H2 produced by the cathode of the electrolytic cell is separated from water by separator II, and then sent to cooler II for cooling, and the cooled hydrogen is again sent to droplet catcher II to collect water droplets, and the dried hydrogen is finally stored in hydrogen storage device II.

[0024] Preferably, when CO is used as the circulating medium of the anode of the electrolytic cell in the hydrogen production by electrolysis of water device, the proportion of CO2 and O2 produced by the anode of the electrolytic cell is 79% and 21%.

[0025] Preferably, the degradation method of the organic pollutants in the wastewater treatment device is electro-catalytic oxidation or ozone oxidation.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] 1. The present application can combine the underground coal gasification technology with the existing hydrogen production by electrolysis of water process to create a new zero-carbon hydrogen production system with a technical system integration and efficient use of resources. The system reasonably uses the CO produced by underground coal gasification and separated and purified for combustion power generation to supply power to the hydrogen production by electrolysis of water device and other power-consuming devices, thereby reducing the transportation cost of electricity, and the surplus electricity can also be stored for standby use. The treated and standard-compliant synthetic gas condensate water is used as the main water for electrolysis of hydrogen, and the cooling water from the separator is also injected, thereby reducing the amount of pure water. In the conventional electrolysis, the H2 produced by the cathode has high purity, and after treatment, it can be stored and transported; the O2 produced by the anode can be used as a gasification agent to be injected into the underground gasification furnace, and can also be used as the raw material for ozone generation in the wastewater treatment process.

[0028] 2, In the electrolytic water hydrogen production device of the application, after CO is sent into the anode of the electrolytic cell as a circulating medium to participate in the electrolysis reaction, CO reacts with O2 to produce CO2, which is a non-conventional electrolysis. In the case of non-conventional electrolysis, the CO produced by underground coal gasification and separated and purified is used as the circulating medium of the electrolytic hydrogen production process, which can reduce part of the hydrogen production power consumption, and the CO2 and O2 produced by the anode of the electrolytic cell can be used as the gasification agent of the gasification process or the combustion-supporting agent of the power generation process. At the same time, the high-purity CO2 produced by the power generation device can also be injected into the underground gasification furnace as a gasification agent. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a schematic diagram of the structure of the zero-carbon hydrogen production system coupled with underground gasification and electrolytic water;

[0030] Figure 2 is a schematic diagram of resource comprehensive utilization of the zero-carbon hydrogen production system coupled with underground gasification and electrolytic water.

[0031] In the figure: 1. Underground gasification furnace; 2. Water cooling and spraying device; 3. Synthetic gas pretreatment device; 4. Coke adsorption device; 5. Synthetic gas compression device; 6. Sewage treatment device; 7. Ozone generation device; 8. Electrolytic water hydrogen production device; 9. Oxygen catcher; 10. Oxygen cooler; 11. Oxygen separator; 12. Hydrogen separator; 13. Hydrogen cooler; 14. Hydrogen catcher; 15. Acid gas removal device; 16. CO2 desorption device; 17. Gas separation device; 18. Hydrogen storage device; 19. Power generation device; 20. Energy storage device; 21. Electrolytic cell; 22. Hydrogen storage device. DETAILED DESCRIPTION

[0032] In order to make the technical means, creative features, purposes and effects of the application easy to understand, the technical solutions in the embodiments of the application will be described clearly and completely below in combination with the drawings in the embodiments of the application.

[0033] In the description of the application, it should be understood that the terms indicating the position used in the description of the subject in the application, such as "height", "length", "width", "front surface", are based on the premise that the subject is placed vertically, i.e. perpendicular to the ground, and are only for the convenience of describing the application, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the application.

[0034] EMBODIMENT

[0035] As shown in Figure 1 , the application gives a zero-carbon hydrogen production system coupled with underground gasification and electrolytic water, which comprises:

[0036] The underground gasification furnace 1 is connected with the first output end of the electrolytic water hydrogen production device 8 through the O2 and CO2 gasification agent delivery pipe at the top first input end, connected with the third output end of the electrolytic water hydrogen production device 8 through the O2 gasification agent delivery pipe at the top second input end, and connected with the output end of the power generation device 19 through the CO2 gasification agent delivery pipe at the bottom input end.

[0037] The water cooling spraying device 2 is connected with the output end of the underground gasification furnace 1 through the synthetic gas delivery pipe at the input end, and connected with the first input end of the sewage treatment device 6 through the synthetic gas condensate water delivery pipe at the first output end.

[0038] The synthetic gas pretreatment device 3 is connected with the second output end of the water cooling spraying device 2 through the gas delivery pipe at the input end, and used for adsorbing impurities, compressing synthetic gas, and removing acid gas and CO2 in the synthetic gas.

[0039] The gas separation device 17 is connected with the output end of the synthetic gas pretreatment device 3 through the gas output pipe at the input end, connected with the hydrogen storage device I 18 through the H2 delivery pipe at the first output end, and connected with the first input end of the power generation device 19 through the CO fuel gas delivery pipe at the second output end.

[0040] The electrolytic water hydrogen production device 8 is connected with the output end of the sewage treatment device 6 through the electrolytic water delivery pipe at the first input end, and connected with the second input end of the power generation device 19 through the O2 and CO2 combustion-supporting agent delivery pipe at the second output end.

[0041] The power generation device 19 is connected with the synthetic gas pretreatment device 3, the sewage treatment device 6, and the electrolytic water hydrogen production device 8 through the power delivery line respectively.

[0042] Specifically, the third output end of the gas separation device 17 is connected with the electrolytic water hydrogen production device 8 through the CO circulating medium delivery pipe, and used for delivering the circulating medium CO of the anode of the electrolytic cell in the electrolytic water hydrogen production device.

[0043] Specifically, the synthetic gas pretreatment device 3 comprises a coke adsorption device 4, a synthetic gas compression device 5, an acid gas removal device 15, and a CO2 desorption device 16 arranged in sequence, wherein the input end of the coke adsorption device 4 is connected with the second output end of the water cooling spraying device 2 through the gas delivery pipe, the input end of the synthetic gas compression device 5 is connected with the output end of the coke adsorption device 4 through the first gas delivery pipe, the input end of the acid gas removal device 15 is connected with the output end of the synthetic gas compression device 5 through the second gas delivery pipe, the input end of the CO2 desorption device 16 is connected with the output end of the acid gas removal device 15 through the third gas delivery pipe, and the output end of the CO2 desorption device 16 is connected with the input end of the gas separation device 17 through the gas output pipe.

[0044] Specifically, the water electrolysis hydrogen production device 8 comprises an electrolytic cell 21, a separator I 11, a cooler I 10, a droplet catcher I 9, a separator II 12, a cooler II 13, a droplet catcher II 14, and a hydrogen storage device II 22, a first input end of the separator I 11 is communicated with the anode of the electrolytic cell 21 through an O2 and CO2 delivery pipe, a second input end of the separator I 11 is communicated with the anode of the electrolytic cell 21 through an O2 delivery pipe, a first output end of the separator I 11 is connected with the first input end of the top of the underground gasification furnace 1 through an O2 and CO2 gasification agent delivery pipe, a second output end of the separator I 11 is connected with the second input end of the power generation device 19 through an O2 and CO2 combustion-supporting agent delivery pipe, a third output end of the separator I 11 is communicated with the input end of the cooler I 10 through a first delivery pipe, the output end of the cooler I 10 is communicated with the input end of the droplet catcher I 9 through a second delivery pipe, a first output end of the droplet catcher I 9 is connected with the second input end of the top of the underground gasification furnace 1 through an O2 gasification agent delivery pipe, an input end of the separator II 12 is communicated with the cathode of the electrolytic cell 21 through an H2 output pipe, a first output end of the separator II 12 is connected with the input end of the cooler II 13 through a third delivery pipe, the output end of the cooler II 13 is communicated with the input end of the droplet catcher II 14 through a fourth delivery pipe, the output end of the droplet catcher II 14 is communicated with the hydrogen storage device II 22 through an H2 delivery pipe.

[0045] Specifically, a second output end of the droplet catcher I 9 is communicated with the input end of the ozone generation device 7 through an O2 delivery pipe, and the output end of the ozone generation device 7 is communicated with the sewage treatment device 6 through an oxidant O3 delivery pipe.

[0046] Specifically, a fourth output end of the separator I 11 is communicated with the electrolytic cell 21 through a first drainage pipe, and a second output end of the separator II 12 is communicated with the electrolytic cell 21 through a second drainage pipe.

[0047] Specifically, the power generation device 19 is further communicated with the energy storage device 20 through a power delivery line.

[0048] Process principle:

[0049] The O2, CO2 or O2 / CO2 is sent into the underground gasification furnace as a gasification agent to participate in the reaction, and the heat value components in the synthesis gas include CO, H2, CH4 and the like, and the non-heat value and environmental pollution gas includes CO2, SO2, H2S and the like. The crude synthesis gas needs to be cooled by a water cooling spraying device, and impurity adsorption, gas compression, acid gas removal and CO2 desorption are carried out by a synthesis gas pretreatment device, and after CO, H2 and the like are separated by a gas separation device, relatively pure fuel gas CO or circulating medium CO can be obtained. The condensate water of the synthesis gas also needs to be treated by a sewage treatment device and meets the standard, and then is sent into an electrolytic water hydrogen production device as electrolytic water. Then, the separated H2 is sent into a hydrogen storage device for storage, the fuel gas CO is sent into a power generation device for combustion and power generation, and the circulating medium CO is sent into the electrolytic water hydrogen production device as a circulating medium of the anode of the electrolytic cell. The power generation device near the electrolytic water hydrogen production device, the sewage treatment device, the synthesis gas pretreatment device and other electric devices can be powered, the produced CO2 can be used as a gasification agent to react with the underground gasification furnace, and the remaining electric energy can be sent into an energy storage device for storage. The electrolytic water hydrogen production device has sufficient electric energy and electrolytic water, and the electric consumption is further reduced due to the effect of the circulating medium CO, the produced H2 is also sent into the hydrogen storage device for storage, the produced O2 or O2 / CO2 can be used as a gasification agent to react with the underground gasification furnace, the O2 can be used as O3 generating raw material and sent into an ozone generation device, and the O2 / CO2 can be used as a combustion supporting agent of the power generation device.

[0050] As shown in Figure 2 The present application provides a resource comprehensive utilization method of an underground gasification and electrolytic water coupling zero-carbon hydrogen production system, comprising the following steps:

[0051] Step S1, coal underground gasification: the crude synthesis gas produced by the underground gasification furnace 1 is sprayed through the water cooling spraying device 2, which is used to condense the oil, dust, organic impurities and part of the water vapor in the crude synthesis gas, thereby forming synthesis gas condensate water, which is sent into the sewage treatment device 6 through the synthesis gas condensate water conveying pipe, and the synthesis gas from which the oil, dust, organic impurities and part of the water vapor are removed is sent into the coke adsorption device 4 through the gas conveying pipe, which is used to adsorb the organic and inorganic pollutants (the organic pollutants are phenols, benzene and naphthalene, and the inorganic pollutants are sulfides, cyanides and ammonia nitrogen) remaining in the coal gas, and the synthesis gas adsorbed by the coke adsorption device 4 is sent into the synthesis gas compression device 5 through the first gas conveying pipe for gas compression, and the compressed synthesis gas is sent into the acid gas removal device 15 through the second gas conveying pipe to remove the acid gas (the acid gas is hydrogen sulfide H2S, sulfur dioxide SO2 and nitrogen oxides (NO, NO2, etc.)), and the synthesis gas from which the acid gas is removed is sent into the CO2 desorption device 16 to remove CO2, and the synthesis gas from which the CO2 is removed is sent into the gas separation device 17 through the gas output pipe to separate CO and H2, and the H2 separated by the gas separation device 17 is sent into the hydrogen storage device I 18, which can be used as industrial fuel gas, chemical synthesis raw material gas, etc. for storage and transportation;

[0052] Step S2, combustion power generation: the CO separated by the gas separation device 17 can be used as fuel gas for the power generation device 19, and the power generation device 19 not only can provide electric energy for the water electrolysis hydrogen production device 8, the sewage treatment device 6, the synthesis gas pretreatment device 3, etc., but also can send the surplus electric power into the energy storage device 20 as standby electricity for storage, and the high-concentration CO2 produced by the power generation device 19 can be injected into the underground gasification furnace 1 as a gasification agent to participate in the reaction;

[0053] Step S3, sewage treatment: the crude synthesis gas produced by the underground gasification furnace 1 is sprayed through the water cooling spraying device 2, which is used to condense the oil, dust, organic impurities and part of the water vapor in the crude synthesis gas, thereby forming synthesis gas condensate water, which is sent into the sewage treatment device 6 through the synthesis gas condensate water conveying pipe, and the wastewater treated by the sewage treatment device 6 is used as electrolytic water;

[0054] Step S4, hydrogen production by electrolysis of water: another part of the CO separated by the gas separation device 17 is used as the circulating medium of the anode of the electrolytic cell of the hydrogen production by electrolysis of water device 8, thereby reducing the power consumption of hydrogen production, the wastewater treated by the wastewater treatment device 6 is used as the electrolysis water for the electrolysis of the hydrogen production by electrolysis of water device 8, the O2 and CO2 generated by the anode of the electrolytic cell 21 are separated by the separator I 11, a part of the O2 and CO2 is used as the combustion-supporting agent for the power generation device 19, another part of the O2 and CO2 is used as the gasification agent for the underground gasification furnace 1, the separated O2 is cooled by the cooler I 10, then is collected by the drip catcher I 9, a part of the O2 is used as the gasification agent for the underground gasification furnace 1, another part of the O2 is used for the ozone generation device 7 to generate O3, which is used as the oxidizing agent for the degradation of the organic pollutants in the wastewater treatment device 6, the H2 generated by the cathode of the electrolytic cell 21 is separated from the water by the separator II 12, then is cooled by the cooler II 13, the cooled H2 is collected by the drip catcher II 14, and the dried H2 is finally stored in the hydrogen storage device II 22.

[0055] Specifically, when the CO is used as the circulating medium of the anode of the electrolytic cell of the hydrogen production by electrolysis of water device 8, the proportion of the CO2 and O2 generated by the anode of the electrolytic cell 21 is 79% and 21% respectively.

[0056] Specifically, the degradation method of the organic pollutants in the wastewater treatment device 6 is the electro-catalytic oxidation method or the ozone oxidation method.

[0057] The above disclosed is only the preferred embodiment of the present application, but the embodiments of the present application are not limited to this, any changes that can be thought by any person skilled in the art should fall within the protection scope of the present application.

Claims

1. Underground gasification and water electrolysis coupled zero-carbon hydrogen production system, characterized by: include: An underground gasifier (1), wherein a first input end at the top is connected to a first output end of a water electrolysis hydrogen production device (8) via an O2 and CO2 gasification agent delivery pipe, a second input end at the top is connected to a third output end of the water electrolysis hydrogen production device (8) via an O2 gasification agent delivery pipe, and a bottom input end is connected to an output end of a power generation device (19) via a CO2 gasification agent delivery pipe; A water cooling spray device (2), the input end of which is connected to the output end of the underground gasifier (1) via a synthesis gas delivery pipe, and the first output end of which is connected to the first input end of the sewage treatment device (6) via a synthesis gas condensate delivery pipe; The synthesis gas pretreatment device (3) has an input end connected to the second output end of the water cooling spray device (2) through a gas transmission pipe, and is used to absorb impurities, compress the synthesis gas, and remove acid gas and CO2 in the synthesis gas; A gas separation device (17), the input end of which is connected to the output end of the synthesis gas pretreatment device (3) via a gas output pipe, the first output end of which is connected to the hydrogen storage device I (18) via an H2 delivery pipe, and the second output end of which is connected to the first input end of the power generation device (19) via a CO fuel gas delivery pipe; The electrolysis water hydrogen production device (8) has a first input end connected to the output end of the sewage treatment device (6) via an electrolysis water delivery pipe, and a second output end connected to the second input end of the power generation device (19) via an O2 and CO2 combustion aid delivery pipe; The power generation device (19) is connected to the synthesis gas pretreatment device (3), the sewage treatment device (6), and the water electrolysis hydrogen production device (8) respectively through the power transmission line.

2. The underground gasification and water electrolysis coupled zero-carbon hydrogen production system according to claim 1, characterized in that: The third output end of the gas separation device (17) is connected to the water electrolysis hydrogen production device (8) via a CO circulating medium delivery pipe, and is used to deliver the circulating medium CO to the anode of the electrolytic cell in the water electrolysis hydrogen production device.

3. The underground gasification and water electrolysis coupled zero-carbon hydrogen production system according to claim 2 is characterized in that: The synthesis gas pretreatment device (3) includes a coke adsorption device (4), a synthesis gas compression device (5), an acid gas removal device (15) and a CO2 desorption device (16) which are arranged in sequence, wherein the input end of the coke adsorption device (4) is connected to the second output end of the water cooling spray device (2) through a gas transmission pipe, the input end of the synthesis gas compression device (5) is connected to the output end of the coke adsorption device (4) through a first gas transmission pipe, the input end of the acid gas removal device (15) is connected to the output end of the synthesis gas compression device (5) through a second gas transmission pipe, the input end of the CO2 desorption device (16) is connected to the output end of the acid gas removal device (15) through a third gas transmission pipe, and the output end of the CO2 desorption device (16) is connected to the input end of the gas separation device (17) through a gas output pipe.

4. The underground gasification and water electrolysis coupled zero-carbon hydrogen production system according to claim 3 is characterized in that: The electrolysis water hydrogen production device (8) includes an electrolytic cell (21), a separator I (11), a cooler I (10), a droplet catcher I (9), a separator II (12), a cooler II (13), a droplet catcher II (14) and a hydrogen storage device II (22), wherein the first input end of the separator I (11) is connected to the anode of the electrolytic cell (21) through an O2 and CO2 delivery pipe, the second input end of the separator I (11) is connected to the anode of the electrolytic cell (21) through an O2 delivery pipe, the first output end of the separator I (11) is connected to the first input end of the top of the underground gasifier (1) through an O2 and CO2 gasification agent delivery pipe, and the second output end of the separator I (11) is connected to the second input end of the power generation device (19) through an O2 and CO2 combustion-supporting agent delivery pipe. The third output end of the separator I (11) is connected to the input end of the cooler I (10) through the first delivery pipe, the output end of the cooler I (10) is connected to the input end of the droplet catcher I (9) through the second delivery pipe, the first output end of the droplet catcher I (9) is connected to the second input end of the top of the underground gasifier (1) through the O2 gasification agent delivery pipe, the input end of the separator II (12) is connected to the cathode of the electrolytic cell (21) through the H2 output pipe, the first output end of the separator II (12) is connected to the input end of the cooler II (13) through the third delivery pipe, the output end of the cooler II (13) is connected to the input end of the droplet catcher II (14) through the fourth delivery pipe, and the output end of the droplet catcher II (14) is connected to the hydrogen storage device II (22) through the H2 delivery pipe.

5. The underground gasification and water electrolysis coupled zero-carbon hydrogen production system according to claim 4, characterized in that: The second output end of the dropper I (9) is connected to the input end of the ozone generator (7) through the O2 delivery pipe, and the output end of the ozone generator (7) is connected to the sewage treatment device (6) through the oxidant O3 delivery pipe.

6. The underground gasification and water electrolysis coupled zero-carbon hydrogen production system according to claim 5, characterized in that: The fourth output end of the separator I (11) is connected to the electrolytic cell (21) through a first drain pipe, and the second output end of the separator II (12) is connected to the electrolytic cell (21) through a second drain pipe.

7. The underground gasification and water electrolysis coupled zero-carbon hydrogen production system according to claim 6, characterized in that: The power generation device (19) is also connected to the energy storage device (20) via a power transmission line.

8. The method for comprehensive resource utilization of the underground gasification and water electrolysis coupled zero-carbon hydrogen production system according to claim 7, characterized in that: The following steps are involved: Step S1, underground coal gasification: The crude synthesis gas produced by the underground gasification furnace (1) is passed through a water cooling spray device (2) to condense the oil, dust, organic impurities and part of the water vapor in the crude synthesis gas, thereby forming synthesis gas condensate. The synthesis gas condensate is sent to a sewage treatment device (6) through a synthesis gas condensate delivery pipe. The synthesis gas from which the oil, dust, organic impurities and part of the water vapor are removed is sent to a coke adsorption device (4) through a gas delivery pipe to adsorb the organic pollutants and inorganic pollutants remaining in the coal gas. After adsorption by the coke adsorption device (4), The synthesis gas is then sent to the synthesis gas compression device (5) through the first gas transmission pipe for gas compression, and the compressed synthesis gas is then sent to the acid gas removal device (15) through the second gas transmission pipe to remove acid gas, and the synthesis gas after the acid gas removal is sent to the CO2 desorption device (16) to remove CO2, and the synthesis gas after the CO2 removal is sent to the gas separation device (17) through the gas output pipe to separate CO and H2, and the H2 separated by the gas separation device (17) is sent to the hydrogen storage device I (18), and can be used as industrial fuel gas, chemical synthesis raw gas, etc. for storage and transportation; Step S2, combustion power generation: The CO separated by the gas separation device (17) can be used as fuel gas for the power generation device (19). The power generation device (19) can not only provide electric energy for the water electrolysis hydrogen production device (8), the sewage treatment device (6), the synthesis gas pretreatment device (3), etc., but also can send the surplus electricity to the energy storage device (20) for storage as backup electricity. The high-concentration CO2 produced can be injected into the underground gasification furnace (1) as a gasifying agent to participate in the reaction; Step S3, sewage treatment: The crude synthesis gas produced by the underground gasification furnace (1) is sprayed through the water cooling spray device (2) to condense oil, dust, organic impurities and part of the water vapor in the crude synthesis gas, thereby forming synthesis gas condensate. The synthesis gas condensate is sent to the sewage treatment device (6) through the synthesis gas condensate delivery pipe. The wastewater treated by the sewage treatment device (6) is used as electrolyzed water; Step S4, electrolysis of water to produce hydrogen: another part of the CO separated by the gas separation device (17) is used as the circulating medium of the electrolytic cell anode in the electrolytic water hydrogen production device (8), thereby reducing the power consumption of hydrogen production. The wastewater treated by the sewage treatment device (6) is sent as electrolytic water to the electrolytic cell (21) of the electrolytic water hydrogen production device (8) for electrolytic hydrogen production. The O2 and CO2, O2 and water generated at the anode of the electrolytic cell (21) are separated by the separator I (11). A part of the O2 and CO2 are sent to the power generation device (19) as a combustion aid to participate in power generation, and the other part of the O2 and CO2 are sent to the underground gasification furnace as a gasification agent. (1) Gasification reaction. The separated O2 is cooled by cooler I (10) and then captured by droplet collector I (9). A portion of the O2 is sent to the underground gasifier (1) as a gasifying agent to participate in the gasification reaction. The other portion of the O2 is sent to the ozone generator (7) to prepare O3, which is used as an oxidant in the sewage treatment device (6) to oxidize and degrade organic pollutants. The H2 produced at the cathode of the electrolytic cell (21) is separated from the water by separator II (12) and sent to cooler II (13) for cooling. The cooled hydrogen is again sent to droplet collector II (14) to capture water droplets. The dried hydrogen is finally stored in hydrogen storage device II (22).

9. The method for comprehensive resource utilization of the underground gasification and water electrolysis coupled zero-carbon hydrogen production system according to claim 8, characterized in that: The degradation method of organic pollutants in the sewage treatment device (6) is an electrocatalytic oxidation method or an ozone oxidation method.

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