Coal in-situ gasification and deep processing treatment system and method

Abstract

The invention provides a coal in-situ gasification and deep processing treatment system and method, and belongs to the technical field of coal development. The coal in-situ gasification and deep processing treatment system comprises an extraction and gasification unit which penetrates through a coal seam from the earth surface, gas to be processed is transmitted to the earth surface through the coal seam, and the gas to be processed comprises coal seam gas and synthesis gas; the gas purification unit is used for receiving and purifying to-be-processed gas to prepare purified gas; the gas processing unit is used for receiving at least part of the purified gas and carrying out steam reforming and hydrogen purification and separation to prepare finish machining gas, and the finish machining gas comprises hydrogen, carbon monoxide and carbon dioxide. Through reasonable selection of technical research and optimal design of the technological process, the recovery rate and the utilization rate of coal and gas resources are improved, efficient and stable hydrogen output is ensured, the industrial chain of in-situ coal gasification is expanded, the additional value of the coal resources is increased, and the effects of being simple in process, safe, reliable, energy-saving and emission-reducing are achieved.

Description

Technical Field

[0001] This invention relates to the field of coal development technology, specifically to a coal in-situ gasification and deep processing system and method. Background Technology

[0002] Coal has made significant contributions to my country's economic and social development, and will remain my country's primary energy source for a considerable period. However, due to the deep burial depth and relatively poor resource endowment of my country's coal resources, these resources face numerous challenges from traditional physical mining methods. Traditional physical coal mining generates pollutants such as coal gangue, coal gas, and mine water, while also causing surface subsidence and soil erosion. Furthermore, to achieve the long-term goal of peak carbon emissions and carbon neutrality, the coal mining industry needs to vigorously promote clean production technologies to create favorable conditions for transforming its development model and achieving clean and efficient development.

[0003] Coal in-situ gasification is a green mining technology that converts underground coal into combustible gas (syngas) through controlled combustion, which is then extracted to the surface for use. This technology eliminates the massive mining and transportation processes, significantly reducing underground engineering and arduous operations, and greatly minimizing the environmental pollution caused by coal mining and the adverse ecological impacts of coal combustion. However, current in-situ gasification methods for deep, thin coal seams are mostly single-gasification studies, resulting in low extraction and utilization rates of coal and gas resources. Therefore, there is an urgent need for a comprehensive coal in-situ gasification and deep processing system and method. Summary of the Invention

[0004] This invention provides a coal in-situ gasification and deep processing system and method. Through reasonable selection of technologies and optimization of process flow design, it improves the extraction and utilization rate of coal and gas resources, and ensures efficient and stable hydrogen production. This not only expands the industrial chain of in-situ coal gasification and increases the added value of coal resources, but also achieves the effects of simple process, safety and reliability, and energy saving and emission reduction.

[0005] A coal in-situ gasification and deep processing system includes: The extraction and gasification unit is set from the surface to the coal seam to produce gas to be processed. The gas to be processed is transported to the surface through the coal seam. The gas to be processed includes coalbed methane and syngas. A gas purification unit is used to receive and purify the gas to be processed to produce purified gas. A gas processing unit is used to receive at least a portion of the purified gas and perform steam reforming and purification separation of hydrogen to produce refined gas, said refined gas comprising hydrogen and carbon dioxide; The carbon capture and storage unit is used to capture and store carbon dioxide in the finishing gas.

[0006] Preferably, the extraction and gasification unit includes: The first injection-production well includes a first submerged section that penetrates from the surface to the coal seam and a first extension section that is distributed along the coal seam and connected to the first submerged section. The second injection-production well is at least one that is distributed side by side with the first injection-production well. The second injection-production well includes a second submerged section that extends from the surface to the coal seam and a second extension section that is distributed along the coal seam and connected to the second submerged section. A connecting section, which is disposed within the coal seam, is used to connect the first extension section and the second extension section. The third injection-production well includes a third submerged section that extends from the surface into the coal seam, with one end of the third submerged section located within the coal seam connected to a connecting section.

[0007] Preferably, the third injection-production well is equipped with a dehydration device, which is used to dehydrate the coalbed methane to produce purified water, and supply the purified water to the extraction and gasification unit and the gas processing unit.

[0008] Preferably, the gas purification unit includes a dust removal tower for dust removal from the gas to be processed, a desulfurization tower for desulfurization of the gas to be processed, and a benzene removal tower for benzene removal from the gas to be processed, connected in sequence.

[0009] Preferably, the gas processing unit includes at least one steam methane reforming skid and at least one separation and purification hydrogen production device. The purified gas is circulated between the steam methane reforming skid and the separation and purification hydrogen production device until the hydrogen content 'a' in the gas phase product meets a preset value and then exits the gas processing unit. The preset value of the hydrogen content 'a' is: a≥70%.

[0010] Preferably, the coal in-situ gasification and deep processing system further includes a methane and syngas power generation unit, which is connected to the gas processing unit and the carbon capture and storage unit, respectively, for receiving at least a portion of the purified gas for combustion power generation and transporting the combustion products to the carbon capture and storage unit.

[0011] Preferably, the coal in-situ gasification and deep processing system further includes a hydrogen and oxygen production unit, which includes a distributed photovoltaic power station and an electrolyzer.

[0012] Preferably, the coal in-situ gasification and deep processing system further includes a green methanol synthesis unit, which receives purified gas from the gas purification unit to synthesize methanol and transports carbon dioxide to the carbon capture and storage unit.

[0013] Preferably, the coal in-situ gasification and deep processing system further includes a green ammonia synthesis unit, which is used to receive purified gas from the gas purification unit for ammonia synthesis.

[0014] A method for in-situ coal gasification and deep processing, using the aforementioned in-situ coal gasification and deep processing system, includes the following steps: Coalbed methane processing steps: Extract coalbed methane, purify the coalbed methane, and then use steam methane reforming technology to react at least part of the coalbed methane to generate hydrogen, and collect carbon dioxide through a carbon capture and storage unit; Coal gasification processing steps: Gasification is achieved by reacting coal with a gasifying agent to produce syngas. The syngas is then purified and hydrogen is separated from it. The syngas is then reacted to produce hydrogen through steam methane reforming technology. Carbon dioxide is collected through a carbon capture and storage unit.

[0015] As can be seen from the above technical solutions, the present invention has the following beneficial effects: The coal in-situ gasification and deep processing system of the present invention can first extract coalbed methane, and then use steam methane reforming technology to generate hydrogen from the coalbed methane on the ground, and collect carbon dioxide through a carbon capture and storage unit; at the same time, it can also utilize the coal in-situ gasification system to generate syngas with hydrogen, carbon monoxide, and methane as the main components, and then use steam methane reforming technology to generate hydrogen from the coalbed methane on the ground, and collect carbon dioxide through a carbon capture and storage unit to reduce the project's carbon emissions. This application, through reasonable selection of technology research and optimized design of process flow, improves the recovery rate and utilization rate of coal and gas resources, ensures efficient and stable hydrogen production, expands the industrial chain of in-situ coal gasification, increases the added value of coal resources, and achieves the effects of simple process, safety and reliability, and energy saving and emission reduction. Attached Figure Description

[0016] Figure 1 A schematic diagram showing the connection relationship of the coal in-situ gasification and deep processing system provided in this application; Figure 2 Another connection diagram of the coal in-situ gasification and deep processing system provided in this application; Figure 3 This is another schematic diagram showing the connection relationship of the coal in-situ gasification and deep processing system provided in this application. Figure 4 This is another schematic diagram showing the connection relationship of the coal in-situ gasification and deep processing system provided in this application. Figure 5 This is another schematic diagram showing the connection relationship of the coal in-situ gasification and deep processing system provided in this application. Figure 6 A schematic diagram showing the connection relationship of the coalbed methane extraction and coal gasification units provided for this application; Figure 7 A flowchart of the coal in-situ gasification and deep processing method provided in this application.

[0017] In the diagram: 10. Extraction and gasification unit; 110. First injection-production well; 111. First submerged section; 112. First extension section; 120. Second injection-production well; 121. Second submerged section; 122. Second extension section; 130. Connecting section; 140. Third injection-production well; 141. Third submerged section; 142. Dehydration unit; 20. Gas purification unit; 210. Dust removal tower; 220. Desulfurization tower; 230. Benzene removal tower; 30. Gas processing unit; 310. Steam methane reforming skid; 320. Separation and purification hydrogen production unit; 40. Carbon capture and storage unit; 50. Methane and syngas power generation unit; 60. Hydrogen and oxygen production unit; 610. Distributed photovoltaic power station; 620. Electrolyzer; 70. Green synthetic methanol unit; 80. Green synthetic ammonia unit; 100. Surface; 101. Coal seam. Detailed Implementation

[0018] A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions: (Refer to...) Figure 1 A coal in-situ gasification and deep processing system includes an extraction and gasification unit 10, a gas purification unit 20, a gas processing unit 30, and a carbon capture and storage unit 40. The extraction and gasification unit 10 extends from the surface 100 to the coal seam 101 and is used to produce gas to be processed, which includes coalbed methane and syngas. The gas to be processed is transported to the surface 100 via the coal seam. The gas purification unit 20 receives and purifies the gas to be processed to produce purified gas. The gas processing unit 30 receives at least a portion of the purified gas and performs steam reforming and hydrogen separation to produce refined gas. Specifically, the refined gas includes hydrogen and carbon dioxide. The carbon capture and storage unit 40 captures and stores the carbon dioxide in the refined gas.

[0020] In the coal in-situ gasification and deep processing system of this application embodiment, the gas purification unit 20 and the gas processing unit 30 are set at the surface 100, and the carbon capture and storage unit 40 can be located at the surface 100 or can be installed from the surface 100 underground. This application integrates the extraction and gasification unit 10, the gas purification unit 20, the gas processing unit 30, and the carbon capture and storage unit 40 through reasonable selection of technologies and optimized design of the process flow. This enables in-situ coal gasification and deep processing, improves the extraction and utilization rate of coal and gas resources, ensures efficient and stable hydrogen production, expands the industrial chain of in-situ coal gasification, increases the added value of coal resources, and achieves the effects of simple process, safety and reliability, and energy saving and emission reduction.

[0021] Specifically, the extraction and gasification unit 10 is used to produce gas to be processed, including coalbed methane and syngas. In this embodiment, the extraction and gasification unit 10 works in two stages. In the first stage, coalbed methane is extracted to obtain gas resources. After that, coal gasification to produce syngas is started in the second stage. This can ensure the effective utilization of resources.

[0022] Regarding the underground strata structure, it includes the coal seam roof, the coal seam, and the coal seam floor. Below the surface is the coal seam roof, below the roof is the coal seam, and below the floor is the coal seam. The coal seam is the primary target for underground gasification and gas extraction processes; its location and thickness directly affect the efficiency and feasibility of gasification and extraction. Coal seams are typically located in specific geological strata, and their thickness varies depending on geological conditions. The coal in-situ gasification and deep processing system of this application can use unminable and difficult-to-mine coal as raw materials to produce clean energy from in-situ coal and coalbed methane, thereby improving resource utilization.

[0023] After the gas to be processed is transported to the surface 100 via the coal seam 101 in the extraction and gasification unit 10, it enters the gas purification unit 20. The gas purification unit 20 can receive the gas to be processed and purify it.

[0024] As a preferred embodiment, at least a portion of the purified gas is further fed to the gas processing unit 30, which can receive at least a portion of the purified gas for steam reforming and hydrogen separation to obtain refined gas. According to embodiments of this application, all of the purified gas can be fed to the gas processing unit 30 for reforming, or a portion of the purified gas can be sold directly, with the remainder fed to the gas processing unit 30 for reforming. The refined gas includes hydrogen and carbon dioxide.

[0025] Steam reforming is highly energy efficient. It uses high-temperature (700-1000°C) steam to produce hydrogen from a methane source (purified coalbed methane or syngas). The two elements, combined with a catalyst, react at pressures of 3–25 Pa (1 Pa = 14.5 psi). This reaction produces CO (carbon monoxide), CO2 (carbon dioxide), and hydrogen.

[0026] Next, the hydrogen is purified and separated, further enriched in a second step called the "water-gas shift reaction." In this step, a reaction is again induced between steam and CO with the aid of a catalyst. This produces a small amount of heat, CO, and a large amount of hydrogen. The chemical formula for this process is as follows: Steam methane reforming: CH4 + H2O → CO + 3H2; Water-gas shift reaction: CO + H₂O → Carbon dioxide + Hydrogen.

[0027] Carbon capture and storage (CCS) unit 40 is used to capture carbon dioxide from the refined gas of gas processing unit 30 and separate the carbon dioxide from the refined gas, transporting it to a storage site and isolating it from the atmosphere for an extended period. Exemplarily, during CCS, the released CO2 is piped underground for storage, such as by injecting it into underground sandstone layers. Carbon dioxide can also be captured and reused, for example, in the production of biofuels, plastics, or concrete. CCS unit 40 can reduce greenhouse gas emissions and mitigate global warming; this method is economical and feasible.

[0028] In some embodiments, storage includes not only storing CO2 deep underground but also monitoring for leaks. Oil and gas fields have undergone extensive geological analysis, and the most suitable locations for CO2 storage are depleted gasification furnaces and deep well fields (such as coalbed methane wells).

[0029] In summary, the coal in-situ gasification and deep processing system of this application embodiment can first extract coalbed methane and then use steam methane reforming (SMR) technology to produce hydrogen from the coalbed methane on the ground. Then, using the coal in-situ gasification system, syngas with H2, CO, and CH4 as the main components is generated, and hydrogen is produced from the coalbed methane on the ground using steam methane reforming (SMR) technology. Finally, CO2 is collected through the carbon capture and storage unit 40 to reduce the project's carbon emissions. This application, through reasonable selection of technologies and optimized design of the process flow, improves the recovery and utilization rate of coal and gas resources, ensuring efficient and stable hydrogen production. This not only expands the industrial chain of in-situ coal gasification and increases the added value of coal resources, but also achieves the effects of simple process, safety and reliability, and energy saving and emission reduction.

[0030] This application's embodiments utilize in-situ coal chemical mining technology, in-situ coalbed methane hydrogen production technology, and CCS technology to produce clean energy, ultimately realizing the development of clean hydrogen energy (blue hydrogen). This project integrates the in-situ application of oil extraction and coal chemical development, showing broad prospects. It can effectively mine deep coal resources and achieve green development and clean utilization of coal from the source, innovating a new clean production model in the coal mining industry. Simultaneously, it can ensure energy supply in a low-carbon, clean, safe, efficient, and inexpensive manner. This clean hydrogen energy development project not only effectively achieves environmentally friendly and low-carbon coal mining to produce clean hydrogen energy, but also effectively complements traditional physical coal mining methods, maximizing the energy development of national coal resources.

[0031] In some embodiments, the gas processing unit 30 includes at least one steam methane reforming skid 310 and at least one separation and purification hydrogen production device 320. When there are multiple steam methane reforming skids 310, the multiple steam methane reforming skids 310 are connected in parallel. When there are multiple separation and purification hydrogen production devices 320, the separation and purification hydrogen production devices 320 are connected in parallel. The purified gas is circulated between the steam methane reforming skid 310 and the separation and purification hydrogen production device 320 until the hydrogen content a in the gas phase product meets a preset value and then exits the gas processing unit 30.

[0032] The steam methane reforming skid 310 integrates the steam methane reforming unit onto a containerized platform, which can be made of metal, such as steel. The steam methane reforming skid 310 is assembled and tested at the manufacturing plant before being transported to the production site for use.

[0033] The hydrogen separation and purification unit 320 can also be a containerized integrated unit, in which various components are integrated and installed on a platform to form a containerized unit. After being assembled and debugged at the manufacturing plant, it is then transported to the production site for use.

[0034] In this embodiment, there can be one or more steam methane reforming skids 310, and one or more separation and purification hydrogen production units 320. The steam methane reforming unit is modularly configured in a containerized manner, which can improve the flexibility of the system. The number can be selected and assembled according to actual needs.

[0035] For example, when the production volume of the gas to be processed is small, a steam methane reforming skid 310 and a separation and purification hydrogen production unit 320 can be assembled. When the production volume of the gas to be processed increases, the original combination of a steam methane reforming skid 310 and a separation and purification hydrogen production unit 320 can no longer meet the production demand, so the number of steam methane reforming skids 310 and separation and purification hydrogen production units 320 can be increased as needed. When the production volume of the gas to be processed decreases again, some of the steam methane reforming skids 310 and separation and purification hydrogen production units 320 can be removed, thus providing high flexibility.

[0036] Multiple steam methane reforming skids 310 can be connected in parallel, multiple separation and purification hydrogen production units 320 can be connected in parallel, and modules formed by multiple steam methane reforming skids 310 and modules formed by multiple separation and purification hydrogen production units 320 can be connected in series. This application is not limited to these.

[0037] In some embodiments, the preset value of hydrogen content 'a' is a≥70%.

[0038] In this embodiment, the gas in the gas processing unit 30 is monitored in real time. When the preset value of hydrogen content a is a≥70%, the hydrogen content in the refined gas is considered to be qualified, and the refined gas can proceed to the next process.

[0039] Preferably, when the preset value of hydrogen content a is a≥90%, the refined gas is then proceeded to the next process.

[0040] Reference Figure 6 In some embodiments, the extraction and gasification unit 10 includes a first injection-production well 110, a second injection-production well 120, a connecting section 130, and a third injection-production well 140. The first injection-production well includes a first submerged section 111 and a first extension section 112. The first submerged section 111 extends from the surface into the coal seam, and the first extension section 112 is distributed along the coal seam and is connected to the first submerged section 111. The second injection-production well is at least one distributed parallel to the first injection-production well. Further, the second injection-production well includes a second submerged section 121 and a second extension section 140. The first extension section 112 and the second submerged section 121 are set from the surface to the coal seam. The second extension section 122 is distributed along the coal seam and is connected to the second submerged section. The connecting section is set in the coal seam and is used to connect the first extension section 112 and the second extension section 122. The third injection-production well 140 includes a third submerged section 141 that extends from the surface to the coal seam. One end of the third submerged section is located in the coal seam and is connected to the connecting section 130. The third injection-production well 140 is used to extract coalbed methane during the coalbed methane extraction stage and to heat coal and gasifying agent during the coal gasification stage.

[0041] In some embodiments, the first extension segment 112 and the second extension segment 122 are disposed in the coal seam and distributed in the horizontal extension direction of the coal seam.

[0042] In the first stage, during coalbed methane extraction, the first injection-production well 110 and the second injection-production well 120 are connected to the drilling wellhead mechanism, and the third injection-production well 140 is connected to the gas extraction mechanism. The drilling wellhead mechanism can regulate the pressure within the first and second injection-production wells 110 and 120. When the gas extraction mechanism starts working, the pressure within the first and second injection-production wells 110 and 120 is regulated by the drilling wellhead mechanism, and the gas extraction mechanism also regulates the pressure simultaneously, thereby achieving efficient gas extraction. Furthermore, an automated drainage device can be installed in the third injection-production well 140 to achieve automated coalbed methane extraction for easier control.

[0043] In the second stage, during coalbed methane synthesis, the first injection-production well 110 is used to inject the gasifying agent (such as oxygen, steam, etc.), the third injection-production well 140 is used for ignition, and the second injection-production well 120 is used to synthesize and output syngas. When in-situ underground coal gasification is performed, the gasifying agent is injected into the first injection-production well 110, ignited in the third injection-production well 140, and then sealed. The combustion location is in the connecting section 130 between the first and second extension sections. At the combustion location, the coal and the gasifying agent undergo a chemical reaction to generate syngas. The syngas mainly consists of combustible gases such as carbon monoxide, hydrogen, and methane, and has a high calorific value and chemical energy. The syngas flows into the gas purification unit 20 through the second injection-production well 120. The first and second injection-production wells 110 and 120 have good sealing properties to ensure that the syngas smoothly enters the gas purification unit 20 without leakage.

[0044] Syngas can be produced using either the oxygen-enriched steam continuous process or the oxygen-enriched carbon steam pulsed continuous process. The oxygen-enriched steam continuous process uses oxygen-enriched steam and water vapor as gasifying agents, implementing a continuous air supply method that can produce semi-water gas on a large scale. Because this method uses oxygen as the gasifying agent, it effectively enhances the heat and mass transfer processes between the combustion face and the gas flow, significantly improving gasification efficiency and thermal efficiency. Therefore, it has the advantages of simple process, large gas production, and a gas calorific value of 2000–2500 kcal / m³. 3 The components directly contain H2 > 40%, and [H2+CO] / N2 ≥ 3.1. It can be used as feedstock gas for the synthesis of ammonia and alcohols, and can also be used for IGCC integrated combined cycle gas turbine power generation.

[0045] The oxygen-enriched carbon steam pulsed continuous method involves mixing oxygen (O2) produced by an oxygen generator with CO2 obtained from a coal chemical decarbonization system (such as low-temperature methanol decarbonization) at a 2:1 ratio to create an oxygen-enriched carbon gas, which is then combined with steam to form a composite gasifying agent. Furthermore, by implementing continuous air supply and pulsed variable pressure exhaust, this process can achieve large-scale continuous production of hydrogen-rich water gas, directly containing H2 ≥ 50%, H2 + CO ≥ 78%, and with a calorific value as high as 2400–2800 kcal / m³. 3The hydrogen-rich water gas produced by this method can serve as an ideal gas source for coal chemical feedstock or coal-to-oil hydrogen extraction projects.

[0046] It is understandable that the gasifying agent may be accompanied by a catalyst, which is used to catalyze the in-situ gasification of coal.

[0047] Furthermore, the first injection-production well 110 includes a first submerged section 111 and a first extension section 112, with the first submerged section 111 and the first extension section 112 connected. The second injection-production well 120 includes a second submerged section 121 and a second extension section 122, with the second submerged section 121 and the second extension section 122 connected. The first submerged section 111 and the second submerged section 121 are respectively set from the surface to the coal seam. The first submerged section 111 is used to inject gasifying agent, and the second submerged section 121 is used to output syngas.

[0048] In some embodiments, the first extension segment 112 and the second extension segment 122 are located on the same plane. In other words, the first extension segment 112 and the second extension segment 122 are arranged side by side at intervals within the coal seam. This side-by-side arrangement is beneficial for coalbed methane extraction and in-situ underground gasification in thin coal seams, effectively reducing construction difficulty. For example, construction can be carried out in coal seams with a thickness of less than 2 meters to more than 1.5 meters.

[0049] In some embodiments, a dehydration device 142 is provided in the third injection-production well 140. The dehydration device 142 is used to dehydrate the coalbed methane to obtain purified water and supply the purified water to the extraction and gasification unit 10 and the gas processing unit 30.

[0050] Before the coalbed methane is output from the pipeline of the third injection-production well 140, it can be purified in advance. The coalbed methane contains a large amount of water, and the dehydration device 142 can dehydrate the coalbed methane to obtain purified water. The purified water can be collected and transported to the extraction and gasification unit 10 and the gas processing unit 30 for application. This can realize the internal utilization of resources, reduce the consumption of external water sources, and the purified water is extracted from underground and has a relatively pure composition, which can avoid the occurrence of side reactions in subsequent applications.

[0051] In some embodiments, the gas purification unit 20 includes a dust removal tower 210, a desulfurization tower 220, and a benzene removal tower 230 connected in sequence. The dust removal tower 210 is used to remove dust from the gas to be processed, the desulfurization tower 220 is used to desulfurize the gas to be processed, and the benzene removal tower 230 is used to remove benzene from the gas to be processed.

[0052] Syngas or dehydrated coalbed methane arrives at gas purification unit 20 through pipelines. After processes such as dust removal, desulfurization, ammonium sulfate removal, and benzene washing, impurities such as dust, moisture, tar, sulfides, benzene, and naphthalene in the coal gas are removed.

[0053] Reference Figure 2 In some embodiments, the coal in-situ gasification and deep processing system further includes a methane and syngas power generation unit 50, which is connected to the gas processing unit 30 and the carbon capture and storage unit 40, respectively, receives at least a portion of the purified gas for combustion power generation, and transports the combustion products to the carbon capture and storage unit 40.

[0054] In this embodiment, the methane and syngas power generation unit 50 can directly utilize the purified gas to generate electricity. The obtained electricity can first be supplied to the internal use of the coal in-situ gasification and deep processing system, and the surplus electricity can be transmitted to the power grid for sale.

[0055] The combustion products generated by the methane and syngas power generation unit 50 are mainly carbon dioxide, which can be transported to the carbon capture and storage unit 40 for storage to reduce greenhouse gas emissions.

[0056] Reference Figure 3 In some embodiments, the coal in-situ gasification and deep processing system further includes a hydrogen and oxygen production unit 60, which includes a distributed photovoltaic power station 610 and an electrolytic cell 620. The distributed photovoltaic power station and the electrolytic cell are used to provide power to the electrolytic cell.

[0057] In the mining area, multi-unit 5-6MW distributed photovoltaic power generation is deployed in suitable locations for water electrolysis to produce green hydrogen. At the same time, part of the power generation is used for self-consumption. In addition, the solar photovoltaic power generation process provides the required green oxygen and water vapor to the on-site coal gasification hydrogen production.

[0058] The electrical energy in the coal in-situ gasification and deep processing system of this application can be self-sufficient, avoiding external consumption.

[0059] In this embodiment, the extraction and gasification unit 10 uses unminable and difficult-to-mine coal as raw materials. It employs a coal in-situ gasification technology using a dual-horizontal well screen pipe well and automated drainage gas extraction process to construct a gasifier. Syngas is produced using oxygen-enriched steam continuous method and oxygen-enriched carbon steam pulsed continuous method gasification processes. The syngas is transported to the surface through the second injection well 120 and then reaches the gas purification unit 20 through pipelines. After pretreatment, desulfurization, ammonium sulfate, and benzene washing processes, impurities such as dust, moisture, tar, sulfides, benzene, and naphthalene in the coal gas are removed. At the same time, a small containerized modular mobile equipment device is used at the surface wellhead to produce hydrogen from the gas using steam methane reforming (SMR) technology. During this process, byproducts such as tar, ammonium sulfate, crude benzene, and sulfur are formed. After the refined gas enters the hydrogen separation device, pure hydrogen is produced, with the amount of hydrogen being more than 50% of the original crude syngas. The separated methane gas enters the steam methane reforming (SMR) system for direct reduction of methane to produce hydrogen. Carbon monoxide and carbon dioxide are treated and stored using CCS technology, collected and sealed underground. On the surface of the mine, multi-unit 5-6MW distributed photovoltaic energy power generation is arranged in suitable locations for water electrolysis to produce green hydrogen. At the same time, part of the power generation is used for self-consumption. During the process of producing hydrogen through solar photovoltaic power generation, the required green oxygen and water vapor are provided to the on-site coal gasification hydrogen production.

[0060] Reference Figure 4 In some embodiments, the coal in-situ gasification and deep processing system further includes a green methanol synthesis unit 70, which is connected to the gas purification unit and the carbon capture and storage unit. The green methanol synthesis unit is used to receive the purified gas from the gas purification unit to synthesize methanol and to transfer carbon dioxide to the carbon capture and storage unit.

[0061] In this embodiment, the green methanol synthesis unit can also directly utilize the purified gas for methanol synthesis. The main components of the purified gas include H2 and CO. The ratio of H2 to CO in the gas is adjusted to meet the requirements of methanol synthesis gas, and impurity gases are removed using relevant methods to obtain synthesis gas that meets the standards. Methanol synthesis is then carried out under the catalysis of a catalyst.

[0062] The carbon dioxide produced by the methanol synthesis unit can be transported to the carbon capture and storage unit 40 for storage, thereby reducing greenhouse gas emissions and achieving green production.

[0063] Reference Figure 5 In some embodiments, the coal in-situ gasification and deep processing system further includes a green ammonia synthesis unit 80, which is connected to a gas purification unit and is used to receive purified gas from the gas purification unit for ammonia synthesis.

[0064] In this embodiment, the green ammonia synthesis unit can also directly utilize the H2 in the purified gas, so that the H2 in the purified gas reacts with N2 to synthesize ammonia, wherein the N2 source can be obtained by separating liquid air.

[0065] Reference Figure 7 This application also provides a method for in-situ coal gasification and deep processing, which utilizes the aforementioned in-situ coal gasification and deep processing system and includes the following steps: S1: Coalbed methane processing steps: Extract coalbed methane, purify the coalbed methane, and then use steam methane reforming technology to react at least part of the coalbed methane to generate hydrogen, and collect carbon dioxide through a carbon capture and storage unit. S2: Coal gasification processing steps: Syngas is produced by reacting coal with a gasifying agent. After purifying and separating the hydrogen from the syngas, hydrogen is produced by steam methane reforming technology. Carbon dioxide is collected through a carbon capture and storage unit.

[0066] After the coal in-situ gasification and deep processing system is laid, the coal seam contains a large amount of coalbed methane. The first step is to process the coalbed methane by extracting it through the third injection-production well 140. Before extraction, the coalbed methane is dehydrated by a dehydration device 142 and then transported to the surface gas purification unit 20. After purification, part or all of the purified gas undergoes steam reforming and hydrogen separation to obtain refined gas. The refined gas includes hydrogen and carbon dioxide. The hydrogen is transported through pipelines to a collection device for sale, while the carbon dioxide is stored in the carbon capture and storage unit 40.

[0067] Pressure regulation can be performed within 140 meters of the third injection-production well during the extraction process, which is more conducive to the smooth and efficient extraction of coalbed methane.

[0068] After coalbed methane extraction is completed, a gasifying agent is injected into the first injection-production well 110. After ignition in the third injection-production well 140, the third injection-production well 140 is sealed. The combustion location is at the connecting section between the first and second extension sections. At the combustion location, coal and the gasifying agent undergo a chemical reaction to generate syngas. The syngas mainly consists of combustible gases such as carbon monoxide, hydrogen, and methane, and has a high calorific value and chemical energy. The syngas flows into the gas purification unit 20 through the second injection-production well 120. The first and second injection-production wells 110 and 120 have good sealing properties to ensure that the syngas can smoothly enter the gas collection device without leakage.

[0069] Syngas flows into gas purification unit 20 through the second injection-production well 120. After pretreatment, desulfurization, ammonium sulfate and benzene washing processes, impurities such as dust, moisture, tar, sulfides, benzene and naphthalene in the coal gas are removed to obtain purified gas.

[0070] Syngas flows into gas purification unit 20 through the second injection-production well 120. After pretreatment, desulfurization, ammonium sulfate and benzene washing processes, impurities such as dust, moisture, tar, sulfides, benzene and naphthalene in the coal gas are removed to obtain purified gas.

[0071] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A coal in-situ gasification and deep processing system, characterized in that, include: The extraction and gasification unit (10) is set from the surface to the coal seam to produce gas to be processed. The gas to be processed is transported to the surface through the coal seam. The gas to be processed includes coalbed methane and syngas. Gas purification unit (20) is used to receive and purify the gas to be processed in order to produce purified gas; A gas processing unit (30) is used to receive at least a portion of the purified gas and perform steam reforming and purification separation of hydrogen to produce refined gas, said refined gas including hydrogen and carbon dioxide; A carbon capture and storage unit (40) is used to capture and collect carbon dioxide from the finishing gas.

2. The coal in-situ gasification and deep processing system according to claim 1, characterized in that, The extraction and gasification unit (10) includes: The first injection-production well (110) includes a first submerged section (111) that extends from the surface to the coal seam and a first extension section (112) that is distributed along the coal seam and connected to the first submerged section. The second injection-production well (120) is at least one that is distributed in parallel with the first injection-production well. The second injection-production well includes a second submerged section (121) that extends from the surface to the coal seam and a second extension section (122) that is distributed along the coal seam and connected to the second submerged section. A connecting section (130) is provided within the coal seam for connecting the first extension section (112) and the second extension section (122). The third injection well (140) includes a third submerged section (141) that extends from the surface into the coal seam, with one end of the third submerged section located within the coal seam connected to a connecting section (130).

3. The coal in-situ gasification and deep processing system according to claim 2, characterized in that, The third injection-production well (140) is equipped with a dehydration device (142), which is used to dehydrate the coalbed methane to produce purified water and supply the purified water to the extraction and gasification unit (10) and the gas processing unit (30).

4. The coal in-situ gasification and deep processing system according to claim 1, characterized in that, The gas purification unit (20) includes a dust removal tower (210) for dust removal of the gas to be processed, a desulfurization tower (220) for desulfurization of the gas to be processed, and a benzene removal tower (230) for benzene removal of the gas to be processed, which are connected in sequence.

5. The coal in-situ gasification and deep processing system according to claim 1, characterized in that, The gas processing unit (30) includes at least one steam methane reforming skid (310) and at least one separation and purification hydrogen production device (320). The purified gas is circulated between the steam methane reforming skid and the separation and purification hydrogen production device until the hydrogen content a in the gas phase product meets a preset value and then leaves the gas processing unit (30). The preset value of the hydrogen content a is: a≥70%.

6. The coal in-situ gasification and deep processing system according to any one of claims 1-5, characterized in that, The coal in-situ gasification and deep processing system also includes a methane and syngas power generation unit (50), which is connected to the gas processing unit (30) and the carbon capture and storage unit (40) respectively, and is used to receive at least part of the purified gas for combustion power generation and transport the combustion products to the carbon capture and storage unit (40).

7. The coal in-situ gasification and deep processing system according to any one of claims 1-5, characterized in that, The coal in-situ gasification and deep processing system also includes a hydrogen and oxygen production unit (60), which includes a distributed photovoltaic power station (610) and an electrolyzer (620).

8. The coal in-situ gasification and deep processing system according to any one of claims 1-5, characterized in that, The coal in-situ gasification and deep processing system also includes a green methanol synthesis unit (70), which receives purified gas from the gas purification unit (20) for methanol synthesis and transports carbon dioxide to the carbon capture and storage unit (40).

9. The coal in-situ gasification and deep processing system according to any one of claims 1-5, characterized in that, The coal in-situ gasification and deep processing system also includes a green ammonia synthesis unit (80), which is used to receive purified gas from the gas purification unit (20) for ammonia synthesis.

10. A method for in-situ coal gasification and deep processing, using the in-situ coal gasification and deep processing system described in any one of claims 1-9, characterized in that, Includes the following steps: Coalbed methane processing steps: Extract coalbed methane, purify the coalbed methane, and then use steam methane reforming technology to react at least part of the coalbed methane to generate hydrogen, and collect carbon dioxide through a carbon capture and storage unit; Coal gasification processing steps: Gasification is achieved by reacting coal with a gasifying agent to produce syngas. The syngas is then purified and hydrogen is separated from it. The syngas is then reacted to produce hydrogen through steam methane reforming technology. Carbon dioxide is collected through a carbon capture and storage unit.

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