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

Abstract

The invention belongs to the technical field of coal development, and provides a coal in-situ gasification and deep processing treatment system and method. The coal in-situ gasification and deep processing treatment system comprises a coal bed gas extraction and coal gasification unit which penetrates from the ground surface to a coal bed, and a gas purification unit, a gas processing unit and a carbon capture and storage unit which are arranged on the ground surface; the coal bed gas extraction and coal gasification unit is used for producing to-be-processed gas, the to-be-processed gas comprises coal bed gas and crude synthesis gas, and the to-be-processed gas is transmitted to the ground surface through a coal bed; the gas purification unit is used for receiving to-be-processed gas and purifying the to-be-processed gas to obtain 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 obtain finish machining gas; and the carbon capturing and sealing unit is used for capturing carbon dioxide in the finish machining gas of the gas processing unit and collecting and sealing the carbon dioxide. The method can improve the recovery rate and utilization rate of coal and coal bed gas.

Description

Technical Field

[0001] The present application relates to the technical field of coal development, and in particular to a system and method for in-situ coal gasification and deep processing. Background Art

[0002] Coal has made important contributions to ensuring the rapid and healthy development of the economy, and will continue to be the main energy source for a period of time in the future. However, the reserves of coal resources with large burial depths and poor resource endowments are huge, and these coal resources face many difficulties in traditional physical mining; and traditional physical mining of coal will produce pollutants such as coal gangue, coal mine gas and mine water, and cause surface subsidence and soil erosion. In order to achieve the long-term goal of carbon reduction, the coal mining industry needs to vigorously promote clean production, take the clean and efficient development of coal as the foothold and primary task of energy transformation and development, and create strong conditions for the coal industry to transform its development mode and achieve clean and efficient development.

[0003] In-situ coal gasification is an overall green mining technology. It is a technology that converts underground coal into combustible gas in-situ through thermochemical reactions. It not only greatly reduces underground engineering and hard work, but also eliminates the pollution of coal mining and the adverse effects and harm of coal combustion on the ecological environment to a great extent. In the existing technology, the in-situ methods of deep coal seams are mostly single gasification research, and the recovery rate and utilization rate of coal and gas resources are low. There is an urgent need for a coal in-situ gasification and deep processing system and method. Summary of the invention

[0004] In view of this, the embodiments of the present application provide a system and method for in-situ coal gasification and deep processing to improve the recovery rate and utilization rate of coal and gas resources.

[0005] First, there are coalbed methane extraction and coal gasification units that extend from the surface to the coal seam, and gas purification units, gas processing units and carbon capture and storage units that are set up on the surface; the coalbed methane extraction and coal gasification units are used to produce gas to be processed, which includes coalbed methane and synthetic gas, and the gas to be processed is transmitted to the surface through the coal seam; the gas purification unit is used to receive the gas to be processed, and purify the gas to be processed to obtain purified gas; the gas processing unit is used to receive at least part of the purified gas for steam reforming and purification and separation of hydrogen to obtain refined gas, which includes hydrogen and carbon dioxide; the carbon capture and storage unit is used to capture carbon dioxide in the refined gas of the gas processing unit and collect and seal it.

[0006] According to an embodiment of the first aspect of the present application, a movable steam methane reforming skid and at least one separation and purification hydrogen production device, the containerized movable steam methane reforming skids are connected in parallel, and the separation and purification hydrogen production devices are connected in parallel. The purified gas circulates between the containerized movable 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.

[0007] According to an embodiment of the first aspect of the present application, the preset value of the hydrogen content a is a≥70%.

[0008] According to an embodiment of the first aspect of the present application, a coalbed methane extraction and coal gasification unit includes an injection well, a production well and an ignition well; The injection well includes a first horizontal section, the production well includes a second horizontal section, the first horizontal section and the second horizontal section are arranged in the coal seam, and the first horizontal section and the second horizontal section are connected at their respective ends away from their wellheads. The ignition well is connected to the injection well and the production well at the remote end. The ignition well is used to extract coalbed methane in the coalbed methane extraction stage and to heat coal and gasification agent in the coal gasification stage.

[0009] According to an embodiment of the first aspect of the present application, the first horizontal section and the second horizontal section are located in the same horizontal plane.

[0010] According to an embodiment of the first aspect of the present application, a dehydration device is provided in the ignition well, and the dehydration device is used to dehydrate the coalbed methane to obtain purified water, and supply the purified water to the coalbed methane extraction and coal gasification unit and the gas processing unit.

[0011] According to the embodiment of the first aspect of the present application, the gas purification unit includes a dust removal tower, a desulfurization tower, and a debenzene tower connected in sequence; the dust removal tower is used to remove dust from the gas to be processed, the desulfurization tower is used to desulfurize the gas to be processed, and the debenzene tower is used to debenzene the gas to be processed.

[0012] According to the embodiment of the first aspect of the present application, the coal in-situ gasification and deep processing system also includes: a methane and synthesis gas power generation unit, which is respectively connected to the gas processing unit and the carbon capture and storage unit, receives at least part of the purified gas for combustion and power generation, and transports the combustion products to the carbon capture and storage unit.

[0013] According to the embodiment of the first aspect of the present application, the coal in-situ gasification and deep processing system also includes: a hydrogen production and oxygen production unit, the hydrogen production and oxygen production unit includes a distributed photovoltaic power station and an electrolyzer, and the distributed photovoltaic power station and the electrolyzer are used to provide electrical energy to the electrolyzer.

[0014] According to an embodiment of the first aspect of the present application, the system also includes a green synthetic methanol unit, which is connected to the gas purification unit and the carbon capture and storage unit respectively. The green synthetic methanol unit is used to receive the purified gas from the gas purification unit for methanol synthesis and transmit carbon dioxide to the carbon capture and storage unit.

[0015] According to an embodiment of the first aspect of the present application, the system further includes a green ammonia synthesis unit, which is connected to the gas purification unit and is used to receive purified gas from the gas purification unit to perform ammonia synthesis.

[0016] In a second aspect, the present application provides a method for in-situ gasification and deep processing of coal, using the above-mentioned in-situ gasification and deep processing system of coal, the method includes: The coal bed methane processing step includes extracting the coal bed methane, purifying the coal bed methane, reacting at least part of the coal bed methane to generate hydrogen through steam methane reforming technology, and collecting carbon dioxide through a carbon capture and storage unit; In the coal gasification processing step, a gasifying agent is used to react with coal to obtain raw synthesis gas. The remaining synthesis gas after purifying the raw synthesis gas to separate the hydrogen is then converted into hydrogen using steam methane reforming technology, and carbon dioxide is collected through a carbon capture and storage unit.

[0017] Compared with the prior art, the embodiments of the present application have at least the following beneficial effects: The coal in-situ gasification and deep processing system of the embodiment of the present application includes a coalbed methane extraction and coal gasification unit, a gas purification unit, a gas processing unit and a carbon capture and storage unit, wherein the coalbed methane extraction and coal gasification unit is used to produce gas to be processed including coalbed methane and synthetic gas, the gas purification unit is used to receive the gas to be processed and purify the gas to be processed to obtain purified gas, the gas processing unit can receive at least part of the purified gas for steam reforming and purification and separation of hydrogen to obtain refined gas, the refined gas includes hydrogen and carbon dioxide, and the carbon capture and storage unit is used to capture the carbon dioxide in the refined gas of the gas processing unit and collect and seal it. The coal in-situ gasification and deep processing system of the embodiment of the present application can first extract coalbed methane, use steam methane reforming (SMR) technology to produce hydrogen on the ground from coalbed methane, and then use the coal in-situ gasification system to generate waste gas with H2, CO, and CH4 as the main components, and use steam methane reforming (SMR) technology to produce hydrogen on the ground from coalbed methane, and finally collect CO2 through a carbon capture and storage unit to reduce the carbon emissions of the project. This application improves the recovery rate and utilization rate of coal and gas resources through reasonable selection of technical research and optimized design of process flow, ensures efficient and stable hydrogen output, expands the industrial chain of in-situ coal gasification, increases the added value of coal resources, and achieves the effects of simple process, safety, reliability, energy saving and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0019] Figure 1 This is a schematic diagram of the connection relationship of the coal in-situ gasification and deep processing system.

[0020] Figure 2 This is another connection diagram of the coal in-situ gasification and deep processing system.

[0021] Figure 3 This is another connection diagram of the coal in-situ gasification and deep processing system.

[0022] Figure 4 This is another connection diagram of the coal in-situ gasification and deep processing system.

[0023] Figure 5 This is another connection diagram of the coal in-situ gasification and deep processing system.

[0024] Figure 6 This is a schematic diagram of the connection relationship between the coalbed methane extraction and coal gasification units in this application.

[0025] Figure 7 This is a flow chart of the in-situ coal gasification and deep processing method of this application.

[0026] Reference numerals: 10. Coalbed methane extraction and coal gasification unit; 11. Injection well; 111. First horizontal section; 112. First vertical section; 12. Production well; 121. Second horizontal section; 122. Second vertical section; 13. Ignition well; 131. Dehydration device; 14. Ignition position 14; 20. Gas purification unit; 30. Gas processing unit; 31. Containerized mobile steam methane reforming skid; 32. Separation and purification hydrogen production device; 40. Carbon capture and storage unit; 50. Methane and synthesis gas power generation unit; 60. Hydrogen and oxygen production unit; 70. Green synthetic methanol unit; 80 Green synthetic ammonia unit; 100. Surface; 101. Coalbed.

[0027] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0028] In order to make the application purpose, technical solution and beneficial technical effect of the present application clearer, the present application is further described in detail in conjunction with the embodiments below. It should be understood that the embodiments described in this specification are only for explaining the present application, not for limiting the present application.

[0029] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unclearly recorded range; and any lower limit can be combined with other lower limits to form an unclearly recorded range, and any upper limit can be combined with any other upper limit to form an unclearly recorded range. In addition, although not clearly recorded, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unclearly recorded range.

[0030] In the description of the present application, it should be noted that, unless otherwise specified, “above” and “below” are inclusive of the number, and the “multiple” in “one or more” means two or more than two.

[0031] In the existing technology, the in-situ methods for deep coal seams are mostly single gasification research, and the recovery rate and utilization rate of coal and gas resources are low.

[0032] In order to solve the problems of the prior art, the embodiment of the present application provides a system and method for in-situ gasification and deep processing of coal. The following first introduces the in-situ gasification and deep processing system of coal provided in the embodiment of the present application.

[0033] Figure 1 A schematic structural diagram of a coal in-situ gasification and deep processing system provided in some embodiments of the present application is shown.

[0034] See also Figure 1 On the one hand, a coalbed methane extraction and coal gasification unit 10 is set up from the surface 100 to the coal seam 101, and a gas purification unit 20, a gas processing unit 30 and a carbon capture and storage unit 40 are set up on the surface 100; the coalbed methane extraction and coal gasification unit 10 is used to produce gas to be processed, and the gas to be processed includes coalbed methane and synthetic gas, and the gas to be processed is transmitted to the surface 100 through the coal seam 101; the gas purification unit 20 is used to receive the gas to be processed and purify the gas to be processed to obtain purified gas; the gas processing unit 30 is used to receive at least part of the purified gas for steam reforming and purification and separation of hydrogen to obtain refined gas, and the refined gas includes hydrogen and carbon dioxide; the carbon capture and storage unit 40 is used to capture carbon dioxide in the refined gas of the gas processing unit 30 and collect and store it.

[0035] The coal in-situ gasification and deep processing system of the embodiment of the present application includes a coalbed methane extraction and coal gasification unit 10, a gas purification unit 20, a gas processing unit 30 and a carbon capture and storage unit 40, wherein the coalbed methane extraction and coal gasification unit 10 is set from the surface 100 to the coal seam 101, the gas purification unit 20 and the gas processing unit 30 are set on the surface 100, and the carbon capture and storage unit 40 can be located on the surface 100, or can be set from the surface 100 to the underground. The present application integrates and assembles the coalbed methane extraction and coal gasification unit 10, the gas purification unit 20, the gas processing unit 30 and the carbon capture and storage unit 40 through technical research and reasonable selection and optimized design of the process flow, which can realize the in-situ gasification and deep processing of coal, improve the recovery rate and utilization rate of coal and gas resources, ensure efficient and stable hydrogen output, expand the industrial chain of in-situ coal gasification, increase the added value of coal resources, and achieve the effects of simple process, safety and reliability, and energy saving and emission reduction.

[0036] Specifically, the coalbed methane extraction and coal gasification unit 10 is used to produce gas to be processed including coalbed methane and raw synthetic gas. In the embodiment of the present application, the coalbed methane extraction and coal gasification unit 10 works in two stages. The first working stage is carried out first, which is divided into two stages. In the first stage, coalbed methane is extracted to obtain gas resources. After completion, coal gasification is started in the second stage to prepare raw synthetic gas. This can ensure the effective utilization of resources.

[0037] With respect to the underground structure, the underground structure includes a coal seam roof, a coal seam and a coal seam floor. The coal seam roof is below the surface, the coal seam is below the coal seam roof, and the coal seam floor is below the coal seam. The coal seam is the main object of the underground gasification process and the gas extraction process, and its position and thickness directly affect the efficiency and feasibility of gasification and extraction. Coal seams are usually located in specific geological strata, and the thickness varies depending on the geological conditions. The coal in-situ gasification and deep processing system of the embodiment of the present application can use non-mineable coal and difficult-to-mine coal as raw materials, and use in-situ coal and in-situ coalbed methane to produce clean energy, thereby improving resource utilization.

[0038] After being transmitted to the surface 100 through the coal seam 101 in the coalbed methane extraction and coal gasification unit 10, the gas to be processed enters the gas purification unit 20, which can receive the gas to be processed and purify the gas to be processed.

[0039] At least part of the purified gas is further transmitted to the gas processing unit 30, and the gas processing unit 30 can receive at least part of the purified gas for steam reforming and purification and separation of hydrogen to obtain finished gas. According to an embodiment of the present application, the purified gas can be completely transported to the gas processing unit 30 for reforming, or part of the purified gas can be directly sold, and the remaining purified gas can be transported to the gas processing unit 30 for reforming. The finished gas includes hydrogen and carbon dioxide.

[0040] Steam reforming is very energy efficient. Steam reforming is the use of high temperatures (700-1000 o C) produces hydrogen from a methane source (cleaned coal bed methane or waste synthesis gas). The two elements combined with a catalyst react at a pressure of 3-25 bar (1 bar = 14.5 pounds per square inch). The reaction produces CO (carbon monoxide), CO2 (carbon dioxide) and hydrogen.

[0041] Next, the separated hydrogen is purified and further enriched in the second step, called the "water-gas shift reaction". In this step, a reaction is induced between steam and CO, again with the help of a catalyst. This produces a small amount of heat, CO and a large amount of hydrogen. The chemical formula for the process is as follows: Steam Methane Reforming CH4+H2O→ CO+3H2 Water Gas Shift Reaction CO+H2O→ Carbon dioxide+Hydrogen The carbon capture and storage unit 40 is used to capture carbon dioxide in the refined gas of the gas processing unit 30 and separate the carbon dioxide from the refined gas, transport it to a storage site, and isolate it from the atmosphere for a long time. For example, during the carbon capture and storage process, the released CO2 is transported to underground storage through a pipeline, such as injected into an underground sandstone layer. Carbon dioxide can also be captured and reused, such as in the production of biofuels, plastics or concrete. The carbon capture and storage unit 40 can reduce greenhouse gas emissions and slow down global warming, and this method is economical and feasible.

[0042] In some embodiments, storage involves not only storing CO2 deep underground but also monitoring for leaks. Oil and gas fields have been extensively geologically analyzed, and the most suitable locations for storing CO2 are depleted gasifiers and deep well fields (such as coal seam methane wells).

[0043] In summary, the coal in-situ gasification and deep processing system of the embodiment of the present application can first extract coalbed methane, use steam methane reforming (SMR) technology to produce hydrogen on the ground from coalbed methane, and then use the coal in-situ gasification system to generate waste gas with H2, CO, and CH4 as the main components, and use steam methane reforming (SMR) technology to produce hydrogen on the ground from coalbed methane, and finally collect CO2 through the carbon capture and storage unit 40 to reduce the carbon emissions of the project. This application improves the recovery rate and utilization rate of coal and gas resources through reasonable selection of technical research and optimized design of process flow, ensures efficient and stable hydrogen output, expands the industrial chain of in-situ coal gasification, increases the added value of coal resources, and achieves the effects of simple process, safety, reliability, energy saving and emission reduction.

[0044] The embodiment of the present application utilizes the technology of in-situ coal chemical mining, in-situ coalbed methane hydrogen production technology, and CCS technology to produce clean energy and ultimately realize the development project of clean hydrogen energy (blue hydrogen). It is an in-situ application of oil mining and coal chemical development, and has broad prospects. It can not only effectively mine deep coal resources, but also realize the green development and clean utilization of coal from the source, innovate a new model of clean production in the coal mining industry, and at the same time ensure energy supply in a low-carbon, clean, safe, efficient, and cheap manner. The clean hydrogen energy development project of the present application not only effectively realizes environmental protection, low-carbon development of coal to produce clean hydrogen energy, but also effectively complements traditional physical coal mining methods to achieve the country's maximum energy development of coal resources.

[0045] In some embodiments, the gas processing unit 30 includes at least one container-type mobile steam methane reforming skid 31 and at least one separation and purification hydrogen production device 32. The container-type mobile steam methane reforming skids 31 are connected in parallel, and the separation and purification hydrogen production devices 32 are connected in parallel. The purified gas circulates between the container-type mobile steam methane reforming skid 31 and the separation and purification hydrogen production device 32 until the hydrogen content a in the gas phase product meets a preset value and then leaves the gas processing unit 30.

[0046] The container-type mobile steam methane reforming skid 31 is a container-type device formed by integrating a steam methane reforming device on a platform, and the platform can be made of metal, such as a steel platform. The container-type mobile steam methane reforming skid 31 is assembled and debugged at the production plant and then transported to the production site for standby use.

[0047] The separation and purification hydrogen production device 32 can also be a container-type integrated device, in which various components are integrated and installed on a platform to form a container-type device, which is assembled and debugged in the production plant and then transported to the production site for use.

[0048] In the embodiment of the present application, there may be one or more container-type movable steam methane reforming skids 31, and there may be one or more separation and purification hydrogen production devices 32. The steam methane reforming device is modularly arranged in a container type, which can improve the flexibility of the system. The number can be selected and assembled according to actual needs.

[0049] For example, when the production volume of the gas to be processed is small, a container-type mobile steam methane reforming skid 31 and a separation and purification hydrogen production device 32 can be assembled. When the production volume of the gas to be processed becomes smaller, the original container-type mobile steam methane reforming skid 31 and the separation and purification hydrogen production device 32 cannot meet the production demand, and the number of container-type mobile steam methane reforming skids 31 and separation and purification hydrogen production devices 32 can be increased as needed. When the production volume of the gas to be processed becomes smaller again, some container-type mobile steam methane reforming skids 31 and separation and purification hydrogen production devices 32 can be dismantled, which is more flexible.

[0050] Multiple container-type mobile steam methane reforming skids 31 can be arranged in parallel, multiple separation and purification hydrogen production devices 32 can be arranged in parallel, and the module formed by multiple container-type mobile steam methane reforming skids 31 and the module formed by multiple separation and purification hydrogen production devices 32 can be arranged in series, but the present application is not limited to this.

[0051] In some embodiments, the preset value of the hydrogen content a is a≥70%.

[0052] In the embodiment of the present application, the gas in the gas processing unit 30 is monitored in real time. When the preset value of the hydrogen content a is a≥70%, it is considered that the hydrogen content in the refined gas is qualified and the refined gas can proceed to the next process.

[0053] Preferably, when the preset value of the hydrogen content a is a≥90%, the refined gas is subjected to the next process.

[0054] See also Figure 6 In some embodiments, the coalbed methane extraction and coal gasification unit 10 includes an injection well 11, a production well 12 and an ignition well 13; the injection well 11 includes a first horizontal section 111, the production well 12 includes a second horizontal section 121, the first horizontal section 111 and the second horizontal section 121 are arranged in the coal seam, the first horizontal section 111 and the second horizontal section 121 are connected at the far end away from their wellheads, the ignition well 13 is connected to the injection well 11 and the production well 12 at the far end, the ignition well 13 is used to extract coalbed methane in the coalbed methane extraction stage, and is used to heat coal and gasification agent in the coal gasification stage.

[0055] The first horizontal section 111 and the second horizontal section 121 are disposed in the coal seam and distributed in the horizontal extension direction of the coal seam.

[0056] In the first stage, when coalbed methane is extracted, the injection well 11 and the production well 12 are simultaneously subjected to gas extraction, and the gas is extracted through the ignition well 13 to improve the extraction efficiency. An automatic drainage device is arranged in the ignition well 13 to realize automatic extraction of coalbed methane for easy control.

[0057] In the second stage, when coalbed methane is synthesized, the injection well 11 is used to inject gasifying agents (such as oxygen, water vapor, etc.), the ignition well 13 is used for ignition, and the production well 12 is used to synthesize and output raw synthesis gas. When the coal is gasified underground in situ, the gasifying agent is injected into the injection well 11, and after ignition in the ignition well 13, the ignition well 13 is blocked, and the combustion position 14 is located at the connecting section of the first horizontal section 111 and the second horizontal section 121. At the combustion position 14, the coal reacts chemically with the gasifying agent to generate raw synthesis gas. The synthesis gas is mainly composed of combustible gases such as carbon monoxide, hydrogen, and methane, and has a high calorific value and chemical energy. The raw synthesis gas flows into the gas purification unit 20 through the production well 12. The injection well 11 and the production well 12 have good sealing properties to ensure that the synthesis gas can smoothly enter the gas collection device without leakage.

[0058] When preparing the raw synthesis gas, the oxygen-enriched steam continuous method and the oxygen-enriched carbon steam pulse continuous method can be used to produce the raw synthesis gas. The oxygen-enriched steam continuous method is a process method that uses oxygen-enriched and water vapor as gasifying agents and implements continuous air supply. It can produce semi-water gas on a large scale. Since this method uses oxygen-enriched as the gasifying agent, it effectively strengthens the heat and mass transfer process between the fire layer and the airflow on the combustion working surface, and significantly improves the gasification efficiency and thermal efficiency. Therefore, it has a simple process, a large gas output, and the calorific value of the gas can reach 2000-2500 kcal / m 3 The direct component contains H2>40%, [H2+CO] / N2≥3.1, which can be used as feed gas for the production of synthetic ammonia and alcohol, and can also be used for IGCC integrated combined cycle gas turbine power generation.

[0059] The oxygen-rich carbon steam pulsation continuous method uses oxygen O2 produced by an oxygen generator and CO2 obtained from a coal chemical decarbonization system (such as low-temperature methanol decarbonization) in a ratio of 2:1 to prepare oxygen-rich carbon gas, which is then compounded with water vapor to form a composite gasification agent. In addition, the implementation of the process of continuous air supply and pulsating variable pressure exhaust can continuously produce hydrogen-rich water gas on a large scale, directly containing H2 ≥ 50%, H2 + CO ≥ 78%, and a calorific value of up to 2400-2800 kcal / m 3 The hydrogen-rich water gas produced by this method can be used as raw gas for coal chemical industry or an ideal gas source for coal-to-oil hydrogen extraction projects.

[0060] It is understandable that the gasification agent may be input along with a catalyst, which is used to catalyze the in-situ gasification of coal.

[0061] It can be understood that the injection well 11 includes a first vertical section 112, which is connected to the first horizontal section 111, and the production well 12 includes a second vertical section 122, which is connected to the second horizontal section 121. The first vertical section 112 and the second vertical section 122 are respectively set from the surface to the coal seam, the first vertical section 112 is used to inject gasification agent, and the second vertical section 122 is used to output raw synthetic gas.

[0062] In some embodiments, the first horizontal segment 111 and the second horizontal segment 121 are located in the same plane.

[0063] The first horizontal section 111 and the second horizontal section 121 are located in the same plane. In other words, the first horizontal section 111 and the second horizontal section 121 are arranged side by side in the coal seam. The side by side arrangement is conducive to the extraction of coal seam gas and in-situ underground gasification of thin coal seams, which effectively reduces the difficulty of construction. For example, the construction can be carried out in coal seams with a thickness of less than 2 meters and more than 1.5 meters.

[0064] In some embodiments, a dehydration device 131 is provided in the ignition well 13 , and the dehydration device 131 is used to dehydrate the coalbed methane to obtain purified water, and supply the purified water to the coalbed methane extraction and coal gasification unit 10 and the gas processing unit 30 .

[0065] Before the coalbed methane is output from the pipeline of the ignition well 13, the coalbed methane can be purified in advance. The coalbed methane contains a large amount of water. A dehydration device 131 is provided in the ignition well 13. The dehydration device 131 dehydrates the coalbed methane to obtain purified water. The purified water obtained can be collected and transported to the coalbed methane extraction and coal gasification unit 10 and the gas processing unit 30 for application. In this way, internal utilization of resources can be achieved and external water consumption can be reduced. In addition, the purified water is extracted from underground and has a relatively pure composition. In subsequent applications, side reactions can be avoided.

[0066] In some embodiments, the gas purification unit 20 includes a dust removal tower, a desulfurization tower, and a debenzene tower connected in sequence; The dust removal tower is used to remove dust from the gas to be processed, the desulfurization tower is used to desulfurize the gas to be processed, and the debenzenization tower is used to debenzene the gas to be processed.

[0067] The raw synthetic gas or dehydrated coalbed methane reaches the gas purification unit 20 through a pipeline, and undergoes processes such as dust removal, desulfurization, ammonium sulfate and benzene elution to remove impurities such as dust, moisture, tar, sulfide, benzene and naphthalene in the coal gas.

[0068] See also Figure 2 and Figure 3In some embodiments, it also includes: a methane and synthesis gas 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 part of the purified gas for combustion and power generation, and transports the combustion products to the carbon capture and storage unit 40.

[0069] In the embodiment of the present application, the methane and synthesis gas power generation unit 50 can directly utilize the purified gas to generate electricity. The obtained electric energy can first be supplied to the coal in-situ gasification and deep processing system for internal use, and the surplus electric energy can be transmitted to the power grid for sale.

[0070] The combustion product produced by the methane and synthesis gas power generation unit 50 is mainly carbon dioxide, which can be transported to the carbon capture and storage unit 40 for storage to reduce greenhouse gas emissions.

[0071] See also Figure 3 In some embodiments, the coal in-situ gasification and deep processing system further includes: The hydrogen and oxygen production unit 60 includes a distributed photovoltaic power station and an electrolyzer, and the distributed photovoltaic power station and the electrolyzer are used to provide electrical energy for the electrolyzer.

[0072] Multi-unit 5-6MW distributed photovoltaic energy power generation is preferentially arranged at appropriate locations on the surface of the well field to be used for electrolysis of water to produce green hydrogen. At the same time, part of the power generated is used for self-use. At the same time, the solar photovoltaic power generation process provides the required green oxygen and water vapor for on-site coal gasification hydrogen production.

[0073] In this application, the electrical energy in the coal in-situ gasification and deep processing system can achieve self-sufficiency and avoid external consumption.

[0074] In the embodiment of the present application, the coalbed methane extraction and coal gasification unit 10 uses non-mineable coal and difficult-to-mine coal as raw materials, adopts a double horizontal well screen pipe well and an automated drainage gas extraction technology to construct a coal in-situ gasification technology for a gasifier, and produces synthesis gas by an oxygen-enriched steam continuous method and an oxygen-enriched carbon steam pulse continuous method gasification process. The raw synthesis gas is transported to the surface through a production well 12 and reaches a gas purification unit 20 through a pipeline. After pretreatment, desulfurization, ammonium sulfate and benzene elution processes, impurities such as dust, moisture, tar, sulfide, benzene and naphthalene in the coal gas are removed. At the same time, a small container modular mobile equipment device is used at the ground wellhead to produce hydrogen on the ground using steam methane reforming (SMR) technology. In this process, by-products such as tar, ammonium sulfate, crude benzene, and sulfur are formed. After the refined gas enters the hydrogen separation device, pure hydrogen is generated, and the amount of hydrogen is more than 50% of the original crude synthesis gas. 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 processed and stored, captured using CCS technology, collected and sealed underground. Multi-unit 5-6MW distributed photovoltaic energy power generation is preferentially arranged at appropriate locations on the ground of the well field to electrolyze water to produce green hydrogen, and part of the power generated is used for self-use. At the same time, the solar photovoltaic power generation process provides the required green oxygen and water vapor to the on-site coal gasification hydrogen production.

[0075] See also Figure 4 In some embodiments, the coal in-situ gasification and deep processing system also includes a green synthetic methanol unit, which is connected to the gas purification unit and the carbon capture and storage unit respectively. The green synthetic methanol unit is used to receive the purified gas from the gas purification unit for methanol synthesis and transmit carbon dioxide to the carbon capture and storage unit.

[0076] In the embodiment of the present application, the green synthetic methanol unit can also directly utilize the purified gas to synthesize methanol. 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 the impurity gas is removed by relevant methods to obtain synthesis gas that meets the standards, and methanol synthesis is carried out under the catalytic action of the catalyst.

[0077] The carbon dioxide produced in the synthetic methanol unit can be transported to the carbon capture and storage unit 40 for storage to reduce greenhouse gas emissions and achieve green production.

[0078] See also Figure 5 In some embodiments, the coal in-situ gasification and deep processing system further includes a green synthetic ammonia unit, which is connected to the gas purification unit and is used to receive the purified gas from the gas purification unit to perform ammonia synthesis.

[0079] In the embodiment of the present application, 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 source of N2 can be obtained by separating liquid air.

[0080] See also Figure 7 The present application provides a method for in-situ gasification and deep processing of coal, using the above-mentioned in-situ gasification and deep processing system of coal, the method includes: S1: coal bed methane processing step, extracting coal bed methane, purifying the coal bed methane and reacting at least part of the coal bed methane to generate hydrogen through steam methane reforming technology, and collecting carbon dioxide through a carbon capture and storage unit 40; S2: coal gasification processing step, using gasification agent to react with coal to obtain raw synthesis gas, purifying the raw synthesis gas to separate hydrogen from the raw synthesis gas, and using steam methane reforming technology to react the raw synthesis gas to generate hydrogen, and collecting carbon dioxide through the carbon capture and storage unit 40.

[0081] After the in-situ coal gasification and deep processing system is laid, the coal seam contains a large amount of coal seam gas. First, the coal seam gas processing step is carried out, and the coal seam gas is extracted through the ignition well 13. Before leaving the ignition well 13, the coal seam gas is first dehydrated by the dehydration device 131, and the coal seam gas is transported to the gas purification unit 20 on the surface. After purification, part or all of the purified gas is steam reformed and purified to separate hydrogen to obtain refined gas. The refined gas includes hydrogen and carbon dioxide, of which hydrogen is transported to the collection device via a pipeline for sale, and carbon dioxide enters the carbon capture and storage unit 40 for storage.

[0082] During the extraction process, pressure control can be performed in the ignition well 13, which is more conducive to the smooth and efficient extraction of coalbed methane.

[0083] After the extraction of coalbed methane is completed, a gasifying agent is injected into the injection well 11. After ignition in the ignition well 13, the ignition well 13 is blocked. The combustion position 14 is located at the connecting section of the first horizontal section 111 and the second horizontal section 121. At the combustion position 14, the coal reacts chemically with the gasifying agent to generate raw synthesis gas. The synthesis gas is mainly composed of combustible gases such as carbon monoxide, hydrogen, and methane, and has a high calorific value and chemical energy. The raw synthesis gas flows into the gas purification unit 20 through the production well 12. The injection well 11 and the production well 12 have good sealing properties to ensure that the synthesis gas can smoothly enter the gas collection device without leakage.

[0084] The raw synthetic gas flows into the gas purification unit 20 through the production well 12, and undergoes pretreatment, desulfurization, ammonium sulfate and benzene elution processes to remove impurities such as dust, moisture, tar, sulfide, benzene and naphthalene in the coal gas to obtain purified gas.

[0085] Part or all of the purified gas enters the gas processing unit 30 for steam reforming and purification to separate hydrogen to obtain refined gas. The refined gas includes hydrogen and carbon dioxide, wherein the hydrogen is transported to a collection device via a pipeline for sale, and the carbon dioxide enters the carbon capture and storage unit 40 for storage.

[0086] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A coal in-situ gasification and deep processing system, characterized in that: include: Coalbed methane extraction and coal gasification units that penetrate from the surface to the coal seam, gas purification units, gas processing units and carbon capture and storage units that are installed on the surface; The coalbed methane extraction and coal gasification unit is used to produce gas to be processed, the gas to be processed includes coalbed methane and waste gas, and the gas to be processed is transmitted to the surface through the coal seam; The gas purification unit is used to receive the gas to be processed and purify the gas to be processed to obtain purified gas; The gas processing unit is used to receive at least part of the purified gas for steam reforming and purification and separation of hydrogen to obtain a refined gas, wherein the refined gas includes hydrogen and carbon dioxide; The carbon capture and storage unit is used to capture the carbon dioxide in the refined gas of the gas processing unit and collect and store it.

2. The coal in-situ gasification and deep processing system according to claim 1 is characterized in that: The gas processing unit comprises at least one container-type mobile steam methane reforming skid and at least one separation and purification hydrogen production device, wherein the container-type mobile steam methane reforming skids are connected in parallel, and the separation and purification hydrogen production devices are connected in parallel, and the purified gas is circulated between the container-type mobile 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.

3. The coal in-situ gasification and deep processing system according to claim 2 is characterized in that: The preset value of the hydrogen content a is a≥70%.

4. The coal in-situ gasification and deep processing system according to claim 1, characterized in that: The coalbed methane extraction and coal gasification unit includes injection wells, production wells and ignition wells; The injection well includes a first horizontal section, the production well includes a second horizontal section, the first horizontal section and the second horizontal section are arranged in the coal seam, and the first horizontal section and the second horizontal section are connected at their respective ends away from their wellheads. The ignition well is connected to the injection well and the production well at the remote end. The ignition well is used to extract coalbed methane in the coalbed methane extraction stage and to heat coal and gasification agent in the coal gasification stage.

5. The coal in-situ gasification and deep processing system according to claim 4, characterized in that: The first horizontal section and the second horizontal section are located in the same horizontal plane.

6. The coal in-situ gasification and deep processing system according to claim 4, characterized in that: A dehydration device is provided in the ignition well, and the dehydration device is used to dehydrate the coalbed methane to obtain purified water, and supply the purified water to the coalbed methane extraction and coal gasification unit and the gas processing unit.

7. The coal in-situ gasification and deep processing system according to claim 1, characterized in that: The gas purification unit includes a dust removal tower, a desulfurization tower, and a debenzene tower connected in sequence; The dust removal tower is used to remove dust from the gas to be processed, the desulfurization tower is used to desulfurize the gas to be processed, and the debenzenization tower is used to debenzene the gas to be processed.

8. The coal in-situ gasification and deep processing system according to any one of claims 1 to 7, characterized in that: It also includes a methane and synthesis gas power generation unit, which is connected to the gas processing unit and the carbon capture and storage unit respectively, receives at least part of the purified gas for combustion and power generation, and transports the combustion products to the carbon capture and storage unit.

9. The coal in-situ gasification and deep processing system according to any one of claims 1 to 7, characterized in that: The system also includes a hydrogen and oxygen production unit, which includes a distributed photovoltaic power station and an electrolyzer. The distributed photovoltaic power station and the electrolyzer are used to provide electrical energy for the electrolyzer.

10. The coal in-situ gasification and deep processing system according to any one of claims 1 to 7, characterized in that: The system also includes a green synthetic methanol unit, which is connected to the gas purification unit and the carbon capture and storage unit respectively. The green synthetic methanol unit is used to receive the purified gas from the gas purification unit to synthesize methanol and transmit carbon dioxide to the carbon capture and storage unit.

11. The coal in-situ gasification and deep processing system according to any one of claims 1 to 7, characterized in that: The system further comprises a green ammonia synthesis unit, which is connected to the gas purification unit and is used for receiving the purified gas from the gas purification unit to perform ammonia synthesis.

12. A method for in-situ gasification and deep processing of coal, using the in-situ gasification and deep processing system of coal as described in any one of claims 1 to 11, characterized in that: The method comprises: A coalbed methane processing step, extracting coalbed methane, purifying the coalbed methane and reacting at least part of the coalbed methane to generate hydrogen using steam methane reforming technology, and collecting carbon dioxide through a carbon capture and storage unit; In the coal gasification processing step, a gasifying agent is used to react with coal to obtain a raw synthesis gas, and the remaining synthesis gas after purifying the raw synthesis gas to separate the hydrogen therein is reacted with the raw synthesis gas to generate hydrogen using steam methane reforming technology, and carbon dioxide is collected by a carbon capture and storage unit.

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