A formation-based hierarchical and quality-based utilization system and method for in-situ pyrolysis-semi-coke gasification of oil-rich coal

Abstract

This invention discloses a formation-level and quality-based utilization system and method for in-situ pyrolysis-semi-coke gasification of oil-rich coal. The system includes an air separation device, a first heat exchanger, a second heat exchanger, and a combustion power generation device. Pyrolysis injection wells and pyrolysis output wells are excavated in oil-rich coal blocks. After in-situ pyrolysis and oil extraction, semi-coke blocks are formed. The pyrolysis injection wells and pyrolysis output wells serve as gasification injection wells and gasification output wells, respectively. The residual heat from the formation and the heat of gasification reaction in the semi-coke blocks are used for the pyrolysis reaction in the next oil-rich coal block. In-situ pyrolysis reactions in different blocks are initiated sequentially. The entire process, through the joint operation of pyrolysis semi-coke blocks and oil-rich coal blocks, extracts oil and gas resources and reaction heat from the oil-rich coal, realizing the graded and quality-based utilization of resources in the in-situ mining process. The use of heat exchangers to sequentially perform graded heat exchange on the pyrolysis products achieves cascaded utilization of thermal energy, avoids coal waste, and reduces production costs.

Description

Technical Field

[0001] This invention belongs to the field of coal utilization technology, specifically relating to a formation-based hierarchical and quality-based utilization system and method for in-situ pyrolysis-semi-coke gasification of oil-rich coal. Background Technology

[0002] Oil-rich coal is coal with a tar content of 7-12%, and its vast reserves ensure large-scale mining. In-situ pyrolysis technology for oil-rich coal is a concept proposed in recent years. This technology produces oil and gas by heating coal seams in situ, reducing the number of processes and equipment required for well construction, mining, washing, and conversion. It represents a major revolution in coal mining technology, while also increasing oil and gas supply, thus possessing significant strategic importance.

[0003] The in-situ pyrolysis of oil-rich coal generates a massive semi-coke layer, leading to insufficient utilization of the land resources. Furthermore, the large accumulation of semi-coke results in a significant waste of space resources, making its subsequent processing crucial. Coal pyrolysis semi-coke, as a high-calorific-value fuel, releases a large amount of heat upon gasification. The combined operation of semi-coke gasification and oil-rich coal pyrolysis can achieve graded and differentiated utilization of oil-rich coal resources, effectively completing the subsequent development of semi-coke. Therefore, developing a stratum-based graded and differentiated utilization system and method for in-situ pyrolysis of oil-rich coal and semi-coke gasification is of great practical significance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a formation-based hierarchical and quality-based utilization system and method for in-situ pyrolysis-semi-coke gasification of oil-rich coal, thereby realizing the hierarchical and quality-based utilization of resources during the in-situ mining of oil-rich coal, avoiding coal waste, and reducing production costs.

[0005] This invention is achieved through the following technical solution:

[0006] A formation-based graded and quality-based utilization system for in-situ pyrolysis-semi-coke gasification of oil-rich coal includes an air separation device, a first heat exchanger, a second heat exchanger, and a combustion power generation device.

[0007] In oil- and coal-rich areas, pyrolysis injection wells and pyrolysis output wells are excavated. After the pyrolysis reaction is completed, the pyrolysis injection wells and pyrolysis output wells serve as gasification injection wells and gasification output wells, respectively. An ignition device is installed at the bottom of the gasification injection well. An air separation device separates the air into low-temperature N2 and low-temperature O2. The oxygen output port of the air separation device is connected to a first heat exchanger and a second heat exchanger, respectively. The first heat exchanger is used to preheat part of the oxygen and send it into the gasification injection well to enter the pyrolysis semi-coke area. Under the action of the ignition device, the gasification reaction of the semi-coke layer is initiated. The second heat exchanger is used to preheat the remaining oxygen and send it into the combustion power generation device to participate in the combustion reaction.

[0008] The gasification output well outlet is connected to the combustion power generation unit. The gasification products flow out of the gasification output well and enter the combustion power generation unit. The flue gas outlet of the combustion power generation unit is connected to the pyrolysis injection well inlet. The high-temperature CO2 generated by the combustion power generation unit enters the oil-rich coal block to start the in-situ pyrolysis reaction. The pyrolysis output well outlet is connected to the hot gas inlet of the first heat exchanger. The cold gas outlet of the first heat exchanger is connected to the gas-liquid separation unit. The liquid phase outlet of the gas-liquid separation unit is connected to an oil storage device. The gas phase outlet of the gas-liquid separation unit is connected to a CO2 separation unit. The carbon dioxide outlet of the CO2 separation unit is connected to the hot gas inlet of the second heat exchanger. The pyrolysis gas outlet of the CO2 separation unit is connected to the injection well of the semi-coke block formed after pyrolysis.

[0009] Preferably, a temperature monitoring well is excavated between the gasification injection well and the gasification output well in the pyrolysis semi-coke block; and a temperature monitoring well is excavated between the pyrolysis injection well and the pyrolysis output well in the oil-rich coal block.

[0010] Preferably, multiple gasification horizontal wells are excavated at different depths in the pyrolysis semi-coke block, and the gasification injection well and gasification output well are connected through the gasification horizontal wells.

[0011] Preferably, multiple pyrolysis horizontal wells are excavated at different depths in oil- and coal-rich blocks, and the pyrolysis injection wells and pyrolysis output wells are connected through the pyrolysis horizontal wells.

[0012] Preferably, a vertical well is excavated in the pyrolysis semi-coke block, and the nitrogen outlet of the air separation device is connected to the inlet of the vertical well to inject low-temperature N2 into the pyrolysis semi-coke block to form a freezing wall.

[0013] Preferably, a vertical shaft is excavated in the oil- and coal-rich land, and the cold gas outlet of the second heat exchanger is connected to the inlet of the vertical shaft to inject low-temperature CO2 into the oil- and coal-rich land to form a freezing wall.

[0014] Preferably, the combustion power generation device supplies energy to the air separation device.

[0015] Preferably, in the pyrolysis semi-coke block, one set of gasification injection wells and gasification output wells are located at the vertex of one diagonal of a quadrilateral, and another set of gasification injection wells and gasification output wells are located at the vertex of the other diagonal of the quadrilateral, with the temperature monitoring well located at the intersection of the two diagonals;

[0016] In a coal-rich oilfield, one set of pyrolysis injection wells and pyrolysis output wells are located at the vertex of one diagonal of a quadrilateral, and another set of pyrolysis injection wells and pyrolysis output wells are located at the vertex of the other diagonal of the quadrilateral. The temperature monitoring well is located at the intersection of the two diagonals.

[0017] A formation-based method for the graded and quality-based utilization of oil-rich coal through in-situ pyrolysis and semi-coke gasification includes the following steps:

[0018] 1) The air separation device separates air into low-temperature N2 and low-temperature O2. Part of the low-temperature O2 exchanges heat with the pyrolysis products through the first heat exchanger and then enters the combustion power generation device to participate in the combustion reaction. The remaining low-temperature O2 exchanges heat with the high-temperature CO2 separated by the CO2 separation device through the second heat exchanger and then enters the pyrolysis semi-coke block. The low-temperature N2 separated by the air separation device is continuously injected into the vertical well of the pyrolysis semi-coke block.

[0019] 2) The gasification reaction of the semi-coke layer is initiated by the gasification injection well and the ignition device at the lower end of the gasification injection well. The gasification products flow out from the gasification output well and enter the combustion power generation device to undergo combustion reaction. The high-temperature CO2 generated by combustion carries a large amount of heat and enters the oil-rich coal block through the pyrolysis injection well to initiate the in-situ pyrolysis reaction under high-temperature fluid convection heating.

[0020] 3) The pyrolysis products flow out along the pyrolysis output well and pass through the first heat exchanger and gas-liquid separation device in sequence. The pyrolysis tar obtained by condensation and separation is collected in the oil storage device. The mixed gas enters the CO2 separation device. The separated CO2 first passes through the second heat exchanger, is cooled down and then injected into the vertical well of the oil-rich coal block to form a freezing wall. The remaining pyrolysis gas is injected into the semi-coke block formed after pyrolysis is completed, and the gasification reaction is started after ignition.

[0021] Preferably, the in-situ pyrolysis reaction of the oil-rich coal block is initiated by the residual heat of pyrolysis and the heat of gasification reaction of the upper half-coke block; after the oil-rich coal block is pyrolyzed and forms the second half-coke block, the pyrolysis gas is injected into the half-coke layer and ignited to trigger the gasification reaction.

[0022] This invention involves establishing pyrolysis injection wells and pyrolysis output wells in oil-rich coalfields. After in-situ pyrolysis of the coal seam to extract oil, a semi-coke layer is formed. The heat from the gasification reaction of the semi-coke layer is then used for the pyrolysis reaction of the next oil-rich coalfield. The entire process achieves graded and quality-based utilization of resources in the in-situ mining of oil-rich coalfields. Each oil-rich coalfield sequentially initiates in-situ pyrolysis reactions without the input of external energy, making full use of the land's resources. Simultaneously, heat exchangers are used to sequentially perform graded heat exchange on the pyrolysis products, achieving cascaded utilization of thermal energy. After extracting oil and gas resources from oil-rich coalfields through pyrolysis and forming a semi-coke layer, the semi-coke is then gasified, utilizing residual heat from the formation and the heat from the gasification reaction, thus achieving graded and quality-based utilization of resources.

[0023] This invention sequentially conducts pyrolysis and semi-coke gasification reactions on oil-rich coal plots. After the joint mining of the current semi-coke plot and the oil-rich coal plot is completed, the oil-rich coal plot is transformed into a semi-coke plot and continues to participate in the pyrolysis reaction of the next oil-rich coal plot. The operation process does not require additional external energy input, effectively realizing the graded and quality-based utilization of resources in the in-situ mining process of oil-rich coal.

[0024] The present invention has at least the following beneficial technical effects:

[0025] (1) After the in-situ pyrolysis of the oil-rich coal block is completed, it is transformed into a semi-coke layer block. At this time, the in-situ gasification reaction of the block can be carried out to realize the graded and quality utilization of resources in the in-situ mining process of oil-rich coal, making full use of the block resources and avoiding coal waste.

[0026] (2) After the current oil-rich coal block in-situ pyrolysis and the upper half coke layer block in-situ gasification are combined and operated, it is transformed into a half coke layer block, and continues to undergo gasification reaction to participate in the in-situ pyrolysis of the next oil-rich coal block. No additional external energy input is required, which reduces production costs and has great economic advantages.

[0027] (3) The pyrolysis products exchange heat with some of the low-temperature O2 after air separation through the first heat exchanger, and the pyrolysis gas combustion flue gas exchanges heat with the remaining low-temperature O2 through the second heat exchanger. This process realizes the cascade utilization of the thermal energy of the pyrolysis products and avoids heat waste.

[0028] (4) Temperature monitoring wells in pyrolysis semi-coke blocks and oil-rich coal blocks can monitor the pyrolysis temperature and gasification in real time, thereby controlling the intensity of the gasification reaction and keeping the pyrolysis reaction within the optimal oil extraction temperature range.

[0029] (5) After the pyrolysis reaction is completed, the gasification reaction is immediately carried out on the semi-coke layer, which can simultaneously realize the recovery and utilization of the residual heat of the formation.

[0030] (6) The development and utilization of pyrolysis semi-coke blocks is based on the well layout method of in-situ pyrolysis. No re-drilling is required during the gasification process, which effectively controls the operating cost.

[0031] (7) During the operation of the system, the pyrolysis products are burned to generate electricity, and the combustion power generation device is used to supply energy to the air separation device, which effectively utilizes the gas resources of the pyrolysis products and saves costs.

[0032] (8) The quadrilateral well layout method is adopted, and the number of injection wells and output wells can be arranged in quadrilaterals according to the actual distribution of coal seams, which makes full use of space resources and improves the utilization rate of coal mining.

[0033] (9) Low-temperature N2 is continuously injected into the pyrolysis semi-coke block and low-temperature CO2 is continuously injected into the oil-rich coal block. According to the operating characteristics of the system, different media are used to prepare the freezing wall in different blocks, which effectively prevents the leakage of groundwater during the in-situ reaction process.

[0034] (10) By connecting the injection well and the output well at different depths excavated in the block, the in-situ development of shallow, medium and deep oil-rich coal was realized; Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the formation-level and quality-differentiated utilization system for in-situ pyrolysis-semi-coke gasification of oil-rich coal according to the present invention.

[0036] Figure 2 This is a top view of the well layout structure in this invention;

[0037] Explanation of reference numerals in the attached diagram: 1 is a rock layer, 2 is a pyrolysis semi-coke layer, 3 is an oil-rich coal layer, 4 is a cryogenic wall, 5 is a gasification injection well, 6 is a gasification output well, 7 is a pyrolysis injection well, 8 is a pyrolysis output well, 9 is a temperature monitoring well, 10 is a gasification horizontal well, 11 is a pyrolysis horizontal well, 12 is an ignition device, 13 is air, 14 is an air separation device, 15 is low-temperature N2, 16 is partially low-temperature O2, 17 is remaining low-temperature O2, 18 is a combustion power generation device, 19 is high-temperature CO2, 20 is the first heat exchanger, 21 is preheated O2, 22 is the second heat exchanger, 23 is low-temperature CO2, 24 is O2 after heat exchange, 25 is a gas-liquid separation device, 26 is a CO2 separation device, 27 is an oil storage device, 28 is a pyrolysis semi-coke block, 29 is an oil-rich coal block, and 30 is the second semi-coke block. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0039] See Figure 1 As shown, the formation-leveling and quality-differentiated utilization system for in-situ pyrolysis-semi-coke gasification of oil-rich coal of the present invention includes injection wells and output wells excavated in adjacent pyrolysis semi-coke blocks 28 and oil-rich coal blocks 29. The pyrolysis semi-coke block 28 includes a rock layer 1 and a pyrolysis semi-coke layer 2. Gasification injection wells 5 and gasification output wells 6 are excavated in the pyrolysis semi-coke block 28, and several horizontal gasification wells 10 of different depths are excavated to connect the gasification injection wells 5 and gasification output wells 6. A temperature monitoring well 9 is excavated between the gasification injection wells 5 and gasification output wells 6. The oil-rich coal block 29 includes an oil-rich coal layer 3 and a rock layer. Pyrolysis injection wells 7 and pyrolysis output wells 8 are excavated in the oil-rich coal block 29, and several horizontal pyrolysis wells 11 of different depths are excavated to connect the pyrolysis injection wells 7 and pyrolysis output wells 8. A temperature monitoring well 9 is excavated between the pyrolysis injection wells 7 and pyrolysis output wells 8. Temperature monitoring wells 9 are installed in pyrolysis semi-coke block 28 and oil-rich coal block 29 to regulate the semi-coke gasification reaction and oil-rich coal pyrolysis reaction in real time within the target temperature range.

[0040] An ignition device 12 is installed at the bottom of the gasification injection well 5. On the surface, an air separation device 14, a combustion power generation device 18, a first heat exchanger 20, a second heat exchanger 22, a gas-liquid separation device 25, a CO2 separation device 26, and an oil storage device 27 are installed. The air separation device 14 separates air 13 into low-temperature N2 and low-temperature O2. The oxygen outlet of the air separation device 14 is connected to the cold gas inlet of the first heat exchanger 20 and the second heat exchanger 22. The hot gas outlets of the first heat exchanger 20 and the second heat exchanger 22 are connected to the inlet of the gasification injection well 5 and the combustion power generation device 18, respectively. A portion of the low-temperature O2 16 is preheated by the first heat exchanger 20 and then enters the combustion power generation device 18 to participate in the combustion reaction. The remaining low-temperature O2 17 is heat-exchanged by the second heat exchanger 22 and then enters the pyrolysis semi-coke block 28 to participate in the gasification reaction. The gasification reaction of the semi-coke layer is initiated by the ignition device 12 at the bottom of the gasification injection well 5. The nitrogen outlet of the air separation device 14 is connected to a vertical well excavated in the pyrolysis semi-coke block 28, and low-temperature N215 is continuously injected into the pyrolysis semi-coke block 28 to form a freezing wall 4.

[0041] The outlet of the gasification output well 6 is connected to the combustion power generation unit 18. The flue gas outlet of the combustion power generation unit 18 is connected to the inlet of the pyrolysis injection well 7. The gasification products flow out from the gasification output well 6 and enter the combustion power generation unit 18. The high-temperature CO2 19 generated by combustion enters the oil-rich coal block 29 and starts the in-situ pyrolysis reaction. The outlet of the pyrolysis output well 8 is connected to the hot gas inlet of the first heat exchanger 20. The cold gas outlet of the first heat exchanger 20 is connected to the gas-liquid separator 25. The liquid phase outlet of the gas-liquid separator 25 is connected to the oil storage device 27. The gas phase outlet of the gas-liquid separator 25 is connected to the CO2 separator 26. The carbon dioxide outlet of the CO2 separator 26 is connected to the hot gas inlet of the second heat exchanger 22. The cold gas outlet of the second heat exchanger 22 is connected to the vertical well excavated in the oil-rich coal block 29. The pyrolysis gas outlet of the CO2 separator 26 is connected to the injection well of the second semi-coke block 30 after pyrolysis. The pyrolysis products pass sequentially through the first heat exchanger 20 and the gas-liquid separation device 25. The pyrolysis tar obtained by condensation is collected in the oil storage device 27. The mixed gas enters the CO2 separation device 26. The separated CO2 first passes through the second heat exchanger 22. After cooling, the low-temperature CO2 23 is injected into the oil-rich coal block 29 to form the freezing wall 4. The remaining pyrolysis gas is injected into the second semi-coke block 30 formed after pyrolysis is completed. After ignition, the gasification reaction is started.

[0042] The combustion power generation device 18 supplies energy to the air separation device 14. This invention continuously injects low-temperature N215 and low-temperature CO223 into the pyrolysis semi-coke block 28 and the oil-rich coal block 29, respectively, thereby lowering the temperature of the surrounding materials and forming a freezing wall 4, effectively preventing groundwater leakage during the in-situ reaction process.

[0043] like Figure 2As shown, the two injection wells and two output wells are arranged in a quadrilateral configuration at the four vertices. For example, in one set of pyrolysis semi-coke blocks 28, the gasification injection well 5 and gasification output well 6 are located at one diagonal vertex of the quadrilateral, while in another set, they are located at the other diagonal vertex. The temperature monitoring well 9 is located at the intersection of the two diagonals. Similarly, in the oil-rich coal block 29, one set of pyrolysis injection well 7 and pyrolysis output well 8 are located at one diagonal vertex of the quadrilateral, while in another set, they are located at the other diagonal vertex. The temperature monitoring well 9 is located at the intersection of the two diagonals. The injection wells and output wells are located at opposite ends of the diagonals, with the temperature monitoring well 9 located at the intersection. The quadrilateral arrangement of injection wells and output wells is rationally arranged according to the actual distribution of the coal seams, thereby making reasonable use of space resources.

[0044] This invention comprehensively considers the slow oxidation portion of pyrolysis semi-coke, the pyrolysis portion of oil-rich coal, the joint operation of two blocks, the cascade utilization of thermal energy from pyrolysis products, and the preparation process of the cryogenic wall. Combined with a unique well layout method, it realizes the coupled operation of slow oxidation of the semi-coke layer and pyrolysis of the oil-rich coal layer, and makes graded and quality-based utilization of oil-rich coal resources.

[0045] On the other hand, the present invention provides a method for the graded and quality-based utilization of oil-rich coal through in-situ pyrolysis-semi-coke gasification, comprising the following steps:

[0046] 1) The air separation device 14 separates air 13 into low-temperature N2 and low-temperature O2. Part of the low-temperature O2 16 exchanges heat with the pyrolysis products through the first heat exchanger 20 and the preheated O2 21 enters the combustion power generation device 18 to participate in the combustion reaction. The remaining low-temperature O2 17 exchanges heat with the high-temperature CO2 separated by the CO2 separation device 26 through the second heat exchanger 22. The O2 24 after heat exchange enters the pyrolysis semi-coke block 28. The low-temperature N2 15 separated by the air separation device 14 is continuously injected into the vertical well of the pyrolysis semi-coke block 28.

[0047] 2) O224 enters the pyrolysis semi-coke block 28 through the gasification injection well 5. Under the action of the ignition device 12 at the lower end of the gasification injection well 5, the gasification reaction of the semi-coke layer is initiated. As O224 is continuously injected and flows, the gasification reaction area gradually moves towards the gasification output well 6 along the gasification horizontal well 10. The gasification products flow out from the gasification output well 6 and enter the combustion power generation device 18 to undergo combustion reaction. The high temperature CO219 generated by combustion carries a large amount of heat and enters the oil-rich coal block 29 through the pyrolysis injection well 7 to initiate the in-situ pyrolysis reaction under high temperature fluid convection heating.

[0048] 3) The pyrolysis products flow out along the pyrolysis output well 8 and pass through the first heat exchanger 20 and the gas-liquid separation device 25 in sequence. The pyrolysis tar obtained by condensation and separation is collected in the oil storage device 27. The mixed gas enters the CO2 separation device 26. The separated CO2 first passes through the second heat exchanger 22, and after cooling, it is injected into the vertical well of the oil-rich coal block 29 to form a freezing wall 4. The remaining pyrolysis gas is injected into the second semi-coke block 30 formed after pyrolysis is completed, and the gasification reaction is started after ignition.

[0049] This invention employs an air separation device 14 to separate air 13 into low-temperature N2 and low-temperature O2. A portion of the low-temperature O2 16 exchanges heat with the pyrolysis products through a first heat exchanger 20, while the remaining low-temperature O2 17 exchanges heat with high-temperature CO2 through a second heat exchanger 22. The heat-exchanged O2 24 enters the pyrolysis semi-coke block 28 through a gasification injection well 5, where the semi-coke layer gasification reaction is initiated by the ignition device 12 below the gasification injection well 5. With the continuous injection and flow of O2 24, the gasification reaction zone gradually moves towards the gasification output well 6 along the gasification horizontal well 10.

[0050] Gasification products flow out of gasification output well 6 and enter combustion power generation unit 18. Combustion occurs with the participation of preheated O221. The high-temperature CO219 generated by combustion carries a large amount of heat and enters oil-rich coal block 29 through pyrolysis injection well 7, initiating an in-situ pyrolysis reaction under high-temperature fluid convection heating. Pyrolysis products flow out along pyrolysis output well 8, exchange heat with a portion of the low-temperature O2 after air separation in the first heat exchanger 20, and then enter the gas-liquid separator 25. The pyrolysis tar obtained from condensation and separation is collected in the oil storage device 27. The mixed gas enters the CO2 separator 26. The separated CO2 first exchanges heat with the remaining low-temperature O2 in the second heat exchanger 22, and after cooling, it is injected into oil-rich coal block 29 to form a freezing wall 4. The remaining pyrolysis gas is injected into the second semi-coke block 30 formed after pyrolysis, ignited, and the gasification reaction is initiated.

Claims

1. A formation-based hierarchical and quality-differentiated utilization system for in-situ pyrolysis-semi-coke gasification of oil-rich coal, characterized in that: It includes an air separation unit (14), a first heat exchanger (20), a second heat exchanger (22), and a combustion power generation unit (18). In the oil-rich coal block (29), pyrolysis injection well (7) and pyrolysis output well (8) are excavated. After the in-situ pyrolysis reaction is completed, the pyrolysis injection well (7) and pyrolysis output well (8) are used as gasification injection well (5) and gasification output well (6), respectively. An ignition device (12) is set at the bottom of the gasification injection well (5). An air separation device (14) is set to separate air (13) into low-temperature N2 and low-temperature O2. The oxygen outlet of the air separation device (14) is connected to the first heat exchanger (20) and the second heat exchanger (22), respectively. The first heat exchanger (20) is used to preheat part of the oxygen and send it into the gasification injection well (5) to enter the pyrolysis semi-coke block (28). Under the action of the ignition device (12), the semi-coke layer gasification reaction is started. The second heat exchanger (22) is used to preheat the remaining oxygen and send it into the combustion power generation device (18) to participate in the combustion reaction. The outlet of the gasification output well (6) is connected to the combustion power generation device (18). The gasification products flow out from the gasification output well (6) and enter the combustion power generation device (18). The flue gas outlet of the combustion power generation device (18) is connected to the inlet of the pyrolysis injection well (7). The high-temperature CO2 generated by the combustion power generation device (18) enters the oil-rich coal block (29) to start the in-situ pyrolysis reaction. The outlet of the pyrolysis output well (8) is connected to the hot gas inlet of the first heat exchanger (20). The cold gas outlet of the first heat exchanger (20) is connected to the gas-liquid separation device (25). The liquid phase outlet of the gas-liquid separation device (25) is connected to the oil storage device (27). The gas phase outlet of the gas-liquid separation device (25) is connected to the CO2 separation device (26). The carbon dioxide outlet of the CO2 separation device (26) is connected to the hot gas inlet of the second heat exchanger (22). The pyrolysis gas outlet of the CO2 separation device (26) is connected to the injection well of the second semi-coke block (30) formed after pyrolysis. A vertical shaft is excavated in the pyrolysis semi-coke block (28). The nitrogen outlet of the air separation device (14) is connected to the inlet of the vertical shaft, and low-temperature N2 is injected into the pyrolysis semi-coke block (28) to form a freezing wall (4). A vertical shaft is excavated in the oil-rich coal block (29). The cold gas outlet of the second heat exchanger (22) is connected to the inlet of the vertical shaft, and low-temperature CO2 is injected into the oil-rich coal block (29) to form a freezing wall (4).

2. The formation-based graded and quality-differentiated utilization system for in-situ pyrolysis-semi-coke gasification of oil-rich coal according to claim 1, characterized in that: Temperature monitoring wells (9) are excavated between the gasification injection well (5) and the gasification output well (6) in the pyrolysis semi-coke block (28); and temperature monitoring wells (9) are excavated between the pyrolysis injection well (7) and the pyrolysis output well (8) in the oil-rich coal block (29).

3. The formation-based graded and quality-differentiated utilization system for in-situ pyrolysis-semi-coke gasification of oil-rich coal according to claim 2, characterized in that: In the pyrolysis semi-coke block (28), multiple gasification horizontal wells (10) are excavated at different depths, and the gasification injection well (5) and the gasification output well (6) are connected through the gasification horizontal wells (10).

4. The formation-based graded and quality-differentiated utilization system for in-situ pyrolysis-semi-coke gasification of oil-rich coal according to claim 3, characterized in that: In the oil and coal rich block (29), multiple pyrolysis horizontal wells (11) are excavated at different depths, and the pyrolysis injection well (7) and the pyrolysis output well (8) are connected through the pyrolysis horizontal wells (11).

5. The formation-based graded and quality-based utilization system for in-situ pyrolysis-semi-coke gasification of oil-rich coal according to claim 1, characterized in that: The combustion power generation device (18) supplies energy to the air separation device (14).

6. The formation-based grading and quality-differentiated utilization system for in-situ pyrolysis-semi-coke gasification of oil-rich coal according to claim 5, characterized in that: In the pyrolysis semi-coke block (28), one set of gasification injection wells (5) and gasification output wells (6) are located at the vertex of one diagonal of the quadrilateral, another set of gasification injection wells (5) and gasification output wells (6) are located at the vertex of the other diagonal of the quadrilateral, and the temperature monitoring well (9) is located at the intersection of the two diagonals; In the oil-rich coal block (29), one set of pyrolysis injection wells (7) and pyrolysis output wells (8) are located at the vertex of one diagonal of the quadrilateral, another set of pyrolysis injection wells (7) and pyrolysis output wells (8) are located at the vertex of the other diagonal of the quadrilateral, and the temperature monitoring well (9) is located at the intersection of the two diagonals.

7. A method for classifying and utilizing oil-rich coal in-situ through pyrolysis-semi-coke gasification based on the classification and grading utilization system described in claim 6, characterized in that... Includes the following steps: 1) The air separation device (14) separates air (13) into low-temperature N2 and low-temperature O2. Part of the low-temperature O2 passes through the first heat exchanger (20) and exchanges heat with the pyrolysis products before entering the combustion power generation device (18) to participate in the combustion reaction. The remaining low-temperature O2 passes through the second heat exchanger (22) and exchanges heat with the high-temperature CO2 separated by the CO2 separation device (26) before entering the pyrolysis semi-coke block (28). The low-temperature N2 separated by the air separation device (14) is continuously injected into the vertical well of the pyrolysis semi-coke block (28). 2) The oxygen entering the pyrolysis semi-coke block (28) through the gasification injection well (5) starts the gasification reaction of the semi-coke layer under the action of the ignition device (12) below the gasification injection well (5). The gasification products flow out from the gasification output well (6) and enter the combustion power generation device (18) to undergo combustion reaction. The high-temperature CO2 generated by combustion carries a large amount of heat and enters the oil-rich coal block (29) through the pyrolysis injection well (7) to start the in-situ pyrolysis reaction under high-temperature fluid convection heating. 3) The pyrolysis products flow out along the pyrolysis output well (8) and pass through the first heat exchanger (20) and the gas-liquid separation device (25) in sequence. The pyrolysis tar obtained by condensation and separation is collected in the oil storage device (27). The mixed gas enters the CO2 separation device (26). The separated CO2 first passes through the second heat exchanger (22), and after cooling, it is injected into the vertical well of the oil-rich coal block (29) to form a freezing wall (4). The remaining pyrolysis gas is injected into the second semi-coke block (30) formed after pyrolysis is completed, and the gasification reaction is started after ignition.

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