Underground drilling type heat exchange system based on heat pipe

Abstract

The utility model relates to an underground well drilling heat exchange system based on a heat pipe, a heat pipe heat exchanger of the system is arranged in a production well, an evaporation section of the heat pipe is arranged on the outer wall of the heat pipe heat exchanger, a heat source is high-temperature coal gas generated by underground coal gasification, and a condensation section of the heat pipe is arranged on the inner wall of the heat pipe heat exchanger to exchange heat with water; a water inlet of the heat pipe exchanger is provided with a straight pipe communicated to the bottom of the heat pipe exchanger, and a water outlet of the heat pipe exchanger is arranged on the ground; the coal gas generated by the gasification furnace is cooled by the heat pipe heat exchanger and then sequentially enters the condensation tank, the water-gas shift device and the acid gas removal device to be purified, and then the coal gas can be used for hydrogen production, natural gas synthesis, IGCC power generation and the like. According to the utility model, the temperature of the underground coal gasification production well is rapidly reduced by utilizing the high thermal conductivity and the automatic heat transfer characteristic of the heat pipe, the stable operation of underground coal gasification is guaranteed, the utilization rate of energy is improved, and the loss of a large amount of sensible heat of coal gas is effectively avoided.

Description

Technical Field

[0001] The utility model relates to an underground drilling type heat exchange system based on a heat pipe, belonging to the technical field of underground drilling type heat exchange. Background Art

[0002] Underground coal gasification is a process of controlled combustion of underground coal to produce combustible gas through thermal and chemical effects on coal. Underground coal gasification is a new multidisciplinary technology for developing clean energy and chemical raw materials that integrates well construction, coal mining, and gasification processes. Its essence is to only extract the energy-containing components in coal and change physical coal mining to chemical coal mining. Therefore, it has the advantages of good safety, low investment, high efficiency, and low pollution. It is known as the second-generation coal mining method. Underground coal gasification technology can not only recover coal resources abandoned by mines, but also be used to mine thin coal seams, deep coal seams, "three-under" compressed coal, and high-sulfur, high-ash, and high-gas coal seams that are difficult for underground workers to mine or have poor economic and safety. Underground gasification coal gas can not only be used as fuel gas for direct civilian use and power generation, but also be used to extract pure hydrogen or as raw gas for synthetic oil, dimethyl ether, ammonia, and methanol. Therefore, underground coal gasification technology has good economic and environmental benefits, greatly improves the utilization rate and utilization level of coal resources, and is an important research and development direction of my country's clean coal technology.

[0003] However, in the actual production process, the high-temperature coal gas (temperature exceeding 900°C) generated by coal gasification is transported to the ground through the production well, which may cause thermal corrosion, deformation or cracking of the production well casing, seriously threatening the safe operation of the underground coal gasification production well. Therefore, how to quickly remove the heat in the coal gas to reduce the temperature of the gas production well has become a key factor in ensuring the stable operation of underground coal gasification.

[0004] The heat pipe has a simple structure, reliable operation, and does not require external energy input. The heat pipe makes full use of the heat conduction principle and the rapid heat transfer properties of the phase change medium. The heat of the heating object is quickly transferred to the outside of the heat source through the heat pipe. Its thermal conductivity exceeds that of any known metal. The heat pipe can work under various environmental conditions. The utility model utilizes the super thermal conductivity of the heat pipe to quickly transfer the sensible heat of the gas. Compared with the traditional cold water spray method, this method not only does not cause secondary environmental pollution, but also effectively avoids the loss of a large amount of sensible heat of the gas, thereby improving energy utilization. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the utility model is to provide an underground drilling heat exchange system based on a heat pipe.

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: an underground drilling type heat exchange system based on a heat pipe, the system comprising a gas production well (1), a heat pipe heat exchanger (2), a high-pressure water pump (3), a condensing tank (4), a water-gas conversion device (5), and an acid gas removal device (6); the heat pipe heat exchanger (2) is placed in the overlying rock layer of the coal layer in the gas production well (1); the water outlet of the high-pressure water pump (3) is connected to the water inlet of the heat pipe heat exchanger (2), and the water inlet of the heat pipe heat exchanger (2) is provided with a straight pipe extending to the bottom of the heat pipe heat exchanger (2); the gas outlet of the gas production well (1) is connected to the inlet of the condensing tank (4); the outlet of the condensing tank (4) is connected to the inlet of the water-gas conversion device (5); and the outlet of the water-gas conversion device (5) is connected to the inlet of the acid gas removal device (6).

[0007] The underground drilling type heat exchange system based on heat pipes is characterized in that the heat pipes of the heat pipe heat exchanger (2) penetrate the pipe wall of the heat pipe heat exchanger (2), the heat pipe evaporation section (2-3) is arranged on the outer wall of the heat pipe heat exchanger (2), and the heat pipe condensation section (2-2) is arranged on the inner wall of the heat pipe heat exchanger (2), the heat pipe evaporation section (2-3) and the condensation section (2-2) are both arranged vertically, and fins can be arranged on the outer walls of the heat pipe evaporation section (2-3) and the condensation section (2-2).

[0008] The underground drilling type heat exchange system based on heat pipes is characterized in that the heat pipe cross-section of the heat pipe heat exchanger (2) is circular, elliptical or polygonal.

[0009] The underground drilling heat exchange system based on heat pipes is characterized in that the heat pipes of the heat pipe heat exchanger (2) can be arranged according to the temperature distribution of coal gas in the gas production well, and high-temperature heat pipes, medium-temperature heat pipes and low-temperature heat pipes can be arranged in sequence from the bottom to the top.

[0010] The underground drilling heat exchange system based on a heat pipe is characterized in that a temperature sensor is provided at the gas outlet of the gas production well (1), and the sensor feeds back temperature information to the high-pressure water pump (3), so that it automatically adjusts the water intake to keep the gas temperature at the outlet of the gas production well stable.

[0011] The underground drilling type heat exchange system based on a heat pipe is characterized in that the high-pressure water vapor in the outlet of the heat pipe heat exchanger (2) is used as a UCG gasifying agent, or is used for heating or power generation.

[0012] Compared with the prior art, the utility model has the following beneficial effects:

[0013] 1. The utility model effectively solves the problems of thermal corrosion, deformation or cracking of the casing of the production wells caused by the high-temperature coal gas (temperature exceeding 900°C) generated by underground coal gasification being transported to the ground through the production wells, thereby ensuring the stable operation of underground coal gasification.

[0014] 2. The utility model utilizes the super heat conduction capacity of the heat pipe to quickly transfer the sensible heat of the gas. Compared with the traditional cold water spray method, this method not only does not cause secondary environmental pollution, but also effectively avoids the loss of a large amount of sensible heat of the gas and improves energy utilization.

[0015] 3. The heat pipe heat exchanger of the utility model has the advantages of simple structure, long service life, and autonomous heat transfer. Compared with the heat exchange of the methane reforming reactor, it does not require external driving force, has less equipment investment, and has low later maintenance costs.

[0016] 4. The medium and high pressure water vapor after heat exchange by the heat pipe heat exchanger of the utility model can be used as UCG gasification agent or for heating, power generation, etc.

[0017] 5. The utility model can be used for heat exchange between high-temperature coal gas and gasifying agent in underground gasification blind hole furnaces, and can also be used for heat extraction from geothermal wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of an underground drilling heat exchange system based on a heat pipe according to the utility model;

[0019] In the figure, 1 is a gas production well, 2 is a heat pipe heat exchanger, 3 is a high-pressure water pump, 4 is a condenser, 5 is a water-gas conversion device, and 6 is an acid gas removal device.

[0020] Figure 2 This is a schematic diagram of a heat pipe heat exchanger of the utility model;

[0021] In the figure, 2 is a heat pipe heat exchanger, 2-1 is a water inlet of a heat pipe heat exchanger, 2-2 is a condensing section of a heat pipe, 2-3 is an evaporating section of a heat pipe, 2-4 is a water outlet of a heat pipe heat exchanger, and 2-5 is a water inlet of a heat pipe reactor;

[0022] Figure 3 It is a schematic diagram of the utility model being applied to underground gasification blind hole furnace where high temperature coal gas heats the gasifying agent through a heat pipe.

[0023] In the figure, 1 is a gas production and gasification agent injection well, 2 is a heat pipe heat exchanger, 4 is a condenser, 5 is a water-gas shift device, and 6 is an acid gas removal device. DETAILED DESCRIPTION

[0024] In order to more clearly understand the technical essence and beneficial effects of the present invention, the specific implementation methods of the present invention are described in detail below with reference to the accompanying drawings.

[0025] Combination Figure 1 and Figure 2The utility model discloses an underground drilling type heat exchange system based on a heat pipe, the system comprising a gas production well (1), a heat pipe heat exchanger (2), a high-pressure water pump (3), a condensing tank (4), a water-gas conversion device (5), and an acid gas removal device (6); the heat pipe heat exchanger (2) is placed in the overlying rock layer of the coal layer in the gas production well (1); the water outlet of the high-pressure water pump (3) is connected to the water inlet of the heat pipe heat exchanger (2), and the water inlet of the heat pipe heat exchanger (2) is provided with a straight pipe extending to the bottom of the heat pipe heat exchanger (2); the gas outlet of the gas production well (1) is connected to the inlet of the condensing tank (4); the outlet of the condensing tank (4) is connected to the inlet of the water-gas conversion device (5); and the outlet of the water-gas conversion device (5) is connected to the inlet of the acid gas removal device (6).

[0026] The underground drilling type heat exchange system based on heat pipes is characterized in that the heat pipes of the heat pipe heat exchanger (2) penetrate the pipe wall of the heat pipe heat exchanger (2), the heat pipe evaporation section (2-3) is arranged on the outer wall of the heat pipe heat exchanger (2), and the heat pipe condensation section (2-2) is arranged on the inner wall of the heat pipe heat exchanger (2), the heat pipe evaporation section (2-3) and the condensation section (2-2) are both arranged vertically, and fins can be arranged on the outer walls of the heat pipe evaporation section (2-3) and the condensation section (2-2).

[0027] The underground drilling type heat exchange system based on heat pipes is characterized in that the heat pipe cross-section of the heat pipe heat exchanger (2) is circular, elliptical or polygonal.

[0028] The underground drilling heat exchange system based on heat pipes is characterized in that the heat pipes of the heat pipe heat exchanger (2) can be arranged according to the temperature distribution of coal gas in the gas production well, and high-temperature heat pipes, medium-temperature heat pipes and low-temperature heat pipes can be arranged in sequence from the bottom to the top.

[0029] The underground drilling heat exchange system based on a heat pipe is characterized in that a temperature sensor is provided at the gas outlet of the gas production well (1), and the sensor feeds back temperature information to the high-pressure water pump (3), so that it automatically adjusts the water intake to keep the gas temperature at the outlet of the gas production well stable.

[0030] The underground drilling type heat exchange system based on a heat pipe is characterized in that the high-pressure water vapor in the outlet of the heat pipe heat exchanger (2) is used as a UCG gasifying agent, or is used for heating or power generation.

[0031] Example

[0032] A coal underground gasification furnace, the coal seam is buried 1000 meters deep, and can produce 300,000 Nm per day 3The initial gas temperature is 900℃, the gas temperature at the outlet of the gas production well is controlled at 300℃, the space diameter of the heat pipe heat exchanger that can be arranged in the production well is 177.8mm, the designed heat pipe heat exchanger diameter is 160mm, the heat pipe diameter is 25mm, the length is 4 meters, the heat pipe evaporation section and condensation section are 2 meters each, and the power of a single heat pipe is 6KW. 8 heat pipes can be arranged on each layer of the heat pipe heat exchanger.

[0033] The coal gas produced by coal gasification passes through the combustion zone and enters the coal gas production well (1). In this process, the high-temperature coal gas is heat exchanged through the heat pipe heat exchanger (2), and the temperature of the coal gas is reduced from 900°C to 300°C. In order to achieve this process, the heat exchange capacity of the heat pipe heat exchanger (2) needs to reach 3819 kilowatts, 640 heat pipes are used, and the heat pipe heat exchanger (2) needs to be arranged with 80 layers of heat pipes. The heat pipe heat exchanger (2) can generate 160kg of water vapor with a temperature of 300°C and a pressure of 15Mpa per minute. The generated water vapor can be used as a UCG gasification agent or for heating, power generation, etc.; the coal gas after heat exchange treatment is discharged from the production well and enters the condenser (4) to remove tar and moisture therein; the coal gas treated by the condenser (4) flows to the water-gas conversion device (5), and the reacted coal gas enters the acid gas removal device (6) from the outlet of the water-gas conversion device (5) to remove CO 2 and H 2 Finally, the purified coal gas can be used as raw material for chemical synthesis, pure hydrogen extraction, natural gas synthesis, IGCC power generation, etc.

[0034] The above describes the specific embodiments of the present invention, but the present invention is not limited to the above examples. Any changes made by technicians in this technical field within the essential scope of the present invention also fall within the protection scope of the present invention.

Claims

1. An underground drilling heat exchange system based on a heat pipe, characterized in that: The system comprises a gas production well (1), a heat pipe heat exchanger (2), a high-pressure water pump (3), a condensing tank (4), a water-gas conversion device (5), and an acid gas removal device (6); the heat pipe heat exchanger (2) is placed in the overlying rock layer of the coal layer in the gas production well (1); the water outlet of the high-pressure water pump (3) is connected to the water inlet of the heat pipe heat exchanger (2), and the water inlet of the heat pipe heat exchanger (2) is provided with a straight pipe extending to the bottom of the heat pipe heat exchanger (2); the gas outlet of the gas production well (1) is connected to the inlet of the condensing tank (4); the outlet of the condensing tank (4) is connected to the inlet of the water-gas conversion device (5); and the outlet of the water-gas conversion device (5) is connected to the inlet of the acid gas removal device (6).

2. The underground drilling heat exchange system based on heat pipe according to claim 1, characterized in that: The heat pipes of the heat pipe heat exchanger (2) penetrate the pipe wall of the heat pipe heat exchanger (2); the heat pipe evaporation section (2-3) is arranged on the outer wall of the heat pipe heat exchanger (2); the heat pipe condensation section (2-2) is arranged on the inner wall of the heat pipe heat exchanger (2); the heat pipe evaporation section (2-3) and the condensation section (2-2) are both arranged vertically; and fins can be arranged on the outer walls of the heat pipe evaporation section (2-3) and the condensation section (2-2).

3. The underground drilling heat exchange system based on heat pipe according to claim 1, characterized in that: The cross section of the heat pipe of the heat pipe heat exchanger (2) is circular, elliptical or polygonal.

4. The underground drilling heat exchange system based on heat pipe according to claim 1, characterized in that: The heat pipes of the heat pipe heat exchanger (2) can be arranged according to the temperature distribution of the coal gas in the coal gas production well. From the bottom to the top, the high-temperature heat pipes, the medium-temperature heat pipes and the low-temperature heat pipes can be arranged in sequence.

5. The underground drilling heat exchange system based on heat pipe according to claim 1, characterized in that: A temperature sensor is provided at the gas outlet of the gas production well (1), and the sensor feeds back temperature information to the high-pressure water pump (3), so that the pump automatically adjusts the water intake to keep the gas temperature at the outlet of the gas production well stable.

6. The underground drilling heat exchange system based on heat pipe according to claim 1, characterized in that: The high-pressure water vapor in the water outlet of the heat pipe heat exchanger (2) is used as a UCG gasifying agent, or for heating or power generation.

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