Integrated system for catalytic combustion power generation, heat supply and refrigeration of low-concentration gas in coal mines

Abstract

The invention discloses an integrated system for catalytic combustion power generation, heat supply and refrigeration of low-concentration gas in coal mines, which includes a low-concentration gas extraction pumping station, a low-concentration gas pipeline transportation guarantee unit, an intelligent gas distribution unit, an air supply unit, a gas concentration compensation unit, a porous medium catalytic combustion device, a waste heat boiler, a steam turbine generator set, a heat supply unit and a refrigeration unit. The low-concentration gas extraction pumping station is connected to the low-concentration gas pipeline transportation guarantee unit, the low-concentration gas pipeline transportation guarantee unit is connected to the intelligent gas distribution unit, the intelligent gas distribution unit is connected to the inlet of the porous medium catalytic combustion device, and the waste heat boiler provides power generation, heat supply and refrigeration in three ways. The invention can stably and efficiently burn 4-5% of low-concentration gas by using the porous medium catalytic combustion technology, generate high-quality flue gas with a temperature higher than 600 °C for combined cooling, heating and power supply, and realize the comprehensive utilization of the energy of low-concentration gas extracted from coal mines.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mine gas utilization, and particularly relates to an integrated system for catalytic combustion power generation, heating, and refrigeration of low-concentration coal mine gas. Background Art

[0002] A large amount of coal mine gas is associated with coal mining. By the end of 2020, the national coal mine gas extraction volume reached 12.8 billion m3, but its utilization rate was only 44.8%. The reasons for the low utilization of coal mine gas mainly include two aspects: First, the concentration of coal mine extracted gas is generally low. The existing technology has not had a good solution for the utilization of gas with a CH4 concentration between 3% and 9%. Usually, it is directly discharged. The amount of gas discharged annually reaches 23.13 million m3, which is equivalent to 115,700 t of standard coal. On the one hand, it causes a large waste of high-quality energy, and on the other hand, it also brings serious greenhouse effects (the greenhouse effect of CH4 is about 21 times that of CO2); Second, coal mine gas varies greatly and fluctuates due to different extraction methods, locations, and times. The fluctuation range is 0.1% - 6%. The existing gas utilization technologies are difficult to directly utilize it to form large-scale applications. In addition, 39% of China's CH4 emissions mainly come from coal mining.

[0003] Therefore, solving the problem of low-concentration coal mine gas is of great practical significance in aspects such as increasing clean energy and reducing greenhouse gas emissions.

[0004] Chinese Patent CN110985202A discloses a combined cooling, heating, and power supply system based on low-concentration gas, including: a gas pump room, a low-concentration gas transportation guarantee unit, a mixer, a gas regenerative oxidation device, a refrigeration unit, a heating unit, and a gas generator set. The low-concentration gas transportation guarantee unit is connected to the gas pump room; the mixer is connected to the low-concentration gas transportation guarantee unit and is adapted to mix a part of the gas with air; the gas regenerative oxidation device is connected to the mixer and is adapted to oxidize the mixed gas to obtain high-temperature flue gas and oxidation tail gas; the refrigeration unit is connected to the gas regenerative oxidation device and is adapted to use a part of the high-temperature flue gas to prepare low-temperature water and refrigeration tail gas; the heating unit is connected to the gas regenerative oxidation device and is adapted to exchange heat between another part of the high-temperature flue gas and cold water; the gas generator set is connected to the low-concentration gas transportation guarantee unit and is adapted to burn another part of the gas for power generation and generate combustion flue gas. The above patent mainly has the following deficiencies: First, it does not specifically solve the problem of stable operation under the fluctuations of the concentration and flow rate of low-concentration coal mine extracted gas; Second, the gas concentration range utilized by the existing technical solution is mainly <3%. The low-concentration gas with <3% generates flue gas with low-quality heat (temperature lower than 250°C), with large heat losses and high power consumption, and it is difficult to achieve integrated utilization of power generation, heating, and refrigeration. Summary of the Invention

[0005] The object of the present invention is to provide an integrated system for catalytic combustion power generation, heat supply and refrigeration of low-concentration gas in coal mines, which not only realizes the efficient and clean utilization of low-concentration gas, but also ensures the stability of the combustion operation of low-concentration gas and improves the comprehensive utilization rate of low-concentration gas.

[0006] To achieve the above object, an integrated system for catalytic combustion power generation, heat supply and refrigeration of low-concentration gas in coal mines according to the present invention includes a low-concentration gas extraction pumping station, a low-concentration gas pipeline transportation guarantee unit, an air supply unit, a steam turbine generator set, a heat supply unit and a refrigeration unit; it also includes an intelligent gas distribution unit, a gas concentration compensation unit, a porous medium catalytic combustion device and a waste heat boiler. The low-concentration gas extraction pumping station is connected to the low-concentration gas pipeline transportation guarantee unit; the low-concentration gas pipeline transportation guarantee unit is connected to the intelligent gas distribution unit, and the air supply unit is connected to the intelligent gas distribution unit; the gas concentration compensation unit is connected to the passage between the low-concentration gas pipeline transportation guarantee unit and the intelligent gas distribution unit; the intelligent gas distribution unit is connected to the inlet of the porous medium catalytic combustion device, the outlet of the porous medium catalytic combustion device is connected to the waste heat boiler, and the heat of the waste heat boiler is divided into three paths leading to the steam turbine generator set, the heat supply unit and the refrigeration unit;

[0007] The intelligent gas distribution unit includes an air-CH4 flow controller, an air-CH4 concentration regulator and a mixing chamber. The air-CH4 flow controller is used to control the flow rate of the air input by the air supply unit and the flow rate of the CH4 input by the gas concentration compensation unit; the air-CH4 concentration regulator is used to monitor the gas concentration in the mixing chamber and feedback it to the air-CH4 flow controller to make the mixing chamber reach a preset concentration;

[0008] The gas concentration compensation unit includes a methane gas tank, a pressure reducing valve and a one-way valve, which are used to provide a certain amount of CH4 through the automatic disturbance compensation control of the intelligent gas distribution unit when the gas concentration fluctuates, so as to ensure that the gas concentration is always maintained within a certain concentration range;

[0009] The porous medium catalytic combustion device includes a flame arrester, a flow equalizing device, a porous medium, a gas collecting hood, a burner body, a heat preservation layer and a support base. The burner body is installed on the support base, and its bottom inlet is connected to the intelligent gas distribution unit through the flame arrester, and its top outlet is provided with the gas collecting hood; the porous medium is arranged in the combustion chamber between the inlet and the outlet, and the porous medium is multi-layered with different porosities; the flow equalizing device is arranged at the bottom of the combustion chamber; the heat preservation layer is arranged outside the burner body.

[0010] Further, in the porous medium combustion device, the porous medium has four layers, and the porosity of the four-layer porous medium is 40 PPI, 30 PPI, 20 PPI, and 10 PPI in sequence from the inlet of the burner body to the outlet.

[0011] Further, the porous medium combustion device further includes a thermocouple, a flue gas analyzer, and a high-energy igniter. The thermocouple is arranged in the heat insulation layer. The flue gas analyzer is used to analyze the combusted gas, and the high-energy igniter is used to ignite the low-concentration gas in the combustion chamber.

[0012] Further, the low-concentration gas transportation guarantee unit includes an anti-backflow device, an explosion-proof device, an explosion suppression device, a water seal fire and explosion relief device, a flame sensor, and a desulfurization device that are connected in sequence through pipelines. The anti-backflow device is connected to the low-concentration gas drainage pump station. The flame sensor is connected between the water seal fire and explosion relief device and the desulfurization device. The anti-backflow device, the explosion-proof device, the explosion suppression device, the water seal fire and explosion relief device, and the flame sensor are all connected to the monitoring system.

[0013] Further, the air supply unit includes an air compressor, a gas storage tank, a filter, and a dryer, and the filter is an oil-water separator.

[0014] Further, the waste heat boiler includes a superheater, an evaporator, an economizer, and a steam drum, and the superheater, the evaporator, and the economizer are respectively connected to the steam drum.

[0015] Further, the steam turbine generator set is composed of a steam turbine and a generator, and the steam turbine is a condensing steam turbine.

[0016] Further, the heat supply unit includes a heat network heater and a heat supply return water device. The heat network heater and the heat supply return water device are connected through pipelines. The heat network heater is used to obtain a part of the high-temperature steam in the steam turbine for heat supply, and the heat supply return water device is used to transport the heat supply return water to the heat network heater to complete the hot water circulation.

[0017] Further, the refrigeration unit includes an absorption refrigeration machine and a refrigeration return water device. The absorption refrigeration machine is used to obtain a part of the high-temperature steam in the steam turbine and then make it into low-temperature water for refrigeration. The refrigeration return water device is used to transport the refrigeration return water to the absorption refrigeration machine to complete the cold water circulation.

[0018] Further, the absorption refrigeration machine is a lithium bromide refrigeration unit.

[0019] The beneficial effects of the present invention: Compared with the prior art, the advantages of the present invention are as follows:

[0020] (1)The present invention utilizes the catalytic combustion of low-concentration coal mine drainage gas in a porous medium combustion device to produce high-quality flue gas with a temperature greater than 600 °C for combined cooling, heating, and power generation, achieving the efficient and clean utilization of low-concentration gas with a CH4 concentration of 4% - 5%, preferably 4.5% - 4.7%.

[0021] (2)By adding a gas concentration compensation unit, the present invention can automatically supply a certain amount of CH4 gas through the feedback regulation of the intelligent gas mixing unit when the concentration of coal mine drainage gas fluctuates, thus ensuring the stable operation of the combustion of coal mine drainage gas.

[0022] (3)Compared with regenerative oxidation and catalytic oxidation devices, the present invention uses a porous medium catalytic combustion device with a porous medium as the catalytic combustion carrier. The low-concentration gas burns in the porous medium, significantly improving the combustion efficiency of the low-concentration gas. In addition, the porous medium is arranged in four layers, and each layer of the porous medium has a different porosity. The porosities of each layer of the porous medium from the burner inlet are 40 PPI, 30 PPI, 20 PPI, and 10 PPI respectively, effectively ensuring the stable propagation of the flame in the porous medium combustion area of the low-concentration gas and avoiding the occurrence of flashback and blowout phenomena. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of the integrated system for catalytic combustion power generation, heating, and refrigeration of low-concentration gas of the present invention;

[0024] In the figure, 1 - low-concentration gas drainage pumping station, 2 - anti-backflow device, 3 - explosion-proof device, 4 - explosion suppression device, 5 - water seal fire and explosion relief device, 6 - flame sensor, 7 - desulfurization device, 8 - air compressor, 9 - gas storage tank, 10 - filter, 11 - dryer, 12 - gas mixing chamber, 13 - methane gas tank, 14 - flame arrester, 15 - flow equalizing device, 16 - porous medium, 17 - thermocouple, 18 - high-energy igniter, 19 - gas collection hood, 20 - burner body, 21 - heat insulation layer, 22 - flue gas analyzer, 23 - support base, 24 - superheater, 25 - evaporator, 26 - economizer, 27 - steam drum, 28 - steam turbine, 29 - generator, 30 - heat network heater, 31 - heating return water device, 32 - absorption refrigeration machine, 33 - refrigeration return water device, 34 - condenser, 35 - condensate pump, 36 - circulating pump, 37 - cooling tower, 38 - induced draft fan, 39 - chimney. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] As Figure 1As shown in the figure, an integrated system for catalytic combustion power generation, heat supply and refrigeration of low-concentration gas in coal mines includes a low-concentration gas extraction pumping station 1, a low-concentration gas pipeline transportation guarantee unit, an intelligent gas distribution unit, an air supply unit, a gas concentration compensation unit, a porous medium catalytic combustion device, a waste heat boiler, a steam turbine generator set, a heat supply unit and a refrigeration unit. Among them, the low-concentration gas extraction pumping station 1 is connected to the low-concentration gas pipeline transportation guarantee unit, the low-concentration gas pipeline transportation guarantee unit is connected to the intelligent gas distribution unit, the air supply unit is connected to the intelligent gas distribution unit, the gas concentration compensation unit is connected to the passage between the low-concentration gas pipeline transportation guarantee unit and the intelligent gas distribution unit, the intelligent gas distribution unit is connected to the inlet of the porous medium catalytic combustion device, the outlet of the porous medium catalytic combustion device is connected to the waste heat boiler, and the heat of the waste heat boiler is divided into three paths leading to the steam turbine generator set, the heat supply unit and the refrigeration unit.

[0027] The intelligent gas distribution unit includes an air-CH4 flow controller, an air-CH4 concentration regulator and a mixing chamber 12. The intelligent gas distribution unit has an automatic disturbance compensation function. When the gas concentration and flow fluctuate, the automatic disturbance compensation function ensures that the mixed gas concentration is stable in the range of 4.5~4.7% through the automatic disturbance compensation function. The air-CH4 flow controller controls the flow of air input by the air supply unit and the flow of CH4 input by the gas concentration compensation unit. The air-CH4 concentration regulator is used to monitor the gas concentration in the mixing chamber 12 and feedback it to the air-CH4 flow controller to make the mixing chamber 12 reach the preset concentration.

[0028] The gas concentration compensation unit includes a methane gas tank 13, a pressure reducing valve and a one-way valve. When the gas concentration fluctuates, a certain amount of CH4 is provided through the automatic disturbance compensation control of the intelligent gas distribution unit to ensure that the gas concentration is always maintained in the stable range of 4.5~4.7%.

[0029] The porous medium catalytic combustion device includes a flame arrester 14, a flow equalizing device 15, a porous medium 16, a thermocouple 17, a high-energy igniter 18, a gas collecting hood 19, a burner body 20, a heat insulation layer 21, a flue gas analyzer 22, and a support base 23. The burner body 20 is installed on the support base 23, and its bottom inlet is connected to the intelligent gas distribution unit through the flame arrester 14, and its top outlet is provided with a gas collecting hood 19; a porous medium 16 is arranged in the combustion chamber between the inlet and the outlet. The porous medium 16 has four layers with different porosities; the flow equalizing device 15 is arranged at the bottom of the combustion chamber; a heat insulation layer 21 is provided outside the burner body 20.

[0030] The flow equalizing device 15 adopts a double-layer flow equalizing plate arrangement to ensure a uniform velocity distribution of the gas mixture entering the burner. The porous medium 16 is an alumina foam ceramic porous medium, which is arranged in four layers. Each layer of the porous medium 16 has a different porosity. Starting from the burner inlet, the porosities of each layer of the porous medium are 40 PPI, 30 PPI, 20 PPI, and 10 PPI respectively, ensuring the stable transfer of the flame in the porous medium combustion area of the gas mixture and avoiding the occurrence of flashback and blowout phenomena. The gas collecting hood 19 is used to collect the high-temperature flue gas generated by the gas combustion. The burner body 20 is flange-connected to the gas collecting hood 19 and the flow equalizing device 15, which is convenient for disassembly. The high-energy igniter 18 is used for igniting the low-concentration gas in the combustion chamber, and the gas analyzer 22 is used for analyzing the gas after combustion. Of course, the material of the porous medium 16 is not limited to the foam ceramic porous medium, and it can also be a metal porous medium. The number of layers, porosity, and arrangement method of the porous medium are not limited by the present invention either.

[0031] The low-concentration gas transportation guarantee unit includes a backflow prevention device 2, an explosion prevention device 3, an explosion suppression device 4, a water seal fire prevention and explosion relief device 5, a flame sensor 6, and a desulfurization device 7 that are connected in sequence through pipelines. The backflow prevention device 2 is connected to the low-concentration gas extraction pumping station 1. The backflow prevention device 2, the explosion prevention device 3, the explosion suppression device 4, and the water seal fire prevention and explosion relief device 5 are connected in sequence. The water seal fire prevention and explosion relief device 5 is connected to the desulfurization device 7. The flame sensor 6 is connected between the water seal fire prevention and explosion relief device 5 and the desulfurization device 7. The backflow prevention device 2, the explosion prevention device 3, the explosion suppression device 4, the water seal fire prevention and explosion relief device 5, and the flame sensor 6 are all connected to the monitoring system. The air supply unit includes an air compressor 8, a gas storage tank 9, a filter 10, and a dryer 11. The filter 10 is an oil-water separator.

[0032] The waste heat boiler includes a superheater 24, an evaporator 25, a economizer 26, and a steam drum 27. The high-temperature flue gas exchanges heat through the superheater 24, the evaporator 25, and the economizer 26 to heat the feed water of the steam drum 27, generating superheated steam with a temperature of 200 - 300 °C and outputting it from the superheater. The flue gas after heat exchange (less than 100 °C) is extracted by an induced draft fan 38 and discharged from the chimney 39.

[0033] The steam turbine generator set consists of a steam turbine 28 and a generator 29. The steam turbine 28 is a condensing steam turbine, which is suitable for introducing the superheated steam with a temperature of 200 - 300 °C generated by the waste heat boiler into the steam turbine to do work and drive the generator 29 to generate electricity.

[0034] The heating unit includes a heat network heater 30 and a heating return water device 31. The heat network heater 30 and the heating return water device 31 are connected through pipelines. The heat network heater 30 is used to input a part of the high-temperature steam extracted from the steam turbine 28 into the heat network heater to heat the feed water for heating. The heating return water device 31 is used to transport the heating return water to the heat network heater 30 to complete the hot water circulation.

[0035] The refrigeration unit includes an absorption chiller 32 and a refrigeration return water device 33. The absorption chiller 32 is used to input a part of the high-temperature steam extracted from the steam turbine into the absorption chiller 32 to obtain low-temperature water for refrigeration. The refrigeration return water device 33 is used to transport the refrigeration return water to the absorption chiller 32 to complete the cold water cycle. The absorption chiller 32 is a lithium bromide refrigeration unit, which can improve the heat exchange efficiency of the steam.

[0036] The condenser 34 is connected to the steam turbine generator set and is used to condense the exhaust steam discharged from the steam turbine 28 into circulating water and send it back to the waste heat boiler to complete the cycle. Specifically, the water condensed by the condenser 34 is first sent to the cooling tower 37 for cooling, and then transported to the waste heat boiler through the circulating water pump 36 and the condensate pump 35 for recycling.

[0037] The present invention combines the porous medium catalytic combustion technology with the combined heat and power supply technology. By using the high-temperature flue gas generated by the catalytic combustion of low-concentration gas in the porous medium combustion device for combined cooling, heating and power supply, on the one hand, the comprehensive utilization of the energy of the low-concentration gas extracted from the coal mine is realized, the direct emission of the low-concentration gas with a concentration below 5% extracted from the coal mine into the air is reduced, and the greenhouse effect is alleviated; on the other hand, the gas mixture with a low concentration of 4-5% is combined with the porous medium burner, and the flue gas generated by it has a high temperature (>600 °C) and a high energy utilization rate; furthermore, by using the automatic disturbance compensation function of the intelligent gas distribution unit, the problem of unstable operation of the porous medium combustion device caused by the parameter fluctuation of the low-concentration gas in the coal mine is solved, and the utilization efficiency of the low-concentration gas in the coal mine is significantly improved.

[0038] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes that can be made within the knowledge scope of those skilled in the art without departing from the purpose of the present invention are within the protection scope of the claims of the present invention.

Claims

1. An integrated system for catalytic combustion power generation, heat supply and refrigeration of low-concentration gas in coal mines, comprising a low-concentration gas drainage pumping station (1), a low-concentration gas pipeline transportation guarantee unit, an air supply unit, a steam turbine generator set, a heat supply unit and a refrigeration unit, characterized in that, It also includes an intelligent gas distribution unit, a gas concentration compensation unit, a porous medium catalytic combustion device, and a waste heat boiler. The low-concentration gas drainage pumping station (1) is connected to the low-concentration gas pipeline transportation guarantee unit; the low-concentration gas pipeline transportation guarantee unit is connected to the intelligent gas distribution unit, and the air supply unit is connected to the intelligent gas distribution unit; the gas concentration compensation unit is connected to the passage between the low-concentration gas pipeline transportation guarantee unit and the intelligent gas distribution unit; the intelligent gas distribution unit is connected to the inlet of the porous medium catalytic combustion device, the outlet of the porous medium catalytic combustion device is connected to the waste heat boiler, and the heat of the waste heat boiler is divided into three paths leading to the steam turbine generator set, the heating unit, and the refrigeration unit; The intelligent gas distribution unit includes an air-CH4 flow controller, an air-CH4 concentration regulator, and a mixing chamber (12). The air-CH4 flow controller is used to control the flow of air input by the air supply unit and the flow of CH4 input by the gas concentration compensation unit; the air-CH4 concentration regulator is used to monitor the gas concentration in the mixing chamber (12) and feedback it to the air-CH4 flow controller to make the mixing chamber (12) reach a preset concentration; The gas concentration compensation unit includes a methane gas tank (13), a pressure reducing valve, and a one-way valve, which are used to provide a certain amount of CH4 through the automatic disturbance compensation control of the intelligent gas distribution unit when the gas concentration fluctuates, ensuring that the CH4 concentration is always maintained in the concentration range of 4-5%; The porous medium catalytic combustion device includes a flame arrester (14), a flow equalizing device (15), a porous medium (16), a gas collecting hood (19), a burner body (20), a heat preservation layer (21), and a support base (23). The burner body (20) is installed on the support base (23), and its bottom inlet is connected to the intelligent gas distribution unit through the flame arrester (14), and its top outlet is provided with the gas collecting hood (19); the porous medium (16) is arranged in the combustion chamber between the inlet and the outlet. The porous medium (16) has multiple layers with different porosities, and the porosity decreases sequentially from the inlet to the outlet of the burner body (20); the flow equalizing device (15) is arranged at the bottom of the combustion chamber, and the flow equalizing device (15) adopts a double-layer flow equalizing plate arrangement; the heat preservation layer (21) is provided outside the burner body (20).

2. The integrated system for catalytic combustion power generation, heat supply, and refrigeration of low-concentration gas in coal mines according to claim 1, wherein, In the porous medium combustion device, the porous medium (16) has four layers, and the porosities of the four layers of porous medium are 40 PPI, 30 PPI, 20 PPI, and 10 PPI in sequence from the inlet to the outlet of the burner body (20).

3. The integrated system for power generation, heat supply and refrigeration by catalytic combustion of low-concentration coal mine gas according to claim 2, wherein The porous medium combustion device also includes a thermocouple (17), a flue gas analyzer (22), and a high-energy igniter (18). The thermocouple (17) is arranged in the heat preservation layer (21), the flue gas analyzer (22) is used to analyze the combustion gas, and the high-energy igniter (18) is used to ignite the low-concentration gas in the combustion chamber.

4. The integrated system for catalytic combustion power generation, heating, and refrigeration of low-concentration coal mine gas according to claim 1, wherein The low-concentration gas transportation guarantee unit includes an anti-backflow device (2), an explosion-proof device (3), an explosion suppression device (4), a water-sealed fire-resistant and explosion-venting device (5), a flame sensor (6), and a desulfurization device (7) connected in sequence through pipelines. The anti-backflow device (2) is connected to the low-concentration gas extraction pumping station (1). The flame sensor (6) is connected between the water-sealed fire-resistant and explosion-venting device (5) and the desulfurization device (7). The anti-backflow device (2), the explosion-proof device (3), the explosion suppression device (4), the water-sealed fire-resistant and explosion-venting device (5), and the flame sensor (6) are all connected to the monitoring system.

5. The integrated system for catalytic combustion power generation, heat supply and refrigeration of low-concentration gas in coal mines according to claim 1, characterized in that, The air supply unit includes an air compressor (8), a gas storage tank (9), a filter (10), and a dryer (11). The filter (10) is an oil-water separator.

6. The integrated system for power generation, heat supply and refrigeration by catalytic combustion of low-concentration gas in coal mines according to claim 1, characterized in that, The waste heat boiler includes a superheater (24), an evaporator (25), an economizer (26), and a steam drum (27). The superheater (24), the evaporator (25), and the economizer (26) are respectively connected to the steam drum (27).

7. The integrated system for power generation, heat supply and refrigeration by catalytic combustion of low-concentration gas in coal mines according to claim 1, wherein The steam turbine generator set is composed of a steam turbine (28) and a generator (29). The steam turbine (28) is a condensing steam turbine.

8. The integrated system for catalytic combustion power generation, heat supply and refrigeration of low-concentration gas in coal mines according to claim 1, characterized in that The heating unit includes a heat network heater (30) and a heating return water device (31). The heat network heater (30) and the heating return water device (31) are connected through pipelines. The heat network heater (30) is used to obtain a part of the high-temperature steam in the steam turbine (28) for heating. The heating return water device (31) is used to transport the heating return water to the heat network heater (30) to complete the hot water circulation.

9. The integrated system for power generation, heat supply and refrigeration by catalytic combustion of low-concentration coal mine gas according to claim 1, wherein The refrigeration unit includes an absorption chiller (32) and a refrigeration return water device (33). The absorption chiller (32) is used to obtain a part of the high-temperature steam in the steam turbine, and then make it into low-temperature water for refrigeration. The refrigeration return water device (33) is used to transport the refrigeration return water to the absorption chiller (32) to complete the cold water circulation.

10. The integrated system for catalytic combustion power generation, heat supply and refrigeration of low-concentration gas in coal mines according to claim 9, characterized in that, The absorption chiller (32) is a lithium bromide refrigeration unit.

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