Coal mine gas extraction comprehensive utilization system

Abstract

The utility model discloses a coal mine gas extraction comprehensive utilization system which comprises a gas generator set, a heat storage oxidation device, a waste heat boiler, a steam header, a quick-closing valve, a regulating valve, a screw expander, a generator, a condenser, a vacuum pump, a condensate pump, a circulating water pump, a cooling tower, a water supply tank and a water supply pump. Coal mine high-negative-pressure extraction gas generates electricity through a gas generator set, high-temperature tail gas enters a waste heat boiler to generate low-pressure steam as a byproduct, coal mine low-negative-pressure extraction gas is treated through a heat storage oxidation device, the high-temperature tail gas enters the waste heat boiler to generate low-pressure steam as a byproduct, and two paths of low-pressure steam are converged into a steam header and connected into a power generation system through a pipeline to generate electricity. According to the system, the problems of energy waste and thermal pollution caused by high-temperature tail gas emission of a traditional gas generator set are well solved; the problems of energy waste and environmental pollution caused by direct emission of traditional coal mine low-negative-pressure extracted gas are solved; the comprehensive utilization rate of enterprise energy is improved, and the coal mining production cost and the production self power consumption are reduced.

Description

Technical Field

[0001] This utility model relates to the field of coal mine gas extraction technology, and in particular to a comprehensive utilization system for coal mine gas extraction. Background Technology

[0002] Coalbed methane refers to unconventional natural gas found in coal seams and surrounding rocks, associated with coal resources; it is also known as coal mine gas. Coal is China's primary energy source, accounting for approximately 70% of China's primary energy consumption. Coal used for power generation accounts for over 50% of coal consumption. Due to the influence of economic development levels and constraints from natural conditions, the coal industry has always been a high-risk industry in my country.

[0003] According to the "Coal Mine Safety Regulations", gas drainage is an essential part of safe coal mine production.

[0004] Methane, a component of natural gas, is the second most important greenhouse gas after CFCs. It depletes the ozone layer, and according to a report by the Intergovernmental Panel on Climate Change, its greenhouse effect is 21 times that of CO2. Large-scale release of natural gas into the atmosphere will enhance the greenhouse effect on Earth's surface, leading to global warming and damaging the planet's ecosystem.

[0005] Currently, coal mines with high-pressure gas extraction concentrations (>8%) can directly use gas generators for power generation. However, the exhaust gas temperature of these generators reaches as high as 550℃, and direct emission without effective recovery results in significant heat loss. Low-pressure gas extraction concentrations (<3%) cannot be directly used for power generation by gas generators because the concentration is too low to ignite. Current direct emission treatment not only causes enormous energy waste but also pollutes the environment. Utility Model Content

[0006] The purpose of this invention is to provide a comprehensive utilization system for coal mine gas extraction.

[0007] The above-mentioned technical objective of this utility model is achieved through the following technical solution:

[0008] A comprehensive coal mine gas extraction and utilization system includes a gas generator set, a primary waste heat boiler, a regenerative thermal oxidation device, a secondary waste heat boiler, a steam distribution cylinder, pipelines, quick-closing valves, regulating valves, a screw expander, a generator, a condenser, a water ring vacuum pump, a circulating water pump, a cooling tower, a condensate pump, a feedwater tank, and a feedwater pump. High-pressure extracted gas is connected to the gas generator set via pipelines. The high-temperature exhaust gas emitted by the gas generator set is connected to the primary waste heat boiler via pipelines. The steam generated by the primary waste heat boiler is connected to the steam distribution cylinder via pipelines. Low-pressure extracted gas is connected to the regenerative thermal oxidation device via pipelines. The high-temperature exhaust gas emitted by the regenerative thermal oxidation device is connected to the secondary waste heat boiler via pipelines. The steam generated by the secondary waste heat boiler is connected to the steam distribution cylinder via pipelines. The steam inlet of the screw expander is connected to the steam distribution cylinder via pipelines. The machine is connected to the generator via a coupling; a quick-closing valve and a regulating valve are installed on the pipeline between the steam distributor and the screw expander; the exhaust port of the screw expander is connected to the steam inlet of the condenser via a pipeline; the water ring vacuum pump is connected to the non-condensable gas outlet of the condenser via a pipeline; the outlet of the circulating water pump is connected to the circulating water inlet of the condenser via a pipeline; the circulating water outlet of the condenser is connected to the return water inlet of the cooling tower via a pipeline; the inlet of the circulating water pump is connected to the outlet of the cooling tower via a pipeline; the outlet of the condenser is connected to the inlet of the condensate pump via a pipeline; the outlet of the condensate pump is connected to the inlet of the feedwater tank via a pipeline; the outlet of the feedwater tank is connected to the inlet of the feedwater pump via a pipeline; the outlet of the feedwater pump is connected to the makeup water inlets of waste heat boiler one and waste heat boiler two via a pipeline.

[0009] Furthermore, the concentration of gas extracted under high negative pressure is greater than 8%, while the concentration of gas extracted under low negative pressure is less than 2%.

[0010] Furthermore, the exhaust steam pressure discharged from the exhaust port of the screw expander is -0.09 MPa.g, and the temperature is 45°C.

[0011] Furthermore, the exhaust gases from waste heat boiler one and waste heat boiler two are directly discharged to the outside.

[0012] In summary, this utility model has the following beneficial effects:

[0013] 1. Compared with traditional gas generator sets, this system can not only fully recover the heat of high negative pressure extracted gas for power generation, but also further recover the heat of emitted flue gas. At the same time, it can comprehensively utilize the low negative pressure extracted gas that was originally directly emitted, thus achieving zero emissions of gas in coal mining.

[0014] 2. According to statistics, a coal mine with an annual output of 1.2 million tons has an installed capacity of 17,500 KW, a rated power generation capacity of 11,000 KW, an annual power generation of 88 million kWh, and an annual absorption capacity of 10 million cubic meters of low-concentration methane from the goaf, which has high economic value and social benefits. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the system structure of this utility model.

[0016] In the diagram, 1. Gas generator set; 2. Waste heat boiler one; 3. Regenerative thermal oxidation device; 4. Waste heat boiler two; 5. Steam distributor; 6. Pipeline; 7. Quick-closing valve; 8. Regulating valve; 9. Screw expander; 10. Generator; 11. Condenser; 12. Water ring vacuum pump; 13. Circulating water pump; 14. Cooling tower; 15. Condensate pump; 16. Feedwater tank; 17. Feedwater pump. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the accompanying drawings. The technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0018] like Figure 1As shown, a comprehensive coal mine gas extraction and utilization system includes a gas generator set 1, a waste heat boiler 1, a regenerative oxidation device 3, a waste heat boiler 2, a steam distribution cylinder 5, a pipeline 6, a quick-closing valve 7, a regulating valve 8, a screw expander 9, a generator 10, a condenser 11, a water ring vacuum pump 12, a circulating water pump 13, a cooling tower 14, a condensate pump 15, a feedwater tank 16, and a feedwater pump 17. High-negative-pressure extracted gas is connected to the gas generator set 1 via pipeline 6. The gas emitted by the gas generator set 1... High-temperature exhaust gas is connected to waste heat boiler 2 via pipe 6. Steam generated by waste heat boiler 2 is connected to steam distributor 5 via pipe 6. Low-negative-pressure extracted gas is connected to regenerative oxidation device 3 via pipe 6. High-temperature exhaust gas emitted by regenerative oxidation device 3 is connected to waste heat boiler 4 via pipe 6. Steam generated by waste heat boiler 4 is connected to steam distributor 5 via pipe 6. The steam inlet of screw expander 9 is connected to steam distributor 5 via pipe 6. Screw expander 9 is connected to generator 10 via coupling. Quick-closing valve 7 and regulating valve 8 are installed on pipe 6 between steam distributor 5 and screw expander 9. The amount of steam entering screw expander 9 is controlled by quick-closing valve 7 and regulating valve 8. The exhaust port of screw expander 9 is connected to the steam inlet of condenser 11 via pipe 6. Water ring vacuum pump 12 is connected to the non-condensable gas outlet of condenser 11 via pipe 6. The outlet of circulating water pump 13 is connected to the circulating water inlet of condenser 11 via pipe 6. The outlet of the condenser 11 is connected to the return water inlet of the cooling tower 14 via pipe 6, and the inlet of the circulating water pump 13 is connected to the outlet of the cooling tower 14 via pipe 6; the outlet of the condenser 11 is connected to the inlet of the condensate pump 15 via pipe 6, the outlet of the condensate pump 15 is connected to the inlet of the water supply tank 16 via pipe 6, the outlet of the water supply tank 16 is connected to the inlet of the water supply pump 17 via pipe 6; the outlet of the water supply pump 17 is connected to the water supply inlet of the waste heat boiler 1-2 and the waste heat boiler 2-4 via pipe 6.

[0019] Furthermore, the concentration of gas extracted under high negative pressure is greater than 8%, while the concentration of gas extracted under low negative pressure is less than 2%.

[0020] Furthermore, the exhaust steam pressure discharged from the exhaust port of the screw expander 9 is -0.09 MPa.g, and the temperature is 45°C.

[0021] Furthermore, the exhaust gas from the waste heat boiler 12 and the waste heat boiler 24 is directly discharged to the outside.

[0022] Workflow: High-pressure extracted gas from the coal mine is fed into gas generator set 1 for power generation. The generated high-temperature exhaust gas enters waste heat boiler 2 for heat exchange. Waste heat boiler 2 produces low-pressure steam which enters steam distributor 5. Low-pressure extracted gas is fed into regenerative thermal oxidation device 3 for treatment. The generated high-temperature exhaust gas enters waste heat boiler 4 for heat exchange. Waste heat boiler 4 produces low-pressure steam which enters steam distributor 5. The low-pressure steam enters screw expander 9 via pipeline 6, quick-closing valve 7, and regulating valve 8 for expansion and work. It is then connected to generator 10 via coupling. The expansion and work drive generator 10 to generate electricity, which is then fed into the enterprise's internal grid. The exhaust steam (pressure -0.09 MPa.g, temperature 45℃) discharged from the exhaust port of screw expander 9 enters condenser 11 for heat exchange with circulating cooling water. The condensate is pumped to boiler feedwater tank 16 via condensate pump 15, and then to boilers 2 and 4 via boiler feedwater pump 17. Non-condensable gases in condenser 11 are removed by water ring vacuum pump 12 to maintain a high vacuum in condenser 11. The return water from condenser 11 after heat exchange flows into cooling tower 14 for cooling. The cooled water in cooling tower 11 is then circulated back to condenser 11 by circulating water pump 13.

[0023] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

Claims

1. A comprehensive utilization system for coal mine gas extraction, characterized in that: The system includes a gas generator set (1), a waste heat boiler I (2), a regenerative oxidation device (3), a waste heat boiler II (4), a steam distribution cylinder (5), a pipeline (6), a quick-closing valve (7), a regulating valve (8), a screw expander (9), a generator (10), a condenser (11), a water ring vacuum pump (12), a circulating water pump (13), a cooling tower (14), a condensate pump (15), a feedwater tank (16), and a feedwater pump (17). High-pressure gas extraction is connected to the gas generator set (1) via pipeline (6). The high-temperature gas emitted by the gas generator set (1)... The exhaust gas is connected to the waste heat boiler 1 (2) via pipe (6), and the steam generated by the waste heat boiler 1 (2) is connected to the steam distributor (5) via pipe (6); the low negative pressure extracted gas is connected to the regenerative oxidation device (3) via pipe (6), and the high temperature exhaust gas discharged by the regenerative oxidation device (3) is connected to the waste heat boiler 2 (4) via pipe (6), and the steam generated by the waste heat boiler 2 (4) is connected to the steam distributor (5) via pipe (6); the steam inlet of the screw expander (9) is connected to the steam distributor (5) via pipe (6), and the screw expander (9) is connected to the steam distributor (5) via a coupling. The generator (10) is connected to the drive; the quick-closing valve (7) and the regulating valve (8) are installed on the pipe (6) between the steam separator (5) and the screw expander (9), and the exhaust port of the screw expander (9) is connected to the steam inlet of the condenser (11) through the pipe (6); the water ring vacuum pump (12) is connected to the non-condensable gas outlet of the condenser (11) through the pipe (6); the outlet of the circulating water pump (13) is connected to the circulating water inlet of the condenser (11) through the pipe (6), and the circulating water outlet of the condenser (11) is connected to the cooling tower through the pipe (6). (14) is connected to the return water inlet, and the inlet of the circulating water pump (13) is connected to the outlet of the cooling tower (14) through the pipe (6); the outlet of the condenser (11) is connected to the inlet of the condensate pump (15) through the pipe (6), the outlet of the condensate pump (15) is connected to the inlet of the water supply tank (16) through the pipe (6), the outlet of the water supply tank (16) is connected to the inlet of the water supply pump (17) through the pipe (6); the outlet of the water supply pump (17) is connected to the water supply inlet of the waste heat boiler one (2) and the waste heat boiler two (4) through the pipe (6).

2. The comprehensive utilization system for coal mine gas extraction according to claim 1, characterized in that: The concentration of gas extracted under high negative pressure is greater than 8%, while the concentration of gas extracted under low negative pressure is less than 2%.

3. The comprehensive utilization system for coal mine gas extraction according to claim 1, characterized in that: The exhaust steam pressure of the screw expander (9) is -0.09 MPa.g and the temperature is 45℃.

4. The comprehensive utilization system for coal mine gas extraction according to claim 1, characterized in that: The waste gas from the first waste heat boiler (2) and the second waste heat boiler (4) is directly discharged to the outside.

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