Zero-carbon emission system and method for direct mineralization and storage of flue gas using full-concentration gas

Abstract

The present invention discloses a zero-carbon emission system and method for direct mineralization and storage of flue gas using full-concentration gas. The system divides and transports the gas according to its concentration extracted from the coal seam. After purification, the medium-concentration gas is utilized together with the high-concentration gas through a gas chemical utilization device. Meanwhile, the low-concentration gas is mixed with the pressure-relieved gas and utilized through a mobile gas power station. In addition, the waste heat of gas-fired power generation flue gas and gas-chemical utilization flue gas is utilized through a hot and cold water unit, so that gases of different concentrations are effectively classified to achieve efficient utilization of full-concentration gas. The gas-fired power generation flue gas, coal-fired flue gas and coal-fired solid fly ash are foamed and pulped together and then injected into goafs or abandoned mines for direct mineralization treatment and storage, so as to achieve coordinated storage and disposal of flue gas containing carbon dioxide and solid waste fly ash and filling and support of goafs, thereby ensuring safe production in coal mines and achieving energy conservation and emission reduction, coordinated management of gas-solid wastes and zero carbon emissions.

Description

Technical Field

[0001] The present invention relates to a zero-carbon emission system and method for direct mineralization and storage of flue gas using full-concentration gas, and belongs to the technical and engineering fields related to coal mine low-carbon technology, energy conservation and emission reduction, and coal mine safety. Background Art

[0002] Coal is the main energy source in my country. More than 70% of my country's coal mines are high-gas mines, which makes my country's coal mine gas (coalbed methane) resources rich. More than 70% of coal mines are high-gas mines. The gas resources within 2000m underground are about 36.8 trillion m 3 . In the process of coal mining, gas is a by-product resource of coal, and its main component is methane. It is not only a clean energy, but also a major disaster source and strong greenhouse gas in coal mines. The greenhouse effect of gas is 28 times that of carbon dioxide. After gas is used by internal combustion generators, it can be converted into carbon dioxide, and its greenhouse effect is significantly reduced, but carbon dioxide is still a greenhouse gas. Therefore, direct discharge after traditional gas utilization will still cause greenhouse effect. It can be seen that gas utilization is to obtain gas energy while significantly reducing the greenhouse effect of the emission gas, but there is still the discharge of flue gas containing carbon dioxide, and zero carbon emissions have not been achieved. At the same time, many coal mines in my country have pit-mouth power plants. In the process of coal-fired power generation, the combustion and utilization of coal leads to a large amount of coal-fired flue gas emissions containing carbon dioxide and the output of fly ash solid waste, which also causes prominent environmental pollution risks.

[0003] Studies have shown that coal's ability to adsorb carbon dioxide is significantly higher than its ability to adsorb gas (methane). If the carbon dioxide produced by gas utilization and conversion can be directly injected into abandoned mines or coal mine goafs, it will be extremely important for the direct storage of flue gas containing carbon dioxide. At the same time, the fly ash produced by coal combustion contains a high level of calcium oxide, which has a strong mineralization reactivity with carbon dioxide. If the carbon dioxide flue gas produced by coal-fired power generation and gas power generation can be mineralized with fly ash, and the reaction products can be directly injected into the goaf for storage, it can not only achieve the joint reduction of gas and solid waste emissions, but also have important practical significance and environmental value for fire prevention and extinguishing in goafs and mitigating ground subsidence caused by coal mining.

[0004] Therefore, in response to the problem of zero carbon emissions from coal-fired power generation and gas-fired power generation, how to achieve safe coal mining, gas extraction, gas-fired power generation, and direct mineralization and underground storage of carbon dioxide-containing flue gas and fly ash is a key and major issue that needs to be urgently addressed in safe and green production of coal mines, low-carbon utilization of gas, and energy conservation and emission reduction. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a zero-carbon emission system and method for direct mineralization and storage of flue gas using full-concentration gas. Through the whole process of gas extraction, gas power generation and direct mineralization and underground storage of flue gas containing carbon dioxide and fly ash, and filling and supporting the goaf, the safe mining of coal, low-carbon utilization of gas and energy conservation and emission reduction are ultimately guaranteed.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a full-concentration gas utilization flue gas direct mineralization and storage zero-carbon emission system, including a pit-mouth coal-fired power plant arranged on the ground, a gas pre-extraction pump station, a gas flow control regulating device, a pressure relief gas extraction pump station, a gas purification device, a gas mixing and purification system, a mobile gas power station, a gas chemical utilization device, a flue gas type lithium bromide absorption hot and cold water unit, a flue gas pressure pump station, a flue gas storage and transportation buffer tank, a slurry tank and a gas-liquid-solid mixed foaming device;

[0007] The pit-mouth coal-fired power station is used to burn coal mined from the main shaft of the coal mine to generate electricity, and produce fly ash and coal-fired flue gas, wherein the coal-fired flue gas is transported to the flue gas pressure pump station; the gas pre-extraction pump station is used to extract coal seam gas through the gas pre-extraction well; the gas flow control and regulation device is provided with an air inlet, a high-concentration gas outlet, a medium-concentration gas outlet and a low-concentration gas outlet, wherein the air inlet is used to receive the extracted coal seam gas, the high-concentration gas outlet is used to transport the high-concentration gas to the gas chemical utilization device, and the medium-concentration gas outlet is used to transport the medium-concentration gas to the gas purification device The gas purification device is used to purify medium-concentration gas to high-concentration gas and then transport it to the gas chemical utilization device. The low-concentration gas outlet is used to transport the low-concentration gas to the gas mixing and purification system. The gas flow control regulating device can monitor the gas concentration of the incoming gas and control the opening and closing of each outlet; the pressure relief gas extraction pump station is used to extract the pressure relief gas through the pressure relief gas extraction well and transport it to the gas mixing and purification system; the gas mixing and purification system is used to mix the low-concentration gas and the pressure relief gas, filter and purify them, and then transport them to the mobile gas power station;

[0008] The gas chemical utilization device is used to generate gas chemical utilization flue gas after utilizing high-concentration gas and transport it to the flue gas type lithium bromide absorption cold and hot water unit; the mobile gas power station is used to generate gas power generation flue gas after utilizing the gas power generation transported by the gas mixing and purification system and transport it to the flue gas type lithium bromide absorption cold and hot water unit; the flue gas type lithium bromide absorption cold and hot water unit is used to generate low-temperature flue gas after utilizing the waste heat of gas chemical utilization flue gas and gas power generation flue gas, and transport it to the flue gas pressurizing pump station; the flue gas pressurizing pump station is used to pressurize the low-temperature flue gas and coal-fired flue gas, and then transport the pressurized flue gas after buffering in the flue gas storage and transportation buffer tank to the gas-liquid-solid mixed foaming device;

[0009] The slurry pool is used to mix fly ash and water to form fly ash slurry, and transport it to the gas-liquid-solid mixing foaming device; the gas-liquid-solid mixing foaming device is used to mix fly ash slurry and pressurized flue gas to form foamed slurry, and transport it to the goaf through the slurry injection well.

[0010] Furthermore, the gas pre-extraction well, pressure relief gas extraction well and slurry injection well are surface wells constructed directly from the ground in the target coal seam, or pipeline wells constructed on the ground for installing gas extraction pipelines and slurry injection pipelines.

[0011] Furthermore, the gas pre-extraction pump station is a negative pressure extraction pump station or a gas drainage pump station.

[0012] Furthermore, the gas pre-extraction pump station, pressure relief gas extraction pump station, mobile gas power station, flue gas type lithium bromide absorption hot and cold water unit, flue gas booster pump station, flue gas storage and transportation buffer tank, slurry tank and gas-liquid-solid mixed foaming device are all vehicle-mounted or skid-mounted, which is convenient for the transportation and installation of each device.

[0013] Furthermore, the gas chemical utilization device is a chemical gas furnace device, and can also be various power devices mainly using gas. Preferably, it is a chemical gas furnace device, which has a higher utilization rate for high-concentration gas.

[0014] The working method of the above-mentioned full-concentration gas direct mineralization storage zero-carbon emission system is as follows:

[0015] A. Well drilling construction and system layout: At a certain distance from the main shaft of the coal mine, several surface wells or surface boreholes are constructed from the ground to the coal seam at a certain interval along the direction of the coal seam. Among them, those in the unmined area of ​​the coal seam are used as gas pre-extraction wells, those in the mining area are used as pressure relief gas extraction wells, and those in the goaf are used as slurry injection wells. After completion, the mineralization storage zero-carbon emission system will be assembled and laid out;

[0016] B. Coal mining and utilization: Coal in the coal seam is mined to the surface through the main shaft of the coal mine, and then burned in the coal-fired power station at the pit mouth to produce fly ash and coal-fired flue gas;

[0017] C. Gas extraction and utilization: The gas pre-extraction pump station extracts coal seam gas through the gas pre-extraction well and transports it to the gas flow control regulating device. The gas flow control regulating device monitors the concentration of the incoming coal seam gas. If it is judged to be high-concentration gas, the high-concentration gas outlet is opened. At this time, the high-concentration gas is transported to the gas chemical utilization device through the high-concentration gas outlet; if it is judged to be medium-concentration gas, the medium-concentration gas outlet is opened. At this time, the medium-concentration gas is transported to the gas purification device through the medium-concentration gas outlet. After being purified by the gas purification device, high-concentration gas is formed, and then transported to the gas chemical utilization device; the gas chemical utilization device utilizes the high-concentration gas to produce gas chemical utilization flue gas; if it is judged to be low-concentration gas, the low-concentration gas outlet is opened. At this time, the low-concentration gas is transported to the gas purification device through the low-concentration gas outlet. The outlet is transported to the gas mixing and purification system; the gas flow control regulating device monitors the gas concentration of the coal seam flowing through in real time, and adjusts the opening and closing of each outlet in real time according to the judgment situation, so as to realize the diversion and transportation of gases of different concentrations; the pressure relief gas extraction pump station extracts the pressure relief gas through the pressure relief gas extraction well, and transports it to the gas mixing and purification system; the gas mixing and purification system mixes the low-concentration gas and the pressure relief gas, filters and purifies them, and then transports them to the mobile gas power station for power generation, and generates gas power generation flue gas; when the gas flow control regulating device monitors that the gas concentration of the extracted coal seam is lower than the lower limit of the low-concentration gas (that is, the gas concentration is less than 8%), the gas pre-extraction pump station is stopped, indicating that the gas extraction has met the standard and subsequent coal seam mining can be carried out; and the utilization value of the subsequent extracted coal seam gas is extremely small.

[0018] D. Flue gas utilization and storage: Flue gas type lithium bromide absorption hot and cold water unit receives flue gas from gas chemical industry and gas power generation, and uses the remaining heat to produce hot and cold water. At the same time, the flue gas after waste heat utilization becomes low-temperature flue gas. The low-temperature flue gas and coal-fired flue gas are both transported to the flue gas pressure pump station for pressurization and enter the flue gas storage and transportation buffer tank for buffering. At the same time, the fly ash produced by the pit mouth coal-fired power station is mixed with water in the slurry pool to prepare fly ash slurry. The fly ash slurry and the pressurized flue gas from the flue gas storage and transportation buffer tank are mixed in the gas-liquid-solid mixing foaming device. The foaming slurry is transported to the goaf through the slurry injection well, and the CO2 in the flue gas in the goaf continues to react with the calcium oxide in the fly ash to form mineralized products, and finally form mineralized products. With the continuous injection of foamed slurry and the continuous formation of mineralized products, the internal space of the goaf continues to shrink. Driven by the continuous shrinkage of space, the pressure relief gas in the goaf migrates to the pressure relief gas extraction well, thereby strengthening the extraction of pressure relief gas. In addition, the mineralized products can solidify and seal CO2 and provide filling support for the goaf.

[0019] Furthermore, the coal seam is a single coal seam with different inclinations, or a group of coal seams with different inclinations and multiple coal seams.

[0020] Furthermore, the full-concentration gas refers to all gases with a concentration higher than 8%, including high-concentration gas, medium-concentration gas and low-concentration gas.

[0021] Furthermore, the high-concentration gas refers to gas with a concentration higher than 90%, the medium-concentration gas refers to gas with a concentration higher than 30% but less than or equal to 90%, and the low-concentration gas refers to gas with a concentration less than or equal to 30% but higher than 8%.

[0022] Furthermore, the calcium oxide content of the fly ash is not less than 30%, which can further ensure the effect of the mineralization reaction and achieve the purpose of better solidification and storage of CO2.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1) The present invention realizes the joint exploitation, joint utilization, waste heat recovery and cascade utilization of cold, heat and power cogeneration of coal and gas through coal-fired power generation, coal mine gas extraction power generation, waste heat recovery of coal-fired flue gas and gas power generation flue gas, and preparation of cold and hot water by lithium bromide absorption unit, thereby improving the comprehensive energy utilization efficiency of coal-fired and gas extraction utilization system;

[0025] 2) The present invention conducts diversion and transportation according to the concentration of gas extracted from the coal seam, wherein the medium-concentration gas is purified and then utilized together with the high-concentration gas through a gas chemical utilization device to generate gas chemical utilization flue gas, while the low-concentration gas is mixed with the pressure-relieved gas and then utilized through a mobile gas power station to generate gas power generation flue gas, and the gas power generation flue gas and the gas chemical utilization flue gas are further utilized for waste heat through a flue gas-type lithium bromide absorption cold and hot water unit. By diverting gas according to concentration, different concentrations of gas can be effectively utilized in a graded manner, thereby realizing efficient utilization of gas of all concentrations;

[0026] 3) The present invention foams and slurries gas-fired power generation flue gas containing carbon dioxide, coal-fired flue gas and solid coal-fired fly ash together and then injects them into goafs or abandoned mines for direct mineralization treatment and sealing. Since the CO2 in the flue gas and the calcium oxide in the fly ash will continue to undergo mineralization reaction and eventually form mineralized products, the internal space of the goaf will continue to shrink with the continuous injection of the foaming slurry and the continuous formation of mineralized products, which can not only drive the depressurized gas in the goaf to migrate to the depressurized gas extraction well, thereby strengthening the extraction of the depressurized gas, but also the mineralized products help to achieve the coordinated sealing and disposal of the flue gas containing carbon dioxide and solid waste fly ash and the filling and support of the goaf; in addition, the injected mineralized solid products also help to achieve fire prevention and extinguishing in the goaf, and at the same time, slow down the surface subsidence caused by coal mining through the filling and support effect, thereby ensuring the safe production of coal mines and achieving energy conservation and emission reduction, coordinated management of gas and solid wastes and zero carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall layout of the present invention.

[0028] In the figure: 1-coal seam, 2-coal mine lifting main shaft, 3-gas pre-extraction well, 4-pressure relief gas extraction well, 5-slurry injection well, 6-pit mouth coal-fired power station, 7-gas pre-extraction pump station, 8-gas flow control regulating device, 9-pressure relief gas extraction pump station, 10-gas purification device, 11-gas mixing and purification system, 12-mobile gas power station, 13-gas chemical utilization device, 14-flue gas type lithium bromide absorption cold and hot water unit, 15-flue gas pressure pump station, 16-flue gas storage and transportation buffer tank, 17- Slurry pool, 18-gas-liquid-solid mixed foaming device, 19-coal, 20-fly ash, 21-coal combustion flue gas, 22-coal bed gas, 23-high concentration gas, 24-medium concentration gas, 25-low concentration gas, 26-purified gas, 27-mixed gas, 28-gas chemical utilization flue gas, 29-goaf, 30-pressure relief gas, 31-gas power generation flue gas, 32-low temperature flue gas, 33-pressurized flue gas, 34-water, 35-fly ash slurry, 36-foaming slurry, 37-mineralized products. DETAILED DESCRIPTION

[0029] The present invention will be further described below.

[0030] like Figure 1 As shown, a full-concentration gas direct mineralization and storage zero-carbon emission system using flue gas comprises a pit-mouth coal-fired power plant 6 arranged on the ground, a gas pre-extraction pump station 7, a gas flow control regulating device 8, a pressure relief gas extraction pump station 9, a gas purification device 10, a gas mixing and purification system 11, a mobile gas power station 12, a gas chemical utilization device 13, a flue gas type lithium bromide absorption cold and hot water unit 14, a flue gas pressurization pump station 15, a flue gas storage and transportation buffer tank 16, a slurry tank 17 and a gas-liquid-solid mixed foaming device 18;

[0031] The pit-mouth coal-fired power station 6 is used to burn the coal mined from the main shaft 2 of the coal mine to generate electricity, and produce fly ash 20 and coal-fired flue gas 21, wherein the coal-fired flue gas 21 is transported to the flue gas pressure pump station 15; the gas pre-extraction pump station 7 is used to extract coal seam gas 22 through the gas pre-extraction well 3; the gas flow control and regulation device 8 is provided with an air inlet, a high-concentration gas outlet, a medium-concentration gas outlet and a low-concentration gas outlet, wherein the air inlet is used to receive the extracted coal seam gas 22, the high-concentration gas outlet is used to transport the high-concentration gas 23 to the gas chemical utilization device 13, and the medium-concentration gas outlet is used to transport the medium-concentration gas 24 to the gas purification device 10, and the gas purification device 1 0 is used to purify the medium-concentration gas 24 to form the purified gas 26 (i.e., the high-concentration gas 23) and then transport it to the gas chemical utilization device 13. The low-concentration gas outlet is used to transport the low-concentration gas 25 to the gas mixing and purification system 11. The gas flow control regulating device 8 can monitor the gas concentration of the incoming gas and control the opening and closing of each outlet; the decompression gas extraction pump station 9 is used to extract the decompression gas 30 through the decompression gas extraction well 4 and transport it to the gas mixing and purification system 11; the gas mixing and purification system 11 is used to mix the low-concentration gas 25 and the decompression gas 30 to form the mixed gas 27 and filter and purify it before transporting it to the mobile gas power station 12;

[0032] The gas chemical utilization device 13 is used to utilize the high-concentration gas 23 to generate gas chemical utilization flue gas 28 and transport it to the flue gas type lithium bromide absorption cold and hot water unit 14; the mobile gas power station 12 is used to utilize the gas power generation delivered by the gas mixing and purification system 11 to generate gas power generation flue gas 31 and transport it to the flue gas type lithium bromide absorption cold and hot water unit 14; the flue gas type lithium bromide absorption cold and hot water unit 14 is used to utilize the waste heat of the gas chemical utilization flue gas 28 and the gas power generation flue gas 31 to generate low-temperature flue gas 32, and transport it to the flue gas pressurizing pump station 15; the flue gas pressurizing pump station 15 is used to pressurize the low-temperature flue gas 32 and the coal-fired flue gas 21, and then transport the pressurized flue gas 33 after buffering by the flue gas storage and transportation buffer tank 16 to the gas-liquid-solid mixed foaming device 18;

[0033] The slurry pool 17 is used to mix fly ash 20 and water 34 to form fly ash slurry 35, and transport it to the gas-liquid-solid mixing foaming device 18; the gas-liquid-solid mixing foaming device 18 is used to mix the fly ash slurry 35 and the pressurized flue gas 33 to form a foamed slurry 36, and transport it to the goaf 29 through the slurry injection well 5.

[0034] As an improvement of the present invention, the gas pre-extraction pump station 7, the pressure relief gas extraction pump station 9, the mobile gas power station 12, the flue gas type lithium bromide absorption cold and hot water unit 14, the flue gas pressure pump station 15, the flue gas storage and transportation buffer tank 16, the slurry pool 17 and the gas-liquid-solid mixed foaming device 18 are all vehicle-mounted mobile or skid-mounted. This facilitates the transportation and installation of each device. The gas pre-extraction pump station 7 is a negative pressure extraction pump station or a gas drainage pump station.

[0035] The above-mentioned pit mouth coal-fired power station 6, gas pre-extraction pump station 7, gas flow control regulating device 8, pressure relief gas extraction pump station 9, gas purification device 10, gas mixing and purification system 11, mobile gas power station 12, gas chemical utilization device 13, flue gas type lithium bromide absorption cold and hot water unit 14, flue gas pressure pump station 15, flue gas storage and transportation buffer tank 16, slurry pool 17 and gas-liquid-solid mixed foaming device 18 are all existing equipment and can be directly obtained through the market. Among them, the gas chemical utilization device 13 is a chemical gas furnace device, and can also be various types of gas-based power devices. Priority is given to chemical gas furnace devices, which have a higher utilization rate of high-concentration gas.

[0036] The working method of the zero-carbon emission system for direct mineralization and storage of full-concentration gas using flue gas, wherein the full-concentration gas refers to all gases with a concentration higher than 8%, including high-concentration gas 23, medium-concentration gas 24 and low-concentration gas 25, specifically:

[0037] A. Well drilling construction and system layout: At a certain distance from the main shaft 2 of the coal mine, several surface wells or surface boreholes are constructed from the ground to the coal seam 1 at a certain interval along the direction of the coal seam 1. Among them, the gas pre-extraction well 3 in the unmined area of ​​the coal seam, the pressure relief gas extraction well 4 in the mining area, and the slurry injection well 5 in the goaf 29. After completion, the mineralization storage zero-carbon emission system is assembled and laid out; the gas pre-extraction well 3, the pressure relief gas extraction well 4 and the slurry injection well 5 are surface wells directly constructed from the ground in the target coal seam, or pipeline wells constructed on the ground for installing gas extraction pipelines and slurry injection pipelines. The coal seam 1 is a single coal seam with different inclinations, or a coal seam group with different inclinations and multiple coal seams.

[0038] B. Coal mining and utilization: Coal from the coal seam 1 is mined to the surface through the main shaft 2 of the coal mine, and is burned in the coal-fired power station 6 at the pit mouth to produce fly ash 20 and coal-fired flue gas 21;

[0039] C. Gas extraction and utilization: The gas pre-extraction pump station 7 extracts coal seam gas 22 through the gas pre-extraction well 3 and transports it to the gas flow control regulating device 8. The gas flow control regulating device 8 monitors the concentration of the incoming coal seam gas 22. If the gas concentration is higher than 90%, it is judged to be high-concentration gas 23, and the high-concentration gas outlet is opened. At this time, the high-concentration gas 23 is transported to the gas chemical utilization device 13 through the high-concentration gas outlet; if the gas concentration is higher than 30% but less than or equal to 90%, If it is judged to be medium-concentration gas 24, the medium-concentration gas outlet is opened. At this time, the medium-concentration gas 24 is transported to the gas purification device 10 through the medium-concentration gas outlet, and is purified by the gas purification device 10 to form purified gas 26 (i.e., high-concentration gas 23), and then transported to the gas chemical utilization device 13; the gas chemical utilization device 13 utilizes the high-concentration gas 23 to generate gas chemical utilization flue gas 28; if the gas concentration is less than or equal to 30% but higher than 8%, it is judged to be low-concentration gas. If the gas concentration is 25, the low-concentration gas outlet is opened, and the low-concentration gas 25 is transported to the gas mixing and purification system 11 through the low-concentration gas outlet; the gas flow control regulating device 8 monitors the gas concentration of the coal seam flowing through in real time, and adjusts the opening and closing of each outlet in real time according to the judgment situation, so as to realize the diversion and transportation of gas with different concentrations; the pressure relief gas extraction pump station 9 extracts the pressure relief gas 30 through the pressure relief gas extraction well 4, and transports it to the gas mixing and purification system 11; the gas mixing and The purification system 11 mixes the low-concentration gas 25 and the pressure relief gas 30, filters and purifies them, and then transports them to the mobile gas power station 12 for power generation, and generates gas power generation flue gas 31; when the gas flow control regulating device 8 detects that the extracted coal seam gas concentration is lower than the lower limit of the low-concentration gas 25 (that is, the gas concentration is less than 8%), the gas pre-extraction pump station 7 is stopped, indicating that the gas extraction has reached the standard and subsequent coal seam mining can be carried out; and the utilization value of the subsequently extracted coal seam gas 22 is extremely small.

[0040] D. Flue gas utilization and storage: The flue gas type lithium bromide absorption cold and hot water unit 14 receives the flue gas 28 for gas chemical utilization and the flue gas 31 for gas power generation, and uses the waste heat to generate cold and hot water. At the same time, the flue gas after waste heat utilization becomes low-temperature flue gas 32. The low-temperature flue gas 32 and the coal-fired flue gas 21 are both transported to the flue gas pressure pump station 15 for pressurization and enter the flue gas storage and transportation buffer tank 16 for buffering; at the same time, the fly ash 20 and water 34 generated by the pit mouth coal-fired power station 6 are stirred in the slurry pool 17 to prepare fly ash slurry 35. The calcium oxide content of the selected fly ash 20 is not less than 30%. The fly ash slurry 35 and the pressurized flue gas from the flue gas storage and transportation buffer tank 16 are mixed. 33 is foamed in the gas-liquid-solid mixed foaming device 18, and the prepared foamed slurry 36 is transported to the goaf 29 by the slurry injection well 5. In the goaf 29, CO2 in the flue gas and calcium oxide in the fly ash 20 continuously undergo mineralization reactions to eventually form mineralized products 37. With the continuous injection of the foamed slurry 36 and the continuous formation of the mineralized products 37, the internal space of the goaf 29 continues to shrink. Driven by the continuous shrinkage of the space, the depressurized gas 30 in the goaf 29 migrates to the depressurized gas extraction well 4, thereby strengthening the extraction of the depressurized gas 30, and the mineralized products 37 can solidify and seal the CO2 and fill and support the goaf 29.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A zero-carbon emission system for direct mineralization and storage of flue gas using full-concentration gas, characterized in that: It includes a pit-mouth coal-fired power station, a gas pre-extraction pump station, a gas flow control regulating device, a pressure relief gas extraction pump station, a gas purification device, a gas mixing and purification system, a mobile gas power station, a gas chemical utilization device, a flue gas type lithium bromide absorption cold and hot water unit, a flue gas pressure pump station, a flue gas storage and transportation buffer tank, a slurry tank and a gas-liquid-solid mixed foaming device. The pit-mouth coal-fired power station is used to burn coal mined from the main shaft of the coal mine to generate electricity, and produce fly ash and coal-fired flue gas, wherein the coal-fired flue gas is transported to the flue gas pressure pump station; the gas pre-extraction pump station is used to extract coal seam gas through the gas pre-extraction well; the gas flow control and regulation device is provided with an air inlet, a high-concentration gas outlet, a medium-concentration gas outlet and a low-concentration gas outlet, wherein the air inlet is used to receive the extracted coal seam gas, the high-concentration gas outlet is used to transport the high-concentration gas to the gas chemical utilization device, and the medium-concentration gas outlet is used to transport the medium-concentration gas to the gas purification device The gas purification device is used to purify medium-concentration gas to high-concentration gas and then transport it to the gas chemical utilization device. The low-concentration gas outlet is used to transport the low-concentration gas to the gas mixing and purification system. The gas flow control regulating device can monitor the gas concentration of the incoming gas and control the opening and closing of each outlet; the pressure relief gas extraction pump station is used to extract the pressure relief gas through the pressure relief gas extraction well and transport it to the gas mixing and purification system; the gas mixing and purification system is used to mix the low-concentration gas and the pressure relief gas, filter and purify them, and then transport them to the mobile gas power station; The gas chemical utilization device is used to generate gas chemical utilization flue gas after utilizing high-concentration gas and transport it to the flue gas type lithium bromide absorption cold and hot water unit; the mobile gas power station is used to generate gas power generation flue gas after utilizing the gas power generation transported by the gas mixing and purification system and transport it to the flue gas type lithium bromide absorption cold and hot water unit; the flue gas type lithium bromide absorption cold and hot water unit is used to generate low-temperature flue gas after utilizing the waste heat of gas chemical utilization flue gas and gas power generation flue gas, and transport it to the flue gas pressurizing pump station; the flue gas pressurizing pump station is used to pressurize the low-temperature flue gas and coal-fired flue gas, and then transport the pressurized flue gas after buffering in the flue gas storage and transportation buffer tank to the gas-liquid-solid mixed foaming device; The slurry pool is used to mix the fly ash and water produced by the pit mouth coal-fired power station to form fly ash slurry, and transport it to the gas-liquid-solid mixed foaming device; the gas-liquid-solid mixed foaming device is used to mix the fly ash slurry and pressurized flue gas to form foamed slurry, and transport it to the goaf through the slurry injection well.

2. The full concentration gas direct mineralization and storage zero carbon emission system according to claim 1 is characterized in that: The gas pre-extraction well, pressure relief gas extraction well and slurry injection well are surface wells constructed directly from the ground in the target coal seam, or pipeline wells constructed on the ground for installing gas extraction pipelines and slurry injection pipelines.

3. The full concentration gas direct mineralization and storage zero carbon emission system according to claim 1 is characterized in that: The gas pre-extraction pump station is a negative pressure extraction pump station or a gas drainage pump station.

4. The full concentration gas direct mineralization and storage zero carbon emission system according to claim 1 is characterized in that: The gas pre-extraction pump station, pressure relief gas extraction pump station, mobile gas power station, flue gas type lithium bromide absorption hot and cold water unit, flue gas pressure pump station, flue gas storage and transportation buffer tank, slurry tank and gas-liquid-solid mixed foaming device are all vehicle-mounted or skid-mounted.

5. The full concentration gas direct mineralization and storage zero carbon emission system according to claim 1 is characterized in that: The gas chemical utilization device is a chemical gas furnace device.

6. A working method of the zero-carbon emission system for direct mineralization and storage of flue gas using full-concentration gas according to any one of claims 1 to 5, characterized in that: Specifically: A. Well drilling construction and system layout: At a certain distance from the main shaft of the coal mine, several surface wells or surface boreholes are constructed from the ground to the coal seam at a certain interval along the direction of the coal seam. Among them, those in the unmined area of ​​the coal seam are used as gas pre-extraction wells, those in the mining area are used as pressure relief gas extraction wells, and those in the goaf are used as slurry injection wells. After completion, the mineralization storage zero-carbon emission system will be assembled and laid out; B. Coal mining and utilization: Coal in the coal seam is mined to the surface through the main shaft of the coal mine, and then burned in the coal-fired power station at the pit mouth to produce fly ash and coal-fired flue gas; C. Gas extraction and utilization: The gas pre-extraction pump station extracts coal seam gas through the gas pre-extraction well and transports it to the gas flow control regulating device. The gas flow control regulating device monitors the concentration of the incoming coal seam gas. If it is judged to be high-concentration gas, the high-concentration gas outlet is opened. At this time, the high-concentration gas is transported to the gas chemical utilization device through the high-concentration gas outlet; if it is judged to be medium-concentration gas, the medium-concentration gas outlet is opened. At this time, the medium-concentration gas is transported to the gas purification device through the medium-concentration gas outlet. After being purified by the gas purification device, high-concentration gas is formed, and then it is transported to the gas chemical utilization device; the gas chemical utilization device utilizes the high-concentration gas to produce The raw gas chemical industry utilizes flue gas; if it is judged to be low-concentration gas, the low-concentration gas outlet is opened, and the low-concentration gas is then transported to the gas mixing and purification system through the low-concentration gas outlet; the gas flow control regulating device monitors the gas concentration of the coal seam flowing through in real time, and adjusts the on and off of each outlet in real time according to the judgment situation, so as to realize the diversion and transportation of gas of different concentrations; the pressure relief gas extraction pump station extracts the pressure relief gas through the pressure relief gas extraction well, and transports it to the gas mixing and purification system; the gas mixing and purification system mixes the low-concentration gas and the pressure relief gas, filters and purifies them, and then transports them to the mobile gas power station for power generation, and generates gas power generation flue gas; D. Flue gas utilization and storage: Flue gas type lithium bromide absorption hot and cold water unit receives flue gas from gas chemical industry and gas power generation, and uses the remaining heat to produce hot and cold water. At the same time, the flue gas after waste heat utilization becomes low-temperature flue gas. The low-temperature flue gas and coal-fired flue gas are both transported to the flue gas pressure pump station for pressurization and enter the flue gas storage and transportation buffer tank for buffering. At the same time, the fly ash produced by the pit mouth coal-fired power station is mixed with water in the slurry pool to prepare fly ash slurry. The fly ash slurry and the pressurized flue gas from the flue gas storage and transportation buffer tank are mixed in the gas-liquid-solid mixing foaming device. The foaming slurry is transported to the goaf through the slurry injection well, and the CO2 in the flue gas in the goaf continues to react with the calcium oxide in the fly ash to form mineralized products, and finally form mineralized products. With the continuous injection of foamed slurry and the continuous formation of mineralized products, the internal space of the goaf continues to shrink. Driven by the continuous shrinkage of space, the pressure relief gas in the goaf migrates to the pressure relief gas extraction well, thereby strengthening the extraction of pressure relief gas. In addition, the mineralized products can solidify and seal CO2 and provide filling support for the goaf.

7. The working method of the zero-carbon emission system for direct mineralization and storage of flue gas using full-concentration gas according to claim 6 is characterized in that: The coal seam is a single coal seam with different inclination angles, or a coal seam group with multiple coal seams with different inclination angles.

8. The working method of the zero-carbon emission system for direct mineralization and storage of flue gas using full-concentration gas according to claim 6 is characterized in that: The full-concentration gas refers to all gases with a concentration higher than 8%, including high-concentration gas, medium-concentration gas and low-concentration gas.

9. The working method of the zero-carbon emission system for direct mineralization and storage of flue gas using full-concentration gas according to claim 6 is characterized in that: The high-concentration gas refers to gas with a concentration higher than 90%, the medium-concentration gas refers to gas with a concentration higher than 30% but less than or equal to 90%, and the low-concentration gas refers to gas with a concentration less than or equal to 30% but higher than 8%.

10. The working method of the zero-carbon emission system for direct mineralization and storage of flue gas using full-concentration gas according to claim 6 is characterized in that: The calcium oxide content of the fly ash is not less than 30%.

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