Room and pillar type goaf coal pillar fluidization mining method

Abstract

The invention discloses a room-and-pillar goaf coal pillar fluidization mining method which comprises the following steps: step 1, detecting a target room-and-pillar goaf to obtain detection content; 2, based on the detection content, goaf disaster control is conducted, then vertical drill holes are formed, and detection sensors are arranged in the goaf through the drill holes; 3, microbial strains for decomposing coal, a nutrient solution and a pH value adjusting buffering agent are injected into the goaf through the drill holes; 4, after the coal pillar is decomposed by the microorganisms, a fluidized product obtained after decomposition and conversion is extracted from the goaf through drilling; and 5, conveying the pumped fluidized product to a ground plant, and carrying out separation and purification operation to obtain a target product. According to the room-pillar type goaf coal pillar fluidization mining method, the problems that in an existing coal seam mining technology, the coal seam mining rate is low, and loss and waste of high-quality coal resources are caused are solved.

Description

Technical Field

[0001] This invention belongs to the field of coal resource recovery technology, specifically relating to a method for fluidized coal pillar mining in room-and-pillar goaf areas. Background Technology

[0002] Coal is a major component of my country's energy supply. With the decreasing recoverable coal reserves in eastern China, the center of gravity of the coal industry is gradually shifting westward. Western my country boasts abundant and high-quality coal resources, characterized by shallow deposits, simple geological conditions, and excellent coal quality. The Shenfu-Dongsheng coalfield, in particular, is currently the largest proven coalfield in my country and is gradually becoming a key development area for the coal industry. However, due to initial mine scale, technical limitations, and equipment issues, some mines in this region have historically relied on room-and-pillar mining for a long period, resulting in a recovery rate far below current requirements, only around 30%. This has led to a large number of abandoned coal pillars lying underground, creating stagnant coal reserves. The presence of these pillars not only results in the loss and waste of high-quality coal resources but also poses a significant risk of mine tremors, goaf fires, and the accumulation of toxic gases, seriously impacting the safe and efficient production of mines. Summary of the Invention

[0003] The purpose of this invention is to provide a fluidized bed mining method for coal pillars in room-and-pillar goaf areas, which solves the problem of low coal seam extraction rate and loss and waste of high-quality coal resources in existing coal seam mining technologies.

[0004] The technical solution adopted in this invention is a method for fluidized coal pillar mining in room-and-pillar goaf areas, comprising the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product.

[0005] The invention is further characterized by: The detection method in step 1 is to use a combination of borehole exploration and three-dimensional laser scanning.

[0006] The detection content in step 1 includes coal type, distribution of coal pillars left in old goaf areas, composition and concentration of toxic gases in old goaf areas, and water distribution.

[0007] In step 2, during the goaf disaster management process, toxic gases in old goaf areas are treated by a combination of extraction and inert gas dilution; water accumulation is treated by drilling drainage to ensure that the goaf environment meets the requirements for subsequent microbial injection and operations.

[0008] In step 2, the boreholes are divided into two groups, a and b. Group a boreholes are used for the injection of microbial strains, nutrient solution and pH adjustment buffer, while group b boreholes serve as channels for the extraction of fluidized products. Once the coal pillars around group a boreholes have been recovered, the functions of the two groups of boreholes are exchanged.

[0009] In step 2, the parameters monitored by the detection sensors include temperature, pressure, fluid composition, and microbial activity in the goaf area. Based on the monitoring data, the injection volume and injection speed of the microbial nutrient solution are adjusted in real time, and the extraction rate of the fluidized products is also adjusted.

[0010] In step 3, the microbial strains selected are one or more mixed groups of methanogenic archaea, lignite-degrading bacteria, or fungi.

[0011] In step 3, sodium bicarbonate solution or phosphate buffer is selected as the pH adjustment buffer, which can stabilize the pH value of the environment in the goaf between 6.5 and 7.5 to meet the needs of microbial growth.

[0012] In step 5, the target products include methane, carbon monoxide, hydrogen, organic acids, and alcohols. When separating and purifying these products in the ground plant, pressure swing adsorption is used to separate the gaseous products, and distillation is used to separate the liquid products.

[0013] The beneficial effects of this invention are: The fluidized bed mining method for coal pillars in goaf areas provided by this invention involves a biological reaction at ambient temperature and pressure throughout the entire mining process, eliminating the need for personnel or large equipment to enter the high-risk goaf area. By simultaneously injecting microorganisms into multiple boreholes, the fluidization conversion efficiency of coal pillars in old goaf areas is significantly improved. The boreholes are used for both microbial injection and extraction of fluidized bed products, saving some drilling costs. The method transforms previously abandoned and unsafe coal pillar resources into clean energy and chemical raw materials with high economic value, realizing the green value-added utilization of waste resources. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the fluidized bed mining stage in Example 10 of the room-and-pillar goaf mining method of the present invention.

[0015] In the diagram: 1. Ground plant; 2. Recycling pipeline; 3. Group a borehole; 4. Group b borehole; 5. Detection sensor; 6. Microbial inoculum, nutrient solution, pH adjusting buffer; 7. Coal pillar; 8. Fluidized bed product. Detailed Implementation The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0016] Example 1 The room-and-pillar goaf fluidized bed mining method proposed in this embodiment includes the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product.

[0017] Example 2 The room-and-pillar goaf fluidized bed mining method proposed in this embodiment includes the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; The detection method in step 1 is: a combination of borehole exploration and three-dimensional laser scanning. Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product.

[0018] Example 3 The room-and-pillar goaf fluidized bed mining method proposed in this embodiment includes the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; The detection method in step 1 is: a combination of borehole exploration and three-dimensional laser scanning. The detection content in step 1 includes coal type, distribution of coal pillars left in old goaf areas, composition and concentration of toxic gases in old goaf areas, and water distribution; Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product.

[0019] Example 4 The room-and-pillar goaf fluidized bed mining method proposed in this embodiment includes the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; The detection method in step 1 is: a combination of borehole exploration and three-dimensional laser scanning. The detection content in step 1 includes coal type, distribution of coal pillars left in old goaf areas, composition and concentration of toxic gases in old goaf areas, and water distribution; Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; In step 2, during the goaf disaster management process, toxic gases in old goaf areas are treated by a combination of extraction and inert gas dilution; water accumulation is treated by drilling drainage to ensure that the goaf environment meets the requirements for subsequent microbial injection and operations. Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product.

[0020] Example 5 The room-and-pillar goaf fluidized bed mining method proposed in this embodiment includes the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; The detection method in step 1 is: a combination of borehole exploration and three-dimensional laser scanning. The detection content in step 1 includes coal type, distribution of coal pillars left in old goaf areas, composition and concentration of toxic gases in old goaf areas, and water distribution; Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; In step 2, during the goaf disaster management process, toxic gases in old goaf areas are treated by a combination of extraction and inert gas dilution; water accumulation is treated by drilling drainage to ensure that the goaf environment meets the requirements for subsequent microbial injection and operations. In step 2, the boreholes are divided into two groups, a and b. Group a boreholes are used for the injection of microbial strains, nutrient solution and pH adjustment buffer, while group b boreholes serve as channels for the extraction of fluidized products. Once the coal pillars around group a boreholes have been recovered, the functions of the two groups of boreholes are exchanged. Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product.

[0021] Example 6 The room-and-pillar goaf fluidized bed mining method proposed in this embodiment includes the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; The detection method in step 1 is: a combination of borehole exploration and three-dimensional laser scanning. The detection content in step 1 includes coal type, distribution of coal pillars left in old goaf areas, composition and concentration of toxic gases in old goaf areas, and water distribution; Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; In step 2, during the goaf disaster management process, toxic gases in old goaf areas are treated by a combination of extraction and inert gas dilution; water accumulation is treated by drilling drainage to ensure that the goaf environment meets the requirements for subsequent microbial injection and operations. In step 2, the boreholes are divided into two groups, a and b. Group a boreholes are used for the injection of microbial strains, nutrient solution and pH adjustment buffer, while group b boreholes serve as channels for the extraction of fluidized products. Once the coal pillars around group a boreholes have been recovered, the functions of the two groups of boreholes are exchanged. In step 2, the parameters monitored by the detection sensor include temperature, pressure, fluid composition and microbial activity in the goaf area, and the injection volume and injection speed of the microbial nutrient solution are adjusted in real time based on the monitoring data, while the extraction rate of fluidized products is also adjusted. Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product.

[0022] Example 7 The room-and-pillar goaf fluidized bed mining method proposed in this embodiment includes the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; The detection method in step 1 is: a combination of borehole exploration and three-dimensional laser scanning. The detection content in step 1 includes coal type, distribution of coal pillars left in old goaf areas, composition and concentration of toxic gases in old goaf areas, and water distribution; Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; In step 2, during the goaf disaster management process, toxic gases in old goaf areas are treated by a combination of extraction and inert gas dilution; water accumulation is treated by drilling drainage to ensure that the goaf environment meets the requirements for subsequent microbial injection and operations. In step 2, the boreholes are divided into two groups, a and b. Group a boreholes are used for the injection of microbial strains, nutrient solution and pH adjustment buffer, while group b boreholes serve as channels for the extraction of fluidized products. Once the coal pillars around group a boreholes have been recovered, the functions of the two groups of boreholes are exchanged. In step 2, the parameters monitored by the detection sensor include temperature, pressure, fluid composition and microbial activity in the goaf area, and the injection volume and injection speed of the microbial nutrient solution are adjusted in real time based on the monitoring data, while the extraction rate of fluidized products is also adjusted. Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; In step 3, the microbial strains selected are one or more mixed groups of methanogenic archaea, lignite-degrading bacteria, or fungi. Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product.

[0023] Example 8 The room-and-pillar goaf fluidized bed mining method proposed in this embodiment includes the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; The detection method in step 1 is: a combination of borehole exploration and three-dimensional laser scanning. The detection content in step 1 includes coal type, distribution of coal pillars left in old goaf areas, composition and concentration of toxic gases in old goaf areas, and water distribution; Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; In step 2, during the goaf disaster management process, toxic gases in old goaf areas are treated by a combination of extraction and inert gas dilution; water accumulation is treated by drilling drainage to ensure that the goaf environment meets the requirements for subsequent microbial injection and operations. In step 2, the boreholes are divided into two groups, a and b. Group a boreholes are used for the injection of microbial strains, nutrient solution and pH adjustment buffer, while group b boreholes serve as channels for the extraction of fluidized products. Once the coal pillars around group a boreholes have been recovered, the functions of the two groups of boreholes are exchanged. In step 2, the parameters monitored by the detection sensor include temperature, pressure, fluid composition and microbial activity in the goaf area, and the injection volume and injection speed of the microbial nutrient solution are adjusted in real time based on the monitoring data, while the extraction rate of fluidized products is also adjusted. Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; In step 3, the microbial strains selected are one or more mixed groups of methanogenic archaea, lignite-degrading bacteria, or fungi. In step 3, sodium bicarbonate solution or phosphate buffer is selected as the pH adjustment buffer, which can stabilize the pH value of the environment in the goaf between 6.5 and 7.5 to meet the growth requirements of microorganisms. Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product.

[0024] Example 9 The room-and-pillar goaf fluidized bed mining method proposed in this embodiment includes the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; The detection method in step 1 is: a combination of borehole exploration and three-dimensional laser scanning. The detection content in step 1 includes coal type, distribution of coal pillars left in old goaf areas, composition and concentration of toxic gases in old goaf areas, and water distribution; Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; In step 2, during the goaf disaster management process, toxic gases in old goaf areas are treated by a combination of extraction and inert gas dilution; water accumulation is treated by drilling drainage to ensure that the goaf environment meets the requirements for subsequent microbial injection and operations. In step 2, the boreholes are divided into two groups, a and b. Group a boreholes are used for the injection of microbial strains, nutrient solution and pH adjustment buffer, while group b boreholes serve as channels for the extraction of fluidized products. Once the coal pillars around group a boreholes have been recovered, the functions of the two groups of boreholes are exchanged. In step 2, the parameters monitored by the detection sensor include temperature, pressure, fluid composition and microbial activity in the goaf area, and the injection volume and injection speed of the microbial nutrient solution are adjusted in real time based on the monitoring data, while the extraction rate of fluidized products is also adjusted. Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; In step 3, the microbial strains selected are one or more mixed groups of methanogenic archaea, lignite-degrading bacteria, or fungi. In step 3, sodium bicarbonate solution or phosphate buffer is selected as the pH adjustment buffer, which can stabilize the pH value of the environment in the goaf between 6.5 and 7.5 to meet the growth requirements of microorganisms. Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product; In step 5, the target products include methane, carbon monoxide, hydrogen, organic acids, and alcohols. When separating and purifying these products in the ground plant, pressure swing adsorption is used to separate the gaseous products, and distillation is used to separate the liquid products.

[0025] Example 10 The method for fluidized bed mining of coal pillars in room-and-pillar goaf, taking a room-and-pillar goaf as an example, includes the following steps: Step 1: Use borehole exploration and three-dimensional laser scanning to determine the distribution of coal pillars in the goaf; Step 2: Based on the detection results, drill holes from the ground surface at 50m intervals. Divide the holes into two groups: group a (hole 3) and group b (hole 4). Figure 1 As shown, in the initial stage, borehole 3 in group a was used as an injection hole, and borehole 4 in group b was used as a recovery hole. The borehole ends were located in the room-and-pillar goaf space. Step 3: Use drilling to place the detection sensor 5 below the goaf; Step 4: Inject the bacterial strain, nutrient solution, and pH adjustment buffer 6 into the goaf area through borehole 3 in group a; Step 5: Extract the gas and liquid generated by the decomposition of the coal pillar 7 in the goaf area through the recovery pipe 2 connected to the borehole 4 in group b; Step 6: Separate and purify the extracted fluidized product 8 in the ground plant 1 to obtain the target product, which is methane, carbon monoxide, hydrogen, organic acids and alcohols.

[0026] Using this method, approximately 60% of the remaining coal pillar resources in the goaf can be converted into clean energy within 3-5 years.

Claims

1. A method for fluidized bed mining of coal pillars in room-and-pillar goaf, characterized in that, Includes the following steps: Step 1: Detect the target room-pillar goaf area and obtain the detection information; Step 2: Based on the detection data, carry out disaster management in the goaf area, then deploy vertical boreholes and install detection sensors into the goaf area through the boreholes; Step 3: Inject coal-decomposing microbial strains, nutrient solution, and pH-adjusting buffer into the goaf through boreholes; Step 4: After the microorganisms have decomposed the coal pillar, the fluidized products after decomposition and conversion are extracted from the goaf through boreholes. Step 5: The extracted fluidized product is transported to the ground plant for separation and purification to obtain the target product.

2. The method for fluidized bed mining of coal pillars in room-and-pillar goaf according to claim 1, characterized in that, The detection method described in step 1 is: a combination of borehole exploration and three-dimensional laser scanning.

3. The method for fluidized bed mining of coal pillars in room-and-pillar goaf according to claim 1, characterized in that, The detection content mentioned in step 1 includes coal type, distribution of coal pillars left in old goaf areas, composition and concentration of toxic gases in old goaf areas, and water distribution.

4. The method for fluidized bed mining of coal pillars in room-and-pillar goaf according to claim 1, characterized in that, In the process of goaf disaster management described in step 2, toxic gases in old goaf areas are treated by a combination of extraction and inert gas dilution; water accumulation is treated by drilling drainage to ensure that the goaf environment meets the requirements for subsequent microbial injection and operations.

5. The method for fluidized bed mining of coal pillars in room-and-pillar goaf according to claim 1, characterized in that, The boreholes described in step 2 are divided into two groups, a and b. Group a boreholes are used for injecting microbial strains, nutrient solutions, and pH-adjusting buffers, while group b boreholes serve as channels for the extraction of fluidized products. Once the coal pillars around group a boreholes have been recovered, the functions of the two groups of boreholes are switched.

6. The method for fluidized bed mining of coal pillars in room-and-pillar goaf according to claim 1, characterized in that, The parameters monitored by the detection sensor in step 2 include temperature, pressure, fluid composition and microbial activity in the goaf area, and the injection volume and injection speed of the microbial nutrient solution are adjusted in real time based on the monitoring data, while the extraction rate of fluidized products is also adjusted.

7. The method for fluidized bed mining of coal pillars in room-and-pillar goaf according to claim 1, characterized in that, The microbial strains mentioned in step 3 are selected from one or more mixed groups of methanogenic archaea, lignite-degrading bacteria, or fungi.

8. The method for fluidized bed mining of coal pillars in room-and-pillar goaf according to claim 1, characterized in that, The pH adjustment buffer mentioned in step 3 is selected from sodium bicarbonate solution or phosphate buffer, which can stabilize the pH value of the environment in the goaf between 6.5 and 7.5 to meet the needs of microbial growth.

9. The method for fluidized bed mining of coal pillars in room-and-pillar goaf according to claim 1, characterized in that, The target products mentioned in step 5 include methane, carbon monoxide, hydrogen, organic acids, and alcohols. When separating and purifying them in the ground plant, pressure swing adsorption is used to separate gaseous products, and distillation is used to separate liquid products.

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