Coal seam in-situ bacterial community methane production increasing system and method

Abstract

The application discloses a coal seam in-situ bacterial flora methane production increasing system and method, and relates to the field of coal seam methane production increasing. The production increasing system comprises a filtering device, a water-based mixing bin, a refrigerated grinder and a liquid nitrogen pump station. The filtering device is internally provided with a filtering layer, and divides an inner cavity into an upper cavity and a lower cavity. The filtering device is configured to obtain drainage water by filtering out samples of coal cinder waste and anaerobic bacteria samples. The first port is connected with a drainage port. The water-based mixing bin is connected with the third port through a first connecting port and connected with a culture medium container through a second connecting port. The refrigerated grinder is configured to freeze and grind the injected liquid into fine particles. The liquid nitrogen pump station is internally provided with liquid nitrogen. The first liquid port is connected with the second connecting port. The low-temperature mixing bin is connected with the fourth connecting port through a first bin port, connected with the third liquid port through a second bin port, and connected with an injection port through a third bin port.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coalbed methane extraction, and particularly relates to a coalbed in-situ microbial community methane production system and method. BACKGROUND

[0002] From the perspective of fracturing, low permeability coal seams hinder the pre-extraction of coalbed methane. In order to ensure the safety of coal production and the efficient extraction of coalbed methane, physical and chemical methods are usually used to increase the permeability of coal seams at home and abroad. The existing coal seam permeability enhancement technologies mainly include hydraulic fracturing, hydrochloric acid chemical method, water jetting, deep hole pre-splitting blasting and water jetting. These methods can significantly improve the extraction rate of coalbed methane, but also have some shortcomings and deficiencies. Although the hydraulic fracturing method has good permeability enhancement effect, it can seriously pollute water sources and threaten the ecological environment and the health of local residents due to the use of a large amount of water mixed with chemicals. The water jetting method requires cutting through the drill holes, which has a high operation difficulty. The deep hole blasting operation is relatively complex and prone to accidents, which threatens the safety of coal production.

[0003] As a high-efficiency and green waterless fracturing technology, the liquid nitrogen fracturing technology can effectively improve the permeability of coal seams and increase the extraction rate of coalbed methane. At the same time, it can effectively save water resources and avoid water locking and water sensitivity damage. As a new fracturing technology, although the liquid nitrogen fracturing technology has not been widely used in practice, its broad prospects have attracted more and more scholars to conduct theoretical and experimental research on it.

[0004] From the perspective of gas production, coal contains a large amount of organic matter that can be utilized and degraded by microorganisms. The biological conversion of coal is the process in which microorganisms degrade or decompose the available organic matter in coal molecules into methane gas. In recent years, scholars at home and abroad have had a deeper understanding of the generation process and mechanism of biological methane in coal seams, and have also confirmed that coal seam microorganisms can degrade coal to produce methane. Microbial gas production has the characteristics of mild reaction conditions, green environmental protection and low energy consumption. It can efficiently produce methane while taking into account economic benefits and green environmental protection, and has broad development prospects in today's era. SUMMARY

[0005] The coal seam in-situ microbial community methane production system and method proposed in the present application can achieve the above technical purposes and bring other technical effects due to the adoption of the following technical features.

[0006] One object of the present application is to provide a coal seam in-situ microbial community methane production system, which is applied to a coal seam, a drill hole is opened in the coal seam, and the drill hole has a mutual communication extraction port and an injection port;

[0007] The production system comprises:

[0008] The filter device is provided with a filter layer in the inner cavity, which divides the inner cavity into an upper chamber and a lower chamber, and the filter device is configured to obtain the drainage water by filtering out the sample of coal residue waste and the sample of anaerobic bacteria, and has a first port, a second port, a third port and a first exhaust hole, wherein the first port is in communication with the extraction port;

[0009] The water-based mixing bin has a first connecting port, a second connecting port, a third connecting port, a fourth connecting port and a second exhaust hole, wherein the first connecting port is in communication with the third port, and the second connecting port is in communication with the culture medium container;

[0010] The freeze grinder has a first connecting port, a second connecting port and a fourth connecting port, wherein the first connecting port is in communication with the third connecting port, and is configured to freeze and grind the injected liquid into fine particles;

[0011] The liquid nitrogen pump station contains liquid nitrogen inside, and has a first liquid port and a third liquid port, wherein the first liquid port is in communication with the second connecting port, and is configured to at least pump out the liquid nitrogen via the first liquid port and the third liquid port;

[0012] The low-temperature mixing bin has a first bin port, a second bin port, a third bin port and a third exhaust hole, wherein the first bin port is in communication with the fourth connecting port, the second bin port is in communication with the third liquid port, and the third bin port is in communication with the injection port;

[0013] In the technical scheme, the working process of the yield increasing system is as follows: the filter device extracts the drainage water in the coal seam from the extraction port, and obtains the drainage water by filtering out the sample of coal residue waste and the sample of anaerobic bacteria; the drainage water in the filter device is injected into the water-based mixing bin via the third port and the first connecting port, and the culture medium in the culture medium container is injected into the water-based mixing bin via the second connecting port, and is fully mixed and uniform to form a nutrient solution; the nutrient solution in the water-based mixing bin is injected into the freeze grinder via the third connecting port and the first connecting port, the nutrient solution is solidified into ice in the freeze grinder, and then is ground into fine particles of micron level; the freeze grinder injects the fine particles of the nutrient solution into the low-temperature mixing bin via the fourth connecting port and the first bin port, the liquid nitrogen pump station injects the liquid nitrogen into the low-temperature mixing bin via the third liquid port and the second bin port, and mixes the liquid nitrogen with the nutrient powder uniformly, and the mixture of the liquid nitrogen and the nutrient powder is injected into the coal seam via the third bin port and the injection port. The above steps are repeated to supplement the culture medium for the anaerobic bacteria in the borehole, and at the same time, the liquid nitrogen is cracked to expand the fissures of the coal seam and increase the contact area between the anaerobic bacteria and the coal matrix, so as to maintain or even improve the gas production efficiency until the coal seam reaches the best cracking effect or the gas production cannot meet the output requirements.

[0014] The yield increasing system combines liquid nitrogen fracturing and microbial gas production, uses liquid nitrogen to expel oxygen to create a favorable living environment for microorganisms, and increases the contact area of microorganisms and coal by fracturing and increasing the permeability of coal seam, thereby improving the gas production efficiency and realizing the systematic process of fracturing and gas production.

[0015] The yield increasing system comprehensively considers the production needs of microorganisms in the coal seam, and formulates schemes such as adjusting the ratio of culture medium and adjusting the interval of carbon dioxide input according to the gas production to ensure that anaerobic bacteria are in an active state.

[0016] The yield increasing system is green and environmentally friendly, saves and protects a large amount of water resources, and the raw materials such as liquid nitrogen and anaerobic bacteria are simple to produce, the production cost is small during the production period, and the gas production efficiency is high.

[0017] In addition, the coal seam in-situ microbial group methane yield increasing system and method according to the present applicationapplicationalso have the following technical features:

[0018] In an example of the present application, it further comprises an anaerobic bacteria container,

[0019] It is connected with the second connecting port and is configured to inject anaerobic bacteria into the water-based mixing bin when the concentration of anaerobic bacteria in the drainage water is lower than the threshold concentration.

[0020] In an example of the present application, the filter layer comprises at least two layers, at least one of which is located on the upper end side and is configured to filter coal slag particles, and at least another of which is located on the lower end side and is configured to extract anaerobic bacteria samples.

[0021] In an example of the present application, the filter layer further comprises at least two valves, at least one of which is located on the upper end of the filter layer and is configured to control the drainage water in the upper chamber, and at least another of which is located on the lower end of the at least two filter layers and is configured to control the drainage water in the upper chamber and the filter layer.

[0022] In an example of the present application, the liquid nitrogen pump station further comprises a second liquid port, and the cryogenic grinder further comprises a third connecting port in communication with the second liquid port, and the liquid nitrogen enters the cryogenic grinder via the second connecting port and flows back to the liquid nitrogen pump station via the third connecting port.

[0023] In an example of the present application, the drill hole comprises a plurality of horizontal sections and at least two inclined sections, the horizontal sections extend along the horizontal direction of the coal seam and are arranged at intervals in the depth direction of the coal seam, and the inclined sections sequentially communicate a plurality of horizontal sections arranged along the depth direction, wherein the lengths of the plurality of horizontal sections increase in turn from deep to shallow in the depth direction.

[0024] In one example of the present invention, the angle between the inclined segment and the horizontal direction is 30 degrees to 45 degrees, and the interval distance of the horizontal segment in the depth direction is 1.5m to 2m.

[0025] In one example of the invention, the production enhancement system further includes a carbon dioxide pumping station.

[0026] It connects the third compartment and the injection port, and is configured to inject carbon dioxide gas into the injection port.

[0027] In one example of the invention, the production enhancement system further includes an inert gas pumping station.

[0028] It has a first air inlet, a second air inlet and a third air inlet. The first air inlet is connected to the second port and the fourth connection port. The second air inlet is connected to the fourth liquid port of the liquid nitrogen pump station. The third air inlet is connected to the second compartment port. It is configured to inject inert gas into the filter device, the water-based mixing compartment and the cryogenic mixing compartment to form a low-oxygen or oxygen-free environment.

[0029] Another object of the present invention is to provide a method for increasing the production of methane using an in-situ microbial community system in coal seams as described above, comprising the following steps:

[0030] S10: Drainage water is extracted from the coal seam by a filtration device, and the drainage water is obtained by filtering out coal slag waste and anaerobic bacteria samples.

[0031] S20: Inject the drained water from the filtration device and the culture medium from the culture medium container into the water-based mixing chamber, and mix them thoroughly to form a nutrient solution;

[0032] S30: The nutrient solution in the water-based mixing chamber is injected into the cryogenic grinder. The nutrient solution is frozen into ice at low temperature in the cryogenic grinder and then ground into micron-sized fine particles.

[0033] S40: Fine nutrient solution particles are injected into the cryogenic mixing chamber by a cryogenic grinder, liquid nitrogen is injected into the cryogenic mixing chamber by a liquid nitrogen pump station and mixed evenly with nutrient solution powder, and the mixture of liquid nitrogen and nutrient solution powder is injected into the coal seam through the injection port from the third chamber outlet.

[0034] S50: Repeat steps S10 to S40 to replenish the culture medium to the anaerobic bacteria in the borehole, while simultaneously performing liquid nitrogen fracturing to expand the fractures in the coal seam and increase the contact area between the anaerobic bacteria and the coal matrix, thereby maintaining or even improving the gas production efficiency until the coal seam reaches the optimal fracturing effect or the gas production cannot meet the production requirements.

[0035] The preferred embodiments of the invention will be described in more detail below with reference to the accompanying drawings, so as to facilitate an understanding of the features and advantages of the invention. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. The drawings are merely illustrative of some embodiments of the present invention and are not intended to limit the scope of the present invention to all embodiments.

[0037] Figure 1 This is a schematic diagram of a coal seam in-situ microbial community methane enhancement system according to an embodiment of the present invention;

[0038] Figure 2 This is a flowchart of a method for increasing methane production using an in-situ microbial community system in coal seams, according to an embodiment of the present invention.

[0039] List of reference numerals in the attached diagram:

[0040] Coal seam 200;

[0041] Drill hole 210;

[0042] Horizontal segment 211;

[0043] Inclined section 212;

[0044] Drainage port 220;

[0045] Note entry 230;

[0046] Production enhancement system 100;

[0047] Filter device 10;

[0048] Filter layer 11;

[0049] Upper chamber 12;

[0050] Inferior chamber 13;

[0051] First port 14;

[0052] Second port 15;

[0053] Third port 16;

[0054] First exhaust port 17;

[0055] Water-based mixing chamber 20;

[0056] First connection port 21;

[0057] Second connection port 22;

[0058] Third connection port 23;

[0059] Fourth connection port 24;

[0060] Second exhaust port 25;

[0061] First stirring blade 26;

[0062] 30°C cryogenic grinder;

[0063] First connecting port 31;

[0064] Second connecting port 32;

[0065] Third connecting port 33;

[0066] Fourth connecting port 34;

[0067] Liquid nitrogen pump station 40;

[0068] First liquid outlet 41;

[0069] Second liquid outlet 42;

[0070] Third liquid outlet 43;

[0071] Fourth liquid outlet 44;

[0072] Low-temperature mixing chamber 50;

[0073] First warehouse entrance 51;

[0074] Second warehouse entrance 52;

[0075] Third warehouse entrance 53;

[0076] Third exhaust port 54;

[0077] Second stirring blade 55;

[0078] Culture medium container 60;

[0079] 70 anaerobic bacteria container;

[0080] Carbon dioxide pump station 80;

[0081] Inert gas pump station 90;

[0082] First air inlet 91;

[0083] Second air inlet 92;

[0084] Third air inlet 93;

[0085] First on / off valve 101;

[0086] Second shut-off valve 102;

[0087] Third shut-off valve 103;

[0088] Fourth shut-off valve 104;

[0089] Fifth shut-off valve 105;

[0090] Sixth shut-off valve 106;

[0091] Seventh shut-off valve 107;

[0092] Eighth on / off valve 108;

[0093] Ninth shut-off valve 109;

[0094] Tenth shut-off valve 110;

[0095] Eleventh shut-off valve 111;

[0096] Twelfth shut-off valve 112;

[0097] Thirteenth shut-off valve 113;

[0098] Horizontal direction S;

[0099] Depth direction H. Detailed Implementation

[0100] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0101] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, “an” or “a” and similar terms do not necessarily indicate a quantity limitation. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0102] According to a first aspect of the present invention, a coal seam in-situ microbial community methane enhancement system 100, such as... Figure 1As shown, applied in the coal seam 200, the coal seam 200 is provided with a drill hole 210, the drill hole 210 is provided with a drainage hole 220 and an injection hole 230 which are communicated with each other;

[0103] The yield increasing system 100 comprises:

[0104] A filter device 10, an inner cavity of the filter device 10 is provided with a filter layer 11, the inner cavity is divided into an upper cavity 12 and a lower cavity 13, the filter device 10 is configured to obtain drainage water by filtering out samples of coal residue waste and samples of anaerobic bacteria, and has a first port 14, a second port 15, a third port 16 and a first exhaust hole 17, the first port 14 is communicated with the drainage hole 220;

[0105] A water-based mixing bin 20, having a first connecting port 21, a second connecting port 22 and a third connecting port 23, a fourth connecting port 24 and a second exhaust hole 25, the first connecting port 21 is communicated with the third port 16, and the second connecting port 22 is communicated with a culture medium container 60; for example, a first stirring blade 26 is arranged at the bottom of the water-based mixing bin 20, when the culture medium and the drainage water enter the water-based mixing bin 20, the first stirring blade 26 is used to stir to make the mixture between the two more uniform. For example, the first stirring blade 26 is a propeller.

[0106] A refrigerated grinder 30, having a first communicating port 31, a second communicating port 32 and a fourth communicating port 34, the first communicating port 31 is communicated with the third connecting port 23, and is configured to freeze and grind the injected liquid into fine particles;

[0107] A liquid nitrogen pump station 40, internally containing liquid nitrogen, having a first liquid port 41 and a third liquid port 43, the first liquid port 41 is communicated with the second communicating port 32, and is configured to at least pump out the liquid nitrogen via the first liquid port 41 and the third liquid port 43;

[0108] A low-temperature mixing bin 50, having a first bin port 51, a second bin port 52, a third bin port 53 and a third exhaust hole 54, the first bin port 51 is communicated with the fourth communicating port 34, the second bin port 52 is communicated with the third liquid port 43, and the third bin port 53 is communicated with the injection hole 230. For example, a second stirring blade 55 is arranged at the bottom of the low-temperature mixing bin 50, when the liquid nitrogen and the nutrient liquid particles enter the low-temperature mixing bin 50, the second stirring blade 55 is used to stir to make the mixture between the two more uniform; for example, the second stirring blade 55 is a propeller.

[0109] The working process of the yield increasing system 100 is as follows: the drainage water in the coal seam 200 is drained from the drainage hole 220 by the filtering device 10, and the drainage water is obtained by filtering out the sample of coal dregs waste and the sample of anaerobic bacteria; the drainage water in the filtering device 10 is injected into the water-based mixing bin 20 through the third port 16, the first connecting port 21, the culture medium in the culture medium container 60, the second connecting port 22, and is fully mixed and uniformly formed into nutrient solution; the nutrient solution in the water-based mixing bin 20 is injected into the frozen grinding machine 30 through the third connecting port 23 and the first communicating port 31, the nutrient solution is solidified into ice at low temperature in the frozen grinding machine 30, and then is ground into micron-sized fine particles; the frozen grinding machine 30 injects the fine particles of the nutrient solution into the low-temperature mixing bin 50 through the fourth communicating port 34 and the first bin port 51, the liquid nitrogen pump station 40 injects liquid nitrogen into the low-temperature mixing bin 50 through the third liquid port 43 and the second bin port, and the liquid nitrogen is mixed with the fine particles of the nutrient solution uniformly, and the mixture of the liquid nitrogen and the fine particles of the nutrient solution is injected into the coal seam 200 through the third bin port 53 and the injection port 230. The above steps are repeated to supplement the culture medium for the anaerobic bacteria in the borehole 210, and at the same time, the liquid nitrogen is used for fracturing to expand the fractures of the coal seam 200 and increase the contact area of the anaerobic bacteria and the coal matrix, so that the gas production efficiency is maintained or even improved, until the coal seam 200 reaches the best fracturing effect or the gas production cannot meet the output requirements.

[0110] The yield increasing system 100 combines the liquid nitrogen fracturing and the microbial gas production together, uses the liquid nitrogen to expel oxygen to create a favorable living environment for the microorganisms, and at the same time, the coal seam 200 is fractured and permeability is increased, and the contact area of the microorganisms and the coal body is increased, so that the gas production efficiency is improved, and the systematic process of fracturing and gas production is realized.

[0111] The yield increasing system 100 comprehensively considers the production demand of the microorganisms in the coal seam 200, formulates schemes such as adjusting the proportion of the culture medium and adjusting the interval of carbon dioxide input according to the gas production, and ensures that the anaerobic bacteria are in an active state.

[0112] The yield increasing system 100 is green and environmentally friendly, saves and protects a large amount of water resources, and at the same time, the raw materials such as liquid nitrogen and anaerobic bacteria are simple to produce, the production cost is small during the production period, and the gas production efficiency is high.

[0113] As preferred, the basic culture medium ingredients are: NH4Cl 1.2 g / L, NaH2PO4 1.6 g / L, KCl 1.3 g / L, MgSO4·7H2O 0.8 g / L, CaCl2·2H2O 0.3 g / L, yeast extract 0.5 g / L, compound vitamin 10 ml / L, trace element 10 ml / L, 1 mL of resazurin is added per liter as an oxidation-reduction indicator, and after being treated in a sterilization box for 20-30 min, it is placed in an anaerobic box for deoxidation, the temperature of the anaerobic bacteria bin should be kept at-70 to-80℃, and before use, it should be placed at room temperature, and after two generations of recovery of activity, it is put into use.

[0114] In one example of the present application, further comprising: an anaerobe container 70,

[0115] which is in communication with the second connecting port 22, configured to inject anaerobes into the water-based mixing bin 20 when the concentration of anaerobes in the drainage water is lower than the threshold concentration;

[0116] For example, the anaerobes are collected by the small-pore filter screen in the filter layer 11, and sent to the laboratory for detection of DNA integrity and concentration. If the concentration of viable bacteria is less than 1.4 x 10 6 , it is determined that the number of anaerobes in the coal pores is small, and additional anaerobes need to be added.

[0117] By setting the anaerobe container 70, anaerobes can be injected into the water-based mixing bin 20 in real time to supplement the concentration of anaerobes in the collected drainage water, increase the contact area between microorganisms and coal, and thus improve the gas production efficiency, realizing the systematic process of fracturing and gas production.

[0118] In one example of the present application, the filter layer 11 includes at least two layers, at least one of which is located on the upper end side and is configured to filter coal cinder particles, and at least another of which is located on the lower end side and is configured to extract anaerobe samples;

[0119] For example, the filter layer 11 is arranged between the upper chamber 12 and the lower chamber 13 of the filter device 10, and the filter layer 11 is divided into two layers, the upper layer being a large-particle filter layer 11 made of dense nylon cotton for filtering particles visible to the naked eye such as coal cinder, and the lower layer being a microorganism sampling layer made of a filter screen with a pore size of less than 0.22 μm for extracting anaerobe samples from water and sending them to the laboratory for detection of DNA integrity and concentration. By arranging the filter layer 11 into at least two layers, corresponding samples can be filtered and extracted.

[0120] In one example of the present application, the filter layer 11 further includes at least two valves, at least one of which is located on the upper end of the filter layer 11 and is configured to control the drainage water in the upper chamber 12, and at least another of which is located on the lower end of the at least two filter layers 11 and is configured to control the drainage water in the upper chamber 12 and the filter layer 11;

[0121] In short, valves are provided on the upper and lower ends of the filter layer 11. Closing the upper valve can control the drainage water in the upper chamber 12, facilitating the static state and replacement of the filter element of the filter layer 11. Closing the lower valve can control the drainage water in the upper chamber 12 and the filter layer 11, facilitating sampling and testing. All valves are opened to normally perform the process of filtering the drainage water.

[0122] As to the filter element for replacing the filter layer 11, the anaerobic bacteria filter screen is contained in the filter layer 11 before replacement, so that the anaerobic bacteria in the produced water can be collected to test the integrity and concentration of the anaerobic bacteria DNA; the filter layer 11 after replacement does not contain the anaerobic bacteria filter screen, and is mainly used for filtering the coal cinder in the produced water, and the produced water in the upper chamber 12 is filtered by the filter layer 11 to flow to the lower chamber 13.

[0123] In one example of the present application, the liquid nitrogen pump station 40 further comprises a second liquid port 42, and the cryogenic grinder 30 further comprises a third communication port 33 in communication with the second liquid port 42, and the liquid nitrogen enters the cryogenic grinder 30 through the second communication port 32 and returns to the liquid nitrogen pump station 40 through the third communication port 33;

[0124] When the cryogenic grinder 30 is working, the liquid nitrogen pump station 40 continuously fills with liquid nitrogen to create a low-temperature and oxygen-free environment, and the excess liquid nitrogen returns to the liquid nitrogen pump station 40 through the third communication port 33 and the second liquid port 42, realizing the circulation of liquid nitrogen. In this way, the liquid nitrogen can be fully utilized, and the loss of excess liquid nitrogen can be avoided.

[0125] It should be noted that the general diameter of anaerobic bacteria is 0.3-1.5 μm, and the target particle diameter after grinding of the cryogenic grinder 30 is 5-10 μm, so that most of the anaerobic bacteria can be completely retained after grinding and can enter the coal seam 200 fractures generated by most of the liquid nitrogen.

[0126] In one example of the present application, the drill hole 210 comprises a plurality of horizontal sections 211 and at least two inclined sections 212, the horizontal sections 211 extend along the horizontal direction S of the coal seam 200 and are arranged at intervals in the depth direction H of the coal seam 200, and the inclined sections 212 sequentially communicate a plurality of horizontal sections 211 arranged along the depth direction H, wherein the lengths of the plurality of horizontal sections 211 increase from deep to shallow in the depth direction H;

[0127] For example, the angle between the inclined section 212 and the horizontal direction S is 30 degrees-45 degrees, and the interval distance of the horizontal section 211 in the depth direction H is 1.5 m-2 m,

[0128] The inclined drill hole 210 structure shown in the schematic view is opened, the extraction hole 220 and the injection port 230 are drilled at the same angle, a trapezoidal structure is formed in the coal seam 200 as shown in the figure, the angle of the inclined section 212 of the drill hole 210 is kept between 30°-45°, which facilitates the adhesion of anaerobic bacteria, and the horizontal section 211 drill hole 210 is drilled in the coal body in the trapezoidal structure, and a drill hole 210 is drilled every 1.5-2 m to ensure that the cracked pores are sufficient for anaerobic bacteria to enter.

[0129] In one example of the present application, the yield-increasing system 100 further comprises a carbon dioxide pump station 80,

[0130] A communication passage is arranged between the third hopper 53 and the injection port 230, and is configured to inject carbon dioxide gas into the injection port 230.

[0131] Firstly, continuously injecting carbon dioxide into the injection port 230 can maintain a low-oxygen or oxygen-free environment in the coal bed 200; secondly, the adjustment method for the amount of methane produced by anaerobic bacteria is optimized. In the gas production process, if it is found that the gas production amount is low, carbon dioxide can be injected into the coal bed 200 to provide raw materials for the reduction reaction of anaerobic bacteria, or beer stock solution or soil leaching solution can be added to the culture medium, with an addition amount of 6 ml / L of beer stock solution and 120 ml / L of soil leaching solution, to increase the amount of methane produced.

[0132] In one example of the present application, the yield-increasing system 100 further comprises an inert gas pump station 90,

[0133] The inert gas (for example, nitrogen) is accommodated inside and has a first gas port 91, a second gas port 92 and a third gas port 93. The first gas port 91 is in communication with the second port 15 and the fourth connecting port 24. The second gas port 92 is in communication with the fourth liquid port 44 of the liquid nitrogen pump station 40. The third gas port 93 is in communication with the second hopper 52, and is configured to inject inert gas (for example, nitrogen) into the filtering device 10, the water-based mixing bin 20 and the low-temperature mixing bin 50 to form a low-oxygen or oxygen-free environment.

[0134] That is, the inert gas pump station 90 forms a low-oxygen or oxygen-free environment in the filtering device 10, the water-based mixing bin 20, the frozen grinder 30 and the low-temperature mixing bin 50 of the yield-increasing system 100.

[0135] Preferably, the inert gas pump station 90 is a nitrogen pump station.

[0136] The liquid nitrogen pump station 40 and the inert gas pump station 90 can be in communication. For example, a thirteenth on-off valve 113 is arranged between the liquid nitrogen pump station 40 and the inert gas pump station 90. When the two need to supplement each other, the thirteenth on-off valve 113 is opened, so that the liquid nitrogen pump station 40 supplements nitrogen into the inert gas pump station 90 through the second gas port 92, and the inert gas pump station 90 supplements liquid nitrogen into the liquid nitrogen pump station 40 through the second gas port 92. When the liquid nitrogen pump station 40 and the inert gas pump station 90 need to work independently, the thirteenth on-off valve 113 is closed.

[0137] It should be noted that the low-oxygen or oxygen-free environment formed in the filtering device 10, the water-based mixing bin 20, the frozen grinder 30 and the low-temperature mixing bin 50 can be formed by injecting inert gas or by pre-treating the above devices by external equipment.

[0138] In one example of the present application, a first on-off valve 101 is arranged between the inert gas pump station 90 and the second port 15, a second on-off valve 102 is arranged between the first port 14 and the extraction port 220, a third on-off valve 103 is arranged between the first connecting port 21 and the third port 16, a fourth on-off valve 104 is arranged between the culture medium container 60 and the second connecting port 22, a fifth on-off valve 105 is arranged between the inert gas pump station and the fourth connecting port 24, a sixth on-off valve 106 is arranged between the third connecting port 23 and the first communicating port 31, a seventh on-off valve 107 is arranged between the first liquid port 41 and the second communicating port 32, an eighth on-off valve 108 is arranged between the third liquid port 43 and the second bin port 52, a ninth on-off valve 109 is arranged between the third gas port 93 and the second bin port 52, a tenth on-off valve 110 is arranged between the first bin port 51 and the fourth communicating port 34, an eleventh on-off valve 111 is arranged between the third bin port 53 and the carbon dioxide container, and a twelfth on-off valve 112 is arranged between the anaerobic bacteria container 70 and the second connecting port 22.

[0139] The working process of the yield increasing system 100 is as follows: open the first on-off valve 101 and the first exhaust hole 17, start the inert gas pump station 90 to inject inert gas (for example, nitrogen) into the filtering device 10 to form a low-oxygen or oxygen-free environment in the filtering device 10, open the second on-off valve 102 to extract the drainage water in the coal seam 200 from the drainage port 220 by the filtering device 10, and obtain the drainage water by filtering out the sample of coal dregs waste and the sample of anaerobic bacteria, wherein, the process includes replacing the filter core of the filtering layer 11 once, adding an anaerobic bacteria filter screen to the filter core of the filtering layer 11 before replacement for obtaining the sample of anaerobic bacteria, closing the second on-off valve 102 after collecting an appropriate amount of sample, and testing the integrity and concentration of anaerobic bacteria DNA; after replacing the filter core of the filtering layer 11 (without anaerobic bacteria filter screen, only for filtering coal dregs), open the second on-off valve 102 until an appropriate amount of drainage water is collected, close the second on-off valve 102, and close the first on-off valve 101 and the first exhaust hole 17; open the fifth on-off valve 105 and the second exhaust hole 25, start the inert gas pump station 90 to continuously inject inert gas (for example, nitrogen) into the water-based mixing bin 20 until a low-oxygen or oxygen-free environment is formed in the water-based mixing bin 20, open the third on-off valve 103 and the fourth on-off valve 104, and inject the drainage water in the filtering device 10 into the water-based mixing bin 20 through the first connecting port 21 from the third port 16 and the culture medium in the culture medium container 60 through the second connecting port 22, and mix them sufficiently to form a nutrient solution, and close the third on-off valve 103 and the fourth on-off valve 104; wherein, when the concentration of anaerobic bacteria in the drainage water is lower than a threshold concentration, open the twelfth on-off valve 112 to inject anaerobic bacteria from the anaerobic bacteria container 70 into the water-based mixing bin 20, close the twelfth on-off valve 112 when the concentration of anaerobic bacteria in the drainage water reaches a suitable concentration, start the first stirring blade 26 to mix the mixture in the water-based mixing bin 20 uniformly, and close the second exhaust hole 25 and the fifth on-off valve 105; open the seventh on-off valve 107 to inject liquid nitrogen from the liquid nitrogen pump station 40 into the cryogenic grinder 30, the liquid nitrogen flows back to the liquid nitrogen pump station 40 through the cryogenic grinder 30 to form a liquid nitrogen conveying loop, start the cryogenic grinder 30 and form a low-oxygen or oxygen-free environment in the cryogenic grinder 30, open the sixth on-off valve 106 to inject the nutrient solution in the water-based mixing bin 20 into the cryogenic grinder 30 through the first communicating port 31 from the third connecting port 23, close the sixth on-off valve 106, and the nutrient solution is solidified into ice in the cryogenic grinder 30 at low temperature, and then is ground into micron-sized fine particles (5-10 microns);The ninth on-off valve 109 and the third exhaust hole 54 are opened, the inert gas pump station 90 is started, and inert gas (for example, nitrogen) is continuously introduced into the low-temperature mixing bin 50 until a low-oxygen or oxygen-free environment is formed. The ninth on-off valve 109 and the third exhaust hole 54 are closed, the tenth on-off valve 110 is opened, the freeze mill 30 injects the fine particles of the nutrient solution into the low-temperature mixing bin 50 through the first bin opening 51 via the fourth communication port 34, the eighth on-off valve 108 is opened, the liquid nitrogen pump station 40 injects liquid nitrogen into the low-temperature mixing bin 50 through the second bin opening 52 via the third liquid port 43, and the liquid nitrogen is mixed with the powder by starting the second stirring blade 55. The eighth on-off valve 108 and the tenth on-off valve 110 are closed, the eleventh on-off valve 111 is opened, and the mixture of liquid nitrogen and nutrient solution powder is injected into the coal seam 200 through the injection port 230 via the third bin opening 53. After the borehole 210 returns to normal temperature, the carbon dioxide pump station 80 is started, and carbon dioxide is intermittently injected into the borehole 210. The extraction hole starts the coal seam 200 gas extraction work. After a period of extraction, the above steps are repeated to supplement the culture medium for anaerobic bacteria in the borehole 210, and liquid nitrogen is cracked to expand the fissures of the coal seam 200 and increase the contact area between the anaerobic bacteria and the coal matrix, thereby maintaining or even improving the gas production efficiency until the coal seam 200 reaches the best cracking effect or the gas production cannot meet the output requirements.

[0140] According to the second aspect of the present application, a method for increasing the production of a coal seam 200 in-situ bacterial community methane production system 100 as described above, as shown in Figure 1 and Figure 2 , comprising the following steps:

[0141] S10: Forming a low-oxygen or oxygen-free environment in the filtering device 10, and extracting the drainage water in the coal seam 200 from the extraction port 220 by the filtering device 10, and obtaining the drainage water by filtering out the sample of coal dregs waste and the sample of anaerobic bacteria;

[0142] S20: Forming a low-oxygen or oxygen-free environment in the water-based mixing bin 20, and injecting the drainage water in the filtering device 10 and the culture medium in the culture medium container 60 into the water-based mixing bin 20, and mixing them sufficiently to form a nutrient solution;

[0143] S30: Forming a low-oxygen or oxygen-free environment in the freeze mill 30, and injecting the nutrient solution in the water-based mixing bin 20 into the freeze mill 30, and freezing the nutrient solution into ice in the freeze mill 30, and then grinding it into micron-level fine particles;

[0144] S40: Forming a low-oxygen or oxygen-free environment in the low-temperature mixing bin 50, injecting the fine particles of the nutrient solution into the low-temperature mixing bin 50 by the cryogenic grinder 30, injecting the liquid nitrogen into the low-temperature mixing bin 50 by the liquid nitrogen pump station 40 and mixing the liquid nitrogen with the nutrient solution powder uniformly, and injecting the mixture of the liquid nitrogen and the nutrient solution powder into the coal seam 200 through the injection inlet 230 by the third bin opening 53.

[0145] S50: Repeating steps S10-S40 to supplement the culture medium for the anaerobic bacteria in the borehole 210, while performing the liquid nitrogen fracturing, expanding the fractures of the coal seam 200, increasing the contact area of the anaerobic bacteria and the coal matrix, thereby maintaining or even improving the gas production efficiency until the coal seam 200 reaches the optimal fracturing effect or the gas production cannot meet the output requirements.

[0146] For example, the inert gas pump station 90 is set in the gas production method, and the inert gas pump station 90 is a nitrogen pump station.

[0147] The specific working process of the yield increasing method is as follows: open the first on-off valve 101 and the first exhaust hole 17, start the inert gas pump station 90 to inject inert gas (for example, nitrogen) into the filtering device 10 to form a low-oxygen or oxygen-free environment in the filtering device 10, open the second on-off valve 102 to extract the drainage water in the coal seam 200 from the drainage port 220 by the filtering device 10, and obtain the drainage water by filtering out the sample of coal dregs waste and the sample of anaerobic bacteria, wherein, the process includes replacing the filter core of the filtering layer 11 once, adding an anaerobic bacteria filter screen to the filter core of the filtering layer 11 before replacement for obtaining the sample of anaerobic bacteria, closing the second on-off valve 102 after collecting an appropriate amount of sample, and testing the integrity and concentration of anaerobic bacteria DNA; after replacing the filter core of the filtering layer 11 (without anaerobic bacteria filter screen, only for filtering coal dregs), open the second on-off valve 102 until an appropriate amount of drainage water is collected, close the second on-off valve 102, and close the first on-off valve 101 and the first exhaust hole 17; open the fifth on-off valve 105 and the second exhaust hole 25, start the inert gas pump station 90 to continuously inject inert gas (for example, nitrogen) into the water-based mixing bin 20 until a low-oxygen or oxygen-free environment is formed in the water-based mixing bin 20, open the third on-off valve 103 and the fourth on-off valve 104, and inject the drainage water in the filtering device 10 into the water-based mixing bin 20 through the first connecting port 21 and the culture medium in the culture medium container 60 through the second connecting port 22 respectively, and mix them sufficiently to form nutrient solution, and close the third on-off valve 103 and the fourth on-off valve 104; wherein, when the concentration of anaerobic bacteria in the drainage water is lower than the threshold concentration, open the twelfth on-off valve 112 to inject anaerobic bacteria from the anaerobic bacteria container 70 into the water-based mixing bin 20, close the twelfth on-off valve 112 when the concentration of anaerobic bacteria in the drainage water reaches a suitable concentration, start the first stirring blade 26 to mix the mixture in the water-based mixing bin 20 uniformly, close the second exhaust hole 25 and the fifth on-off valve 105; open the seventh on-off valve 107 to inject liquid nitrogen from the liquid nitrogen pump station 40 into the cryogenic grinder 30, the liquid nitrogen flows back to the liquid nitrogen pump station 40 through the cryogenic grinder 30 to form a liquid nitrogen conveying loop, start the cryogenic grinder 30 and form a low-oxygen or oxygen-free environment in the cryogenic grinder 30, open the sixth on-off valve 106 to inject the nutrient solution in the water-based mixing bin 20 into the cryogenic grinder 30 through the first communicating port 31, close the sixth on-off valve 106, the nutrient solution is solidified into ice in the cryogenic grinder 30, and then is ground into micron-sized fine particles (5-10 microns);Open the ninth on-off valve 109 and the third exhaust hole 54, start the inert gas pump station 90 and continuously input inert gas (for example, nitrogen) into the low-temperature mixing bin 50 until a low-oxygen or oxygen-free environment is formed, close the ninth on-off valve 109 and the third exhaust hole 54, open the tenth on-off valve 110, and the frozen grinder 30 injects the fine particles of the nutrient solution into the low-temperature mixing bin 50 through the first bin opening 51 from the fourth communication port 34, open the eighth on-off valve 108 to inject liquid nitrogen into the low-temperature mixing bin 50 through the second bin opening 52 from the third liquid port 43 and mix with the nutrient solution powder, start the second stirring blade 55 to uniformly mix the liquid nitrogen and the powder, close the eighth on-off valve 108 and the tenth on-off valve 110, open the eleventh on-off valve 111, and inject the mixture of liquid nitrogen and nutrient solution powder into the coal seam 200 through the injection port 230 from the third bin opening 53; after the borehole 210 returns to normal temperature, start the carbon dioxide pump station 80 to intermittently inject carbon dioxide into the borehole 210, and the extraction hole starts the coal seam 200 gas extraction work, after a period of extraction, repeat the above steps to supplement the culture medium for anaerobic bacteria in the borehole 210, and at the same time, liquid nitrogen is used for fracturing to expand the fractures of the coal seam 200 and increase the contact area between the anaerobic bacteria and the coal matrix, so as to maintain or even improve the gas production efficiency until the coal seam 200 reaches the best fracturing effect or the gas production cannot meet the output requirements.

[0148] The production increasing method combines liquid nitrogen fracturing and microbial gas production together, uses liquid nitrogen to expel oxygen to create a favorable living environment for microorganisms, and at the same time, increases the contact area between the microorganisms and the coal body by fracturing and increasing the permeability of the coal seam 200, thereby improving the gas production efficiency and realizing the systematic process of fracturing and gas production.

[0149] The production increasing method comprehensively considers the production needs of microorganisms in the coal seam 200, and formulates schemes such as adjusting the culture medium ratio and adjusting the carbon dioxide input interval according to the gas production, to ensure that the anaerobic bacteria are in an active state.

[0150] The production increasing method is green and environmentally friendly, saves and protects a large amount of water resources, and at the same time, the raw materials such as liquid nitrogen and anaerobic bacteria are simple to produce, the production cost is small during the production period, and the gas production efficiency is high.

[0151] In one example of the present application, the production increasing system 100 further comprises an anaerobic bacteria container 70 connected to the second connection port 22.

[0152] In the step S20, when the concentration of anaerobic bacteria in the drainage water is lower than the threshold concentration, the anaerobic bacteria are injected into the water-based mixing bin 20.

[0153] By setting the anaerobic bacteria container 70, the anaerobic bacteria can be injected into the water-based mixing bin 20 in real time to supplement the concentration of the collected drainage water, increase the contact area between the microorganisms and the coal body, thereby improving the gas production efficiency and realizing the systematic process of fracturing and gas production.

[0154] The exemplary embodiment of the coal seam in-situ bacterial population methane production system 100 and method proposed by the present application is described in detail above with reference to the preferred embodiments, however, those skilled in the art can understand that various modifications and improvements can be made to the above specific embodiments without departing from the concept of the present application, and various technical features and structures proposed by the present application can be combined without exceeding the protection scope of the present application, and the protection scope of the present application is determined by the appended claims.

Claims

1. A coal seam in-situ microbial community methane enhancement system, applied in a coal seam (200), characterized in that, A borehole (210) is formed in the coal seam (200), and the borehole (210) has an extraction port (220) and an injection port (230) that are interconnected. The production enhancement system (100) includes: The filter device (10) has a filter layer (11) in its inner cavity, which divides the inner cavity into an upper chamber (12) and a lower chamber (13). The filter device (10) is configured to obtain the drainage water by filtering out samples of coal slag waste and anaerobic bacteria. It has a first port (14), a second port (15), a third port (16) and a first exhaust port (17). The first port (14) is connected to the extraction port (220). The water-based mixing chamber (20) has a first connection port (21), a second connection port (22), a third connection port (23), a fourth connection port (24) and a second vent (25). The first connection port (21) is connected to the third port (16), and the second connection port (22) is connected to the culture medium container (60). The cryogenic grinder (30) has a first connecting port (31), a second connecting port (32) and a fourth connecting port (34), wherein the first connecting port (31) is connected to the third connecting port (23), and is configured to freeze and grind the injected liquid into fine particles; The liquid nitrogen pump station (40) contains liquid nitrogen and has a first liquid port (41) and a third liquid port (43). The first liquid port (41) is connected to a second connecting port (32) and is configured to pump out liquid nitrogen through at least the first liquid port (41) and the third liquid port (43). The liquid nitrogen pump station (40) also includes the second liquid port (42), and the cryogenic grinder (30) also includes the third connecting port (33) connected to the second liquid port (42). The liquid nitrogen enters the cryogenic grinder (30) through the second connecting port (32) and flows back to the liquid nitrogen pump station (40) through the third connecting port (33). The low-temperature mixing chamber (50) has a first chamber opening (51), a second chamber opening (52), a third chamber opening (53) and a third vent (54). The first chamber opening (51) is connected to the fourth connecting port (34), the second chamber opening (52) is connected to the third liquid port (43), and the third chamber opening (53) is connected to the injection port (230). The anaerobic bacteria container (70) is connected to the second connection port (22) and is configured to inject anaerobic bacteria into the water-based mixing chamber (20) when the concentration of anaerobic bacteria in the discharged water is lower than the threshold concentration. A carbon dioxide pump station (80) is connected between the third compartment (53) and the injection port (230) and is configured to inject carbon dioxide gas into the injection port (230); An inert gas pump station (90) has a first gas port (91), a second gas port (92) and a third gas port (93). The first gas port (91) is connected to the second port (15) and the fourth connection port (24). The second gas port (92) is connected to the fourth liquid port (44) of the liquid nitrogen pump station (40). The third gas port (93) is connected to the second chamber port (52). It is configured to inject inert gas into the filter device (10), the water-based mixing chamber (20) and the cryogenic mixing chamber (50) to form a low-oxygen or oxygen-free environment.

2. The coal seam in-situ microbial community methane enhancement system according to claim 1, characterized in that, The filter layer (11) includes at least two layers, wherein at least one layer is located on the upper side and is configured to filter coal slag particles, and at least another layer is located on the lower side and is configured to extract anaerobic bacteria samples.

3. The coal seam in-situ microbial community methane enhancement system according to claim 2, characterized in that, The filter layer (11) also includes at least two valves, wherein at least one valve is located at the upper end of the filter layer (11) and is configured to control the drainage water in the upper chamber (12), and at least another valve is located at the lower end of at least two filter layers (11) and is configured to control the drainage water in the upper chamber (12) and the filter layer (11).

4. The coal seam in-situ microbial community methane enhancement system according to claim 1, characterized in that, The borehole (210) includes multiple horizontal segments (211) and at least two inclined segments (212). The horizontal segments (211) extend along the horizontal direction (S) of the coal seam (200) and are spaced apart along the depth direction (H) of the coal seam (200). The inclined segments (212) sequentially connect the multiple horizontal segments (211) arranged along the depth direction (H). The length of the multiple horizontal segments (211) increases sequentially from deep to shallow in the depth direction (H).

5. The coal seam in-situ microbial community methane enhancement system according to claim 4, characterized in that, The angle between the inclined segment (212) and the horizontal direction (S) is 30-45 degrees, and the interval between the horizontal segments (211) in the depth direction (H) is 1.5-2m.

6. A method for increasing methane production using a coal seam in-situ microbial community methane enhancement system as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S10: The drainage water in the coal seam (200) is extracted from the extraction port (220) by the filtration device (10), and the drainage water is obtained by filtering out the coal slag waste sample and the anaerobic bacteria sample; S20: Inject the drained water from the filter device (10) and the culture medium from the culture medium container (60) into the water-based mixing chamber (20) and mix them thoroughly to form a nutrient solution; S30: The nutrient solution in the water-based mixing chamber (20) is injected into the cryogenic grinder (30). The nutrient solution is frozen into ice at low temperature in the cryogenic grinder (30) and then ground into micron-sized fine particles. S40: Nutrient solution fine particles are injected into the low-temperature mixing chamber (50) by the cryogenic grinder (30), liquid nitrogen is injected into the low-temperature mixing chamber (50) by the liquid nitrogen pump station (40) and mixed evenly with nutrient solution powder, and the mixture of liquid nitrogen and nutrient solution powder is injected into the coal seam (200) through the injection port (230) via the third chamber opening (53); S50: Repeat steps S10 to S40 to supplement the culture medium for anaerobic bacteria in the borehole (210), and at the same time perform liquid nitrogen fracturing to expand the cracks in the coal seam (200) and increase the contact area between anaerobic bacteria and coal matrix, thereby maintaining or even improving gas production efficiency until the coal seam (200) reaches the best fracturing effect or the gas production cannot meet the production requirements.

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