Nutrient solution for promoting in-situ biogasification of coal rock as well as preparation method and application of nutrient solution

Abstract

The invention provides a nutrient solution for promoting coal rock in-situ biogasification as well as a preparation method and application of the nutrient solution. The nutrient solution comprises an inorganic salt culture medium and a synergistic culture medium; the dosage ratio of the inorganic salt culture medium to the synergistic culture medium is 1L: (2.4-4.3) g. The inorganic salt culture medium comprises an electron acceptor, a nitrogen source, a phosphorus source, a stabilizer, an enzyme cofactor, a buffering agent and trace metal mother liquor. The synergistic culture medium comprises peptone and a yeast extract. The nutrient solution can stimulate growth of microorganisms, promote continuous gas production of a coal seam and improve the gas production rate and the gas production rate; the nutrient solution does not need to consider coal seam temperature change, is low in cost and has the advantages of being green and environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of coal gas layer production enhancement, and specifically relates to a nutrient solution for promoting in-situ biogasification of coal rocks, and a preparation method and application thereof. Background Art

[0002] At present, the promotion of coal biogasification into coal-bed methane, also known as gas, is mainly composed of methane, which is a clean energy. Compared with burning coal, burning coal-bed methane releases only half of the CO2, and CO and NO x The emission of coalbed methane can be reduced by 80%. Under natural conditions, microbial anaerobic fermentation is an important cause of coalbed methane generation. This process requires the synergistic action of multiple coalbed microorganisms to gradually degrade coal composed of many very complex heterocyclic macromolecules and finally generate coalbed methane. However, due to various conditions, the process of microbial decomposition of coal to generate coalbed methane is slow, and the efficient utilization of coalbed methane is subject to certain constraints. At present, efficient in-situ biogasification of coalbed methane is an important way to achieve the "dual carbon" goals of the coal-based industry and the clean utilization of coal. Revealing the key factors that restrict the efficient biogas production of coal rocks has become a technical difficulty that needs to be overcome urgently.

[0003] At present, the method of adding exogenous microorganisms and nutrient solution to stimulate native microorganisms is often used. CN 107058451A discloses a method of using microbial composite agents to degrade and transform low-rank coal to increase coalbed methane production. In this method, aerobic composite agents and anaerobic composite agents are injected into low-rank coal seams in stages to alternately achieve aerobic and anaerobic environments. However, the underground coal seam environment is relatively harsh, in which N, P and certain trace essential elements necessary for microbial growth may be insufficient. Simply adding exogenous microorganisms often has the defect that the gas production and gas production rate are still low.

[0004] CN 111155975A discloses a method for increasing the production of biogas by fed-batch fermentation. The patent collects the ectopic enrichment culture of the coalbed methane-producing microbial flora in the coal seam, and adds nutrients in the middle or late stage of the biogas production to increase the coalbed methane production. However, the patent does not consider the environmental conditions in the underground coal seam in detail, so there is a problem that it may not be compatible with the coal seam environment, which may cause the waste of nutrients and groundwater pollution.

[0005] CN 103060245A discloses a composite microbial agent for producing biogas from coal seam organic impurities and its application. The composite microbial agent provided by the patent has a strong digestion ability for various types of cellulose, humus and various carbon-containing macromolecules in coal seams, but the efficiency of promoting rapid gas production is slow. The value-added time of this composite microbial agent is 30 to 45 days.

[0006] CN 113667594A discloses a new type of constant temperature culture pool for coalbed methane bioengineering in low-temperature and high-cold areas. This patent forms a constant temperature culture system by building a greenhouse, a base, a solar panel group, a wind turbine generator set and an electric energy storage box, etc., which solves the problem that the nutrient solution temperature of coalbed methane bioengineering in low-temperature and high-cold areas is difficult to meet the bacterial activity. However, the equipment construction is relatively complex, and the temperature of the underground coal seam changes little in winter and summer.

[0007] Although the above patents provide a variety of methods for increasing coalbed methane production, the above methods are not fully applicable to the environment in underground coal seams and may even cause further groundwater pollution, and the increase in biogas production has not been significantly improved. Summary of the invention

[0008] In view of the shortcomings of the prior art, the present invention aims to provide a nutrient solution for promoting in-situ biogasification of coal rocks and a preparation method and application thereof. The nutrient solution can stimulate the growth of microorganisms, promote continuous gas production in coal seams, and increase the gas production rate and gas production; and the nutrient solution does not need to consider the temperature change of the coal seams, and has a low cost. It is a nutrient solution that can improve the in-situ gas production of coal seams in an environmentally friendly way.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a nutrient solution for promoting in-situ biogasification of coal rock, the nutrient solution comprising an inorganic salt culture medium and a synergistic culture medium;

[0011] The dosage ratio of the inorganic salt culture medium and the enhanced culture medium is 1L:(2.4-4.3)g, for example, it can be 1L:2.4g, 1L:2.8g, 1L:3.2g, 1L:3.6g, 1L:4g or 1L:4.3g, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0012] The inorganic salt culture medium of the present invention can provide basic nutrients for the growth of microorganisms, and the enhanced culture medium is used to provide organic nitrogen sources and biologically active substances for the growth of microorganisms; wherein too high a content of the enhanced culture medium will lead to an increase in the osmotic pressure of the nutrient solution, which is not conducive to the growth of microorganisms; too low a content will affect the effect of the nutrient solution in promoting coal rock biogasification.

[0013] As a preferred technical solution of the present invention, the inorganic salt culture medium comprises an electron acceptor, a nitrogen source, a phosphorus source, a stabilizer, an enzyme cofactor, a buffer and a trace metal mother solution.

[0014] Preferably, the inorganic salt culture medium comprises, in terms of concentration: 0.2-0.3 g / L of an electron acceptor, 0.2-0.3 g / L of a nitrogen source, 0.8-1.5 g / L of a phosphorus source, 0.3-0.4 g / L of a stabilizer, 0.2-0.35 g / L of an enzyme cofactor, 0.8-1.6 g / L of a buffer and 8-15 mL / L of a trace metal mother solution.

[0015] Exemplarily, the concentration of the electron acceptor in the inorganic salt culture medium of the present invention is 0.2-0.3 g / L, for example, it can be 0.2 g / L, 0.22 g / L, 0.24 g / L, 0.26 g / L, 0.28 g / L or 0.3 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] The concentration of the nitrogen source is 0.2-0.3 g / L, for example, 0.2 g / L, 0.22 g / L, 0.24 g / L, 0.26 g / L, 0.28 g / L or 0.3 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] The concentration of the phosphorus source is 0.8-1.5 g / L, for example, 0.8 g / L, 1.0 g / L, 1.2 g / L, 1.4 g / L or 1.5 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] The concentration of the stabilizer is 0.3-0.4 g / L, for example, 0.3 g / L, 0.32 g / L, 0.34 g / L, 0.36 g / L, 0.38 g / L or 0.4 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] The concentration of the enzyme cofactor is 0.2-0.35 g / L, for example, it can be 0.2 g / L, 0.23 g / L, 0.26 g / L, 0.29 g / L, 0.32 g / L or 0.35 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] The concentration of the buffer is 0.8-1.6 g / L, for example, 0.8 g / L, 1.0 g / L, 1.2 g / L, 1.4 g / L or 1.6 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] The concentration of the trace metal mother solution is 8-15 mL / L, for example, 8 mL / L, 10 mL / L, 12 mL / L or 15 mL / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the electron acceptor comprises potassium nitrate and / or sodium nitrate.

[0023] It is worth noting that the calculation method of the amount of acceptor electrons in the present invention is as follows:

[0024] A portion (a%) of the bioavailable carbon (CA) in coal powder needs to be activated and utilized by hydrolytic bacteria / anaerobic degrading bacteria (C:H≈1:4) and converted into carbon dioxide; the other portion (b%) is easily fermented and acidified to produce methane in combination with methanogens, a%+b%=100%.

[0025] Among them, bioavailable carbon (CA) = coal powder mass × carbon content × C bioavailable percentage.

[0026] Then, the acceptor electron usage is calculated using the principle.

[0027] Preferably, the nitrogen source comprises any one of ammonium chloride, ammonium nitrate or ammonium sulfide or a combination of at least two thereof. Typical but non-limiting combinations include a combination of ammonium chloride and ammonium nitrate, a combination of ammonium chloride and ammonium sulfide, a combination of ammonium nitrate and ammonium sulfide, or a combination of ammonium chloride, ammonium nitrate and ammonium sulfide.

[0028] Preferably, the phosphorus source comprises dipotassium hydrogen phosphate and / or disodium hydrogen phosphate.

[0029] It is worth noting that the calculation method of the nitrogen source and phosphorus source in the nutrient solution of the present invention is as follows:

[0030] According to the energy material ratio required for microbial growth (BOD5:N:P is 100:5:1), 1g coal (0.1gCA) requires 0.001mol / 20=5E10 -5 mol N (calculated as NH4Cl, 0.0027 g / g coal), and 0.001 mol / 100 = 1E10 -5 mol P (if calculated as K2HPO4, 0.0023 g / gram of coal).

[0031] Preferably, the stabilizer comprises potassium chloride.

[0032] As a preferred technical solution of the present invention, the enzyme cofactors include MgCl2·2H2O and CaCl2·2H2O.

[0033] Preferably, the mass ratio of MgCl2·2H2O to CaCl2·2H2O is (0.8-1.2):1, for example, it can be 0.8:1, 0.9:1, 1:1, 1.1:1 or 1.2:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable; more preferably, it is 1:1.

[0034] The enzyme cofactors of the present invention mainly include the synergistic effect of MgCl2·2H2O and CaCl2·2H2O, and the lack of any one of them will affect the enzymatic reaction activity of the microorganism.

[0035] Preferably, the buffer comprises sodium bicarbonate.

[0036] As a preferred technical solution of the present invention, the trace metal mother liquor comprises, in terms of concentration, the following: MnCl2·4H2O 800-1500 mg / L, ZnCl2 500-1000 mg / L, H3BO3 200-500 mg / L, CuCl2 50-120 mg / L, NiCl2·6H2O 50-120 mg / L, Na2MoO4.2H2O 150-250 mg / L, CoCl2·6H2O 200-300 mg / L and Fe(III) citrate 800-1500 mg / L.

[0037] In the trace metal mother liquor of the present invention, MnCl2·4H2O, ZnCl2, H3BO3 and CoCl2·6H2O play a major role.

[0038] Exemplarily, the content of MnCl2·4H2O in the trace metal mother liquor of the present invention is 800-1500 mg / L, for example, 800 mg / L, 1100 mg / L or 1400 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] The content of ZnCl2 is 500-1000 mg / L, for example, 500 mg / L, 700 mg / L, 900 mg / L or 1000 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] The content of H3BO3 is 200-500 mg / L, for example, 200 mg / L, 300 mg / L, 400 mg / L or 500 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0041] The content of CuCl2 is 50-120 mg / L, for example, 50 mg / L, 70 mg / L, 90 mg / L or 110 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] The content of NiCl2·6H2O is 50-120 mg / L, for example, 50 mg / L, 70 mg / L, 90 mg / L or 110 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] The content of Na2MoO4.2H2O is 150-250 mg / L, for example, it can be 150 mg / L, 170 mg / L, 190 mg / L, 210 mg / L, 230 mg / L or 250 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] The content of CoCl2·6H2O is 200-300 mg / L, for example, 200 mg / L, 220 mg / L, 240 mg / L, 260 mg / L, 280 mg / L or 300 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0045] The content of Fe(III) citrate is 800-1500 mg / L, for example, 800 mg / L, 1100 mg / L or 1400 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0046] The role of the trace metal mother solution in the nutrient solution is as follows: the metal ions in the trace metal mother solution are important cofactors of microbial enzymes and can play an important role in improving the activity of microbial enzymes.

[0047] As a preferred technical solution of the present invention, the enhanced culture medium includes peptone and yeast extract.

[0048] Preferably, the mass ratio of peptone to yeast extract is 1:(0.8-1.2), for example, 1:0.8, 1:0.9, 1:1, 1:1.1 or 1:1.2, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0049] Preferably, the yeast extract comprises yeast extract powder and / or yeast extract.

[0050] In a second aspect, the present invention provides a method for preparing a nutrient solution for promoting in-situ biogasification of coal rock as provided in the first aspect, the preparation method comprising the following steps:

[0051] (1) mixing an electron acceptor, a nitrogen source, a phosphorus source, a stabilizer, an enzyme cofactor, a buffer, and a trace metal mother solution according to a formula to obtain an inorganic salt culture medium;

[0052] (2) mixing peptone and yeast extract according to the formula amount to obtain an enhanced culture medium;

[0053] (3) mixing the inorganic salt culture medium obtained in step (1) and the enhanced culture medium obtained in step (2) according to the formula amount to obtain the nutrient solution;

[0054] There is no distinction between the order of steps (1) and (2).

[0055] As a preferred technical solution of the present invention, the mixing speed in step (1) is 50-100 r / min, for example, it can be 50 r / min, 60 r / min, 70 r / min, 80 r / min, 90 r / min or 100 r / min, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable; the time is 20-40 s, for example, it can be 20 s, 25 s, 30 s, 35 s or 40 s, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0056] Preferably, the mixing speed in step (2) is 30 to 60 r / min, for example, it can be 30 r / min, 35 r / min, 40 r / min, 50 r / min, 55 r / min or 60 r / min, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable; the time is 30 to 50 s, for example, it can be 30 s, 35 s, 40 s, 45 s or 50 s, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0057] Preferably, the mixing speed in step (3) is 50 to 80 r / min, for example, it can be 50 r / min, 55 r / min, 60 r / min, 65 r / min, 70 r / min, 75 r / min or 80 r / min, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable; the time is 30 to 60 s, for example, it can be 30 s, 40 s, 50 s or 60 s, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0058] In a third aspect, the present invention provides an application of the nutrient solution for promoting in-situ biogasification of coal rock as provided in the first aspect, the application comprising the following steps:

[0059] Under anaerobic conditions, pulverized coal, exogenous bacterial agents and nutrient solution were mixed and then cultured anaerobically, and the gas production of pulverized coal was determined by gas chromatography.

[0060] As a preferred technical solution of the present invention, the dosage ratio of the coal powder, exogenous bacterial agent and nutrient solution is 1g: (1-2)mL: (45-55)mL, for example, it can be 1g: 1mL: 50mL, 1g: 1.2mL: 50mL, 1g: 2mL: 50mL, 1g: 1mL: 48mL, 1g: 1mL: 52mL or 1g: 1.8mL: 52mL, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0061] Preferably, the exogenous bacterial agent includes activated sludge.

[0062] Preferably, the temperature of the anaerobic culture is 25-35°C, for example, it can be 25°C, 26°C, 27°C, 28°C, 30°C, 32°C or 35°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0063] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] (1) The nutrient solution for promoting in-situ biogasification of coal rock provided by the present invention accurately adds the amount of N, P, etc. according to the quality of coal rock and the growth nutrient requirements of microorganisms, and has the advantages of being economical, environmentally friendly, and highly efficient;

[0066] (2) The nutrient solution for promoting in-situ biogasification of coal rock provided by the present invention can stimulate the growth of microorganisms, promote continuous gas production in coal seams, and increase the gas production rate and gas production;

[0067] (3) The nutrient solution provided by the present invention for promoting in-situ biogasification of coal rocks does not need to consider the temperature changes of the coal seam, has low cost, and has the advantage of being green and environmentally friendly. DETAILED DESCRIPTION

[0068] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0069] Example 1

[0070] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal rock, the nutrient solution comprising: a nutrient solution including an inorganic salt culture medium and a synergistic culture medium at a dosage ratio of 1L:2.4g;

[0071] The inorganic salt culture medium comprises, in terms of concentration, 0.28 g / L potassium nitrate, 0.28 g / L ammonium chloride, 1 g / L dipotassium hydrogen phosphate, 0.335 g / L potassium chloride, 0.1 g / L MgCl2·2H2O, 0.14 g / L CaCl2·2H2O, 1.0 g / L sodium bicarbonate and 10 mL / L trace metal mother liquor;

[0072] The trace metal mother solution includes, by concentration, 1000 mg / L of MnCl2·4H2O, 700 mg / L of ZnCl2, 300 mg / L of H3BO3, 100 mg / L of CuCl2, 100 mg / L of NiCl2·6H2O, 200 mg / L of Na2MoO4.2H2O, 250 mg / L of CoCl2·6H2O and 1000 mg / L of Fe(III) citrate.

[0073] The enhanced culture medium comprises peptone and yeast extract in a mass ratio of 1:1; the yeast extract powder is described.

[0074] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock comprises the following steps:

[0075] (1) mixing an electron acceptor, a nitrogen source, a phosphorus source, a stabilizer, an enzyme cofactor, a buffer, and a trace metal mother solution according to a formula to obtain an inorganic salt culture medium; the mixing speed is 60 r / min, and the mixing time is 30 s;

[0076] (2) mixing peptone and yeast extract according to the formula to obtain an enhanced culture medium; the mixing speed is 45 r / min and the time is 40 s;

[0077] (3) mixing the inorganic salt culture medium obtained in step (1) and the enhanced culture medium obtained in step (2) according to the formula amount to obtain the nutrient solution; the mixing speed is 65 r / min and the mixing time is 45 s;

[0078] There is no distinction between the order of steps (1) and (2).

[0079] Example 2

[0080] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal rock, the nutrient solution comprising: a nutrient solution including an inorganic salt culture medium and a synergistic culture medium in a dosage ratio of 1L:4.3g;

[0081] The inorganic salt culture medium comprises, in terms of concentration, 0.2 g / L of sodium nitrate, 0.2 g / L of ammonium nitrate, 0.8 g / L of disodium hydrogen phosphate, 0.3 g / L of potassium chloride, 0.1 g / L of MgCl2·2H2O, 0.1 g / L of CaCl2·2H2O, 0.8 g / L of sodium bicarbonate and 8 mL / L of trace metal mother liquor;

[0082] The trace metal mother solution includes, by concentration, 800 mg / L of MnCl2·4H2O, 500 mg / L of ZnCl2, 20 mg / L of H3BO3, 50 mg / L of CuCl2, 50 mg / L of NiCl2·6H2O, 150 mg / L of Na2MoO4.2H2O, 200 mg / L of CoCl2·6H2O and 800 mg / L of Fe(III) citrate.

[0083] The enhanced culture medium comprises peptone and yeast extract in a mass ratio of 1:0.8; the yeast extract is described.

[0084] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0085] Example 3

[0086] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal rock, the nutrient solution comprising: a nutrient solution including an inorganic salt culture medium and a synergistic culture medium in a dosage ratio of 1L:3.2g;

[0087] The inorganic salt culture medium comprises, in terms of concentration, 0.3 g / L potassium nitrate, 0.3 g / L ammonium chloride, 1.5 g / L dipotassium hydrogen phosphate, 0.4 g / L potassium chloride, 0.15 g / L MgCl2·2H2O, 0.2 g / L CaCl2·2H2O, 1.6 g / L buffer and 15 mL / L trace metal mother solution;

[0088] The trace metal mother solution includes, by concentration, 1500 mg / L of MnCl2·4H2O, 1000 mg / L of ZnCl2, 500 mg / L of H3BO3, 120 mg / L of CuCl2, 120 mg / L of NiCl2·6H2O, 250 mg / L of Na2MoO4.2H2O, 300 mg / L of CoCl2·6H2O and 1500 mg / L of Fe(III) citrate.

[0089] The enhanced culture medium comprises peptone and yeast extract in a mass ratio of 1:1.2; the enhanced culture medium comprises yeast extract powder and yeast extract in a mass ratio of 1:1.2.

[0090] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0091] Example 4

[0092] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0093] This example omits the trace metal mother solution in the inorganic salt culture medium.

[0094] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0095] Example 5

[0096] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0097] In this example, the content of the electron acceptor is modified to 0.15 g / L.

[0098] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0099] Example 6

[0100] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0101] In this example, the content of the electron acceptor is modified to 0.35 g / L.

[0102] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0103] Example 7

[0104] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0105] In this embodiment, the content of the nitrogen source is modified to 0.15 g / L, and the content of the phosphorus source is modified to 0.5 g / L.

[0106] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0107] Example 8

[0108] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0109] In this example, the content of nitrogen source is modified to 0.35 g / L, and the content of phosphorus source is modified to 2 g / L. 。

[0110] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0111] Example 9

[0112] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0113] In this embodiment, the stabilizer in the inorganic salt culture medium is omitted.

[0114] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0115] Example 10

[0116] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0117] In this example, the enzyme cofactor in the inorganic salt culture medium was modified to 0.24 g / L MgCl2·2H2O.

[0118] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0119] Embodiment 11

[0120] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0121] In this example, the enzyme cofactor in the inorganic salt culture medium was modified to 0.24 g / L CaCl2·2H2O.

[0122] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0123] Example 12

[0124] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0125] In this embodiment, peptone in the enhancement medium is omitted, that is, the enhancement medium is yeast extract powder.

[0126] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0127] Embodiment 13

[0128] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0129] In this embodiment, yeast extract powder in the enhancement medium is omitted, that is, the enhancement medium is peptone.

[0130] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0131] Comparative Example 1

[0132] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0133] The enhanced culture medium was omitted in this comparative example.

[0134] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0135] Comparative Example 2

[0136] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0137] In this comparative example, the usage ratio of the inorganic salt culture medium and the enhanced culture medium was modified to 1L:2g.

[0138] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0139] Comparative Example 3

[0140] This embodiment provides a nutrient solution for promoting in-situ biogasification of coal and rock. The nutrient solution is different from that of embodiment 1 only in that:

[0141] In this comparative example, the usage ratio of the inorganic salt culture medium and the enhanced culture medium was modified to 1L:5g.

[0142] The method for preparing the nutrient solution for promoting in-situ biogasification of coal rock is the same as that in Example 1.

[0143] Application Examples

[0144] The nutrient solution provided in the above examples and comparative examples is applied to promote in-situ biogasification of coal rock, and the specific steps of the application are as follows:

[0145] Under anaerobic conditions, pulverized coal, exogenous bacterial agent (activated sludge) and the nutrient solution provided in the above embodiments and comparative examples are mixed, and then anaerobic culture is carried out, and the gas production of the pulverized coal is measured by gas chromatography.

[0146] Among them, the dosage ratio of coal powder, coal seam produced water, exogenous bacterial agent (activated sludge) and nutrient solution is 1g:5mL:45mL.

[0147] Gas production was measured using gas chromatography on the 7th, 14th, 21st, 30th, 40th, 50th, 60th, 70th, 90th and 120th day of culture until the end of fermentation. The maximum gas production and gas production rate are shown in Table 1.

[0148] According to the above detection cycle, 0.1 mL of gas was extracted from the headspace of the anaerobic bottle using a microinjection needle and injected into the gas chromatograph for detection under the detection mode of a flame ionization detector. High-purity nitrogen was used as the carrier gas. The chromatographic conditions for the detection were a column chamber temperature of 40°C, a vaporization temperature of 220°C, and a detector temperature of 160°C.

[0149] Table 1

[0150]

[0151]

[0152] By analyzing Table 1, we can know the following points

[0153] (1) Comprehensive analysis of Examples 1-3 shows that the nutrient solution formula provided by the present invention can effectively promote coal biogasification within the appropriate concentration range, with the maximum gas production reaching 6 cubic meters per ton of coal;

[0154] (2) Comprehensive analysis of Example 1 and Example 4 shows that trace amounts of metal mother liquor will affect the maximum gas production and gas production efficiency;

[0155] (3) Comprehensive analysis of Example 1 and Examples 5-6 shows that the amount of electron acceptor content affects the maximum gas production and gas production efficiency;

[0156] (4) Comprehensive analysis of Example 1 and Examples 7-8 shows that the content of phosphorus source and nitrogen source will affect the maximum gas production and gas production efficiency;

[0157] (5) Comprehensive analysis of Example 1 and Examples 10-11 shows that the enzyme cofactor requires the synergistic effect of MgCl2·2H2O and CaCl2·2H2O, otherwise it will affect the maximum gas production and gas production efficiency;

[0158] (6) Comprehensive analysis of Example 1 and Examples 12-13 shows that the enhanced culture medium requires the synergistic effect of peptone and yeast extract, otherwise it will affect the maximum gas production and gas production efficiency;

[0159] (7) Comprehensive analysis of Example 1 and Comparative Examples 1-3 shows that the presence of the enhanced culture medium can further improve the biogasification potential of coal, and its content in the range of 1:2.4-1:4.3 has no significant effect on gas production.

[0160] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A nutrient solution for promoting in-situ biogasification of coal rock, characterized in that: The nutrient solution includes an inorganic salt culture medium and an enhanced culture medium; The usage ratio of the inorganic salt culture medium and the enhanced culture medium is 1L:(2.4-4.3)g.

2. The nutrient solution for promoting in-situ biogasification of coal rock according to claim 1, characterized in that: The inorganic salt culture medium comprises an electron acceptor, a nitrogen source, a phosphorus source, a stabilizer, an enzyme cofactor, a buffer and a trace metal mother solution; Preferably, the inorganic salt culture medium comprises, in terms of concentration: 0.2-0.3 g / L of an electron acceptor, 0.2-0.3 g / L of a nitrogen source, 0.8-1.5 g / L of a phosphorus source, 0.3-0.4 g / L of a stabilizer, 0.2-0.35 g / L of an enzyme cofactor, 0.8-1.6 g / L of a buffer and 8-15 mL / L of a trace metal mother solution.

3. The nutrient solution for promoting in-situ biogasification of coal rock according to claim 2, characterized in that: The electron acceptor comprises potassium nitrate and / or sodium nitrate; Preferably, the nitrogen source includes any one of ammonium chloride, ammonium nitrate or ammonium sulfide, or a combination of at least two thereof; Preferably, the phosphorus source comprises dipotassium hydrogen phosphate and / or disodium hydrogen phosphate; Preferably, the stabilizer comprises potassium chloride.

4. The nutrient solution for promoting in-situ biogasification of coal rock according to claim 2, characterized in that: The enzyme cofactors include MgCl2·2H2O and CaCl2·2H2O; Preferably, the mass ratio of MgCl2·2H2O to CaCl2·2H2O is (0.8-1.2):1; Preferably, the buffer comprises sodium bicarbonate.

5. The nutrient solution for promoting in-situ biogasification of coal rock according to claim 2, characterized in that: The trace metal mother solution includes, by concentration, 800-1500 mg / L of MnCl2·4H2O, 500-1000 mg / L of ZnCl2, 200-500 mg / L of H3BO3, 50-120 mg / L of CuCl2, 50-120 mg / L of NiCl2·6H2O, 150-250 mg / L of Na2MoO4.2H2O, 200-300 mg / L of CoCl2·6H2O and 800-1500 mg / L of Fe(III) citrate.

6. The nutrient solution for promoting in-situ biogasification of coal rock according to any one of claims 1 to 5, characterized in that: The enhanced culture medium comprises peptone and yeast extract; Preferably, the mass ratio of peptone to yeast extract is 1:(0.8-1.2); Preferably, the yeast extract comprises yeast extract powder and / or yeast extract.

7. A method for preparing a nutrient solution for promoting in-situ biogasification of coal rock according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) mixing an electron acceptor, a nitrogen source, a phosphorus source, a stabilizer, an enzyme cofactor, a buffer, and a trace metal mother solution according to a formula to obtain an inorganic salt culture medium; (2) mixing peptone and yeast extract according to the formula amount to obtain an enhanced culture medium; (3) mixing the inorganic salt culture medium obtained in step (1) and the enhanced culture medium obtained in step (2) according to the formula amount to obtain the nutrient solution; There is no distinction between the order of steps (1) and (2).

8. The preparation method according to claim 7, characterized in that: The mixing speed in step (1) is 50 to 100 r / min and the mixing time is 20 to 40 s; Preferably, the mixing speed in step (2) is 30 to 60 r / min, and the mixing time is 30 to 50 s; Preferably, the mixing speed in step (3) is 50 to 80 r / min and the mixing time is 30 to 60 s.

9. An application of the nutrient solution for promoting in-situ biogasification of coal rock as claimed in any one of claims 1 to 6, characterized in that: The application comprises the following steps: Under anaerobic conditions, pulverized coal, exogenous bacterial agents and nutrient solution were mixed and then cultured anaerobically, and the gas production of pulverized coal was determined by gas chromatography.

10. The use according to claim 9, characterized in that: The usage ratio of the coal powder, exogenous bacterial agent and nutrient solution is 1g: (1-2)mL: (45-55)mL; Preferably, the exogenous bacterial agent includes activated sludge; Preferably, the temperature of the anaerobic culture is 25-35°C.

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