A calculation method for the carbon sequestration amount in a goaf filled with high-water solidified carbon dioxide

Abstract

The invention discloses a calculation method for the carbon sequestration amount in the gob area filled with high-water solidified carbon dioxide, belonging to the field of carbon dioxide sequestration assessment. The mining range is determined according to materials such as the coal mine excavation engineering plan, and the gob volume that can be filled in the coal mine is obtained; according to the density information of the filling material, the total mass of the filling material in the gob area is calculated; it is known that the filling material is composed of aggregate and supercritical carbon dioxide mixed in proportion: the molecular weight of the aggregate is obtained by using the molecular formula of the aggregate and water forming the filling material, and the molar amount of carbon dioxide that can be solidified by the aggregate is inferred according to the chemical equation of the solidification reaction of the aggregate and carbon dioxide; finally, the mass of the aggregate used in all the filling materials in the gob area and the mass of the supercritical carbon dioxide participating in the solidification reaction are calculated. Its steps are simple and the calculation results are accurate, which has important value for the design of the filling amount of the gob area in the coal mine filled with supercritical carbon dioxide solidified by high-water materials.

Description

Technical Field

[0001] The present invention relates to a calculation method for the carbon sequestration amount in a gob area filled with high-water cured carbon dioxide, and belongs to the field of carbon dioxide sequestration assessment. Technical Background

[0002] Carbon dioxide capture, utilization, and storage (CCUS), as an important part of negative carbon technologies, is an important means to achieve carbon dioxide emission reduction. Geological sequestration of carbon dioxide, that is, injecting the captured and collected carbon dioxide into an underground closed space to achieve the purpose of sequestering carbon dioxide, is considered the most realistic and effective carbon dioxide emission reduction method at present. However, the existing geological sequestration of carbon dioxide still has problems such as high cost and lack of reliable closed sequestration space, which greatly limits the popularization and application of this project technology. Therefore, to achieve large-scale geological sequestration of CO2, not only a new technology with low cost and feasibility is needed, but also a large number of underground sequestration spaces with good safety and tightness.

[0003] On the other hand, coal mining over the past century and on a large scale has formed a large number of underground gob areas. The existence of gob areas in coal mines around the world not only causes a large amount of waste of underground space and surface land resources, but also seriously threatens the engineering construction of surface buildings (structures) and the lives of residents. Therefore, it is imperative to control the coal gob areas.

[0004] Combining the problems of geological sequestration of carbon dioxide and the treatment of coal mine gob areas, the gob area formed after underground coal mining can be used as a carbon dioxide sequestration space to realize the coupling of gob area treatment and carbon dioxide sequestration. In this way, the underground gob area can be utilized, "turning waste into treasure" to protect the safety of surface buildings (structures); and it can also provide a sequestration space for CCUS to achieve the purpose of carbon dioxide sequestration and the purpose of emission reduction. However, there is currently a lack of an assessment method for the carbon dioxide sequestration capacity of this technology, resulting in a lack of scientific basis for its production design.

[0005] Most current carbon dioxide geological sequestration methods directly inject liquid or supercritical carbon dioxide into the ground for sequestration. For example, carbon dioxide is sequestered in depleted oil and gas reservoirs and saline aquifers. Due to the complex underground environment, the temperature and pressure change with the change of the sequestration depth. Therefore, the density and state of carbon dioxide will also change accordingly. Therefore, the physical properties of carbon dioxide in conventional geological sequestration are unstable, making it difficult to accurately calculate the carbon dioxide sequestration amount. By using the method of curing reaction between high-water materials and supercritical carbon dioxide, carbon dioxide can be stably cured into calcium carbonate through chemical reaction, and at the same time, the coal mine gob area can be filled and cured with high-water materials; however, there is currently no accurate assessment and calculation method for the corresponding carbon dioxide sequestration amount. Summary of the Invention

[0006] To solve the above technical problems, a calculation method for the carbon sequestration amount in a goaf filled with high-water cured carbon dioxide is provided, which has simple calculation steps, high accuracy, and easy-to-obtain calculation parameters.

[0007] To achieve the above technical purpose, a calculation method for the carbon sequestration amount in a goaf filled with high-water cured carbon dioxide according to the present invention is directed to a goaf treatment area where an alkaline high-water material and acidic liquid carbon dioxide are simultaneously filled into a coal mine goaf, and a filling body is formed through the chemical reaction of the high-water material and liquid carbon dioxide to solidify and seal carbon dioxide.

[0008] The specific steps are as follows:

[0009] Determine the mining range based on materials such as the coal mine excavation engineering plan, and obtain the volume of the goaf that can be filled in this coal mine;

[0010] Calculate the total mass of the filling material in the goaf according to the density information of the filling material.

[0011] It is known that the filling material is composed of aggregate and supercritical carbon dioxide mixed in proportion:

[0012] Use the molecular formula of the aggregate and water that form the filling material to obtain the molecular weight of the aggregate, and infer the molar amount of carbon dioxide that the aggregate can solidify according to the chemical equation of the solidification reaction of the aggregate and carbon dioxide.

[0013] Finally, calculate the mass of the aggregate used in all the filling materials in the goaf and the mass of the supercritical carbon dioxide participating in the solidification reaction, which is of great value for the design of the filling volume of the high-water material solidifying supercritical carbon dioxide to fill the coal mine goaf.

[0014] Furthermore, collect information such as the excavation engineering plan, borehole columnar diagram, and geological mining data within the area, determine the volume V of the goaf; obtain the density ρ of the goaf filling material according to the physical properties of the used filling material, and calculate the mass of the filling material in the goaf by using the density and volume of the goaf filling material, and calculate the mass m of the filling material in the goaf 总 :

[0015] m 总 = ρ * V,

[0016] Since the goaf filling material is a mixture composed of high-water material and supercritical carbon dioxide, the mass of the filling material in the goaf satisfies:

[0017] m 总 = m 高 + m 碳 ,

[0018] wherein, m 高 is the mass of the high-water material, m 碳is the mass of carbon dioxide.

[0019] Furthermore, the high water-repellent material is formed by mixing high water-repellent material aggregate and water in mass. Assuming the ratio of high water-repellent material aggregate to water is β, the mass of the high water-repellent material is:

[0020] m 高 =(1+β)m 骨 ;

[0021] Among them, m 骨 For the quality of high water material aggregate.

[0022] Furthermore, the molecular weight of the high water content material aggregate is deduced based on the molecular formula of the high water content material aggregate;

[0023] Assume that the molecular formula of high water-rich material aggregate is A, and the molecular weight of high water-rich material aggregate A is a;

[0024] The molar ratio of high-water material aggregate A to carbon dioxide is obtained as b through the chemical equation of the curing reaction of high-water material aggregate and supercritical carbon dioxide, and the mass of carbon dioxide participating in the curing reaction is deduced to satisfy:

[0025] m 碳 =44b*m 骨 / a,

[0026] Here, 44 is the molecular weight of carbon dioxide.

[0027] Further, through the combined formula:

[0028] m 总 =m 高 +m 碳 ,

[0029] m 高 =(1+β)m 骨 ,

[0030] m 碳 =44b*m 骨 / a,

[0031] Get the calculated aggregate mass m of high water material 骨 The formula is:

[0032]

[0033] The calculated m 骨 Substitute m 碳 The final mass m of supercritical carbon dioxide involved in the curing reaction is obtained by the calculation formula 碳 ;

[0034]

[0035] Furthermore, a fitted mathematical model is constructed, and the final result can be obtained by inputting the variable V:

[0036]

[0037] Where ρ is the density of the predicted parameter filling material; β is the ratio of the high-water material to water; a is the molecular weight of the high-water material; b is the reaction molar amount.

[0038] Beneficial effects

[0039] This method addresses the scientific issue of carbon dioxide geological storage. Considering the full utilization of the underground space in coal mine goafs, a prediction method for the carbon dioxide storage volume in coal mine goafs is scientifically and reasonably proposed. It realizes the potential evaluation of the technology method of solidifying and filling goafs with high-water materials and supercritical carbon dioxide, proves that the technology of solidifying and filling goafs with high-water materials and supercritical carbon dioxide is a practical method to achieve the dual-carbon goal, and at the same time proves that solidifying and filling goafs with high-water materials and supercritical carbon dioxide can effectively control the goafs formed after the full exploitation of coal mines. It is of great significance to the ecological civilization construction in coal mining areas.

[0040] Through scientific and reasonable analysis, referring to the mass density conversion formula and the reaction mechanism of chemical equations, the mass m of the filling mixture in this method 总 The mass m of the high-water material aggregate is obtained through rigorous mathematical calculations 骨 , and finally, through the chemical reaction equation, a mathematical formula is constructed to obtain the mass m of carbon dioxide that can be stored in the V-volume coal mine goaf. 碳 . The volume V of the goaf can be used as the independent variable, and the predicted value m of the carbon dioxide storage volume 碳 as the dependent variable, and the density ρ of the filling material, the ratio β of the high-water material to water, the molecular weight a of the high-water material, and the reaction molar amount b are used as parameters to construct a mathematical function model to achieve rapid and effective calculation of the carbon dioxide storage volume in coal mine goafs. Description of the drawings

[0041] Figure 1 It is a flow chart of the calculation method for the carbon storage volume in the high-water solidified carbon dioxide filled goaf of the embodiment of the present invention. Specific implementation manners

[0042] The present invention will be further described in detail below in conjunction with the drawings and specific implementation processes:

[0043] In order to solve the problem of lack of a large amount of enclosed underground space for coal mine goaf management and carbon dioxide storage, the idea of solidifying carbon dioxide and filling it into coal mine goafs was proposed. That is, weakly alkaline high-water material and weakly acidic liquid carbon dioxide are simultaneously filled into the coal mine goafs. Through the chemical reaction of high-water material and liquid carbon dioxide, the carbon dioxide is solidified and sealed in the coal mine goafs, thereby achieving the purpose of carbon dioxide storage and goaf management.

[0044] In order to calculate the carbon storage amount during the implementation of the above technologies, Figure 1 As shown, the present invention proposes a method for calculating the carbon storage amount in the high-water solidification carbon dioxide filling goaf, assuming that the volume of the entire coal mine goaf is V, that is, the volume of the filling material that can be used to participate in the carbon dioxide solidification and storage is also V. According to m 总 =ρ*V, and the filling material mass m is obtained 总 Then, the mass ratio of high-water material aggregate to water and the solidification reaction of high-water material aggregate and carbon dioxide are used to deduce the equation to obtain the mass of high-water material aggregate m 骨 , m 骨 Substitute into the calculation formula m 碳 =44b*m 骨 / aThe mass of supercritical carbon dioxide finally obtained and involved in the curing reaction m 碳 .

[0045] First, the volume V of the coal mine goaf is determined based on engineering data (mining engineering plan, etc.), and the density ρ of the filling material and the density formula m 总 =ρ*V, calculate the mass m of the filling material in the goaf 总 ;

[0046] Afterwards, since the filling material is a mixture of high-water material (including aggregate and water) and supercritical carbon dioxide, that is, m 总 =m 高 +m 碳 ; High water-repellent material is made by mixing high water-repellent material aggregate and water in a mass ratio of β. The formula for calculating the mass of high water-repellent material is inferred to be m 高 =(1+β)m 骨 ;

[0047] Then, the molecular weight of the high-water-density aggregate is deduced based on its molecular formula. Here, we take high-water-density aggregate A as an example, and the molecular weight of A is a. At the same time, through the chemical equation of the curing reaction of high-water-density aggregate and supercritical carbon dioxide, we can infer that 1 mole of high-water-density aggregate A can cure b moles of carbon dioxide. The mass of carbon dioxide participating in the curing reaction can be calculated by m 碳 =44b*m 骨 / a is calculated (where 44 is the molecular weight of carbon dioxide);

[0048] Finally, the combined formula m 总 = m 高 + m 碳 , m 高 = (1 + β)m 骨 and m 碳 = 44b * m 骨 / a, the mass of the aggregate of the high-water material can be calculated Substitute the calculated m 骨 into m 碳 's calculation formula to finally obtain the mass of supercritical carbon dioxide participating in the curing reaction

[0049] The specific steps are as follows:

[0050] Step 1: For the gob area of the coal mine where the carbon dioxide sequestration volume needs to be predicted, collect information such as the mining engineering plan, borehole columnar diagram, and geological and mining data within the area to determine the volume V of the gob area; refer to the properties of the filling material to determine the parameters for calculating the carbon dioxide sequestration volume this time, including: the density ρ of the filling material, the ratio β of the high-water material to water, and the molecular weight a of the high-water material. According to the physical properties (density ρ) of the adopted filling material, calculate the mass m of the filling material with a volume of V 总 ; then, according to the ratio β of the high-water material to water in the filling material, obtain the relationship between the mass of the high-water material and the mass of the high-water material aggregate as m 高 = (1 + β)m 骨 ;

[0051] Step 2: According to the chemical properties of the high-water material aggregate adopted, taking the high-water material aggregate A as an example here, the molecular weight of A is a at this time. Refer to the chemical reaction equation to obtain the molar ratio b of the high-water material aggregate to carbon dioxide. Then, the mass m of the supercritical carbon dioxide participating in the reaction 碳 = b * m 骨 / a * 44; Combine the formulas for calculating m 总 , m 碳 and m 高 to obtain

[0052] Step 3: Finally, substitute m 骨 into the formula m 碳 = 44b * m 骨 / a to calculate the mass of the supercritical carbon dioxide participating in the reaction

[0053] Step 4: The parameters obtained from Step 1 and Step 2, including: the density ρ of the filling material, the ratio β of the high-water material to water, the molecular weight a of the high-water material, and the reaction molar amount b. Use the mathematical calculation model to calculate the mass m of carbon dioxide participating in the solidification reaction that can be accommodated in the coal mine goaf with a volume of V. 碳 , which is the predicted value of the mass of carbon dioxide that can be sequestered in the coal mine goaf.

[0054] Construct a fitted mathematical model. By inputting the variable V, the final result can be obtained (that is, substituting m 总 = ρV into the formula in Step 3):

[0055]

[0056] where ρ is the density of the filling material, which is a predicted parameter; β is the ratio of the high-water material to water; a is the molecular weight of the high-water material; b is the reaction molar amount.

[0057] Example 1

[0058] Step 1: It is known that after sufficient mining in a certain coal mine, a large number of goafs have been formed. According to the mining engineering plan and geological mining information of the mining area, the volume V of the coal mine goaf is obtained as V = 20000 m 3 . The molecular formula of the high-water material aggregate A is 3CaO·Al2O3·CaSO4·12H2O, its molecular weight a = 622, and its chemical reaction equation with supercritical carbon dioxide is:

[0059] 3CaO·Al2O3·CaSO4·12H2O + 3CO2 = 3CaCO3 + Al2O3 + CaSO4·2H2O + 10H2O

[0060] It can be inferred from the chemical reaction equation that 1 mole of the high-water material aggregate A can react with 3 moles of carbon dioxide, that is, b = 3. The mass ratio β of the high-water material aggregate A to water is 1, and the density ρ of the filling material is 1.5 t / m 3 ;

[0061] Step 2: According to the formula m 总 = ρ * V, m 总 = 30000 t is obtained. Substitute m 总 into the formula to obtain the mass m 骨 = 13561 t of the high-water material aggregate; substitute m 骨 into the formula m 碳 = 44b * m 骨 / a to calculate and obtain m 碳 = 2877.90 t;

[0062] Step 3: Verification: According to the mass ratio β = 1 of the high-water material aggregate to water, m 水 = 13561t; and at this time, the total mass of the filling material is equal to the sum of the mass of the high-water material (including aggregate and water) and the solidified supercritical carbon dioxide. Therefore, it can be inferred that m 总 = m 骨 + m 水 + m 碳 = 13561 + 13561 + 2877.90 = 29999.9t. So the calculation result is correct, and the mass m 碳 of the supercritical carbon dioxide that can be sealed in the goaf of this coal mine is

[0063] Example 2

[0064] Step 1: It is known that after sufficient mining in a certain coal mine, a large number of goafs have been formed. Now, the molecular formula of the high-water material aggregate B is 3CaO·Al2O3·3CaSO4·31H2O, and its molecular weight a = 1236. The other conditions are the same as in Example 1. The chemical reaction equation between the high-water material aggregate B and supercritical carbon dioxide is:

[0065] 3CaO·Al2O3·3CaSO4·31H2O + 3CO2 = 3CaCO3 + Al2O3 + 3CaSO4·2H2O + 25H2O

[0066] It can be inferred from the chemical reaction equation that 1 mole of the high-water material aggregate B can react with 3 moles of carbon dioxide, that is, b = 3. The mass ratio β of the high-water material aggregate B to water is 1, and the density ρ of the filling material is 1.5t / m 3 ;

[0067] Step 2: According to the formula m 总 = ρ * V, m 总 = 30000t is obtained. Substitute m 总 into Equation to obtain the mass m 骨 of the high-water material aggregate = 14239.63t; Substitute m 骨 into the formula m 碳 = 44b * m 骨 / a for calculation to obtain m 碳 = 1520.74t;

[0068] Step 3: Verification: According to the mass ratio β = 1 of the high-water material aggregate to water, m 水 = 14239.63t; and at this time, the total mass of the filling material is equal to the sum of the mass of the high-water material (including aggregate and water) and the solidified supercritical carbon dioxide. Therefore, it can be inferred that m 总 = m 骨 + m 水 + m碳 = 14239.63 + 14239.63 + 1520.74 = 30000 t. Therefore, the calculation result is correct, and the mass m of supercritical carbon dioxide that can be sequestered in the goaf of this coal mine 碳 = 1520.74 t.

[0069] Note: This method is applicable to all high-water materials. The filling material density ρ, the ratio β of high-water material to water, the molecular weight a of high-water material, and the reaction molar amount b of different high-water materials are different. The parameters can be substituted into the established mathematical model to determine the carbon sequestration amount efficiently and accurately.

[0070]

Claims

1. A calculation method for the carbon sequestration amount in a gob filled with high-water solidified carbon dioxide, characterized in that: The alkaline high-water material and acidic liquid carbon dioxide are simultaneously filled into the coal mine goaf, and the chemical reaction between the high-water material and the liquid carbon dioxide generates a filling body to solidify and seal the carbon dioxide in the goaf area. The specific steps are as follows: Collect the mining engineering plan, borehole columnar diagram, and geological and mining data information within the collection area to determine the volume V of the goaf; obtain the density ρ of the goaf filling material based on the physical properties of the adopted filling material, and calculate the mass of the filling material in the goaf by using the density and volume of the goaf filling material, and calculate the mass of the filling material in the goaf : ， Since the filling material in the goaf is a mixture of high-water material and supercritical carbon dioxide, the quality of the filling material in the goaf meets the following requirements: ， Among them, is the mass of the high-water material, is the mass of carbon dioxide; Joint formula: ， ， ， High water-repellent material is made by mixing high water-repellent material aggregate and water in a mass ratio. Assuming the ratio of high water-repellent material aggregate to water is β, the mass of high water-repellent material is: ； Among them, is the mass of the high-water material aggregate; The molecular weight of high water-rich aggregate is derived from its molecular formula; Assume that the molecular formula of high water-rich material aggregate is A, and the molecular weight of high water-rich material aggregate A is a; The molar ratio of high-water material aggregate A to carbon dioxide is obtained as b through the chemical equation of the curing reaction of high-water material aggregate and supercritical carbon dioxide, and the mass of carbon dioxide participating in the curing reaction is deduced to satisfy: ， Among them, 44 is the molecular weight of carbon dioxide; Calculating the aggregate quality of high-water materials : ； Substitute the calculated into to finally obtain the mass of supercritical carbon dioxide participating in the curing reaction ; 。 2. The calculation method for the carbon sequestration amount in a goaf filled with high-water solidified carbon dioxide according to claim 1, wherein Construct a fitted mathematical model and input variable V to get the final result: 。

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