Experimental method and device for determining the storage amount of CO2 in different storage states in pores

Abstract

The present invention provides an experimental method and device for measuring the storage amounts of CO2 in different storage states in pores. The method includes obtaining the pore throat radius distribution of a core through a nitrogen adsorption / desorption experiment; obtaining an excess adsorption amount curve of carbon dioxide within a preset temperature and a preset pressure range based on a thermogravimetric carbon dioxide adsorption experiment, wherein the preset pressure range is 1 to 30 MPa; correcting the excess adsorption amount curve by using a Monte Carlo molecular simulation method; and calculating the absolute adsorption amount of carbon dioxide in the core according to the pore throat radius distribution and the corrected excess adsorption amount curve. The measurement method of the present invention takes into account the volume of the adsorbed phase and overcomes the heterogeneity of the pore throat distribution when measuring the storage amounts of CO2 in different storage states in pores, and the measurement result is more accurate.

Description

Technical Field

[0001] The invention belongs to the technical field of geological exploration, and in particular relates to an experimental method and a device for determining the storage amount of CO2 in different storage states in pores. Background Art

[0002] When domestic and foreign scholars study the adsorption properties of coal-bearing mudstone and shale, the main methods used are volumetric method and thermogravimetric method. The former is more targeted and the latter is more accurate. In recent years, with the vigorous development of shale gas exploration and development, thermogravimetric method has been used more and more, and the thermogravimetric method uses magnetic suspension balance as the main detection tool.

[0003] In the prior art, when using the volumetric method to study the isothermal adsorption characteristics of coal-bearing mudstone and shale, it was found that the adsorption data directly obtained from the isothermal adsorption experiment is the excess adsorption amount. Since the excess adsorption amount ignores the influence of the volume of the adsorbed phase, its test results cannot truly reflect the adsorption capacity of shale. At present, the commonly used method is to use the density of the adsorbed phase combined with the Gibbs excess adsorption definition formula for correction, so the accuracy and rationality of the adsorbed phase density have an important influence on the correction results. However, based on previous studies, whether it is the volumetric method or the thermogravimetric method, the adsorption amount obtained is the excess adsorption amount of the core under a single pore size. In summary, previous studies on the density of the adsorbed phase cannot reflect the true adsorption capacity of shale, and the research results of different scholars vary greatly, which will inevitably have a great impact on the objective evaluation of the gas adsorption capacity of shale. Summary of the invention

[0004] The main purpose of the present invention is to propose an experimental method and device for determining the storage amount of CO2 in different storage states in pores, aiming to solve the technical problem of inaccurate calculation of the whole core scale carbon dioxide adsorption storage amount in the prior art.

[0005] In order to achieve the above object, the present invention provides an experimental method for determining the storage amount of CO2 in different storage states in pores, comprising:

[0006] The pore throat radius distribution of the core was obtained through nitrogen adsorption / desorption experiments;

[0007] Obtaining an excess adsorption curve of carbon dioxide within a preset temperature and a preset pressure range based on a thermogravimetric carbon dioxide adsorption experiment, wherein the preset pressure range is 1 to 30 MPa;

[0008] The excess adsorption amount curve is corrected by using a Monte Carlo molecular simulation method;

[0009] The absolute adsorption amount of carbon dioxide in the core is calculated according to the pore throat radius distribution and the corrected excess adsorption amount curve.

[0010] In an embodiment of the present invention, the step of obtaining the excess adsorption curve of carbon dioxide within a preset temperature and a preset pressure range based on a thermogravimetric carbon dioxide adsorption experiment comprises:

[0011] At a preset temperature, filling the sealed cavity of the core with carbon dioxide within a preset pressure range;

[0012] Thermogravimetric method is used to conduct carbon dioxide adsorption test experiments and obtain the excess adsorption amount of carbon dioxide at each system pressure within a preset pressure range;

[0013] An excess adsorption amount curve of carbon dioxide at a preset temperature is plotted according to the excess adsorption amount data of carbon dioxide within a preset pressure range.

[0014] In an embodiment of the present invention, the step of correcting the excess adsorption amount curve using the Monte Carlo molecular simulation method comprises:

[0015] The Monte Carlo molecular simulation method is used to calculate the average density of the carbon dioxide adsorption layer corresponding to different pore throat radii within the preset temperature and preset pressure range;

[0016] The excess adsorption curve of the core is corrected according to the average density of the carbon dioxide adsorption layer.

[0017] In an embodiment of the present invention, the step of using the Monte Carlo molecular simulation method to calculate the average density of the carbon dioxide adsorption layer corresponding to different pore throat radii within a preset temperature and a preset pressure range includes:

[0018] Calculate the carbon dioxide density corresponding to the pore throat radius R1 within the preset temperature and preset pressure range and draw a carbon dioxide density distribution curve;

[0019] The adsorption layer is divided according to the diameter of the carbon dioxide molecule, and the carbon dioxide adsorption layer with a pore throat radius of R1 is obtained;

[0020] Calculate the average density of the carbon dioxide adsorption layer corresponding to the pore throat radius R1 within the preset temperature and preset pressure range;

[0021] The selected pore throat radius is changed and the above steps are repeated in sequence, and the average density curve of the carbon dioxide adsorption layer corresponding to different pore throat radii within the preset temperature and preset pressure range is obtained.

[0022] In an embodiment of the present invention, the step of calculating the absolute adsorption amount of carbon dioxide in the core according to the pore throat radius distribution and the corrected excess adsorption amount curve comprises:

[0023] The average density of the carbon dioxide adsorption layer of the entire core is calculated based on the core pore throat radius distribution and the average density of the carbon dioxide adsorption layer corresponding to different pore throat radii;

[0024] The absolute adsorption amount of the core under a preset temperature and a preset pressure range is calculated according to the excess adsorption amount and the average density of the carbon dioxide adsorption layer of the entire core.

[0025] In an embodiment of the present invention, the average density of a single carbon dioxide adsorption layer of the core is calculated using the following calculation formula:

[0026]

[0027] In the formula, ρ ave is the average density of a single carbon dioxide adsorption layer, kg / m 3 ρ ads is the in-situ density of the carbon dioxide adsorption layer, kg / m 3 ; a is the starting point of the carbon dioxide adsorption layer, b is the end point of the carbon dioxide adsorption layer, z ab is the distance between a and b, which is the diameter of a single carbon dioxide molecule, nm.

[0028] In an embodiment of the present invention, the average density of the carbon dioxide adsorption layer of the entire core is calculated using the following formula:

[0029]

[0030] In the formula, is the average density of the carbon dioxide adsorption layer in the entire core, kg / m 3 ; α1, α2, α3...α n The pore throat radii are R1, R2, R3, ...R n The frequency of The pore throat radii are R1, R2, R3, ...R n The average density of the corresponding carbon dioxide adsorption layer, kg / m 3 .

[0031] In an embodiment of the present invention, the absolute adsorption amount of the core can be obtained by using the following calculation formula:

[0032]

[0033] Where M ads is the absolute adsorption amount of the core, mmol / g; M ex is the excess adsorption of the core, mmol / g; ρ is the bulk density of carbon dioxide in the core, kg / m 3 ; is the average density of the carbon dioxide adsorption layer in the entire core, kg / m 3 .

[0034] In an embodiment of the present invention, an experimental device for measuring the storage amount of CO2 in different sealing states in pores is also proposed, which is applied to the experimental method for measuring the storage amount of CO2 in different sealing states in pores as described above. The experimental device for measuring the storage amount of CO2 in different sealing states in pores comprises a constant temperature box, a core crusher and a core sealing box connected in sequence, the core crusher is used to crush the core transported in the constant temperature box, a receiving cavity for containing the core is formed in the core sealing box, the core sealing box is optionally connected to a nitrogen bottle and a carbon dioxide bottle, and a thermometer and a pressure gauge are provided on the core sealing box.

[0035] In an embodiment of the present invention, the experimental device for determining the storage amount of CO2 in different storage states in pores also includes a waste bottle, which is connected to the core sealing box pipeline and is used to collect waste gas generated in the experiment.

[0036] Through the above technical solution, the experimental method for determining the storage amount of CO2 in different storage states in pores provided by the embodiment of the present invention has the following beneficial effects:

[0037] When conducting the test experiment, the pore throat radius distribution of the core is first obtained through a nitrogen adsorption / desorption experiment; based on the thermogravimetric carbon dioxide adsorption experiment, the excess adsorption curve of carbon dioxide within a preset temperature and preset pressure range is obtained, wherein the preset pressure range is set to 1-30MPa; then the Monte Carlo molecular simulation method is used to correct the excess adsorption curve; finally, the absolute adsorption amount of carbon dioxide in the core is calculated based on the pore throat radius distribution and the corrected excess adsorption curve. The determination method of the present invention takes into account the volume of the adsorbed phase when determining the storage amount of CO2 in different storage states in the pores and overcomes the heterogeneity of the pore throat distribution, and the measurement result is more accurate.

[0038] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings are used to provide an understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention. In the accompanying drawings:

[0040] Figure 1 It is a schematic flow chart of an experimental method for determining the storage amount of CO2 in different storage states in pores according to one embodiment of the present invention;

[0041] Figure 2It is a schematic diagram of the structure of an experimental device for determining the storage amount of CO2 in different storage states in pores according to one embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of pore throat distribution of two shale samples in the core selected according to an embodiment of the present invention;

[0043] Figure 4 is a schematic diagram of excess adsorption capacity distribution curves corresponding to two shale samples in a core selected according to an embodiment of the present invention;

[0044] Figure 5 is a schematic diagram of absolute / excess adsorption capacity distribution curves corresponding to two shale samples according to an embodiment of the present invention;

[0045] Figure 6 It is a schematic diagram of a curve showing the average density of the carbon dioxide adsorption layer changing with pressure when the temperature is 353.15K and the pore throat radius is 2.9nm according to an embodiment of the present invention.

[0046] Description of Reference Numerals

[0047] Label name Label name 1 Constant temperature box 6 valve 2 Core Crusher 7 Second flow meter 3 Core sealing box 8 Nitrogen cylinder 4 First flow meter 9 Carbon dioxide bottle 5 Waste bottles DETAILED DESCRIPTION

[0048] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0049] The following describes the experimental method for determining the storage amount of CO2 in different storage states in pores according to the present invention with reference to the accompanying drawings.

[0050] like Figure 1 As shown, in an embodiment of the present invention, an experimental method for determining the storage amount of CO2 in different storage states in pores is provided, comprising:

[0051] Step S10: obtaining the pore throat radius distribution of the core through nitrogen adsorption / desorption experiments;

[0052] A shale core with a diameter of 3.0 cm and a length of 6.0 cm was placed in a thermostat at a temperature of 353.15 K and dried for 24 hours until it was dried to a constant weight; the sample was taken out and placed in a core clamping device, and the pore throat distribution of the core was obtained by N2 adsorption / desorption test. The N2 adsorption / desorption test experimental method is a conventional test method in the prior art, and the specific experimental steps are not described here one by one. In order to reduce the error of the entire test experiment, multiple shale samples can be selected for the experiment, such as Figure 3 As shown in the figure, two shale samples were selected for pore throat distribution test, and the results were as follows: Figure 3 The two pore throat radius distribution diagrams a and b are shown in the figure. Figure 3 a represents the pore throat radius distribution diagram of shale sample one, and b represents the pore throat radius distribution diagram of shale sample two. From the pore throat radius distribution diagram, it can be clearly concluded that the pore throat distribution of the selected shale samples is mainly concentrated in which range, and the frequency corresponding to each pore throat radius provides favorable assistance for the subsequent calculation of the average density of the carbon dioxide adsorption layer corresponding to each pore throat radius.

[0053] Step S20: obtaining an excess adsorption curve of carbon dioxide within a preset temperature and a preset pressure range based on a thermogravimetric carbon dioxide adsorption experiment, wherein the preset pressure range is 1 to 30 MPa;

[0054] Step S30: using a Monte Carlo molecular simulation method to correct the excess adsorption curve;

[0055] Step S40: Calculate the absolute adsorption amount of carbon dioxide in the core according to the pore throat radius distribution and the corrected excess adsorption amount curve.

[0056] Dubinin (1960) proposed that the density of the adsorbed phase is a constant related to the van der Waals constant b. Later, the density of the adsorbed phase was considered to be equal to the density of the liquid adsorbate. Li et al. (2002) compared the above methods and claimed that the density of the adsorbed phase is a function of the system temperature, but its value is close to that proposed by Dubinin (1960). Recently, through molecular simulation, Ambrose et al. (2012) proposed that the density of the adsorbed phase is related to the system temperature, pressure and pore size. Whether it is the volumetric method or the thermogravimetric method, the adsorption amount obtained is the excess adsorption of the core under a single pore size. Since the excess adsorption of carbon dioxide in the core does not take into account the volume of the adsorbed phase, there is a large error in the calculation result. For shale samples, the internal pore throats are not evenly distributed, but are heterogeneous. Therefore, in order to obtain the actual adsorption of carbon dioxide in the shale sample, it is necessary to correct the excess adsorption according to the average density of the carbon dioxide adsorption layer obtained by the pore throat radius distribution. In other words, the volume factor of the adsorbed phase is considered on the basis of the calculation result of the excess adsorption to more accurately obtain the actual adsorption of carbon dioxide, also known as the absolute adsorption of carbon dioxide. The method of the present invention is based on the Monte Carlo molecular simulation method combined with the N2 adsorption / desorption test to obtain the pore throat distribution of the core and the thermogravimetric isothermal adsorption experimental test data, and the method and idea of ​​weighted average of the core pore throat distribution are adopted to obtain the storage capacity of CO2 in different storage states in the pores. This method takes into account the volume of the adsorbed phase and overcomes the heterogeneity of the pore throat distribution, and the obtained results are more reasonable and reliable. At the same time, it provides technicians with accurate determination of the storage capacity of CO2 in different storage states in the pores, so that shale gas can be efficiently developed.

[0057] Wherein, step S20 also includes the following steps:

[0058] Step S21: filling the sealed cavity of the core with carbon dioxide within a preset pressure range at a preset temperature;

[0059] Step S22: performing a carbon dioxide adsorption test experiment using a thermogravimetric method and obtaining the excess adsorption amount of carbon dioxide at each system pressure within a preset pressure range; wherein the excess adsorption amount refers to the difference between the measured carbon dioxide gas inflow amount and the pore volume;

[0060] Step S23: drawing a curve of excess adsorption of carbon dioxide at a preset temperature according to the excess adsorption data of carbon dioxide within a preset pressure range.

[0061] In a specific embodiment, carbon dioxide is charged into a shale core at a system temperature of 353.15K until the system pressure is 1-30MPa, and an adsorption test is performed at each test pressure using a thermogravimetric method to obtain the excess adsorption amount at a temperature of 353.15K and a pressure of 1-30MPa, and a curve of excess adsorption amount under the conditions is plotted; Figure 4 As shown in the figure, the excess adsorption capacity on the ordinate represents the excess adsorption amount. A part of the data points were selected in the experiment and drawn into a curve. It can be seen that for shale sample 1 and shale sample 2, with the increase of system pressure, the excess adsorption amount increases. When the system pressure reaches about 10MPa, the adsorption sites on the shale surface are completely occupied, the excess adsorption amount basically no longer changes, and the adsorption reaches saturation.

[0062] Furthermore, step S30 further includes:

[0063] Step S31: using a Monte Carlo molecular simulation method to calculate the average density of the carbon dioxide adsorption layer corresponding to different pore throat radii within a preset temperature and a preset pressure range;

[0064] Step S32: Correcting the excess adsorption curve of the core according to the average density of the carbon dioxide adsorption layer.

[0065] The present invention calculates the absolute adsorption amount of the carbon dioxide adsorption layer of the core based on the Monte Carlo simulation method. The principle of the Monte Carlo method is based on analyzing the research target by randomly sampling. Its basic steps are to first construct a corresponding probability model to replace the actual system, and then randomly sample and simulate on the basis of this probability model, so as to calculate some approximate solutions related to statistics of the actual system. Among them, the detailed steps of the Monte Carlo molecular simulation method are as follows:

[0066] (1) A corresponding molecular conformation is generated by a random number generator, and then the adsorbate molecules to be studied are randomly added to any position in the conformation in any direction.

[0067] (2) Change the position of related particles in this molecular conformation to produce another new conformation. Each change should include three types of disturbances: inserting molecules; deleting molecules; moving molecules.

[0068] (3) Calculate and analyze the energy change ΔE between the new conformation and the original conformation, and determine whether the new conformation should be included in the statistical average based on the value of ΔE.

[0069] (4) If it cannot be included in the statistical average, this configuration is abandoned and the calculation is repeated until the most stable molecular conformation can be selected.

[0070] (5) When the system reaches the statistical average, the adsorption amount calculated by the current system is the final carbon dioxide adsorption amount.

[0071] Further, step S31 includes:

[0072] Step S311: calculating the carbon dioxide density corresponding to the pore throat radius R1 within the preset temperature and preset pressure range and drawing a carbon dioxide density distribution curve;

[0073] Step S312: Divide the adsorption layer according to the diameter of the carbon dioxide molecule to obtain the carbon dioxide adsorption layer under the pore throat radius R1; in this embodiment, since the diameter of the carbon dioxide molecule is 0.38nm, and the adsorption layer is a monolayer adsorption, the adsorption layer with a diameter of about 0.38 nanometers is selected as the carbon dioxide adsorption layer, and the carbon dioxide adsorption layer when the pore throat radius is 2.9nm is obtained.

[0074] Step S313: Calculate the average density of the carbon dioxide adsorption layer corresponding to the pore throat radius R1 within the preset temperature and preset pressure range; wherein the average density of a single carbon dioxide adsorption layer of the core is calculated using the following calculation formula:

[0075]

[0076] In the formula, ρ ave is the average density of a single carbon dioxide adsorption layer, kg / m 3 ρ ads is the in-situ density of the carbon dioxide adsorption layer, kg / m 3 ; a is the starting point of the carbon dioxide adsorption layer, b is the end point of the carbon dioxide adsorption layer, z ab is the distance between a and b, which is the diameter of a single carbon dioxide molecule, nm.

[0077] Step S314: changing the selected pore throat radius and repeating the above steps in sequence, and obtaining the average density curve of the carbon dioxide adsorption layer corresponding to different pore throat radii within the preset temperature and preset pressure range.

[0078] like Figure 6 As shown in FIG. 1 , a curve of the average density of the carbon dioxide adsorption layer of shale sample 1 at a temperature of 353.15 K and a pore throat radius of 2.9 nm is shown as a function of pressure. The system pressure range is selected from 1 to 30 MPa. It can be seen from the figure that with the increase of pressure, the average density of the carbon dioxide adsorption layer under the pore throat radius gradually increases. When the pressure reaches 15 MPa, the increasing trend of the average density of the carbon dioxide adsorption layer gradually slows down. Repeat the above steps and change the selected pore throat radius, and calculate the average density of the carbon dioxide adsorption layer when the temperature is 353.15 K and the pore throat radius is 5.8 nm, 10.2 nm, ... 37.6 nm in turn. Finally, the curve of the average density of the carbon dioxide adsorption layer at a temperature of 353.15 K and a pore throat radius of 2.9 nm, 5.8 nm, 10.2 nm, ... 37.6 nm as a function of pressure (1 to 30 MPa) is obtained. Since the trends of the change curves are similar, they will not be repeated here one by one.

[0079] In an embodiment of the present invention, step S40 further includes:

[0080] Step S41: Calculate the average density of the carbon dioxide adsorption layer of the entire core according to the core pore throat radius distribution and the average density of the carbon dioxide adsorption layer corresponding to different pore throat radii; wherein the average density of the carbon dioxide adsorption layer of the entire core can be obtained by using the weighted average method of pore throat distribution, and the specific calculation formula is as follows:

[0081]

[0082] In the formula, is the average density of the carbon dioxide adsorption layer in the entire core, kg / m 3 ; α1, α2, α3...α n The pore throat radii are R1, R2, R3, ...R n The frequency of The pore throat radii are R1, R2, R3, ...R n The average density of the corresponding carbon dioxide adsorption layer, kg / m 3 .

[0083] Specifically, in order to calculate the average density of the carbon dioxide adsorption layer of the entire shale sample 1, α1, α2, α3, ... n It is set to the frequency occupied by pore throats with radii of 2.9nm, 5.8nm, 10.2nm, ... 37.6nm; They are the average density of the carbon dioxide adsorption layer with pore throat radius of 2.9nm, 5.8nm, 10.2nm...37.6nm respectively. The average density of the carbon dioxide adsorption layer of the entire shale sample can be calculated based on the average density of the carbon dioxide adsorption layer corresponding to each pore throat radius calculated above. The average density of the carbon dioxide adsorption layer obtained by this weighted average method of pore throat distribution can take into account the different pore throat distributions in the shale sample, and the calculation result is more accurate.

[0084] Step S42: Calculate the absolute adsorption amount of the core under a preset temperature and a preset pressure range according to the excess adsorption amount and the average density of the carbon dioxide adsorption layer of the entire core. The absolute adsorption amount of the core can be obtained using the following calculation formula:

[0085]

[0086] Where M ads is the absolute adsorption amount of the core, mmol / g; M ex is the excess adsorption of the core, mmol / g; ρ is the bulk density of carbon dioxide, kg / m 3 ; is the average density of the carbon dioxide adsorption layer in the entire core, kg / m 3 .

[0087] Among them, the absolute adsorption amount refers to the actual adsorption amount of carbon dioxide in shale. When the system pressure increases to a certain level, the adsorption will inevitably reach saturation, which is manifested as the absolute adsorption amount no longer increasing. And from the calculation formula of the absolute adsorption amount, it can be seen that the calculation of the absolute adsorption amount takes into account the volume of the adsorption phase and overcomes the heterogeneity of the pore throat distribution, so that the calculated absolute adsorption amount of carbon dioxide is closer to the actual adsorption amount of carbon dioxide; Figure 5 As shown in the figure, they are the curve distribution diagrams of the absolute adsorption amount and the excess adsorption amount of the two whole shale samples. Since the adsorption is a monolayer adsorption at low pressure, the absolute adsorption amount and the excess adsorption amount are basically the same; while at high pressure, the difference between the absolute adsorption amount and the excess adsorption amount increases with the increase of pressure. It can be seen from the figure that when the pressure exceeds 6MPa, the difference between the absolute adsorption amount and the excess adsorption amount increases with the increase of pressure. It can be seen that when the pore throat radius distribution of the adsorption phase and the average density of the adsorption layer are considered, the calculated value of the absolute adsorption amount is greater than the calculated value of the excess adsorption amount under the same conditions, and the calculated result is closer to the actual adsorption amount of carbon dioxide. In addition, since each system pressure in the figure corresponds to a different storage state of carbon dioxide, the storage amount of carbon dioxide in different storage states in the pores can be obtained.

[0088] In an embodiment of the present invention, Figure 2As shown, an experimental device for determining the amount of CO2 stored in different storage states in pores is also proposed, which is applied to the experimental method for determining the amount of CO2 stored in different storage states in pores as mentioned above. The experimental device for determining the amount of CO2 stored in different storage states in pores includes a thermostat 1, a core crusher 2 and a core sealing box 3 connected in sequence. The core crusher 2 is used to crush the core transported in the thermostat 1. A receiving chamber for holding the core is formed in the core sealing box 3. The core sealing box 3 is selectively connected with a nitrogen bottle 8 and a carbon dioxide bottle 9. A thermometer for detecting the temperature in the receiving chamber and a pressure gauge for detecting the pressure are provided on the core sealing box 3. Among them, the core crusher 2 is a structural principle form of mechanical crushing, which can be carried out in the conventional structural form of the core crusher 2 in the prior art, but is not limited to the embodiment of the present invention. The lower end of the core sealing box 3 is connected to the nitrogen bottle 8 and the carbon dioxide bottle 9 respectively through the branch pipes on the connecting pipe, and valves 6 are provided on the main pipe and the two branch pipes of the connecting pipe to select nitrogen or carbon dioxide to pass into the core sealing box 3. A first flow meter 4 for detecting gas flow or velocity is provided on the main pipeline of the connecting pipeline. The flow of gas charged into the core sealing box 3 is monitored in real time by the first flow meter 4 so as to adjust the system pressure in the entire core sealing box 3.

[0089] In an embodiment of the present invention, the experimental device for determining the storage amount of CO2 in different storage states in the pores also includes a waste bottle 5, which is connected to the core sealing box 3 by a pipeline and is used to collect the waste gas generated in the experiment, and a second flow meter 7 for detecting the waste gas flow is arranged on the connecting pipe between the waste bottle 5 and the core sealing box 3.

[0090] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0091] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0092] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0093] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An experimental device for determining the storage amount of CO2 in different storage states in pores, characterized in that: The experimental device for determining the storage amount of CO2 in different storage states in pores comprises a thermostatic box (1), a core crusher (2) and a core sealing box (3) connected in sequence, wherein the core crusher (2) is used to crush the core transported in the thermostatic box, and the core sealing box (3) is formed with a receiving cavity for containing the core, and the core sealing box (3) is selectively connected to a nitrogen bottle (8) and a carbon dioxide bottle (9), and a thermometer and a pressure gauge are arranged on the core sealing box (3). The experimental device is applied to an experimental method for determining the storage amount of CO2 in different storage states in pores, and the experimental method for determining the storage amount of CO2 in different storage states in pores comprises: The pore throat radius distribution of the core was obtained through nitrogen adsorption / desorption experiments; Based on the thermogravimetric carbon dioxide adsorption experiment, an excess adsorption curve of carbon dioxide within a preset temperature and a preset pressure range is obtained, wherein the preset pressure range is 1-30 MPa; The excess adsorption amount curve is corrected by using a Monte Carlo molecular simulation method; Calculating the absolute adsorption amount of carbon dioxide in the core according to the pore throat radius distribution and the corrected excess adsorption amount curve; The step of correcting the excess adsorption amount curve using the Monte Carlo molecular simulation method comprises: The Monte Carlo molecular simulation method is used to calculate the average density of the carbon dioxide adsorption layer corresponding to different pore throat radii within the preset temperature and preset pressure range; Correcting the excess adsorption curve of the core according to the average density of the carbon dioxide adsorption layer; The step of using the Monte Carlo molecular simulation method to calculate the average density of the carbon dioxide adsorption layer corresponding to different pore throat radii within a preset temperature and a preset pressure range comprises: Calculate the pore throat radius within the preset temperature and preset pressure range. R 1 and draw the carbon dioxide density distribution curve; According to the diameter of carbon dioxide molecules, the adsorption layer is divided and the pore throat radius is obtained as R 1. The carbon dioxide adsorption layer below; Calculate the pore throat radius within the preset temperature and preset pressure range. R The average density of the carbon dioxide adsorption layer corresponding to 1; Changing the selected pore throat radius and repeating the above steps in sequence, and obtaining an average density curve of the carbon dioxide adsorption layer corresponding to different pore throat radii within a preset temperature and a preset pressure range; The step of calculating the absolute adsorption amount of carbon dioxide in the core according to the pore throat radius distribution and the corrected excess adsorption amount curve comprises: The average density of the carbon dioxide adsorption layer of the entire core is calculated based on the core pore throat radius distribution and the average density of the carbon dioxide adsorption layer corresponding to different pore throat radii; Calculate the absolute adsorption amount of the core under a preset temperature and a preset pressure range according to the excess adsorption amount and the average density of the carbon dioxide adsorption layer of the entire core; The average density of a single carbon dioxide adsorption layer in the core is calculated using the following formula: In the formula, is the average density of a single carbon dioxide adsorption layer, kg / m 3 ; is the in-situ density of the carbon dioxide adsorption layer, kg / m 3 ; a It is the starting point of the carbon dioxide adsorption layer. b is the end point of the carbon dioxide adsorption layer. yes a and b The distance between them is the diameter of a single carbon dioxide molecule, nm; The average density of the carbon dioxide adsorption layer of the entire core is calculated using the following formula: In the formula, is the average density of the carbon dioxide adsorption layer in the entire core, kg / m 3 ; The pore throat radius is R 1 、R 2 、R 3 、…R n The frequency of The pore throat radius is R 1 、R 2 、 R 3 、…R n The average density of the corresponding carbon dioxide adsorption layer, kg / m 3 .

2. The experimental device for determining the storage amount of CO2 in different storage states in pores according to claim 1 is characterized in that: The step of obtaining the excess adsorption curve of carbon dioxide within a preset temperature and a preset pressure range based on the thermogravimetric carbon dioxide adsorption experiment comprises: At a preset temperature, filling the sealed cavity of the core with carbon dioxide within a preset pressure range; Thermogravimetric method is used to conduct carbon dioxide adsorption test experiments and obtain the excess adsorption amount of carbon dioxide at each system pressure within a preset pressure range; An excess adsorption amount curve of carbon dioxide at a preset temperature is plotted according to the excess adsorption amount data of carbon dioxide within a preset pressure range.

3. The experimental device for determining the storage amount of CO2 in different storage states in pores according to claim 1 is characterized in that: The absolute adsorption amount of the core can be obtained by the following calculation formula: In the formula, is the absolute adsorption amount of the core, mmol / g; is the excess adsorption of the core, mmol / g is the bulk density of carbon dioxide in the core, kg / m 3 ; is the average density of the carbon dioxide adsorption layer in the entire core, kg / m 3 .

4. The experimental device for determining the storage amount of CO2 in different storage states in pores according to claim 1 is characterized in that: The experimental device for determining the amount of CO2 stored in pores under different storage conditions also includes a waste bottle (5), which is connected to the core sealing box (3) by a pipeline and is used to collect waste gas generated in the experiment.

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