A high-temperature and high-pressure gas-liquid-rock multiphase chemical reaction experimental device and method

Abstract

The application discloses a high-temperature and high-pressure gas-liquid-rock multiphase chemical reaction experimental device and method, and relates to the technical field of experimental devices. The experimental device comprises a medium preparation and injection assembly, which comprises a CO2 gas cylinder, a refrigeration unit and an intermediate container which are sequentially connected; the intermediate container comprises a gas piston container and a liquid piston container which are connected in parallel with each other; a reaction kettle assembly, which comprises a reaction kettle body and a ring pressure pump connected with the reaction kettle body; the reaction kettle body has an input end and an output end, the input end is connected with a first common node and a second common node, a coal rock sample is loaded in the reaction kettle, and the reaction kettle is configured to heat the coal rock sample at high temperature; and a multiphase substance separation and metering assembly, which comprises a gas-liquid separator and a gas reciprocating metering device; the gas-liquid separator has an input port, a gas output port and a liquid output port, the input port is connected with the output end, and the gas output port is connected with the gas reciprocating metering device.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide mineralization and storage, and to a high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus and method. Background Technology

[0002] Geological CO2 sequestration is an important approach to achieving large-scale permanent CO2 emission reduction. Based on water-rock interaction, CO2 aqueous solution is injected into rock masses rich in divalent metal ions such as magnesium and iron to induce water-rock interaction. Through a geochemical process of dissolution, migration, and precipitation, CO2 is ultimately transformed into thermodynamically stable secondary carbonate minerals, achieving long-term stable solid-state CO2 sequestration.

[0003] Several international engineering projects have been launched, with the Icelandic CarbFix project being the most representative, validating the feasibility of terrestrial geological sequestration. Gas-liquid-rock interactions under natural reservoir conditions involve multi-field, multi-phase, and multi-scale coupling mechanisms, including thermochemical reaction kinetics and fracture seepage. The mineralization rate is comprehensively influenced by multiple factors such as reaction conditions, medium properties, and reservoir structure, and this process exhibits high heterogeneity in both time and space. Existing high-temperature, high-pressure reaction testing systems can only control temperature or pressure variables, lacking monitoring of dynamic indicators such as pH, stress state, fracture development, and permeability evolution during the reaction process. Furthermore, they cannot integrate reservoir stimulation measures into experiments, making it difficult to verify permeability enhancement and accelerated mineralization technologies. Therefore, there is an urgent need for a high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental device and method that can solve the above-mentioned technical problems. Summary of the Invention

[0004] This solution addresses the problems and needs raised above by proposing a high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus and method. The above-mentioned technical objectives can be achieved by adopting the following technical features, and other technical effects are also brought about.

[0005] One object of the present invention is to provide a high-temperature and high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus, comprising:

[0006] A medium preparation and injection assembly includes: a CO2 cylinder, a refrigeration unit, and an intermediate container connected in sequence; the refrigeration unit is configured to convert gaseous CO2 into liquid CO2; the intermediate container includes: a gas piston container and a liquid piston container connected in parallel, with their two ends forming a first common node and a second common node, respectively, and is configured to output CO2 gas or liquid from the first common node.

[0007] The reactor assembly includes a reactor body and an annular pressure pump connected thereto. The reactor body has an input end and an output end. The input end is connected to the first common node and the second common node. The reactor body contains a coal and rock sample. The reactor body is configured to heat the coal and rock sample at high temperature. The annular pressure pump is configured to apply and maintain a constant confining pressure on the coal and rock sample.

[0008] A multiphase separation and metering assembly includes a gas-liquid separator and a gas reciprocating metering device. The gas-liquid separator has an input port, a gas output port, and a liquid output port. The input port is connected to the output port, and the gas output port is connected to the gas reciprocating metering device. The gas-liquid separator is configured to separate the gas-liquid mixture at the output port, and the gas reciprocating metering device is configured to receive and analyze the gas components separated by the gas-liquid separator.

[0009] In one example of the present invention, a permeation measurement component is further included, comprising: an N2 gas cylinder, a first on / off valve, and a second on / off valve connected in sequence; a fourth common node is formed between the first and second on / off valves, the fourth common node being connected to the input terminal; a third on / off valve is also provided between the fourth common node and the input terminal; the second on / off valve is connected to the output terminal and forms a fifth common node with the output terminal; the fifth common node is connected to the gas-liquid separator; a fourth on / off valve is also provided between the fifth common node and the gas-liquid separator, the fourth on / off valve being connected to the outside; wherein a differential pressure sensor is also provided between the fourth and fifth common nodes, configured to sense the pressure difference between the input terminal and the output terminal.

[0010] In one example of the present invention, a back pressure regulation and flow path switching component is further included, comprising a back pressure pump, a back pressure container, and a back pressure valve. The back pressure pump is connected to the back pressure container, and the back pressure valve has a first interface, a second interface, and a third interface. The first interface is connected to the back pressure container, the second interface is connected to the output terminal, and the third interface is connected to the gas-liquid separator. The back pressure valve is configured to inject the pressure generated by the back pressure pump into the reactor body.

[0011] In one example of the present invention, the refrigeration unit includes: a storage tank coil and a refrigerated water washer. The storage tank coil has an inlet end and an outlet end. The inlet end is connected to the CO2 cylinder, and the outlet end is connected to a gas piston container. The refrigerated water washer is connected to the storage tank coil and configured to convert the gaseous CO2 introduced into the storage tank coil into liquid CO2.

[0012] In one example of the present invention, the medium preparation and injection assembly further includes:

[0013] A constant speed and constant pressure pump, connected to the second common node, is configured to drive the acidic liquid in the liquid piston container or the CO2 gas in the gas piston container to the reactor body via the first common node.

[0014] In one example of the invention, a fifth on-off valve is further included, which is connected between the second common node and the input terminal and forms a third common node between the first common node and the input terminal. The fifth on-off valve is configured to control the on-off of an external water source from a constant-speed, constant-pressure pump toward the input terminal.

[0015] Another objective of this invention is to provide an experimental method for a high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus as described above, comprising the following steps:

[0016] S10: The rock is processed into a cubic coal and rock sample with a regular surface; the two opposite end faces are used as the inflow and outflow faces along the proposed seepage direction; after roughening and degreasing the four side surfaces, the remaining surfaces except the inflow and outflow faces are fully encapsulated and cured with epoxy resin resistant to CO2 and carbonic acid to block the lateral bypass flow.

[0017] S20: Device installation: Fix the packaged coal and rock sample into the reactor body, so that the inflow surface is connected to the input end and the outflow surface is connected to the output end. Apply the preset confining pressure to the confining pressure chamber to the target value through the ring pressure pump, and perform a sealing check and sensor zero point calibration.

[0018] S30: Liquid Filling and Pre-equilibrium: CO2 gas is cooled by the refrigeration unit to form liquid CO2. The liquid CO2 is injected into the reactor body through the gas piston container, and the liquid piston container continues to fill the reactor body with a solution that has reached dissolution equilibrium with the liquid CO2 at the experimental temperature and pressure; the target temperature T and the average pore pressure P are set and stabilized. m To achieve initial system equilibrium; viscosity μ is taken from (T, P) m The physical properties of CO2-saturated water were determined; the input, output, and coal / rock sample pore pressures were adjusted to the same initial value P0 to achieve initial system equilibrium.

[0019] S40: Capacity Calibration: Under initial equilibrium conditions, the effective storage coefficients of the input and output terminals are calibrated respectively to obtain the effective storage coefficient C of the input terminal. u With the effective storage coefficient C at the output end d ;

[0020] S50: Model Establishment: Import the collected differential pressure-time data into the control and data processing system; establish the relationship between instantaneous flow rate and differential pressure based on the pulse decay method principle;

[0021] S60: Unsteady-state loading: Open the N2 bottle simultaneously, opening the first, second, and third on / off valves, and closing the fourth on / off valve. After the N2 pressure at the input and output ends stabilizes, close the first and second on / off valves and open the fourth on / off valve, releasing some N2 to the outside through the fourth on / off valve, creating a small pressure difference ΔP0 between the input and output ends as a pulse pressure signal; quickly open the first and second on / off valves, allowing the N2 gas to flow from the coal / rock sample to the output end under the pressure difference; use a differential pressure sensor to record the pressure decay process at the input and output ends over time; simultaneously acquire temperature signals.

[0022] S70: Data Acquisition and Processing: After pulse loading is completed, continuously acquire the input pressure Pu(t) and output pressure Pd(t) until the difference between them approaches zero; calculate the change of pressure difference with time, and perform least squares regression within the linear interval of lnΔP on time to obtain the attenuation coefficient m. When the goodness of regression satisfies R... 2 When the value is ≥0.995, the noise curves of the initial transition phase and the final phase are discarded.

[0023] S80: Based on the attenuation coefficient m, combined with the known input and output storage coefficients C. u C d Based on the geometric parameters of the rock sample and the fluid viscosity μ, the equivalent storage capacity C is obtained. The permeability k of the rock sample is calculated based on Darcy's law and the gas law. Considering the storage coefficient of the rock sample itself, the input and output ends of the storage coefficient are corrected to obtain the corrected permeability k'.

[0024] S90: Outputs the permeability k of the coal and rock sample, generates a permeability-time curve and permeability change data under CO2 mineralization reaction conditions; compares the permeability changes before and after the reaction and during the reaction process, outputs the gas-liquid mixture in the reactor body from the output end into the gas-liquid separator, separates the gas-liquid mixture into gas and liquid, and receives and analyzes the gas composition by a gas reciprocating metering device, thereby analyzing the mineralization reaction efficiency of the coal and rock sample to evaluate the impact of CO2 mineralization reaction on the pore structure of the rock sample.

[0025] In one example of the present invention, establishing the relationship between instantaneous flow rate and pressure difference in step S50 specifically includes the following process:

[0026] Under laminar flow and small disturbance conditions, the instantaneous flow rate q(t) and pressure difference Satisfying Relationship:

[0027]

[0028] In the formula, A is the cross-sectional area of ​​the core; L is the length of the core; μ is the fluid viscosity; and k is the permeability. Inlet and outlet pressure difference;

[0029] Pressure difference Defined as:

[0030]

[0031] In the formula, P u (t) represents the inlet pressure; P d (t) represents export pressure;

[0032] And the input and output terminals satisfy:

[0033]

[0034] In the formula, q(t) is the instantaneous volumetric flow rate; C u Import effective storage coefficient; C d This is the effective storage coefficient for exports;

[0035] Therefore, a first-order linear equation for the pressure difference is established:

[0036]

[0037] In the formula, m is the differential pressure exponential decay coefficient; Inlet and outlet pressure difference;

[0038] Its analytical solution is:

[0039]

[0040] In the formula, Apply an instantaneous initial pressure difference to the pulse; e is the natural constant and the base of the exponential function.

[0041] In one example of the present invention, the derivation process of the corrected permeability in step S80 is as follows:

[0042] Considering the rock sample's own storage coefficient C s In this case, ,in, Where A is the porosity, L is the cross-sectional area of ​​the core, and c is the core length. t To ensure overall compressibility, the storage coefficients at the input and output terminals are adjusted, with the storage coefficient at the input terminal being adjusted accordingly. and the storage coefficient at the output end The expression is:

[0043]

[0044] The corrected permeability k' formula is obtained as follows:

[0045]

[0046] In the formula, m is the differential pressure exponential decay coefficient; μ is the fluid viscosity.

[0047] Another object of the present invention is to provide an experimental method for a high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus as described above, characterized by comprising the following steps:

[0048] W10: Process to obtain a cubic coal and rock sample, measure and record the initial volume V0. Except for the end face that needs to be exposed as a seepage contact, the other five faces are coated and cured with epoxy resin, and the strain sensor and wire are sealed and fixed with epoxy resin.

[0049] W20: Strain gauges or fiber Bragg grating strain sensors are arranged in three mutually orthogonal directions on the coal and rock sample, and an independent fiber optic temperature compensation element is set up. The sensor leads or optical fibers are led out of the reactor body and connected to the data acquisition system.

[0050] W30: The encapsulated coal and rock sample is fixedly installed in the working cavity inside the reactor body, so that the two ends of the coal and rock sample are connected to the input end and the output end respectively.

[0051] W40: Calibrate the zero point, sensitivity, and temperature coefficient of strain and temperature sensors under set temperature and pressure conditions; calibrate the system compliance and thermally induced baseline volume change using rigid substitutes under the same installation conditions.

[0052] W50: CO2 gas is cooled by the refrigeration unit to form liquid CO2. Liquid CO2 is injected into the reactor body through the gas piston container, and water that has reached dissolution equilibrium with CO2 at the experimental temperature and pressure is filled through the liquid piston container. Back pressure and temperature are set so that the average pore pressure is at least 1~2 MPa higher than the CO2 saturation pressure at that temperature, and stabilized to an isothermal and isobaric state.

[0053] W60: CO2-water-rock chemical reaction was carried out under constant temperature, back pressure and selectable confining pressure conditions, and triaxial strain, temperature and pressure signals were continuously collected.

[0054] W70: Temperature compensation and pressure coupling correction are applied to the strain signal to obtain the triaxial corrected strain ε. x ε y ε z The change of volumetric strain ε over time v The expression is:

[0055]

[0056] In the formula, ε x For volumetric strain in the X direction, ε y For volumetric strain in the y-direction, ε z The volumetric strain is in the Z direction;

[0057] Calculate the volume change of the coal and rock sample using the initial volume V0. Its expression is:

[0058]

[0059] In the formula, V0 represents the initial volume; ε represents the initial volume. v (t) Volumetric strain;

[0060] Thus, the expression for the evolution of volume over time is obtained as follows:

[0061]

[0062] W80: Statistical analysis and curve fitting are performed on the volumetric strain data from multiple repeated experiments. The gas-liquid mixture in the reactor body is output from the output end into the gas-liquid separator to separate the gas and liquid mixture. The gas composition is received and analyzed by the gas reciprocating metering device to obtain the evolution curve of volumetric strain over time during the CO2 mineralization reaction, so as to reveal the volume evolution mechanism and reaction stage characteristics in the mineralization reaction process.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] This invention overcomes the shortcomings of traditional methods, such as the need to interrupt the reaction and data dispersion, by combining the unsteady-state pulse decay method with dynamic correction of the system storage coefficient. It achieves continuous in-situ measurement of rock sample permeability under high temperature and high pressure sealed conditions. Through strain sensing and temperature-pressure coupling compensation, it solves the problem of simultaneously acquiring multi-directional strain data within the autoclave, enabling real-time and accurate monitoring of rock sample volumetric strain during the mineralization reaction. This invention provides a complete and reliable technical means to reveal the dynamic evolution of physical parameters during gas-liquid-rock multiphase reactions.

[0065] This invention enables real-time integrated monitoring of multiple physical parameters. The device integrates high-precision temperature and pressure sensors, combines timed liquid sampling and analysis to obtain the pH value of the reaction solution, and uses stress-strain monitoring methods such as strain gauges and optical fibers to measure strain data and calculate volumetric strain. Simultaneously, it incorporates permeability testing to achieve the synchronous acquisition of key reaction parameters such as temperature, pressure, pH, volumetric strain, and permeability during high-temperature and high-pressure multiphase chemical reactions. This solves the problem of existing devices requiring multiple start-ups and shutdowns for single-parameter measurements, reduces sources of experimental error, shortens the experimental cycle, and significantly improves the continuity and completeness of experimental data.

[0066] This invention enables quantitative correlation analysis between the evolution of microstructure and changes in macroscopic mechanical properties during CO2 mineralization. By acquiring strain data in real time using stress-strain monitoring methods such as strain gauges and optical fibers, the volumetric strain is calculated. Furthermore, fluid flow rate and pressure changes are measured during the experiment, and permeability is calculated using a non-steady-state method. This allows for the dynamic reflection of the physical response and the evolution of mechanical properties of rocks during CO2 capture. It provides direct and reliable experimental evidence for elucidating the kinetic mechanism of mineralization reactions and the evolution of pore structure, information that existing technologies typically cannot obtain during the reaction process.

[0067] The preferred embodiments of the invention will be described in more detail below with reference to the accompanying drawings, so as to facilitate an understanding of the features and advantages of the invention. Attached Figure Description

[0068] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. The drawings are merely illustrative of some embodiments of the present invention and are not intended to limit the scope of the present invention to all embodiments.

[0069] Figure 1 This is a schematic diagram of a high-temperature and high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus according to an embodiment of the present invention;

[0070] Figure 2 This is a schematic diagram of the structure of the reactor body according to an embodiment of the present invention;

[0071] Figure 3 This is a flowchart of the permeability test method for coal and rock samples according to an embodiment of the present invention;

[0072] Figure 4 This is a flowchart of the strain test method for coal and rock samples according to an embodiment of the present invention;

[0073] Figure 5 This is a flowchart of the pH value experimental method for CO2 mineralization reaction according to an embodiment of the present invention.

[0074] List of reference numerals in the attached diagram:

[0075] Experimental setup 100;

[0076] Medium preparation and injection assembly 10; CO2 cylinder 11; refrigeration unit 12; storage tank coil 121; refrigerated water washer 122; CO2 pressure gauge 123; safety valve 124; intermediate container 13; gas piston container 131; liquid piston container 132; constant speed and constant pressure pump 14; fifth on / off valve 15; ninth on / off valve 16; tenth on / off valve 17; eleventh on / off valve 18; twelfth on / off valve 19; first common node A; second common node B; third common node C;

[0077] Reactor assembly 20; Reactor body 21; Input end 211; Output end 212; Reactor body 213; Reactor cover 214; Heating furnace 215; Speed ​​regulating motor 216; External magnet 217; Stirring magnet 218; Circulating pressure pump 22; Drain valve 23; Fourth common node D; Fifth common node E;

[0078] Multiphase separation and metering component 30; gas-liquid separator 31; input port 311; gas output port 312; liquid output port 313; gas reciprocating metering device 32; multi-component gas analyzer 321; dryer 33; electronic balance 34; beaker 341; eighth shut-off valve 35;

[0079] Permeation measurement assembly 40; N2 gas cylinder 41; pressure regulating valve 411; standard chamber 42; first on / off valve 43; second on / off valve 44; third on / off valve 45; differential pressure sensor 46; fourth on / off valve 47; fine-tuning valve 471; pressure gauge 48; sixth on / off valve 49;

[0080] Back pressure regulation and flow path switching component 50; back pressure pump 51; back pressure container 52; back pressure valve 53; first interface 531; second interface 532; third interface 533; seventh on / off valve 54; display pressure gauge 55;

[0081] Coal and rock sample 200; enclosure 201; epoxy resin 202; acoustic probe 203. Detailed Implementation

[0082] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0083] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, “an” or “a” and similar terms do not necessarily indicate a quantity limitation. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0084] According to a first aspect of the present invention, a high-temperature and high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus 100 is provided, such as... Figure 1 , Figure 2 As shown, it includes:

[0085] The medium preparation and injection assembly 10 includes: a CO2 cylinder 11, a refrigeration unit 12, and an intermediate container 13 connected in sequence. The refrigeration unit 12 is configured to convert gaseous CO2 into liquid CO2. The intermediate container 13 includes: a gas piston container 131 and a liquid piston container 132 connected in parallel, with a first common node A and a second common node B formed at their two ends, respectively. It is configured to output CO2 gas or liquid from the first common node A.

[0086] The reactor assembly 20 includes a reactor body 21 and a ring pressure pump 22 connected thereto. The reactor body 21 has an input end 211 and an output end 212. The input end 211 is connected to the first common node A and the second common node B. The reactor body 21 contains a coal and rock sample 200. The reactor body 21 is configured to heat the coal and rock sample 200 at high temperature. The ring pressure pump 22 is configured to apply and maintain a constant confining pressure on the coal and rock sample 200.

[0087] The multiphase separation and metering component 30 includes a gas-liquid separator 31 and a gas reciprocating metering device 32. The gas-liquid separator 31 has an input port 311, a gas output port 312, and a liquid output port 313. The input port 311 is connected to the output port 212, and the gas output port 312 is connected to the gas reciprocating metering device 32. The gas-liquid separator 31 is configured to separate the gas-liquid mixture at the output port 212, and the gas reciprocating metering device 32 is configured to receive and analyze the gas components separated by the gas-liquid separator 31.

[0088] For example, during a permeation test: the rock is processed into a cubic coal-rock sample 200 with a regular surface; two opposite end faces are used as the inflow and outflow faces along the intended seepage direction; after roughening and degreasing the four side surfaces, all surfaces except the inflow and outflow faces are fully encapsulated and cured with CO2 and carbonic acid resistant epoxy resin 202 to block lateral bypass flow; the encapsulated coal-rock sample 200 is fixed in the reactor body 21, with the inflow face connected to the input end 211 and the outflow face connected to the output end 212; a preset confining pressure is applied to the confining pressure chamber to the target value through the ring pressure pump 22, and a sealing check and sensor zero-point calibration are performed; CO2 gas is cooled by the refrigeration unit 12 to form liquid CO2, and the liquid CO2 is injected into the reactor body 21 through the gas piston container 131, and the liquid piston container 132 continues to fill the reactor body 21 with a solution that has reached dissolution equilibrium with the liquid CO2 at the experimental temperature and pressure; the target temperature T and the average pore pressure P are set and stabilized. m To achieve initial system equilibrium; viscosity μ is taken from (T, P) m The physical properties of CO2-saturated water were assessed. The pore pressure of the input terminal 211, output terminal 212, and coal / rock sample 200 were adjusted to the same initial value P0 to achieve initial system equilibrium. Under these initial equilibrium conditions, the effective storage coefficients of the input terminal 211 and output terminal 212 were calibrated to obtain the effective storage coefficient C of the input terminal 211. u The effective storage coefficient C of the output terminal 212 dThe collected pressure difference-time data is imported into the control and data processing system. Based on the pulse decay method, the relationship between instantaneous flow rate and pressure difference is established. Unsteady-state loading is performed: unsteady-state recording is carried out at the input end 211 and output end 212 of the reactor body 21, creating a small pressure difference ΔP0 between the input end 211 and output end 212, which serves as a pulse pressure signal. The pulsed gas is driven by the pressure difference to flow from the coal and rock sample 200 to the output end 212, and the pressure decay process of the input end 211 and output end 212 over time is recorded. Temperature signals are collected synchronously. After the pulse loading is completed, the pressure Pu(t) at the input end 211 and the pressure Pd(t) at the output end 212 are continuously collected until the difference approaches zero. The change in pressure difference over time is calculated, and least squares regression is performed within the linear interval of lnΔP against time to obtain the decay coefficient m. When the goodness of regression satisfies R... 2 When the value is ≥0.995, the initial transition section and the final noise curve are discarded; based on the attenuation coefficient m, combined with the known storage coefficient C of input terminal 211 and output terminal 212. u C d The equivalent storage capacity C is obtained by taking the geometric parameters of the rock sample and the fluid viscosity μ. The permeability k of the rock sample is calculated based on Darcy's law and the gas equation of state. Considering the storage coefficient of the rock sample itself, the input end 211 and the output end 212 of the storage coefficient are corrected to obtain the corrected permeability k'. The permeability k of the coal and rock sample 200 is output, and the permeability-time curve and permeability change data under CO2 mineralization reaction conditions are generated. The permeability changes before and after the reaction and during the reaction process are compared to evaluate the influence of CO2 mineralization reaction on the pore structure of the rock sample. At the end of the permeation experiment, the gas-liquid mixture in the reaction vessel body 21 is output from the output end 212 into the gas-liquid separator 31 to separate the gas and liquid mixture. The gas reciprocating metering device 32 receives and analyzes the gas composition, thereby analyzing the mineralization reaction efficiency of the coal and rock sample 200.

[0089] For example, in strain experiments, a cubic coal and rock sample is prepared, and its initial volume V0 is measured and recorded. Except for the end face exposed for seepage contact, the other five faces are coated and cured with epoxy resin, and the strain sensor and wires are sealed and fixed using epoxy resin. Strain gauges or fiber Bragg grating strain sensors are arranged in three mutually orthogonal directions on the coal and rock sample, with independent fiber optic temperature compensation elements. The sensor leads or optical fibers are led out of the reactor body and connected to the data acquisition system. The encapsulated coal and rock sample is fixedly installed in the working cavity inside the reactor body, with both ends of the coal and rock sample connected to... After sealing the input and output terminals, connect to the back pressure system. Under set temperature and pressure conditions, calibrate the zero point, sensitivity, and temperature coefficient of the strain measurement system. Using a rigid substitute, calibrate the system compliance and thermally induced baseline volume change under the same installation conditions. Cool CO2 gas to form liquid CO2 via a refrigeration unit. The liquid CO2 is injected into the reactor body through a gas piston container, and water that has reached dissolution equilibrium with CO2 at the experimental temperature and pressure is added through the liquid piston container. Set the back pressure and temperature so that the average pore pressure is at least 1-2 MPa higher than the CO2 saturation pressure at that temperature, stabilizing to an isothermal and isobaric state. Perform the CO2-water-rock chemical reaction under constant temperature, back pressure, and optional confining pressure conditions, continuously acquiring triaxial strain, temperature, and pressure signals. Perform temperature compensation and pressure coupling correction on the strain signals to obtain the triaxially corrected strain ε. x ε y ε z The change of volumetric strain ε over time v Based on the initial volume V0, the volume change of the coal and rock sample is calculated. This allows for the acquisition of an expression for the volume evolution over time. Statistical analysis and curve fitting are performed on the volumetric strain data from multiple repeated experiments to obtain the evolution curve of volumetric strain over time during the CO2 mineralization reaction, revealing the volume evolution mechanism and reaction stage characteristics in the mineralization process. At the end of the strain experiment, the gas-liquid mixture in the reactor body 21 is output from the output end 212 into the gas-liquid separator 31 for gas-liquid separation. The gas is then received and analyzed by the gas reciprocating metering device 32, thereby enabling the analysis of the mineralization reaction efficiency of the coal and rock sample 200.

[0090] This experimental system overcomes the shortcomings of traditional methods, such as the need to interrupt the reaction and data dispersion, by combining the unsteady-state pulse decay method with dynamic correction of the system storage coefficient. It achieves continuous in-situ measurement of rock sample permeability under high temperature and high pressure sealed conditions. Through strain sensing and temperature-pressure coupling compensation, it solves the problem of simultaneously acquiring multi-directional strain data within the autoclave, enabling real-time and accurate monitoring of rock sample volumetric strain during the mineralization reaction. This invention provides a complete and reliable technical means to reveal the dynamic evolution of physical parameters during gas-liquid-rock multiphase reactions.

[0091] This experimental system enables real-time integrated monitoring of multiple physical parameters. The device integrates high-precision temperature and pressure sensors, combines timed liquid sampling and analysis to obtain the pH value of the reaction solution, and uses strain gauges, optical fibers, and other stress-strain monitoring methods to measure strain data and calculate volumetric strain. Simultaneously, it is equipped with a permeability testing module to achieve the synchronous acquisition of key reaction parameters such as temperature, pressure, pH, volumetric strain, and permeability during high-temperature and high-pressure multiphase chemical reactions. This solves the problem of existing devices requiring multiple start-ups and shutdowns for single-parameter measurements, reduces sources of experimental error, shortens the experimental cycle, and significantly improves the continuity and completeness of experimental data.

[0092] This experimental system enables quantitative correlation analysis between the evolution of microstructure and changes in macroscopic mechanical properties during CO2 mineralization. By acquiring strain data in real time using stress-strain monitoring methods such as strain gauges and optical fibers, it calculates volumetric strain and measures fluid flow rate and pressure changes during the experiment. Permeability is calculated using a non-steady-state method, dynamically reflecting the physical response and evolution of mechanical properties of rocks during CO2 capture. This provides direct and reliable experimental evidence for elucidating the kinetic mechanism of mineralization reactions and the evolution of pore structure, information that current technologies typically cannot obtain during the reaction process.

[0093] It is worth noting that both the gas piston container 131 and the liquid piston container 132 are piston structures. The gas in the gas piston container 131 is located at the upper end of the piston, and the liquid in the liquid piston container 132 is located at the upper end of its piston. The liquid is injected into the lower end of the piston of both the gas piston container 131 and the liquid piston container 132 by a constant speed and constant pressure pump 14, thereby controlling the injection volume of the gas piston container 131 and the liquid piston container 132.

[0094] It is understandable that, such as Figure 2As shown, the reactor body 21 includes a vessel body 213, a vessel cover 214, a heating furnace 215, a speed-regulating motor 216, an external magnetic magnet 217, and a stirring magnetic magnet 218. The vessel body 213 has an open-ended cavity. The vessel cover 214 is sealed and fixedly connected to the open end of the vessel body 213 by fasteners. The input end 211 and the output end 212 are respectively located on the vessel cover 214. The speed-regulating motor 216 is fixedly connected to the bottom end of the vessel body 213, and the external magnetic magnet 217 is fixedly connected to the speed-regulating motor 216. On the output shaft of the motor 216, the stirring magnet 218 is pivotally connected to the bottom end of the vessel cavity and is positioned opposite to the outer magnet 217. The output shaft of the speed-regulating motor 216 drives the outer magnet 217 located at the bottom of the vessel body 213. The rotating magnetic field generated by it penetrates the non-magnetic vessel body 213 and drives the stirring magnet 218 and the stirring paddle placed in the vessel cavity to rotate synchronously, thereby stirring the solution in the vessel cavity. The heating furnace 215 is arranged around the circumference of the vessel body 213 and is used to heat the vessel cavity to form a high-temperature environment.

[0095] It should be noted that, regarding the coal and rock sample 200, a surrounding plate 201 is provided inside the reactor body 21. For example, two surrounding plates 201 can be symmetrically arranged to facilitate the connection of the coal and rock sample 200 inside the reactor body 21. The outer periphery of the coal and rock sample 200 is covered with epoxy resin 202. During the experiment, the surrounding plate 201 can be covered inside the epoxy resin 202. An inlet end and an outlet end are provided on both sides of the surrounding plate 201. Acoustic wave probes 203 are provided at the upper and lower ends of the coal and rock sample 200 to detect signals such as the development of internal cracks, stress changes, and damage degree of the coal and rock sample 200. Acoustic emission probes are provided on both symmetrical sides of the coal and rock sample 200 to detect the elastic wave signals generated by the fracture of the coal and rock sample 200.

[0096] Preferably, the medium preparation and injection assembly 10 further includes: a CO2 pressure gauge 123, a safety valve 124, a ninth shut-off valve 16, a tenth shut-off valve 17, an eleventh shut-off valve 18, and a twelfth shut-off valve 19. The CO2 pressure gauge 123 is mounted on the storage tank coil to monitor the CO2 pressure within it. The safety valve 124 is connected to the inlet end of the storage tank coil 121 to ensure the stability and safety of the pressure in the entire experimental apparatus 100. The ninth shut-off valve 16 controls the flow of CO2 from the CO2 cylinder 11 towards the storage tank coil 121. The tenth shut-off valve 17 is connected between the ninth shut-off valve 16 and the CO2 pressure gauge 123 and is connected to the outside, configured to discharge gas to the outside (for example, to discharge pipeline gas at the end of the experiment); the eleventh shut-off valve 18 and the twelfth shut-off valve 19 are located at the outlet end of the storage tank coil 121. The eleventh shut-off valve 18 is used to control the flow of CO2 from the storage tank coil 121 toward the intermediate container 13; the twelfth shut-off valve 19 is located between the eleventh shut-off valve 18 and the intermediate container 13 and is connected to the outside, configured to discharge gas to the outside.

[0097] In one example of the present invention, the device further includes a permeation measurement component 40, comprising: an N2 gas cylinder 41, a first on / off valve 43, and a second on / off valve 44 connected in sequence; a fourth common node D is formed between the first on / off valve 43 and the second on / off valve 44; the fourth common node D is connected to the input terminal 211; a third on / off valve 45 is also provided between the fourth common node D and the input terminal 211; the second on / off valve 44 is connected to the output terminal 212 and forms a fifth common node E between the second on / off valve 44 and the output terminal 212; the fifth common node E is connected to the gas-liquid separator 31; a fourth on / off valve 47 is also provided between the fifth common node E and the gas-liquid separator 31; the fourth on / off valve 47 is connected to the outside; wherein a differential pressure sensor 46 is also provided between the fourth common node D and the fifth common node E, configured to sense the pressure difference between the input terminal 211 and the output terminal 212.

[0098] For example, the permeation measurement assembly 40 further includes: a pressure regulating valve 411, a standard chamber 42, a pressure gauge 48, and a sixth on / off valve 49. The pressure regulating valve 411 is located between the N2 cylinder 41 and the first on / off valve 43 and is configured to adjust the N2 pressure. The standard chamber 42 and the pressure gauge 48 are respectively located at the input end 211 and the output end 212. For example, they can be located between the first on / off valve 43 and the fourth common node D. The standard chamber 42 is used to maintain the gas balance and stability of the test device. The pressure gauge 48 is used to measure the pressure values ​​at the input end 211 and the output end 212. The sixth on / off valve 49 is used to control the flow of liquid or gas from the input end 211 toward the fourth on / off valve 47.

[0099] For example, a fine-tuning valve 471 is provided on the fourth on / off valve 47, and exhaust is performed through the fine-tuning valve 471.

[0100] Specifically, the permeability measuring device is used to measure permeability, and its working principle is as follows: The N2 bottle is opened simultaneously with the first shut-off valve 43, the second shut-off valve 44, the third shut-off valve 45, and the sixth shut-off valve 49, while the fourth shut-off valve 47 is closed. N2 flows through the first shut-off valve 43 and the second shut-off valve 44, entering the reactor body 21 from the input end 211, and then exiting from the output end 212. After the N2 pressure at the input end 211 and the output end 212 stabilizes, the first shut-off valve 43 and the second shut-off valve 44 are closed, and the fourth shut-off valve 47 is opened. The fourth shut-off valve 47 releases a portion of N2 to the outside, creating a small pressure difference ΔP0 between the input end 211 and the output end 212, which serves as a pulse pressure signal. The first shut-off valve 43 and the second shut-off valve 44 are quickly opened, allowing the N2 gas to flow from the coal and rock sample 200 to the output end 212 under the pressure difference. The differential pressure sensor 46 records the process of pressure decay at the input end 211 and the output end 212 over time, while the pressure gauge 48 measures the pressure values ​​at the input end 211 and the output end 212.

[0101] In one example of the present invention, a back pressure regulation and flow path switching component 50 is further included, comprising a back pressure pump 51, a back pressure container 52, and a back pressure valve 53. The back pressure pump 51 is connected to the back pressure container 52. The back pressure valve 53 has a first interface 531, a second interface 532, and a third interface 533. The first interface 531 is connected to the back pressure container 52, the second interface 532 is connected to the output terminal 212, and the third interface 533 is connected to the gas-liquid separator 31. The back pressure valve 53 is configured to inject the pressure generated by the back pressure pump 51 into the reactor body 21.

[0102] For example, the back pressure regulation and flow path switching component 50 also includes a seventh on / off valve 54 and a display pressure gauge 55. The back pressure pump 51 can be a manual back pressure pump. The pressure generated by the back pressure pump 51 is stored in the back pressure container 52. The back pressure valve 53 then regulates the on / off of the first interface 531 and the second interface 532 to control whether the pressure is injected into the reactor body 21.

[0103] It should be noted that the back pressure regulation and flow path switching component 50 generally does not participate in the operation of the entire experimental device 100. It can inject pressure into the experimental device 100 only when the pressure inside is insufficient. For example, when the constant speed and constant pressure pump 14 injects liquid into the reaction vessel body 21 during the strain experiment, if it is found that the injection pressure of the constant speed and constant pressure pump 14 cannot be increased further, in order to better inject the liquid into the core of the coal and rock sample 200, the first port 531 and the second port 532 of the back pressure valve 53 can be connected, so that the back pressure regulation and flow path switching component 50 acts as a back pressure system.

[0104] In one example of the present invention, the refrigeration unit 12 includes a storage tank coil 121 and a refrigerated water washer 122. The storage tank coil 121 has an inlet end and an outlet end. The inlet end is connected to the CO2 cylinder 11, and the outlet end is connected to the gas piston container 131. The refrigerated water washer 122 is connected to the storage tank coil 121 and is configured to convert the gaseous CO2 introduced into the storage tank coil 121 into liquid CO2.

[0105] In one example of the present invention, the medium preparation and injection component 10 further includes:

[0106] A constant speed and constant pressure pump 14 is connected to the second common node B and is configured to drive the acidic liquid in the liquid piston container 132 or the CO2 gas in the gas piston container 131 to the reactor body 21 via the first common node A.

[0107] The intermediate container 13 can inject liquid CO2 or a solution into the reactor body 21. The solution generally includes an acidic solution and water. The acidic solution is located in the liquid piston container 132. When it is necessary to inject an acidic solution into the reactor body 21, the fifth shut-off valve 15 is closed, and the constant speed and pressure pump 14 injects liquid into the liquid piston container 132 to push the piston to move, so that the acidic solution at the upper end is sequentially transported to the input end 211 through the first common node A and the third common node C. When it is necessary to inject water into the reactor body 21, the fifth shut-off valve 15 can be opened, and the constant speed and pressure pump 14 can directly inject external water into the reactor body 21.

[0108] In one example of the present invention, a drain valve 23 is further provided on the reactor body 21. The drain valve 23 is configured to open or close the reactor body 21 to collect liquid inside the reactor body 21 or to maintain a high-temperature and high-pressure environment inside the reactor. A drain valve 23 communicating with the internal fluid is provided at the lower part of the reactor body for liquid extraction operations.

[0109] In one example of the invention, a fifth on / off valve 15 is also included, which is connected between the second common node B and the input terminal 211 and forms a third common node C between the first common node A and the input terminal 211. The fifth on / off valve 15 is configured to control the on / off of an external water source from the constant speed and pressure pump 14 toward the input terminal 211.

[0110] When water needs to be injected into the reactor body 21, the fifth shut-off valve 15 is opened, and the constant speed and constant pressure pump 14 directly delivers the external water source to the input end 211 via the fifth shut-off valve 15.

[0111] In one example of the present invention, the multiphase separation and metering assembly 30 further includes: an eighth on / off valve 35, an electronic balance 34, and a dryer 33. The eighth on / off valve 35 is located at the third port 533 of the gas-liquid separator 31 and is used to control the flow of liquid in the gas-liquid separator 31 through the third port 533. The electronic balance 34 is located at the third port 533 and is equipped with a beaker 341 for receiving and weighing the liquid in the gas-liquid separator 31. The dryer 33 is located between the second port 532 and the gas reciprocating metering device 32 and is used to dry the gas separated by the gas-liquid separator 31. The gas reciprocating metering device 32 is equipped with a multi-component gas analyzer 321 for analyzing the composition of the gas.

[0112] According to a second aspect of the present invention, an experimental method for a high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus 100 as described above is provided. Figure 3 As shown, it includes the following steps:

[0113] S10: The rock is processed into a 60×60×60 mm cube coal rock sample 200 with a regular surface; along the proposed seepage direction, the two opposite end faces are used as the inflow and outflow surfaces, and the seepage length L = 60 mm and the cross-sectional area A = 60 mm × 60 mm are recorded; after roughening and degreasing the four side surfaces, the remaining surfaces except the inflow and outflow surfaces are fully encapsulated and cured with epoxy resin 202 that is resistant to CO2 and carbonic acid to block the lateral bypass flow;

[0114] S20: Device installation: Fix the packaged coal and rock sample 200 inside the reactor body 21, so that the inflow surface is connected to the input end 211 and the outflow surface is connected to the output end 212. Load the preset confining pressure to the confining pressure chamber to the target value through the ring pressure pump 22, and perform a sealing check and sensor zero point calibration.

[0115] S30: Liquid Filling and Pre-equilibrium: CO2 gas is cooled by the refrigeration unit 12 to form liquid CO2. The liquid CO2 is injected into the reactor body 21 through the gas piston container 131, and the solution that has reached dissolution equilibrium with the liquid CO2 at the experimental temperature and pressure is continuously filled into the reactor body 21 through the liquid piston container 132; the target temperature T and the average pore pressure P are set and stabilized. m To achieve initial system equilibrium; viscosity μ is taken from (T, P) m The physical properties of CO2-saturated water were determined; the pore pressure of the input end 211, the output end 212, and the coal and rock sample 200 were adjusted to the same initial value P0 to achieve initial system equilibrium.

[0116]

[0117] In the formula, P u (0) represents the initial inlet pressure; P d (0) represents the initial pressure at the export;

[0118] S40: Capacity Calibration: Under the initial equilibrium conditions, the effective storage coefficient is calibrated for input terminal 211 and output terminal 212 respectively. The expression for the effective storage coefficient C is:

[0119]

[0120] In the formula, For pressure difference, For volume difference;

[0121] The effective storage coefficient C of input terminal 211 is obtained. u The effective storage coefficient C of the output terminal 212 d The effective storage coefficient includes the combined contribution of the cavity, connecting pipelines, and device compliance;

[0122] S50: Model Establishment: Import the collected differential pressure-time data into the control and data processing system; establish the relationship between instantaneous flow rate and differential pressure based on the principle of pulse decay method;

[0123] S60: Unsteady-state loading: Open the N2 bottle and simultaneously open the first shut-off valve 43, the second shut-off valve 44, and the third shut-off valve 45, and close the fourth shut-off valve 47. After the N2 pressure at the input end 211 and the output end 212 stabilizes, close the first shut-off valve 43 and the second shut-off valve 44, and open the fourth shut-off valve 47. Release some N2 to the outside through the fourth shut-off valve 47, so that a small pressure difference ΔP0 is formed between the input end 211 and the output end 212, which serves as a pulse pressure signal. Quickly open the first shut-off valve 43 and the second shut-off valve 44, so that the N2 gas flows from the coal and rock sample 200 to the output end 212 under the pressure difference. Use the differential pressure sensor 46 to record the process of pressure decay at the input end 211 and the output end 212 over time. Simultaneously collect temperature signals to correct the fluid density and compressibility coefficient.

[0124] S70: Data Acquisition and Processing: After pulse loading is completed, continuously acquire the pressure Pu(t) at input terminal 211 and the pressure Pd(t) at output terminal 212 until the difference between them approaches zero; calculate the change of pressure difference with time, and perform least squares regression within the linear interval of lnΔP on time to obtain the attenuation coefficient m. When the goodness of regression satisfies R... 2 When the value is ≥0.995, the noise curves of the initial transition section and the final section are discarded, and the pressure difference ratio ΔP / ΔP0∈[0.1, 0.8] is preferred;

[0125] The expression for calculating the change in pressure difference over time is:

[0126]

[0127] In the formula, P u (t) represents the inlet pressure; P d (t) represents export pressure;

[0128] S80: Based on the attenuation coefficient m, combined with the known storage coefficient C of input terminal 211 and output terminal 212. u C d The equivalent storage capacity C is obtained by taking the geometric parameters of the rock sample and the fluid viscosity μ. The permeability k of the rock sample is calculated based on Darcy's law and the gas law. Considering the storage coefficient of the rock sample itself, the input end 211 and the output end 212 of the storage coefficient are corrected to obtain the corrected permeability k'.

[0129] Based on the attenuation coefficient m, and combined with the known storage coefficients C of input terminal 211 and output terminal 212... u C d The geometric parameters of the rock sample, the fluid viscosity μ, and the equivalent storage capacity C are given by the expression for the equivalent storage capacity C:

[0130]

[0131] The permeability k of a rock sample is calculated based on Darcy's law and the gas law, and its expression is as follows:

[0132]

[0133] Where A is the cross-sectional area of ​​the core, L is the length of the core, and m is the pressure differential index attenuation coefficient.

[0134] S90: Output the permeability k' of the coal and rock sample at 200 m³ (SI units), and calculate the result according to 1 mD = 9.869233 × 10⁻⁶. −16 m 2 Converted to commonly used units mD; the control and safety system generates permeability-time curves and permeability change data under CO2 mineralization reaction conditions; comparing the permeability changes before and after the reaction and during the reaction process, the gas-liquid mixture in the reactor body 21 is output from the output end 212 into the gas-liquid separator 31 to separate the gas-liquid mixture, and the gas reciprocating metering device 32 receives and analyzes the gas composition, thereby analyzing the mineralization reaction efficiency of the coal and rock sample 200 to evaluate the impact of CO2 mineralization reaction on the pore structure of the rock sample.

[0135] In one example of the present invention, in step S50, the relationship between instantaneous flow rate and pressure difference is established: under laminar flow and small disturbance conditions, the instantaneous flow rate q(t) and pressure difference satisfy the following relationship:

[0136]

[0137] In the formula, A is the cross-sectional area of ​​the core; L is the length of the core; μ is the fluid viscosity; and k is the permeability. Inlet and outlet pressure difference;

[0138] Where the pressure difference is defined as:

[0139]

[0140] In the formula, P u (t) represents the inlet pressure; P d (t) represents export pressure;

[0141] And input terminal 211 and output terminal 212 satisfy:

[0142]

[0143] In the formula, q(t) is the instantaneous volumetric flow rate (m³ / s). 3 / s), gas volume flux from top to bottom along the core; C u Import effective storage coefficient (m) 3 / Pa); C d Export effective storage coefficient (m) 3 / Pa);

[0144] Therefore, a first-order linear equation for the pressure difference is established:

[0145]

[0146] In the formula, m is the differential pressure exponential decay coefficient; Inlet and outlet pressure difference;

[0147] Its analytical solution is:

[0148]

[0149] In the formula, Apply an instantaneous initial pressure difference to the pulse; e is the natural constant and the base of the exponential function.

[0150] In one example of the present invention, considering the rock sample's own storage coefficient C s In this case, ,in, Where A is the porosity, L is the cross-sectional area of ​​the core, and c is the core length. t To improve overall compressibility, the storage coefficients at input 211 and output 212 are adjusted. The storage coefficient at input 211 is... and the storage coefficient of output terminal 212 The expression is:

[0151]

[0152] The corrected permeability k' formula is obtained as follows:

[0153] .

[0154] According to a third aspect of the present invention, an experimental method for a high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus 100 as described above is provided. Figure 4 As shown, it includes the following steps:

[0155] W10: Process to obtain a cubic coal and rock sample 200, for example, process a cubic rock sample with a side length of 60 mm; measure and record the initial volume V0; except for the end face that needs to be exposed as a seepage contact, the other five faces are coated and cured with epoxy resin 202, and the strain sensor and wire are sealed and fixed with epoxy resin 202.

[0156] W20: Strain gauges or fiber Bragg grating strain sensors are arranged in three mutually orthogonal directions on the coal and rock sample 200. Independent fiber temperature compensation elements are set up, and the sensor leads or optical fibers are led out of the reactor body 21 and connected to the data acquisition system.

[0157] W30: The sealed coal and rock sample 200 is fixedly installed in the working cavity inside the reactor body 21, so that the two ends of the coal and rock sample 200 are connected to the input end 211 and the output end 212 respectively. After sealing, the back pressure regulation and flow path switching component 50 is connected.

[0158] W40: Calibrate the zero point, sensitivity, and temperature coefficient of strain and temperature sensors under set temperature and pressure conditions; calibrate the system compliance and thermally induced baseline volume change using rigid substitutes under the same installation conditions.

[0159] W50: CO2 gas is cooled by the refrigeration unit 12 to form liquid CO2. The liquid CO2 is injected into the reactor body 21 through the gas piston container 131, and water that has reached dissolution equilibrium with CO2 at the experimental temperature and pressure is filled by the liquid piston container 132. The back pressure and temperature are set so that the average pore pressure is at least 1~2 MPa higher than the CO2 saturation pressure at that temperature, and stabilized to an isothermal and isobaric state.

[0160] W60: CO2-water-rock chemical reaction was carried out under constant temperature, back pressure and selectable confining pressure conditions, and triaxial strain, temperature and pressure signals were continuously collected.

[0161] W70: Temperature compensation and pressure coupling correction are applied to the strain signal to obtain the triaxial corrected strain ε. x ε y ε z The change of volumetric strain ε over time v The expression is:

[0162]

[0163] In the formula, ε x For volumetric strain in the X direction, ε y For volumetric strain in the y-direction, ε z The volumetric strain is in the Z direction;

[0164] Calculate the volume change of the coal and rock sample using the initial volume V0. Its expression is:

[0165]

[0166] In the formula, V0 represents the initial volume; ε represents the initial volume. v (t) Volumetric strain;

[0167] Thus, the expression for the evolution of volume over time is obtained as follows:

[0168]

[0169] W80: Statistical analysis and curve fitting are performed on the volumetric strain data from multiple repeated experiments. The gas-liquid mixture in the reactor body 21 is output from the output end 212 into the gas-liquid separator 31 to separate the gas and liquid mixture. The gas composition is received and analyzed by the gas reciprocating metering device 32 to obtain the evolution curve of volumetric strain over time during the CO2 mineralization reaction, so as to reveal the volumetric evolution mechanism and reaction stage characteristics in the mineralization reaction process.

[0170] An experimental method according to a fourth aspect of the present invention, using the high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus 100 as described above, is as follows: Figure 5 As shown, it includes the following steps:

[0171] V10: Manually open the drain valve 23 during the predetermined reaction stage to drain a certain amount of reaction solution into the sampling container;

[0172] V20: Close the drain valve 23 to restore the sealing state of the reactor body 21 and maintain the stability of the high temperature and high pressure environment inside the reactor;

[0173] V30: pH value detection of the liquid sample is used to help determine the reaction progress and analyze the chemical change trend of the mineralization process in the reaction system.

[0174] In summary, this experimental method has the following beneficial effects:

[0175] This experimental method overcomes the shortcomings of traditional methods, such as the need to interrupt the reaction and data dispersion, by combining the unsteady-state pulse decay method with dynamic correction of the system storage coefficient. It achieves continuous in-situ measurement of rock sample permeability under high temperature and high pressure sealed conditions. Through strain sensing and temperature-pressure coupling compensation, it solves the problem of simultaneously acquiring multi-directional strain data within the autoclave, enabling real-time and accurate monitoring of rock sample volumetric strain during the mineralization reaction. This invention provides a complete and reliable technical means to reveal the dynamic evolution of physical parameters during gas-liquid-rock multiphase reactions.

[0176] This experimental method enables real-time integrated monitoring of multiple physical parameters. The device integrates high-precision temperature and pressure sensors, combines timed liquid sampling and analysis to obtain the pH value of the reaction solution, and uses stress-strain monitoring methods such as strain gauges and optical fibers to measure strain data and calculate volumetric strain. Simultaneously, it is combined with a permeability testing module to achieve the synchronous acquisition of key reaction parameters such as temperature, pressure, pH, volumetric strain, and permeability during high-temperature and high-pressure multiphase chemical reactions. This solves the problem of existing devices requiring multiple start-ups and shutdowns for single-parameter measurements, reduces sources of experimental error, shortens the experimental cycle, and significantly improves the continuity and completeness of experimental data.

[0177] This experimental method enables quantitative correlation analysis between the evolution of microstructure and changes in macroscopic mechanical properties during CO2 mineralization. By acquiring strain data in real time using stress-strain monitoring methods such as strain gauges and optical fibers, volumetric strain is calculated. Fluid flow rate and pressure changes are measured during the experiment, and permeability is calculated using a non-steady-state method. This allows for the dynamic reflection of the physical response and evolution of mechanical properties of rocks during CO2 capture. It provides direct and reliable experimental evidence for elucidating the kinetic mechanism of mineralization reactions and the evolution of pore structure, information that current techniques typically cannot obtain during the reaction process.

[0178] The foregoing description, with reference to preferred embodiments, details exemplary implementations of the high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus 100 and method proposed in this invention. However, those skilled in the art will understand that various modifications and alterations can be made to the above specific embodiments without departing from the concept of this invention, and various combinations can be made to the various technical features and structures proposed in this invention without exceeding the protection scope of this invention, which is determined by the appended claims.

Claims

1. A high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus, characterized in that, include: The medium preparation and injection assembly (10) includes: a CO2 cylinder (11), a refrigeration unit (12), and an intermediate container (13) connected in sequence. The refrigeration unit (12) is configured to convert gaseous CO2 into liquid CO2. The intermediate container (13) includes: a gas piston container (131) and a liquid piston container (132) connected in parallel, with a first common node (A) and a second common node (B) formed at their two ends, respectively. The intermediate container (132) is configured to output CO2 gas or liquid from the first common node (A). The reactor assembly (20) includes a reactor body (21) and a ring pressure pump (22) connected thereto. The reactor body (21) has an input end (211) and an output end (212). The input end (211) is connected to the first common node (A) and the second common node (B). The reactor body (21) is loaded with a rock sample (200). The reactor body (21) is configured to heat the rock sample (200) at high temperature. The ring pressure pump (22) is configured to apply and maintain a constant confining pressure on the rock sample (200). A multiphase separation and metering assembly (30) includes a gas-liquid separator (31) and a gas reciprocating metering device (32). The gas-liquid separator (31) has an input port (311), a gas output port (312), and a liquid output port (313). The input port (311) is connected to the output end (212), and the gas output port (312) is connected to the gas reciprocating metering device (32). The gas-liquid separator (31) is configured to separate the gas-liquid mixture at the output end (212), and the gas reciprocating metering device (32) is configured to receive and analyze the gas components separated by the gas-liquid separator (31). The permeation measurement assembly (40) includes: an N2 gas cylinder (41), a first on / off valve (43), and a second on / off valve (44) connected in sequence. A fourth common node (D) is formed between the first on / off valve (43) and the second on / off valve (44). The fourth common node (D) is connected to the input terminal (211). A third on / off valve (45) is also provided between the fourth common node (D) and the input terminal (211). The second on / off valve (44) is connected to the output terminal (212) and is connected to the output terminal. A fifth common node (E) is formed between (212), and the fifth common node (E) is connected to the gas-liquid separator (31). A fourth shut-off valve (47) is also provided between the fifth common node (E) and the gas-liquid separator (31), and the fourth shut-off valve (47) is connected to the outside. A differential pressure sensor (46) is also provided between the fourth common node (D) and the fifth common node (E), which is configured to sense the pressure difference between the input end (211) and the output end (212).

2. The high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus according to claim 1, characterized in that, It also includes a back pressure regulation and flow path switching component (50), which includes a back pressure pump (51), a back pressure container (52) and a back pressure valve (53). The back pressure pump (51) is connected to the back pressure container (52). The back pressure valve (53) has a first interface (531), a second interface (532) and a third interface (533). The first interface (531) is connected to the back pressure container (52), the second interface (532) is connected to the output end (212), and the third interface (533) is connected to the gas-liquid separator (31). The back pressure valve (53) is configured to inject the pressure generated by the back pressure pump (51) into the reactor body (21).

3. The high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus according to claim 1, characterized in that, The refrigeration unit (12) includes a storage tank coil (121) and a refrigerated water washer (122). The storage tank coil (121) has an inlet end and an outlet end. The inlet end is connected to the CO2 cylinder (11), and the outlet end is connected to the gas piston container (131). The refrigerated water washer (122) is connected to the storage tank coil (121) and is configured to convert the gaseous CO2 introduced into the storage tank coil (121) into liquid CO2.

4. The high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus according to claim 1, characterized in that, The medium preparation and injection assembly (10) further includes: A constant speed and constant pressure pump (14), connected to the second common node (B), is configured to drive the acidic liquid in the liquid piston container (132) or the CO2 gas in the gas piston container (131) to the reactor body (21) via the first common node (A).

5. The high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus according to claim 4, characterized in that, It also includes: a fifth on / off valve (15), which is connected between the second common node (B) and the input end (211) and forms a third common node (C) between the first common node (A) and the input end (211), the fifth on / off valve (15) being configured to control the on / off of the external water source from the constant speed and pressure pump (14) toward the input end (211).

6. An experimental method for the high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus as described in claim 1, characterized in that, Includes the following steps: S10: The rock is processed into a cubic rock sample with a regular surface (200); the two opposite end faces are used as the inflow and outflow faces along the proposed seepage direction; after roughening and degreasing the four side surfaces, the remaining surfaces except the inflow and outflow faces are fully encapsulated and cured with epoxy resin (202) that is resistant to CO2 and carbonic acid to block the lateral bypass flow. S20: Device installation: Fix the sealed rock sample (200) inside the reactor body (21), so that the inflow surface is connected to the input end (211) and the outflow surface is connected to the output end (212). Load the preset confining pressure to the target value through the ring pressure pump (22), and perform a sealing check and sensor zero point calibration. S30: Liquid filling and pre-equilibrium: CO2 gas is cooled by the refrigeration unit (12) to form liquid CO2. The liquid CO2 is injected into the reactor body (21) through the gas piston container (131), and the solution that has reached dissolution equilibrium with the liquid CO2 at the experimental temperature and pressure is continuously filled into the reactor body (21) through the liquid piston container (132); the target temperature T and the average pore pressure P are set and stabilized. m To achieve initial system equilibrium; viscosity μ is taken from (T, P) m The physical properties of CO2-saturated water were determined; the pore pressure of the input end (211), the output end (212), and the rock sample (200) was adjusted to the same initial value P0 to achieve the initial equilibrium of the system. S40: Capacity Calibration: Under initial equilibrium conditions, the effective storage coefficients of the input terminal (211) and the output terminal (212) are calibrated respectively to obtain the effective storage coefficient C of the input terminal (211). u The effective storage coefficient C of the output terminal (212) d ; S50: Unsteady loading: Open the N2 bottle and simultaneously open the first shut-off valve (43), the second shut-off valve (44), and the third shut-off valve (45), and close the fourth shut-off valve (47). After the N2 pressure at the input end (211) and the output end (212) stabilizes, close the first shut-off valve (43) and the second shut-off valve (44), and open the fourth shut-off valve (47). Release some N2 to the outside through the fourth shut-off valve (47), so that a small pressure difference ΔP0 is formed between the input end (211) and the output end (212), which serves as a pulse pressure signal. Quickly open the first shut-off valve (43) and the second shut-off valve (44), so that the N2 gas flows from the rock sample (200) to the output end (212) under the pressure difference. Use the differential pressure sensor (46) to record the process of pressure decay at the input end (211) and the output end (212) over time. Collect temperature signals simultaneously. S60: Model Establishment: Import the collected differential pressure-time data into the control and data processing system; establish the relationship between instantaneous flow rate and differential pressure based on the principle of pulse decay method; S70: Data Acquisition and Processing: After the pulse loading is completed, continuously acquire the pressure Pu(t) at the input end (211) and the pressure Pd(t) at the output end (212) until the difference between the two approaches zero; calculate the change of pressure difference with time, perform least squares regression within the linear interval of lnΔP on time, and obtain the attenuation coefficient m. When the goodness of regression satisfies R 2 When the value is ≥0.995, the noise curves of the initial transition phase and the final phase are discarded. S80: Based on the attenuation coefficient m, combined with the known storage coefficient C of the input terminal (211) and output terminal (212). u C d The geometric parameters of the rock sample and the fluid viscosity μ are used to obtain the equivalent storage capacity C. Based on Darcy's law and the gas state equation, the permeability k of the rock sample is calculated. Considering the storage coefficient of the rock sample itself, the input end (211) and output end (212) of the storage coefficient are corrected to obtain the corrected permeability k' of the rock sample (200). S90: Output the corrected permeability k' of the rock sample (200), generate the permeability-time curve and permeability change data under CO2 mineralization reaction conditions; compare the permeability changes before and after the reaction and during the reaction process, output the gas-liquid mixture in the reactor body (21) from the output end (212) into the gas-liquid separator (31), separate the gas-liquid mixture into gas and liquid, and receive and analyze the gas composition by the gas reciprocating metering device (32), thereby analyzing the mineralization reaction efficiency of the rock sample (200) to evaluate the influence of CO2 mineralization reaction on the pore structure of the rock sample.

7. The experimental method of the high-temperature and high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus according to claim 6, characterized in that, In step S50, establishing the relationship between instantaneous flow rate and differential pressure specifically includes the following process: Under laminar flow and small disturbance conditions, the instantaneous flow rate q(t) and the inlet / outlet pressure difference are related. Satisfying Relationship: In the formula, A is the cross-sectional area of ​​the core; L is the core length; μ is the fluid viscosity; and k is the permeability. The pressure difference between the inlet and outlet; Among them, the pressure difference between inlet and outlet Defined as: In the formula, P u (t) represents the inlet pressure; P d (t) represents export pressure; And the input terminal (211) and the output terminal (212) satisfy: In the formula, q(t) is the instantaneous volumetric flow rate; C u Import effective storage coefficient; C d This is the effective storage coefficient for exports; Therefore, a first-order linear equation for the pressure difference is established: In the formula, m is the differential pressure exponential decay coefficient; The pressure difference between the inlet and outlet; Its analytical solution is: In the formula, Apply an instantaneous initial pressure difference to the pulse; e is the natural constant and the base of the exponential function.

8. The experimental method of the high-temperature and high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus according to claim 6, characterized in that, In step S80, the derivation process of the corrected permeability is as follows: Considering the storage coefficient C of the rock sample (200) S In the case of, , Where A is the porosity, L is the cross-sectional area of ​​the core, and c is the core length. t For overall compressibility, the storage coefficients of the input (211) and output (212) are modified, and the storage coefficient of the input (211) is... Storage coefficient of output terminal (212) The expression is: The corrected permeability k' formula is obtained as follows: In the formula, m is the differential pressure exponential decay coefficient; μ is the fluid viscosity.

9. An experimental method for a high-temperature, high-pressure gas-liquid-rock multiphase chemical reaction experimental apparatus as described in any one of claims 1 to 5, characterized in that, Includes the following steps: W10: Process to obtain a cubic rock sample (200), measure and record the initial volume V0. Except for the end face that needs to be exposed as a seepage contact, the other five faces are coated and cured with epoxy resin (202), and the strain sensor and wire are sealed and fixed with epoxy resin (202). W20: Arrange strain gauges or fiber Bragg grating strain sensors in three mutually orthogonal directions on the rock sample (200), set up independent fiber temperature compensation elements, and lead the above sensor leads or optical fibers out of the reactor body (21) and connect them to the data acquisition system. W30: The encapsulated rock sample (200) is fixedly installed in the working cavity inside the reactor body (21), so that the two ends of the rock sample (200) are connected to the input end (211) and the output end (212) respectively. W40: Calibrate the zero point, sensitivity, and temperature coefficient of strain and temperature sensors under set temperature and pressure conditions; calibrate the system compliance and thermally induced baseline volume change using a rigid replacement under the same installation conditions. W50: CO2 gas is cooled by the refrigeration unit (12) to form liquid CO2. Liquid CO2 is injected into the reactor body (21) through the gas piston container (131). Water that has reached dissolution equilibrium with CO2 at the experimental temperature and pressure is filled by the liquid piston container (132). Back pressure and temperature are set so that the average pore pressure is at least 1~2 MPa higher than the CO2 saturation pressure at that temperature, and stabilized to an isothermal and isobaric state. W60: CO2-water-rock chemical reaction was carried out under constant temperature, back pressure and selectable confining pressure conditions, and triaxial strain, temperature and pressure signals were continuously collected. W70: Temperature compensation and pressure coupling correction are applied to the strain signal to obtain the triaxial corrected strain ε. x ε y ε z The change of volumetric strain ε over time v The expression is: In the formula, ε x For volumetric strain in the X direction, ε y For volumetric strain in the y-direction, ε z The volumetric strain is in the Z direction; Calculate the volume change of rock sample (200) based on the initial volume V0. Its expression is: In the formula, V0 represents the initial volume; ε represents the initial volume. v (t) Volumetric strain; Thus, the expression for the evolution of volume over time is obtained as follows: W80: Statistical analysis and curve fitting are performed on the volumetric strain data of repeated experiments. The gas-liquid mixture in the reactor body (21) is output from the output end (212) into the gas-liquid separator (31). The gas-liquid mixture is separated into gas and liquid. The gas composition is received and analyzed by the gas reciprocating metering device (32) to obtain the evolution curve of volumetric strain with time during the CO2 mineralization reaction process, so as to reveal the volume evolution mechanism and reaction stage characteristics in the mineralization reaction process.

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