An indirect method for measuring carbon sequestration based on air pressure measurement

Abstract

The application discloses a kind of indirect determination methods of carbon fixation amount based on air pressure determination, is implemented in a closed wet carbon fixation system equipped with inlet gas flow meter and reactor pressure gauge, total input in system is N in CO2According to distribution position and occurrence state, can be divided into carbon fixation amount N I , water-soluble amount N II , free amount N III Three parts.By inlet gas flow meter and reactor pressure gauge directly determine N in And N III , simultaneously, this method contains first round pressure determination, i.e.prior calibration and establish the corresponding relationship of N II In the range of effective stable pressure P d Under liquid-gas two-phase condition.N II Then carry out the second round pressure determination of solid-liquid-gas three-phase carbon fixation process, combine the directly determined N in , N III , according to formula N I =N in -N II -N III Obtain N I The application does not need sampling, avoids the error caused by material uneven, sampling not representative, derives carbon fixation amount by direct measurement of pressure, can reflect the overall carbon fixation level of material, significantly improves the accuracy of carbon fixation amount analysis.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon fixation amount determination, in particular to an indirect determination method of carbon fixation amount based on gas pressure determination. BACKGROUND

[0002] The accurate determination of the carbon fixation amount in the rapid carbonation process of solid carbon fixation materials is of great significance for carbon sequestration technology evaluation, solid waste resource utilization, carbon fixation method performance evaluation and optimization guidance, carbon neutralization path design, environmental benefit quantification, and carbon accounting system construction. Currently, the carbon fixation amount determination methods mainly include thermogravimetric analysis and acid-base titration.

[0003] Thermogravimetric analysis monitors the mass change by heating the sample to monitor the release amount of CO2, thereby inversely deducing the carbon fixation amount. However, this method has two limitations: 1. Uncertainty of thermal decomposition temperature: due to the significant difference in CO2 release temperature of different minerals and crystal forms of carbon fixation products, it is difficult to uniformly select the thermal decomposition temperature range, resulting in deviation of the results; 2. Insufficient sample representativeness: due to the extremely small sample mass (generally 10-50 mg) during testing, the material heterogeneity can easily affect the results, making it difficult to reflect the overall material carbon fixation performance.

[0004] The acid-base titration method determines the carbon fixation amount by measuring the consumption of alkaline substances before and after carbon fixation. Since this method requires a large number of chemical experimental instruments such as dryers, burettes, conical flasks, and pH meters during testing, the operation process is complicated and is easily affected by human error, resulting in poor data repeatability and insufficient accuracy of the results.

[0005] Patent application CN117686657A proposes a carbon fixation amount calculation method for high-alkali solid waste, which is based on the measurement of the concentration and flow rate of the gas entering and exiting the carbon fixation container, and then determines the amount of CO2 sequestered by the solid waste. However, this method has the following defects: 1. Since the residual gas in the system is ignored in the design process, the carbon fixation amount is not complete; 2. Since this method relies on the measurement of the concentration of flowing gas by a concentration instrument, the accuracy of the instrument in a flowing state cannot be guaranteed, which affects the accuracy of the calculation. SUMMARY

[0006] The purpose of the present application is to provide an indirect determination method of carbon fixation amount based on gas pressure determination, to improve the accuracy and completeness of carbon fixation amount determination, to overcome the errors caused by sample heterogeneity, and to solve the problems of complex operation, poor representativeness, and large measurement errors in existing carbon fixation amount determination methods.

[0007] Technical solution: An indirect determination method of carbon fixation amount based on gas pressure determination, which is based on the total input CO2 amount N inThe material conservation principle that is equal to the sum of the carbon fixation amount N I , the water content amount N II , and the free amount N III includes the following steps:

[0008] Step one: basic parameter measurement;

[0009] M1: key volume parameter measurement;

[0010] Calibrate the volume of the reaction kettle in the system as V1, measure the total volume V2 of the water or solid carbon fixation material and water mixture of a certain mass injected into the reaction kettle, and obtain the volume V3 = V1-V2 of the remaining gas free space;

[0011] M2: measurement method of total input CO2 amount N in ;

[0012] The CO2 standard condition volume data V in measured by the gas flow meter at the inlet of the system is converted to obtain the total input amount N in :

[0013] N in = P st ×V in / (R × T st );

[0014] Wherein, P st is the standard atmospheric pressure, R is the ideal gas constant, and T st is the standard temperature;

[0015] M3: measurement method of real-time free amount N III in the reaction kettle;

[0016] The indicated pressure P e measured by the reaction kettle pressure gauge is converted to obtain the free amount N III :

[0017] N III = P abs ×V3 / (Z×R×T g );

[0018] Wherein, P abs is the absolute pressure of the gas in the reaction kettle, P abs = P e + P st ; Z is the compression factor of CO2 gas; T g is the gas temperature in the reaction kettle;

[0019] Step two: pressure measurement;

[0020] S1: First round of pressure measurement: water content N II Calibration process

[0021] S11: Add water to the reactor and input CO2 without adding solid carbon sequestration material, at this time according to the material balance relationship, we can get N II = N in - N III ;

[0022] S12: Perform a series of calibration experiments of water and CO2 combined stirring, according to M1 to M3, a series of liquid-gas two-phase stable apparent pressure P d and corresponding N in , N III data after a specified stirring time, and use the relationship N II = N in - N III to get a series of (P d , N II ) data groups

[0023] S13: According to the (P d , N II ) data group, establish the corresponding relationship between N II and stable apparent pressure P d in the effective P d range

[0024] S2: Second round of pressure measurement of solid-liquid-gas three-phase carbon sequestration process: obtain carbon sequestration amount N I ;

[0025] S21: Add a certain amount of solid carbon sequestration material and water to the reactor and input CO2, start stirring carbon sequestration, stop stirring at a specified time, and measure N in , N III of this round of test according to steps M2 and M3 respectively, and record the stable gas pressure value P s ;

[0026] S22: Substitute P s into the N II corresponding relationship database established in step S13 to determine the water content N II at this time, and obtain the carbon sequestration amount N I according to N I = N in - N II - N III .

[0027] Furthermore, in step M1, the volume V1 of the reactor is calibrated using the water calibration method, and the CO2 gas compressibility factor Z is obtained by querying the NIST Chemistry WebBook property database.

[0028] Furthermore, in step S12, the calibration experiment of multiple sets of combined stirring is to conduct multiple stirring experiments by changing only the initial gas pressure while keeping the water volume, temperature, gas-liquid contact area, and stirring time constant. The experiment continues until the gas pressure drops to P. d Record the P at that time d Value and determine the corresponding N in N III data.

[0029] Furthermore, in step S13, the effective P d The range is the smallest P used to form the corresponding relational database in the multiple sets of calibration experiments. d Value up to maximum P d For continuous intervals of values, linear interpolation is performed between similar data in the database.

[0030] The best, P d The value is less than 10 MPa.

[0031] Ideally, in step S21, the measured stable air pressure value P s The value of is in the effective P d Within the range.

[0032] Ideally, in step S2, during the complete solid-liquid-gas three-phase carbon fixation process, the conditions of water volume, temperature, gas-liquid contact area, and stirring time are kept consistent with the calibration experimental conditions in step S1.

[0033] Ideally, in step S2, after determining the amount of carbon fixation N... I Then, combined with the initial mass m of the solid carbon fixation material s To further determine the unit carbon fixation content Q of this material:

[0034] Q = M CO2 ×N I / m s ;

[0035] Where Q is the unit carbon fixation content of the sample, and M CO2 is the molar mass of CO2.

[0036] This invention is implemented in a closed wet carbon fixation system equipped with an inlet gas flow meter and a reactor pressure gauge. The inlet gas flow meter is a mass flow meter. The accuracy of this gas flow meter is calibrated based on CO2 gas, and the monitored and recorded data is the equivalent volume V of the CO2 gas introduced into the system under standard conditions.in .

[0037] The first round of pressure measurement is to complete the water content N II The specific measurement operation process of calibration is as follows: I, water is added to the reaction kettle, all pipelines of the system are connected, and the temperature control unit of the reaction kettle is started to maintain the internal temperature of the closed reaction kettle at the set temperature; II, the gas valve is closed and the vacuum pump is started, and when the reaction kettle pressure gauge shows that the relative gas pressure is stable below-0.098 MPa and lasts for 10 min, it is considered that the excess gas in the system has been exhausted and the system has good airtightness, and the vacuum pump is closed; III, the gas valve is opened to start injecting CO2 gas into the closed reaction kettle, and the gas valve is closed to stop injecting when the reaction kettle pressure gauge shows that the gas pressure reaches the set value; IV, the stirring paddle is started to start stirring; V, after reaching the set time, the stirring paddle is closed, and the real-time data of flow, pressure, temperature and the like in the carbon fixation process are collected and counted by the data collector; VI, after completing data collection and storage, the closed wet carbon fixation system is disassembled and cleaned, VII, different gas pressure set values are changed, and the above steps I~VI are repeated to obtain (P d ,N II ) data group.

[0038] The second round of pressure measurement is to complete the carbon fixation amount N I The specific measurement operation process is as follows: I, the total volume of the solid-liquid material to be loaded into the reaction kettle is measured, and the solid-liquid material is loaded into the closed reaction kettle, all pipelines of the system are connected, and the temperature control unit of the reaction kettle is started to maintain the internal temperature of the closed reaction kettle at the set temperature; II, the gas valve is closed and the vacuum pump is started, and when the reaction kettle pressure gauge shows that the relative gas pressure is stable below-0.098 MPa and lasts for 10 min, it is considered that the excess gas in the system has been exhausted and the system has good airtightness, and the vacuum pump is closed; III, the gas valve is opened to start injecting CO2 gas into the closed reaction kettle, and the gas valve is closed to stop injecting when the reaction kettle pressure gauge shows that the gas pressure reaches the set value; IV, the stirring paddle is started to start stirring; V, after reaching the set time, the stirring paddle is closed, and the real-time data of flow, pressure, temperature and the like in the carbon fixation process are collected and counted by the data collector; VI, after completing data collection and storage, the closed wet carbon fixation system is disassembled and cleaned, VII, different gas pressure set values are changed, and the above steps I~VI are repeated to obtain (P d ,N II ) data group.

[0039] The solid carbon fixation material suitable for the application is a material that does not release gas, only dissolves and releases metal ions such as calcium and magnesium ions in the stirring carbon fixation process.

[0040] Advantages: Compared with the prior art, the application has the following advantages:

[0041] ① Strong integrity, the results are representative;

[0042] The present application directly takes the complete material system as the determination object, avoids the error caused by small sample quality and strong heterogeneity in the traditional method, and the measured carbon sequestration capacity can more truly reflect the carbon sequestration capacity of the whole material.

[0043] ② The equipment is mature, and the data is accurate and reliable;

[0044] The monitoring equipment adopted includes a gas flow meter and a pressure gauge, which are both mature and stable performance instruments, and the determination process is simple and the data is accurate, thereby significantly reducing the determination deviation caused by equipment error.

[0045] ③ The gas statistics are complete, and the determination precision is high;

[0046] The whole process of carbon sequestration before, during and after carbon sequestration is comprehensively monitored and quantified through the closed wet carbon sequestration system, so that the problems of gas leakage or incomplete statistics are effectively avoided, and the carbon sequestration capacity determination is more accurate.

[0047] In summary, the present application uses the closed wet carbon sequestration system to completely quantify and statistically analyze all parts of the gas in the carbon sequestration process, avoids gas leakage and omission, and improves the integrity and precision of the carbon sequestration capacity determination. At the same time, the present method does not need to rely on high-precision gas concentration instruments, simplifies the experimental conditions, reduces the dependence on equipment performance, enhances the operability and stability of the method, and is superior to the prior art in terms of representativeness, accuracy and integrity. It has high precision, high reliability and good engineering adaptability, and has broad application prospect and promotion value. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 The present application is a method flowchart;

[0049] Figure 2 The present application is a structure diagram of the closed wet carbon sequestration system;

[0050] Figure 3 The present application is a CO2 distribution state diagram in the system;

[0051] Figure 4 The present application is a (P d , N II ) data set of an embodiment. DETAILED DESCRIPTION

[0052] The present application will be further illustrated below in combination with the drawings and specific embodiments, and it should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application.

[0053] An indirect carbon sequestration capacity determination method based on gas pressure determination is suitable for accurately determining the carbon sequestration capacity of solid carbon sequestration material in a closed wet carbon sequestration process. Figure 3As shown, carbon fixation is performed using a closed wet carbon fixation system equipped with an inlet gas flow meter and a reactor pressure gauge. The total system input is N. in CO2 is classified as carbon sequestration N based on its distribution location and occurrence state in the system. I Water solubility N II Free amount N III Three parts, obtain N in sequence in N II N III Finally, based on N I =N in -N II -N III Obtain carbon fixation amount N I .like Figure 1 As shown, the specific steps for determining the basic parameters include:

[0054] Step M1: Determination of key volumetric parameters;

[0055] The volume of the reactor in the system is calibrated as V1. The total volume V2 of a certain mass of water or solid carbon material mixed with water used to inject into the reactor is measured. The volume of the remaining free gas space is obtained as V3 = V1 - V2.

[0056] Step M2: Total CO2 input N in The determination method;

[0057] CO2 standard condition volume data V measured by the gas flow meter at the system inlet. in The total input N is calculated. in :

[0058] N in = P st ×V in / (R × T st );

[0059] Among them, P st The pressure is standard atmospheric pressure, 101.325 kPa; R is the ideal gas constant, 8.31 J / (mol·K); T st The standard temperature is 273.15 K.

[0060] Step M3: Real-time free N in the reactor III The determination method;

[0061] The pressure P measured by the pressure gauge of the reactor e The free amount N is obtained by conversion. III :

[0062] N III = P abs×V3 / (Z×R×T g );

[0063] Among them, P abs P is the absolute pressure of the gas inside the reactor. abs = P e + P st , kPa; Z is the compressibility factor of CO2 gas, dimensionless; T g The temperature of the gas inside the reactor is K;

[0064] like Figure 1 As shown, the present invention also includes the following two rounds of pressure measurement steps:

[0065] Step S1: First round of pressure measurement: water solubility N II Calibration process;

[0066] S11: Under conditions where no solid carbon-fixing materials are present, only water and CO2 are added to the reactor. In this state, N... I At 0 mol, according to the material balance relationship, N can be obtained as follows: II = N in - N III ;

[0067] S12: Conduct calibration experiments with multiple sets of water and CO2 combined stirring, and measure the stable pressure P of multiple sets of liquid-gas two-phase systems after a specified stirring time according to M1 to M3. d and the corresponding N in N III Data, and utilize N II = N in - N III The relational expression yields multiple sets (P) d , N II ) data group;

[0068] Multiple sets of liquid-gas two-phase calibration experiments were conducted by changing only the initial gas pressure while keeping the water volume, temperature, gas-liquid contact area, and stirring time constant. The experiments continued until the gas pressure dropped to P. d Record the P at time d Value and determine the corresponding N in N III data.

[0069] S13: According to (P) d , N II Data group establishment N II With stable pressure P d In effective P d Correspondence within the range.

[0070] Effective P dthe minimum P d value to the maximum P d value in the multiple sets of calibration experiments for establishing the corresponding relationship database, and linear interpolation is performed between the adjacent data in the database. Generally, the P d value is less than 10 MPa.

[0071] Step S2: second round of pressure measurement: obtain the carbon sequestration amount N I ;

[0072] S21: add a certain mass of solid carbon sequestration material, water and CO2 into the reaction kettle, start stirring carbon sequestration, stop stirring at a specified time, and measure N in , N III and record the stable apparent pressure P s at this time according to steps M2 and M3; the measured stable gas pressure value P s should be within the effective P d range.

[0073] S22: substitute P s into the N II corresponding relationship database established in step S13 to determine the water content N II at this time, and obtain the carbon sequestration amount N I according to N in = N II - N III - N I .

[0074] In parameter determination M1, the volume V1 of the reaction kettle is calibrated by water calibration method, and the CO2 gas compression factor Z is obtained by querying the NIST Chemistry WebBook property database.

[0075] In step S2, during the complete solid-liquid-gas three-phase carbon sequestration process, the water amount, temperature, gas-liquid contact area, stirring time and other conditions are kept consistent with the calibration experiment conditions in step S1. In step S2, after determining the carbon sequestration amount N I , the initial mass m s of the solid carbon sequestration material is combined to further determine the unit carbon sequestration amount Q of the material:

[0076] Q = M CO2 ×N I / m s ;

[0077] wherein Q is the unit carbon sequestration amount of the sample, g / kg; M CO2 is the molar mass of CO2, 44 g / mol; m sThe initial mass of the solid carbon sequestration material not contacted with CO2, kg.

[0078] The first round of pressure measurement is to complete the water content N II The specific measurement operation process of calibration is as follows: I, add water to the reaction kettle, connect all the pipelines of the system, and open the temperature control unit of the reaction kettle to maintain the internal temperature of the sealed reaction kettle at the set temperature; II, close the gas valve and open the vacuum pump, and when the reaction kettle pressure gauge shows that the relative gas pressure is stable below-0.098 MPa and lasts for 10 minutes, it is considered that the excess gas in the system has been exhausted and the system has good airtightness, and the vacuum pump is closed; III, open the gas valve to start injecting CO2 gas into the sealed reaction kettle, and close the gas valve to stop injecting when the reaction kettle pressure gauge shows that the gas pressure reaches the set value; IV, start stirring by opening the stirring paddle; V, after reaching the set time, close the stirring paddle, and collect and count the real-time data such as flow, pressure and temperature of the carbon sequestration process through the data collector; VI, after completing data collection and storage, disassemble and clean the sealed wet carbon sequestration system; VII, change the different gas pressure set value, repeat the above steps I~VI, and obtain (P d ,N II ) data group.

[0079] The second round of pressure measurement is to complete the carbon sequestration N I The specific measurement operation process is as follows: I, measure the total volume of the solid-liquid material to be loaded into the reaction kettle, and load it into the sealed reaction kettle, connect all the pipelines of the system, and open the temperature control unit of the reaction kettle to maintain the internal temperature of the sealed reaction kettle at the set temperature; II, close the gas valve and open the vacuum pump, and when the reaction kettle pressure gauge shows that the relative gas pressure is stable below-0.098 MPa and lasts for 10 minutes, it is considered that the excess gas in the system has been exhausted and the system has good airtightness, and the vacuum pump is closed; III, open the gas valve to start injecting CO2 gas into the sealed reaction kettle, and close the gas valve to stop injecting when the reaction kettle pressure gauge shows that the gas pressure reaches the set value; IV, start stirring by opening the stirring paddle; V, after reaching the set time, close the stirring paddle, and collect and count the real-time data such as flow, pressure and temperature of the carbon sequestration process through the data collector; VI, after completing data collection and storage, disassemble and clean the sealed wet carbon sequestration system, ready for the next measurement.

[0080] The solid carbon sequestration material suitable for the application is a material that does not release gas, only dissolves and releases metal ions such as calcium and magnesium ions in the stirring carbon sequestration process.

[0081] The present application directly measures the total carbon sequestration amount of the solid material with the complete sample system as the object; since the deviation caused by sample difference is excluded, the carbon sequestration amount measured by the present application has the advantages of integrity and strong representativeness; can truly reflect the carbon sequestration capacity of the whole material, and improve the engineering applicability and scientificity of the results.

[0082] In a preferred embodiment, this method can be implemented as follows: Figure 2 The system is implemented in a closed wet carbon fixation system, which includes: a CO2 cylinder 1, a pressurized storage tank 2, a gas valve 3, an inlet gas flow meter 4, a reactor pressure gauge 5, a reactor 6, a stirrer 7, a reactor temperature control unit 8, a vacuum pump 9, and a data acquisition unit 10. The CO2 cylinder 1 is connected to the inlet of the reactor 6 through the pressurized storage tank 2. The gas valve 3 and the inlet gas flow meter 4 are installed sequentially on the connecting pipe between the pressurized storage tank 2 and the reactor 6. The reactor pressure gauge 5 is installed on the reactor 6. The vacuum pump 9 is connected to the inside of the reactor 6. The stirrer 7 and the reactor temperature control unit 8 are installed inside the reactor 6. The inlet gas flow meter 4, the reactor pressure gauge 5, and the reactor temperature control unit 8 are connected to the data acquisition unit 10 for signal transmission.

[0083] This closed wet carbon fixation system is supplied with gas from a CO2 cylinder 1. The gas pressure is increased by a pressurized storage tank 2, and the gas supply to the closed reactor 6 is controlled by a gas valve 3. The total amount of gas entering the closed reactor 6 is monitored by an inlet gas flow meter 4, and the internal pressure of the closed reactor 6 is monitored by a reactor pressure gauge 5. A stirring paddle 7 is installed on the central axis inside the closed reactor 6 to achieve stirring. A reactor temperature control unit 8 is installed at the bottom of the closed reactor 6 to control the internal temperature. In addition, the system is equipped with a vacuum pump 9 to vent excess gas from the system before the wet stirring carbon fixation process, and a data acquisition unit 10 to collect real-time data from the inlet gas flow meter 4, reactor pressure gauge 5, and reactor temperature control unit 8.

[0084] The inlet gas flow meter is a mass flow meter. Its accuracy is calibrated based on CO2 gas, and the monitored and recorded data is the equivalent volume V of the CO2 gas introduced into the system under standard conditions. in .

[0085] This invention uses mature instruments such as gas flow meters and pressure gauges, combined with a closed system, to directly measure gas changes, which has advantages such as high reliability, small error, and simple maintenance. The monitoring equipment used in this invention is technically mature, has good stability, and provides accurate and reliable measurement data, which significantly reduces the uncertainty caused by instrument errors.

[0086] This invention enables complete monitoring and precise quantification of all gases (including gases before, during, and after carbon fixation) within a closed wet carbon fixation system. The system's airtightness and continuous gas monitoring ensure no omissions, fundamentally solving the problem of incomplete gas data. It achieves full statistical analysis and precise control of gases, making the carbon fixation measurement results more accurate, repeatable, and reliable.

[0087] The application will be further described in connection with specific examples.

[0088] In a preferred embodiment, the application is demonstrated by taking coal gangue-based carbon fixation material as an example. The temperature conditions are set at four levels of 303.15, 333.15, 363.15 and 393.15 K, the initial gas pressure is set at four levels of 1, 2, 3 and 4 MPa, the stirring speed is 1400 r / min, the solid material mass of each sample is 0.035 kg, the solid-liquid ratio is 50 g / kg, the volume V2 of the solid-liquid mixed raw materials is 700 cm 3 , and the stirring time is set at 30 min. The volume V1 of the reactor is 1417.6 cm 3 , the volume V3 of the remaining gas free space is V1-V2= 717.6 cm 3 .

[0089] Based on the above basic data, according to the steps of the application, the equivalent relationship N I = N in - N II - N III is determined, the input quantity N in is obtained, and the free quantity N III is obtained.

[0090] In step S1, pure water is used for stirring carbon fixation, and the basic conditions are: temperature 303.15, 333.15, 363.15, 393.15 K, initial gas pressure 1, 2, 3, 4 MPa, stirring speed 1400 r / min, water volume 700 cm 3 , and the stirring time is set at 30 min. The specific scheme and conditions are shown in Table 1.

[0091]

[0092] After the scheme shown in Table 1 is completed, the (P d , N II ) data group of the example and its linear interpolation are shown in Table 1. Figure 4 Finally, according to step S22, the carbon fixation amount N I of the coal gangue-based carbon fixation material under different determination conditions and the unit carbon fixation amount Q are shown in Table 2.

[0093]

[0094] In conclusion, the present application utilizes the closed wet carbon fixation system to completely quantify and count each part of all gases in the carbon fixation process, avoids gas leakage and omission, and improves the integrity and precision of the carbon fixation determination. At the same time, the present method does not need to rely on high-precision gas concentration meters, simplifies the experimental conditions, reduces the dependence on the performance of the equipment, and enhances the operability and stability of the method. It is superior to the prior art in representativeness, accuracy and integrity, has high precision, high reliability and good engineering adaptability, and has broad application prospect and popularization value.

[0095] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. An indirect method for determining carbon sequestration based on atmospheric pressure measurement, wherein the method is based on the total input CO2 amount N in a closed wet carbon sequestration system. in Equal to carbon fixation N I Water solubility N II and free amount N III The principle of conservation of mass of the sum of its components is characterized by the fact that... Includes the following steps: Step 1: Determination of basic parameters; M1: Determination of key volumetric parameters; The volume of the reactor in the system is calibrated as V1. The total volume V2 of a certain mass of water or solid carbon material mixed with water used to inject into the reactor is measured. The volume of the remaining free gas space is obtained as V3 = V1 - V2. M2: Total CO2 input N in The determination method; CO2 standard condition volume data V measured by the gas flow meter at the system inlet in The total input N is calculated. in : N in = P st ×V in / (R × T st ); Among them, P st Where is standard atmospheric pressure, R is the ideal gas constant, and T is... st Standard temperature; M3: Real-time free N in the reactor III The determination method; The pressure P measured by the pressure gauge of the reactor e The free amount N is calculated. III : N III = P abs ×V3 / (Z×R×T g ); Among them, P abs P is the absolute pressure of the gas inside the reactor. abs = P e + P st Z is the compressibility factor of CO2 gas; T g The temperature of the gas inside the reactor; Step 2: Pressure Measurement; S1: First round of pressure measurement: water solubility N II Calibration process; S11: Under conditions where no solid carbon-fixing materials are present, only water and CO2 are added to the reactor. Based on the material balance, the following can be obtained: N II = N in - N III ; S12: Conduct calibration experiments with multiple sets of water and CO2 combined stirring, and measure the stable two-phase pressure P of multiple sets of liquid-gas two-phase systems after a specified stirring time according to M1 to M3. d and the corresponding N in N III Data, and utilize N II = N in - N III The relational expression yields multiple sets (P) d , N II ) data group; S13: According to (P) d , N II Data group establishment N II With stable displayed pressure P d In effective P d Correspondence within the range; S2: Second round of pressure measurement of the solid-liquid-gas three-phase carbon fixation process: obtaining the carbon fixation amount N. I ; S21: Add a specified mass of solid carbon-fixing material and water to the reactor, and introduce CO2. Start stirring for carbon fixation. Stop stirring after the specified time. Simultaneously, measure the N in this round of testing according to steps M2 and M3. in N III And record the stable air pressure value P at this time. s ; S22: P s Substitute the value into the N established in step S13 II By referring to the relational database, determine the water solubility N at this time. II And according to N I =N in - N II - N III Obtain carbon fixation amount N I .

2. The method for indirect determination of carbon fixation based on gas pressure measurement according to claim 1, characterized in that: In step M1, the volume V1 of the reactor is calibrated using the water calibration method, and the CO2 gas compressibility factor Z is obtained by querying the NIST ChemistryWebBook property database.

3. The method for indirect determination of carbon fixation based on gas pressure measurement according to claim 1, characterized in that: In step S12, the calibration experiment of multiple sets of combined stirring is to conduct multiple stirring experiments by changing only the initial gas pressure while keeping the water volume, temperature, gas-liquid contact area, and stirring time constant. The experiment continues until the gas pressure drops to P. d Record the P at that time d Value and determine the corresponding N in N III data.

4. The indirect method for determining carbon fixation based on gas pressure measurement according to claim 1, characterized in that: In step S13, the effective P d The range is the smallest P used to form the corresponding relational database in the multiple sets of calibration experiments. d Value up to maximum P d For continuous intervals of values, linear interpolation is performed between similar data in the database.

5. A method for indirect determination of carbon fixation based on gas pressure measurement according to claim 1 or 4, characterized in that: P d The value is less than 10 MPa.

6. The indirect method for determining carbon fixation based on gas pressure measurement according to claim 1, characterized in that: In step S21, the measured stable air pressure value P s The value of is in the effective P d Within the range.

7. A method for indirect determination of carbon fixation based on gas pressure measurement according to claim 1 or 3, characterized in that: In step S2, during the complete solid-liquid-gas three-phase carbon fixation process, the conditions for water volume, temperature, gas-liquid contact area, and stirring time are kept consistent with the calibration experimental conditions in step S1.

8. The indirect method for determining carbon fixation based on gas pressure measurement according to claim 1, characterized in that: In step S2, the amount of carbon fixation N is determined. I Then, combined with the initial mass m of the solid carbon fixation material s To further determine the unit carbon fixation content Q of this material: Q = M CO2 ×N I / m s ; Where Q is the unit carbon fixation content of the sample, and M CO2 is the molar mass of CO2.

Images