Air pressure measurement-based carbon sequestration indirect measurement method

Abstract

The invention discloses an air pressure measurement-based carbon sequestration amount indirect measurement method, which is implemented on a closed wet-process carbon sequestration system equipped with an inlet gas flowmeter and a reaction kettle pressure gauge, and CO2 with the total input amount of Nin in the system can be divided into three parts, namely carbon sequestration amount NI, water soluble amount NII and free amount NIII according to the distribution position and the occurrence state. Nin and NIII are directly measured through an inlet gas flowmeter and a reaction kettle pressure gauge. Meanwhile, the method comprises a first round of pressure measurement, that is, a corresponding relation of NII in an effective stable pressure Pd range under the liquid-gas two-phase condition is calibrated and established in advance. And then carrying out a second round of pressure measurement in a solid-liquid-gas three-phase carbon sequestration process, and obtaining NI according to a formula NI = Nin-NII-NIII by combining the pre-measured NII with the directly measured Nin and NIII. According to the method, sampling is not needed, errors caused by non-uniform materials and non-representative sampling are avoided, the carbon sequestration amount is deduced by directly measuring the pressure, the overall carbon sequestration level of the materials can be reflected, and the analysis accuracy of the carbon sequestration amount is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of carbon fixation measurement technology, and in particular to an indirect method for measuring carbon fixation based on air pressure measurement. Background Technology

[0002] Accurate determination of carbon sequestration during the rapid carbonation process of solid carbon sequestration materials is of great significance for carbon sequestration technology evaluation, solid waste resource utilization, performance evaluation and optimization guidance of carbon sequestration methods, carbon neutrality pathway design, environmental benefit quantification, and the construction of carbon accounting systems. Currently, the main methods for determining carbon sequestration include thermogravimetric analysis and acid-base titration.

[0003] Thermogravimetric analysis (TGA) monitors the change in mass of heated samples to track CO2 release and thus deduce the amount of carbon fixation. However, this method has two limitations: 1. Uncertainty in thermal decomposition temperature: Due to significant differences in CO2 release temperatures among carbon fixation products of different minerals and crystal forms, it is difficult to uniformly select a thermal decomposition temperature range, leading to result bias; 2. Insufficient sample representativeness: Because the sample mass used in TGA is extremely small (typically 10–50 mg), it is easily affected by the heterogeneity of the material, resulting in a lack of representativeness and difficulty in reflecting the overall carbon fixation performance of the material.

[0004] The acid-base titration method determines the amount of carbon fixed by measuring the consumption of alkaline substances before and after carbon fixation. However, this method requires a large number of chemical experimental instruments such as a dryer, burette, conical flask, and pH meter, making the operation cumbersome and susceptible to human error. Consequently, it often results in poor data repeatability and insufficient accuracy.

[0005] Patent application CN117686657A proposes a method for calculating the amount of carbon sequestration in highly alkaline solid waste. This method is based on measuring the concentration and flow rate of gases entering and exiting the carbon sequestration container to determine the amount of CO2 sequestrated in the solid waste. However, this method has the following drawbacks: 1. Because the method's design ignores residual gases in the system, the carbon sequestration statistics are incomplete; 2. Because this method relies on a concentration meter to measure the concentration of flowing gas, and the accuracy of the instrument under flowing conditions is difficult to guarantee, it affects the accuracy of the calculation. Summary of the Invention

[0006] Purpose of the invention: To address the above-mentioned problems, the purpose of this invention is to provide an indirect method for determining carbon fixation based on gas pressure measurement, thereby improving the accuracy and completeness of carbon fixation determination, overcoming errors caused by sample heterogeneity, and solving the problems of complex operation, poor representativeness, and large measurement errors in existing carbon fixation determination methods.

[0007] Technical solution: An indirect method for determining carbon sequestration based on atmospheric pressure measurement. This method is based on the total input CO2 N in a closed wet carbon sequestration system. inEqual to carbon fixation N I Water solubility N II and free amount N III The principle of conservation of mass includes the following steps:

[0008] Step 1: Determination of basic parameters;

[0009] M1: Determination of key volumetric parameters;

[0010] 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.

[0011] M2: Total CO2 input N in The determination method;

[0012] CO2 standard condition volume data V measured by the gas flow meter at the system inlet. in The total input N is calculated. in :

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

[0014] Among them, P st Where is standard atmospheric pressure, R is the ideal gas constant, and T is... st Standard temperature;

[0015] M3: Real-time free N in the reactor III The determination method;

[0016] The pressure P measured by the pressure gauge of the reactor e The free amount N is calculated. III :

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

[0018] 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;

[0019] Step 2: Pressure Measurement;

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

[0021] 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 ;

[0022] 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;

[0023] 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;

[0024] S2: Second round of pressure measurement of the solid-liquid-gas three-phase carbon fixation process: obtaining the carbon fixation amount N. I ;

[0025] 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 ;

[0026] 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 .

[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 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 measurements was used to determine the water-soluble N content. II The specific calibration procedure is as follows: I. Add water to the reactor, connect all pipelines in the system, and turn on the reactor temperature control unit to maintain the internal temperature of the sealed reactor at the set temperature; II. Close the gas valve and turn on the vacuum pump. When the reactor pressure gauge shows a stable relative pressure below -0.098 MPa for 10 minutes, it is considered that the excess gas in the system has been purged and the system is airtight. Then, turn off the vacuum pump; III. Open the gas valve to start injecting CO2 gas into the sealed reactor. After the reactor pressure gauge shows that the pressure has reached the set value, close the gas valve to stop the injection; IV. Turn on the agitator to start stirring; V. After the set time is reached, turn off the agitator and collect and statistically analyze the real-time data such as flow rate, pressure, and temperature of the carbon fixation process using the data acquisition device; VI. After completing the data acquisition and storage, disassemble and clean the sealed wet carbon fixation system; VII. Change different gas pressure set values ​​and repeat steps I to VI above to obtain (P d N II ) data group.

[0038] The second round of pressure testing was conducted to determine the carbon fixation N. I The specific measurement procedure is as follows: I. Measure the total volume of the solid and liquid materials to be loaded into the reactor, load it into the sealed reactor, connect all pipelines in the system, and turn on the reactor temperature control unit to maintain the internal temperature of the sealed reactor at the set temperature; II. Close the gas valve and turn on the vacuum pump. When the pressure gauge of the reactor shows a relative pressure that is consistently below -0.098 MPa for 10 minutes, it is considered that the excess gas in the system has been purged and the system is airtight. Turn off the vacuum pump; III. Open the gas valve to start injecting CO2 gas into the sealed reactor. After the pressure gauge of the reactor shows that the pressure has reached the set value, close the gas valve to stop the injection; IV. Turn on the agitator to start stirring; V. After the set time is reached, turn off the agitator and collect and statistically analyze the real-time data such as flow rate, pressure, and temperature of the carbon fixation process using the data acquisition device; VI. After completing the data acquisition and storage, disassemble and clean the sealed wet carbon fixation system for the next measurement.

[0039] The solid carbon fixation material applicable to this invention is a material that does not release gas during the stirring carbon fixation process, but only dissolves and releases metal ions such as calcium and magnesium ions.

[0040] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0041] ① It has strong overall characteristics and the results are representative;

[0042] This invention directly uses the complete material system as the measurement object, avoiding the errors caused by small sample mass and strong heterogeneity in traditional methods. The measured carbon fixation amount can more accurately reflect the overall carbon fixation capacity of the material.

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

[0044] The monitoring equipment used includes gas flow meters and pressure gauges, all of which are technically mature and stable instruments. The measurement process is simple and the data is accurate, significantly reducing the measurement deviation caused by equipment errors.

[0045] ③ Complete gas statistics and high measurement accuracy;

[0046] By using a closed wet carbon fixation system, the entire process of carbon fixation, including pre-fixation, during carbon fixation, and residual gas, is comprehensively monitored and quantified, effectively avoiding gas leakage or incomplete statistics, and making the carbon fixation amount more accurate.

[0047] In summary, this invention utilizes a closed wet carbon fixation system to comprehensively quantify and statistically analyze all components of the gas during the carbon fixation process, avoiding gas leakage and omission, and improving the completeness and accuracy of carbon fixation measurement. Simultaneously, this method does not rely on a high-precision gas concentration meter, simplifying experimental conditions, reducing dependence on equipment performance, and enhancing the operability and stability of the method. It surpasses existing technologies in representativeness, accuracy, and completeness, possessing high precision, high reliability, and good engineering adaptability, and has broad application prospects and promotional value. Attached Figure Description

[0048] Figure 1 This is a flowchart of the method of the present invention;

[0049] Figure 2 This is a schematic diagram of the closed wet carbon fixation system of the present invention;

[0050] Figure 3 This is a diagram illustrating the CO2 distribution state within the system of the present invention;

[0051] Figure 4 For the embodiments of the present invention (P) d , N II ) data group. Detailed Implementation

[0052] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0053] An indirect method for determining carbon fixation based on gas pressure measurement is applicable to accurately determining the carbon fixation content of solid carbon-fixing materials during closed wet carbon fixation processes. For example... 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 calculated. 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 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;

[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 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 used between similar data in the database. Typically, P... d The value is less than 10 MPa.

[0071] Step S2: Second round of pressure measurement: Obtain carbon fixation N I ;

[0072] 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 Record the stable pressure P at this time. s ;Measured stable air pressure value P s The value of should be within the valid P range. d Within the range.

[0073] 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 .

[0074] In parameter measurement M1, the volume V1 of the reactor was calibrated using the water calibration method, and the CO2 gas compressibility factor Z was obtained by querying the NIST Chemistry WebBook property database.

[0075] In step S2, during the complete solid-liquid-gas three-phase carbon fixation process, the water volume, temperature, gas-liquid contact area, stirring time, and other conditions are maintained consistent with the calibration experimental conditions in step S1. In step S2, the carbon fixation amount 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:

[0076] Q = M CO2 ×N I / m s ;

[0077] Where Q is the unit carbon fixation content of the sample, g / kg; M CO2 The molar mass of CO2 is 44 g / mol; m sThe initial mass of the solid carbon fixation material before it comes into contact with CO2 is expressed in kg.

[0078] The first round of pressure measurements was used to determine the water-soluble N content. II The specific calibration procedure is as follows: I. Add water to the reactor, connect all pipelines in the system, and turn on the reactor temperature control unit to maintain the internal temperature of the sealed reactor at the set temperature; II. Close the gas valve and turn on the vacuum pump. When the reactor pressure gauge shows a stable relative pressure below -0.098 MPa for 10 minutes, it is considered that the excess gas in the system has been purged and the system is airtight. Then, turn off the vacuum pump; III. Open the gas valve to start injecting CO2 gas into the sealed reactor. After the reactor pressure gauge shows that the pressure has reached the set value, close the gas valve to stop the injection; IV. Turn on the agitator to start stirring; V. After the set time is reached, turn off the agitator and collect and statistically analyze the real-time data such as flow rate, pressure, and temperature of the carbon fixation process using the data acquisition device; VI. After completing the data acquisition and storage, disassemble and clean the sealed wet carbon fixation system; VII. Change different gas pressure set values ​​and repeat steps I to VI above to obtain (P d N II ) data group.

[0079] The second round of pressure testing was conducted to determine the carbon fixation N. I The specific measurement procedure is as follows: I. Measure the total volume of the solid and liquid materials to be loaded into the reactor, load it into the sealed reactor, connect all pipelines in the system, and turn on the reactor temperature control unit to maintain the internal temperature of the sealed reactor at the set temperature; II. Close the gas valve and turn on the vacuum pump. When the pressure gauge of the reactor shows a relative pressure that is consistently below -0.098 MPa for 10 minutes, it is considered that the excess gas in the system has been purged and the system is airtight. Turn off the vacuum pump; III. Open the gas valve to start injecting CO2 gas into the sealed reactor. After the pressure gauge of the reactor shows that the pressure has reached the set value, close the gas valve to stop the injection; IV. Turn on the agitator to start stirring; V. After the set time is reached, turn off the agitator and collect and statistically analyze the real-time data such as flow rate, pressure, and temperature of the carbon fixation process using the data acquisition device; VI. After completing the data acquisition and storage, disassemble and clean the sealed wet carbon fixation system for the next measurement.

[0080] The solid carbon fixation material applicable to this invention is a material that does not release gas during the stirring carbon fixation process, but only dissolves and releases metal ions such as calcium and magnesium ions.

[0081] This invention uses a complete sample system as the object to directly determine the total carbon sequestration of solid materials. Since it eliminates the bias caused by sample differences, the carbon sequestration measured by this invention has the advantages of integrity and strong representativeness. It can truly reflect the overall carbon sequestration capacity of the material and improve the engineering applicability and scientific validity 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 present invention will be further described below with reference to specific embodiments.

[0088] In a preferred embodiment, coal gangue-based carbon fixation material is used as an example to demonstrate the specific application and effects of the method of the present invention. Temperature conditions are set at four levels: 303.15, 333.15, 363.15, and 393.15 K; initial air pressure is set at four levels: 1, 2, 3, and 4 MPa; stirring speed is 1400 r / min; the mass of solid material in each sample is 0.035 kg; the solid-liquid ratio is 50 g / kg; and the volume V2 of the solid-liquid mixed raw material is 700 cm³. 3 The stirring time was set to 30 min. The measured volume V1 of the reactor was 1417.6 cm³. 3 The volume of the remaining free gas space is V3 = V1 - V2 = 717.6 cm³. 3 .

[0089] Based on the above basic data, the equality relationship N is clarified according to the steps of this invention. I = N in - N II - N III Obtain the input quantity N in Obtain the free amount N III .

[0090] In step S1, pure water is used for carbon fixation by stirring. 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; and water volume 700 cm³. 3 The stirring time was set to 30 minutes. Specific details and conditions are shown in Table 1.

[0091]

[0092] After completing the tests of the schemes shown in Table 1, the results of the embodiment (P) were obtained. d , N II Data sets and their linear interpolations, such as Figure 4 As shown. Finally, according to step S22, the carbon fixation amount N of the coal gangue-based carbon fixation material under different measurement conditions was obtained. I The unit carbon sequestration amount Q is shown in Table 2.

[0093]

[0094] In summary, this invention utilizes a closed wet carbon fixation system to comprehensively quantify and statistically analyze all components of the gas during the carbon fixation process, avoiding gas leakage and omission, and improving the completeness and accuracy of carbon fixation measurement. Simultaneously, this method does not rely on a high-precision gas concentration meter, simplifying experimental conditions, reducing dependence on equipment performance, and enhancing the operability and stability of the method. It surpasses existing technologies in representativeness, accuracy, and completeness, possessing high precision, high reliability, and good engineering adaptability, and has broad application prospects and promotional value.

[0095] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which 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 obtained by conversion. 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 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