An experimental optimization method and experimental device for mud carbonization flocculation

Abstract

The present application provides a kind of experimental optimization method and experimental device of slurry carbonization flocculation, including sludge sampling and pretreatment, do early experiment to obtain sludge sample parameter;Set calcium-based reagent and CO2 gas experimental parameters and corresponding experimental parameters, construct experimental parameter combination and carry out carbonization flocculation experiment;Collect upper clear liquid and lower sediment to determine clear liquid index and sediment index, determine engineering performance and carbon sequestration capacity based on clear liquid index and sediment index;Quantitative and qualitative analysis of each type of experimental parameters and engineering performance, carbon sequestration capacity correlation is determined by using Pearson method, based on response surface method and qualitative analysis method, the change rule of engineering performance and carbon sequestration capacity under experimental parameter coupling is determined, to obtain the optimal experimental parameter combination.The present application can obtain the correlation rule of key parameters such as reagent content, CO2 aeration timing and aeration pressure and slurry treatment effect, provide basis and reference for construction, improve the practicability of carbonization flocculation treatment method.

Description

Technical Field

[0001] This invention relates to the field of sludge carbonization and flocculation technology, specifically to an experimental optimization method and experimental apparatus for sludge carbonization and flocculation. Background Technology

[0002] The massive emission of carbon dioxide is one of the main causes of rising global temperatures, and protecting the Earth's environment has become a consensus among countries around the world.

[0003] In recent years, chemical flocculants have been introduced into the treatment of high-moisture-content mud. Through chemical flocculation, the water content of the mud is significantly reduced, achieving efficient volume reduction. Commonly used inorganic chemical flocculants are CaO and Ca(OH)2. Their flocculation mechanisms include: 1) Ca2+ ions in the mud compress the diffuse double layer of soil particles, thinning the hydration film; 2) Volcanic ash reacts to generate hydrated calcium silicate, hydrated calcium aluminate, and other cementing substances, binding soil particles together to form larger particles, thus causing flocculation; 3) CaO and Ca(OH)2 react with CO2 to form calcium carbonate (CaCO3) cement, which adheres to the surface of soil particles, acting as a connector and allowing CO2 to exist in the soil in compound form for a long time.

[0004] This mud treatment method causes a decrease in pH after CO2 introduction, which enhances the carbonization reaction during flocculation but hinders the pozzolanic reaction. Calcium-based agents require Ca2+ ions to neutralize the charge, compressing the electrical double layer and causing soil particle aggregation, flocculation, and precipitation. Therefore, premature CO2 introduction inevitably affects the flocculation effect of the agents. It can be seen that there is an extremely complex interaction between carbonization and flocculation. The unclear mechanism of influence between carbon fixation and flocculation performance makes the mud treatment method impractical. Summary of the Invention

[0005] In view of this, the problem to be solved by the present invention is to provide an experimental optimization method and experimental device for mud carbonization and flocculation, which can obtain the correlation between key parameters such as reagent dosage, CO2 aeration timing and aeration pressure and mud treatment effect, provide a basis and reference for on-site construction of high water content mud treatment, and improve the practicality of carbonization and flocculation treatment method.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] An experimental optimization method for mud carbonization and flocculation includes sludge sampling, sludge sampling and pretreatment, and obtaining sludge sample parameters through preliminary experiments.

[0008] In the sludge experiment, the experimental parameters and corresponding experimental parameters of calcium-based reagent and CO2 gas were set. Based on the orthogonal model experiment, the experimental parameter combination of different experimental parameters was determined, and carbonization flocculation experiment was carried out according to the experimental parameter combination.

[0009] Data processing: After carbonization and flocculation experiments, the upper clear liquid and lower sediment were collected to determine the clear liquid index and sedimentation index. The weights of the clear liquid index and sedimentation index were set based on the AHP method. The engineering performance was calculated by the normalized values ​​of the clear liquid index and sedimentation index and their corresponding weights. The carbon fixation capacity was determined based on the carbon fixation amount of the sedimentation index.

[0010] Parameter optimization was performed by using the Pearson method to quantitatively and qualitatively analyze the correlation between each type of experimental parameter and engineering performance and carbon sequestration. Based on response surface methodology and qualitative analysis, the variation law of engineering performance and carbon sequestration under the coupling of experimental parameters was determined to obtain the optimal combination of experimental parameters.

[0011] Furthermore, the experimental parameters include the mass ratio of calcium-based reagents, CO2 ventilation pressure, CO2 ventilation time, CO2 circulation time, CO2 circulation interval, and CO2 circulation flow rate.

[0012] Furthermore, the clear liquid indicators include pH value, turbidity and TDS, and the precipitation indicators include water content, particle size distribution, liquid limit and plastic limit, filtration resistance, zeta potential, carbon fixation and mineral composition variation.

[0013] Furthermore, the preliminary experiments include moisture content testing, particle size distribution analysis, density measurement, specific gravity measurement, liquid limit and plastic limit measurement, zeta potential testing, pH testing and XRD testing. The results of the preliminary experiments together constitute the sample parameters.

[0014] Based on the optimal combination of experimental parameters, on-site construction was carried out, and silt was collected and pretreated after construction to obtain on-site parameters. The on-site parameters and sample parameters were compared, and the combination of experimental parameters was optimized in reverse based on the comparison results.

[0015] An experimental apparatus for sludge carbonization and flocculation includes a base plate, a cover, and a glass tube. The glass tube is sealed between the base plate and the cover to form a cavity for holding sludge. The cover is provided with a first three-way valve for discharging CO2 gas, and the base plate is provided with a second three-way valve for introducing CO2 gas. The C port of the second three-way valve is connected to a CO2 storage tank. The top surface of the base plate is provided with an aeration disc for introducing CO2 into the cavity. The B port of the second three-way valve is connected to the air inlet of the aeration disc. A booster pump is connected in series between the A port of the first three-way valve and the A port of the second three-way valve.

[0016] Furthermore, a first check valve is provided between the booster pump and port A of the first three-way valve, and a second check valve is provided between the booster pump and port A of the second three-way valve. The opening pressure of the first check valve and the second check valve is adjustable, and a pressure regulating valve is provided at the outlet of the CO2 storage tank.

[0017] Furthermore, a protective sleeve is installed on the outer wall of the glass tube, and several observation windows are evenly opened on the protective sleeve.

[0018] Furthermore, a first flow meter is provided between the booster pump and the second three-way valve, and a second flow meter is provided between the CO2 storage tank and the second three-way valve. The output flow of the CO2 storage tank is controlled according to the first flow meter, and the output flow of the CO2 storage tank is adjusted by feedback through the second flow meter.

[0019] Furthermore, the top surface of the cover is provided with positive and negative pressure gauges for detecting the pressure inside the cavity and a quick-release vacuum interface for extracting excess gas from the cavity.

[0020] Furthermore, the bottom surface of the base plate is provided with a drain outlet.

[0021] The advantages and positive effects of this invention are:

[0022] By setting experimental parameters and corresponding experimental quantities for calcium-based reagents and CO2 gas, and by setting several combinations of experimental parameters through orthogonal experimental principles, the clear liquid index and precipitation index of different combinations of experimental parameters were obtained. The indexes include pH value, turbidity, TDS, water content, particle size distribution, liquid limit and plastic limit, filtration resistance, Zeta potential, carbon fixation, and changes in mineral composition.

[0023] By assigning weights to each indicator to calculate engineering performance, and by converting multiple indicators into engineering performance, and transforming the correlation analysis between multiple parameters into the correlation analysis between multiple parameters and a single parameter, the workload of data analysis in the early stage and on-site construction is reduced, making it easier to quickly determine the optimal combination of experimental parameters, and also making it easier to optimize the combination of experimental parameters on-site.

[0024] By setting up a cavity to hold the mud, an aeration disc for introducing CO2 gas is set on the bottom surface of the cavity. The aeration disc is connected to a CO2 storage tank. The top surface of the cavity is connected to the aeration disc through a booster pump, which can circulate the gas supply. The CO2 storage tank and the booster pump work together to continuously introduce CO2 gas with a fixed flow rate and pressure into the cavity for carbonization flocculation experiments. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0026] Figure 1 This is an overall structural diagram of an experimental optimization method and experimental apparatus for mud carbonization and flocculation according to the present invention.

[0027] Figure 2 This is a diagram of an experimental optimization method and experimental apparatus for mud carbonization and flocculation according to the present invention;

[0028] Figure 3 This is a diagram of an experimental optimization method and experimental apparatus for mud carbonization and flocculation according to the present invention;

[0029] Figure 4 This is a diagram of an experimental optimization method and experimental apparatus for mud carbonization and flocculation according to the present invention;

[0030] In the diagram: 1. Cover; 2. Flange ring; 3. Glass tube; 4. Base plate; 5. Sliding support; 501. Caster wheel; 502. Load-bearing bracket; 6. Fastening rod; 602. Nut; 7. Positive and negative pressure gauges; 8. First three-way valve; 9. Quick-release vacuum interface; 10. Lifting ring; 11. Protective sleeve; 1101. Observation window; 1102. Scale; 12. Pressure reducer; 13. Sealing ring; 14. First one-way valve; 141. Second one-way valve; 15. Booster pump; 16. Third three-way valve; 17. First flow meter; 171. Second flow meter; 18. Pressure regulating valve; 19. Second three-way valve; 20. Drain outlet; 21. Aeration disc; 2101. Filter membrane; 22. CO2 storage tank. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is described as "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is described as "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] This invention provides an experimental apparatus for mud carbonization and flocculation, such as... Figures 1 to 2As shown, the system includes a base plate 4, a cap 1, and a glass tube 3. The glass tube 3 is sealed between the base plate 4 and the cap 1 to form a cavity for holding mud. Several flange holes are provided at the edges of both the base plate 4 and the cap 1. The base plate 4 and the cap 1 are sealed and fixed to both ends of the glass tube 3 by fastening rods 6 and nuts 602. In one embodiment of this application, an installation groove is provided on the bottom surface of the base plate 4. The lower end of the glass tube 3 is sealed and installed in the installation groove, and the cap 1 is installed on the upper end of the glass tube 3. The fastening rod 6 is a long rod structure with threads at both ends. During installation, the flange holes on the cap 1 and the base plate 4 are placed opposite each other. The fastening rod 6 passes through both the flange holes on the cap 1 and the base plate 4 simultaneously, and nuts 602 are installed at both ends of the fastening rod 6. The two nuts 602 respectively press the top surface of the cap 1 and the bottom surface of the base plate 4, so that both ends of the glass tube 3 are completely sealed.

[0035] To improve the sealing performance of the upper end of the glass tube 3, a flange ring 2 is installed at the upper end of the glass tube 3. A flange hole matching the cap 1 is formed on the top surface of the flange ring 2. By increasing the contact area with the cap 1, the sealing performance of the cavity is improved. In one embodiment of this application, a sealing ring 13 is provided on the top surface of the flange ring 2, which can further improve the sealing performance of the cavity.

[0036] The cover 1 is equipped with a first three-way valve 8 for discharging CO2 gas, and the base plate 4 is equipped with a second three-way valve 19 for introducing CO2 gas. Port C of the second three-way valve 19 is connected to the CO2 storage tank 22. The top surface of the base plate 4 is equipped with an aeration disc 21 for introducing CO2 into the cavity. Port B of the second three-way valve 19 is connected to the air inlet of the aeration disc 21. The CO2 storage tank 22 is used to continuously introduce CO2 gas into the cavity. The CO2 gas reacts with the mud to produce a carbonization reaction, increasing mud sedimentation while absorbing CO2 gas. The surface of the aeration disc 21 is equipped with a filter membrane 2101, which ensures normal CO2 gas flow into the aeration disc 21 and prevents sludge leakage.

[0037] A sliding support 5 is fixedly installed below the base plate 4. The sliding support 5 includes a self-locking caster wheel 501 and a load-bearing bracket 502. The top end of the load-bearing bracket 502 is fixedly connected to the base plate 4, and the bottom end of the load-bearing bracket 502 is connected to the caster wheel 501 to facilitate the movement of the experimental device. A lifting ring 10 is provided on the fixed top surface of the cover 1 to facilitate the handling of the experimental device.

[0038] like Figure 3 As shown, a protective sleeve 11 is installed on the outer wall of the glass tube 3 to improve its compressive strength. Several observation windows 1101 are evenly distributed on the protective sleeve 11, and a vertical scale 1102 is provided on the protective sleeve 11 to facilitate observation of changes in sedimentation and the height of the clear liquid within the cavity. In one embodiment of this application, the observation windows 1101 are circular holes, and several observation windows 1101 are arranged vertically, with different rows of observation windows 1101 staggered to avoid affecting the observation of the height of the clear liquid and sediment.

[0039] The carbonization reaction of sludge in the cavity cannot completely absorb the introduced CO2 gas. In order to improve the utilization rate of CO2 gas and enable the sludge to absorb more CO2 gas, a booster pump 15 is connected in series between port A of the first three-way valve 8 and port A of the second three-way valve 19. Port B of the first three-way valve 8 is connected to the top surface of the cavity to form a CO2 gas circulation path, which allows CO2 gas to circulate in the cavity.

[0040] To improve the stability of the gas supply pressure, a first check valve 14 is provided between the booster pump 15 and port A of the first three-way valve 8, and a second check valve 141 is provided between the booster pump 15 and port A of the second three-way valve 19. The opening pressure of the first check valve 14 and the second check valve 141 is adjustable. A pressure regulating valve 18 is provided at the outlet of the CO2 storage tank 22. The pressure regulating valve 18 is used to adjust the exhaust pressure of the CO2 storage tank 22 so as to stably supply CO2 gas at a set pressure into the cavity.

[0041] One embodiment of this application is as follows: the gas supply pressure of the cavity is set to 0.1 MPa, the opening pressure of the first one-way valve 14 and the second one-way valve 141 are both 0.1 MPa, the booster pump 15 operates to open the second one-way valve 141 to output 0.1 MPa of CO2 gas; the outlet pressure of the pressure regulating valve 18 is adjusted to 0.1 MPa to stably provide 0.1 MPa of CO2 gas.

[0042] During the mud sedimentation experiment, the absorption of CO2 gas by the sludge decreases towards the end of the experiment. If the liquid in the chamber cannot be discharged in time, the pressure inside the chamber gradually increases, which can easily cause the glass tube 3 to break or leak between the glass tube 3 and the base plate 4 and the cap 1, resulting in liquid or sludge leakage. All of the above problems will affect the experimental results. The C port of the first three-way valve 8 is connected to the pressure reducer 12. When the pressure inside the chamber exceeds the threshold, the pressure reducer 12 opens to release the pressure in the chamber in time. In one embodiment of this application, the pressure reducer 12 is a pressure-controlled relief valve with adjustable opening pressure. When the pressure at the inlet of the relief valve exceeds the threshold, the relief valve opens and discharges excess CO2; when the pressure at the inlet is lower than the threshold, the relief valve closes and CO2 does not flow.

[0043] During mud sedimentation experiments, the CO2 flow rate within the chamber needs to be set and kept stable to detect the impact of flow rate on mud sedimentation. A first flow meter 17 is installed between the booster pump 15 and the second three-way valve 19, and a second flow meter 171 is installed between the CO2 storage tank 22 and the second three-way valve 19. The first flow meter 17 and the second flow meter 171 jointly determine the flow rate of CO2 gas within the chamber. One embodiment of this application involves: acquiring the sampling parameters of the first flow meter 17, dynamically adjusting the exhaust flow rate of the CO2 storage tank 22 based on the parameters of the first flow meter 17, and adjusting the exhaust flow rate of the CO2 storage tank 22 based on the feedback of the sampling parameters of the second flow meter 171, thereby improving the stability of the CO2 gas flow rate.

[0044] The top surface of the cover 1 is equipped with a positive and negative pressure gauge 7 for detecting the pressure inside the cavity and a quick-release vacuum port 9 for extracting excess gas from the cavity. Before introducing CO2 gas into the cavity, connect the vacuum pump to the quick-release vacuum port 9 to extract excess air from the cavity until the positive and negative pressure gauge 7 displays a negative value and the value stabilizes. Then, turn off and remove the vacuum pump. Next, introduce CO2 gas at a preset pressure and flow rate into the cavity. The positive and negative pressure gauge 7 is used to monitor the gas pressure inside the cavity.

[0045] The bottom surface of the base plate 4 is provided with a drain port 20. After one experiment is completed, the sediment and liquid are discharged through the drain port 20. A third three-way valve 16 is connected in series between the booster pump 15 and the second three-way valve 19. In one embodiment of this application, when the quick-release vacuum interface 9 is not provided and CO2 gas is circulated, the third three-way valve 16 connects the booster pump 15 to the second three-way valve 19. When CO2 gas is not circulated, the third three-way valve 16 connects the booster pump 15 to an external connection to discharge excess gas in the cavity.

[0046] An experimental optimization method for mud carbonization and flocculation based on an experimental apparatus, such as... Figure 4 As shown, the process includes sludge sampling, sludge collection and pretreatment, and obtaining sludge sample parameters through preliminary experiments.

[0047] Sludge sampling involves pumping sludge into a plastic bucket at different locations and depths using a sludge pump, filtering out household waste or gravel and other debris from the sludge using a 1cm mesh screen at the bucket opening, and sealing the bucket opening with plastic wrap after sampling to prevent moisture loss.

[0048] Pretreatment includes transporting the mud to the laboratory and then using a constant-speed mixer to stir the mud evenly to prevent uneven mud properties caused by weight-induced dehydration during transportation; according to the mass required for basic physicochemical property testing and carbonization flocculation test chamber model test, the mud is divided into multiple portions in small buckets and sealed with plastic wrap. Before each use, the mud in the small buckets is stirred evenly with a constant-speed mixer.

[0049] Preliminary experiments included moisture content testing, particle size distribution analysis, density determination, specific gravity determination, liquid limit and plastic limit determination, Zeta potential testing, pH testing, and XRD testing. The results of these tests constituted the sample parameters of the sludge, which were used to characterize the basic physicochemical properties of the sludge. Sludge was collected after the carbonization and flocculation experiments, and the same methods were used to test the sample parameters (defined as implementation parameters). During on-site construction, the implementation parameters and sample parameters were compared, and the results were used to optimize the engineering performance and carbon sequestration variation under the coupling of calcium-based agents and CO2 ventilation parameters, thereby improving the accuracy of the optimal experimental parameter combination.

[0050] Parameter comparison reveals the changes in the basic physicochemical properties of raw mud without carbonization and flocculation and mud after carbonization and flocculation, thus revealing the improvement mechanism of higher strength, better permeability, and less supernatant pollution in the flocculated mud. In summary, these parameters are physicochemical properties of the mud and provide strong evidence for the effectiveness of this technology.

[0051] The specific procedures for the preliminary experiments were as follows: Approximately 80g of mud was taken, divided into three portions of 20-30g each, and placed in an oven for moisture content testing; approximately 20g of mud was taken, divided into three samples, and particle size distribution analysis was performed using a MasterSizer2000 laser particle size analyzer; approximately 2000g of mud was taken, divided into two portions, and density was measured using a 500ml standard graduated cylinder; approximately 200g of mud was taken, divided into two portions, dried, and the specific gravity of the mud particles was determined using the sand bath hydrometer method; approximately 2000g of mud was taken, divided into two portions... After drying, the soil was sieved through a 0.5 mm sieve and divided into six samples of approximately 70 g each. Water was added to three soil samples according to their near-liquid limit, plastic limit, and intermediate state, and the liquid and plastic limits were determined using a combined liquid and plastic limit analyzer. Approximately 20 g of mud was filtered through a 0.45 μm filter to obtain a clear liquid, and the zeta potential of the mud was determined using a zeta potential meter. Approximately 15 g of mud was divided into three portions, and the acidity and alkalinity were determined using a benchtop pH meter. Approximately 50 g of mud was dried and ground to ensure a particle size of approximately 40 μm, and the mineral composition was determined using XRD technology.

[0052] In the sludge experiment, experimental parameters and corresponding experimental parameters for calcium-based reagents and CO2 gas were set. Based on orthogonal model experiments, different combinations of experimental parameters were determined, and carbonization flocculation experiments were carried out based on the combinations of experimental parameters.

[0053] The experimental parameters included the mass ratio of calcium-based reagent, CO2 aeration pressure, CO2 aeration time, CO2 circulation time, CO2 circulation interval, and CO2 circulation flow rate. The experimental parameters included a calcium-based reagent to sludge mass ratio of 0.5%, 1%, 2%, 4%, 6%, 8%, and 10%; CO2 aeration pressures of 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, and 0.6 MPa; CO2 aeration times of 4 h, 8 h, and 12 h; CO2 circulation time of 5 min; CO2 circulation intervals of 4 h, 6 h, and 8 h; and CO2 circulation flow rates of 1 L / min, 2 L / min, 3 L / min, and 4 L / min.

[0054] Based on the orthogonal experimental model and the corresponding experimental parameters, several parameter combinations were determined, and carbonization flocculation experiments were conducted for each parameter combination. One embodiment of this application is as follows: the parameter combination may be 2% calcium-based reagent mass ratio, 0.3 MPa CO2 aeration pressure, 4 h CO2 aeration time, 5 min CO2 circulation time, 4 h CO2 circulation interval, and 2 L / min CO2 circulation flow rate.

[0055] To improve the accuracy of experimental results, parallel experiments are conducted. Specifically, multiple carbonization and flocculation experiments are performed with a single parameter combination. The average of the multiple experimental results is taken, or the average is taken after removing extreme values, and the final experimental result is output.

[0056] Data processing: After carbonization and flocculation experiments, the upper clear liquid and lower sediment were collected to determine the clear liquid index and sedimentation index. The weights of the clear liquid index and sedimentation index were set based on the AHP method. The engineering performance was calculated by the normalized values ​​of the clear liquid index and sedimentation index and their corresponding weights. The carbon fixation capacity was determined based on the carbon fixation amount of the sedimentation index.

[0057] The supernatant parameters include pH, turbidity, and TDS. A benchtop pH meter was used to measure the pH of the supernatant, a benchtop turbidity meter to measure the turbidity, and a TDS meter to measure the total dissolved solids (TDS).

[0058] Sedimentation parameters included moisture content, particle size distribution, liquid limit, plastic limit, filtration resistance, zeta potential, carbon fixation, and mineral composition variation. Soil samples were collected from the upper, middle, and lower parts of the lower sedimentary layer. Moisture content was determined using the drying method, particle size distribution was determined using a laser particle size analyzer, filtration resistance was determined using a vacuum filtration flask, carbon fixation was determined using a nitric acid acidification test, and carbonate content was determined using XRD.

[0059] The weights of pH, turbidity, TDS, moisture content, particle size distribution, liquid limit, plastic limit, filtration resistance, Zeta potential, carbon fixation, and mineral composition variation were determined using the AHP method. The clear liquid and sedimentation indices were normalized, and the engineering performance of the comprehensive experimental indicators was calculated through weighted summation. The total carbon fixation was calculated using the carbon fixation within the sedimentation index, and this total carbon fixation was used to characterize the carbon fixation capacity.

[0060] Parameter optimization involves using the Pearson method to quantitatively and qualitatively analyze the correlation between each type of experimental parameter and engineering performance and carbon sequestration. Based on response surface methodology and qualitative analysis, the variation patterns of engineering performance and carbon sequestration under the coupling of experimental parameters are determined. The parameters of each experimental parameter are dynamically adjusted to form several combinations of experimental parameters. The experimental results of the combinations of experimental parameters are obtained based on the variation patterns to obtain the optimal combination of experimental parameters.

[0061] The Pearson method was used to analyze the correlations between calcium-based reagent dosage and engineering performance and carbon fixation, CO2 ventilation pressure and engineering performance and carbon fixation, CO2 ventilation time and engineering performance and carbon fixation, CO2 circulation time and engineering performance and carbon fixation, CO2 circulation interval and engineering performance and carbon fixation, and CO2 circulation flow rate and engineering performance and carbon fixation.

[0062] The Pearson method analysis results were obtained, and the variation law of engineering performance and carbon sequestration under the coupling of calcium-based reagents and CO2 ventilation parameters was determined based on response surface methodology and qualitative analysis.

[0063] By adjusting the dosage of each parameter individually to form several parameter combination schemes, and based on the variation law of engineering performance and carbon fixation under the coupling of base agent and CO2 ventilation parameters, the experimental results (multidimensional surface or fitting equation) of the parameter combination schemes are analyzed. By comparing the experimental results of different parameter combination schemes, the better parameter combination scheme (optimal parameter combination) is determined.

[0064] On-site construction is conducted based on the optimal parameter combination. On-site results, including engineering performance and carbon sequestration, are obtained. These results are compared with laboratory experimental results using the optimal parameter combination. When the on-site results do not meet the ideal laboratory values, one or more parameters are adjusted according to the variation patterns of engineering performance and carbon sequestration under the coupling of calcium-based reagents and CO2 ventilation parameters to improve performance indicators during on-site construction. One embodiment of this application involves increasing the carbon sequestration pressure when the carbon sequestration is less than the theoretical value, possibly due to air leakage (resulting in a loss of carbonization pressure). This reverse optimization is achieved by increasing the carbonization pressure.

[0065] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of this patent.

Claims

1. An experimental optimization method for mud carbonization and flocculation, characterized in that, include, Sludge sampling, sludge sampling and pretreatment, and obtaining sludge sample parameters through preliminary experiments; In the sludge experiment, the experimental parameters and corresponding experimental parameters of calcium-based reagent and CO2 gas were set. Based on the orthogonal model experiment, the experimental parameter combination of different experimental parameters was determined, and carbonization flocculation experiment was carried out according to the experimental parameter combination. Data processing: After carbonization and flocculation experiments, the upper clear liquid and lower sediment were collected to determine the clear liquid index and sedimentation index. The weights of the clear liquid index and sedimentation index were set based on the AHP method. The engineering performance was calculated by the normalized values ​​of the clear liquid index and sedimentation index and their corresponding weights. The carbon fixation capacity was determined based on the carbon fixation amount of the sedimentation index. Parameter optimization involves using the Pearson method to quantitatively and qualitatively analyze the correlation between each type of experimental parameter and engineering performance and carbon sequestration. Based on response surface methodology and qualitative analysis, the variation patterns of engineering performance and carbon sequestration under the coupling of experimental parameters are determined. The parameters of each experimental parameter are dynamically adjusted to form several combinations of experimental parameters. The experimental results of the combinations of experimental parameters are obtained based on the variation patterns to obtain the optimal combination of experimental parameters.

2. The experimental optimization method for mud carbonization and flocculation according to claim 1, characterized in that, The experimental parameters include the mass ratio of calcium-based reagents, CO2 ventilation pressure, CO2 ventilation time, CO2 circulation time, CO2 circulation interval, and CO2 circulation flow rate.

3. The experimental optimization method for mud carbonization and flocculation according to claim 1, characterized in that, The clear liquid indicators include pH value, turbidity and TDS, and the precipitation indicators include water content, particle size distribution, liquid limit and plastic limit, filtration resistance, zeta potential, carbon fixation and mineral composition variation.

4. The experimental optimization method for mud carbonization and flocculation according to claim 1, characterized in that, The preliminary experiments included moisture content testing, particle size distribution analysis, density measurement, specific gravity measurement, liquid limit and plastic limit measurement, zeta potential testing, pH testing and XRD testing. The results of the preliminary experiments together constitute the sample parameters. Based on the optimal combination of experimental parameters, on-site construction was carried out, and silt was collected and pretreated after construction to obtain on-site parameters. The on-site parameters and sample parameters were compared, and the combination of experimental parameters was optimized in reverse based on the comparison results.

5. The experimental optimization method for mud carbonization and flocculation according to any one of claims 1-4, characterized in that, The experimental apparatus used in the experimental optimization method of mud carbonization flocculation includes a base plate (4), a cover (1) and a glass tube (3). The glass tube (3) is sealed between the base plate (4) and the cover (1) to form a cavity for holding mud. The cover (1) is provided with a first three-way valve (8) for discharging CO2 gas. The base plate (4) is provided with a second three-way valve (19) for introducing CO2 gas. The C port of the second three-way valve (19) is connected to the CO2 storage tank (22). The top surface of the base plate (4) is provided with an aeration disc (21) for introducing CO2 into the cavity. The B port of the second three-way valve (19) is connected to the air inlet of the aeration disc (21). A booster pump (15) is connected in series between the A port of the first three-way valve (8) and the A port of the second three-way valve (19).

6. The experimental optimization method for mud carbonization and flocculation according to claim 5, characterized in that, A first check valve (14) is provided between the booster pump (15) and port A of the first three-way valve (8), and a second check valve (141) is provided between the booster pump (15) and port A of the second three-way valve (19). The opening pressure of the first check valve (14) and the second check valve (141) is adjustable, and a pressure regulating valve (18) is provided at the outlet of the CO2 storage tank (22).

7. The experimental optimization method for mud carbonization and flocculation according to claim 5, characterized in that, The outer wall of the glass tube (3) is covered with a protective sleeve (11), and several observation windows (1101) are evenly opened on the protective sleeve (11).

8. The experimental optimization method for mud carbonization and flocculation according to claim 5, characterized in that, A first flow meter (17) is provided between the booster pump (15) and the second three-way valve (19), and a second flow meter (171) is provided between the CO2 storage tank (22) and the second three-way valve (19). The output flow of the CO2 storage tank (22) is controlled according to the first flow meter (17), and the output flow of the CO2 storage tank (22) is adjusted by feedback through the second flow meter (171).

9. The experimental optimization method for mud carbonization and flocculation according to claim 5, characterized in that, The top surface of the cover (1) is provided with a positive and negative pressure gauge (7) for detecting the pressure inside the cavity and a quick-release vacuum interface (9) for extracting excess gas from the cavity.

10. The experimental optimization method for mud carbonization and flocculation according to claim 5, characterized in that, The bottom surface of the base plate (4) is provided with a drain outlet (20).

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