Experimental optimization method and experimental device for slurry carbonization and flocculation

Abstract

The invention provides an experimental optimization method and an experimental device for slurry carbonization and flocculation. The experimental optimization method comprises the following steps: sampling and pretreating sludge, and performing an early-stage experiment to obtain sample parameters of the sludge; setting experimental parameters and corresponding experimental parameters of the calcium-based medicament and the CO2 gas, constructing an experimental parameter combination, and performing a carbonization flocculation experiment; collecting the supernatant and the lower precipitate to determine a supernatant index and a precipitate index, and determining the engineering performance and the carbon sequestration capability based on the supernatant index and the precipitate index; the correlation between each type of experimental parameters and the engineering performance and the carbon sequestration amount is quantitatively and qualitatively analyzed through a Pearson method, and the change rule of the engineering performance and the carbon sequestration amount under experimental parameter coupling is determined based on a response surface method and a qualitative analysis method so as to obtain the optimal experimental parameter combination. According to the method, related rules of key parameters such as the agent mixing amount, the CO2 ventilation time and the ventilation pressure and the mud treatment effect can be obtained, basis and reference are provided for construction, and the practicability of the carbonization and flocculation treatment method is improved.

Description

Technical Field

[0001] The invention relates to the technical field of sludge carbonization and flocculation, and in particular to an experimental optimization method and an experimental device for sludge carbonization and flocculation. Background Art

[0002] The massive emission of carbon dioxide is one of the main reasons for the global temperature rise. Protecting the earth's environment has become a consensus among countries around the world. The amount of high-water content mud dredged out in my country every year is as high as hundreds of millions of cubic meters. A large amount of high-water content mud cannot be piled up or abandoned arbitrarily. It is necessary to find a suitable place to accommodate or treat it. No matter which disposal method is used, the water content of the mud must be reduced first.

[0003] In recent years, people have introduced chemical flocculants into the treatment of high-water content mud. Through the flocculation of the agent, the water content of the mud is greatly reduced, and the efficient reduction is achieved. Commonly used inorganic chemical flocculants are CaO and Ca(OH)2, and their flocculation mechanism includes: 1) Ca2+ ions in the mud compress the diffuse double layer of soil particles and thin the thickness of the hydration film; 2) Volcanic ash reacts to form cementing materials such as hydrated calcium silicate and hydrated calcium aluminate, which cement the soil particles together to form larger particles and cause flocculation; 3) CaO, Ca(OH)2 and CO2 undergo carbonization reaction to form calcium carbonate (CaCO3) cement, which is attached to the surface of soil particles to play a connecting role and can make CO2 exist in the soil body in the form of compounds for a long time.

[0004] This mud treatment method will cause the pH value to drop after the introduction of CO2, which will strengthen the carbonization reaction in flocculation, but will hinder the occurrence of volcanic ash reaction. Calcium-based agents require Ca2+ ions to play an electrical neutralization role, compress the double electrical layer, and cause soil particles to aggregate and flocculate. Therefore, premature introduction of CO2 is bound to affect the flocculation effect of the agent. It can be seen that there is an extremely complex interaction between carbonization reaction and flocculation, and the influence mechanism between carbon fixation and flocculation performance is unclear, which makes the practicability of mud treatment methods poor. 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 flocculation, which can derive the correlation between key parameters such as agent dosage, CO2 ventilation timing and ventilation pressure and mud treatment effects, provide a basis and reference for on-site construction of high-water content mud treatment, and improve the practicability of the carbonization flocculation treatment method.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] An experimental optimization method for sludge carbonization 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 the calcium-based reagent and CO2 gas are set, the experimental parameter combination of different experimental parameters is determined based on the orthogonal model test, and the carbonization flocculation experiment is carried out according to the experimental parameter combination;

[0009] Data processing: After the carbonization flocculation experiment, 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 through the normalized values ​​and corresponding weights of the clear liquid index and sedimentation index. The carbon fixation capacity was determined based on the carbon fixation amount of the sedimentation index.

[0010] Parameter optimization, using the Pearson method to quantitatively and qualitatively analyze the correlation between each type of experimental parameter and engineering performance, carbon fixation, based on the response surface method and qualitative analysis method to determine the change law of engineering performance and carbon fixation under the coupling of experimental parameters, in order to obtain the optimal combination of experimental parameters.

[0011] Furthermore, the experimental parameters include the mass ratio of calcium-based agents, 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 composition, liquid limit, plastic limit, suction resistance, Zeta potential, carbon fixation amount and mineral composition changes.

[0013] Furthermore, the preliminary experiments include moisture content test, particle size composition analysis, density measurement, specific gravity measurement, liquid and plastic limit measurement, Zeta potential test, pH test and XRD test, and the results of the preliminary experiments together constitute the sample parameters;

[0014] According to the optimal experimental parameter combination, on-site construction is carried out, the sludge after construction is collected and pre-treated to obtain the on-site parameters, the on-site parameters and sample parameters are compared, and the experimental parameter combination is reversely optimized based on the comparison results.

[0015] An experimental device for mud carbonization and flocculation comprises a base plate, a cover and a glass tube, wherein a glass tube is sealed between the base plate and the cover to form a cavity for containing mud, a first three-way valve for discharging CO2 gas is provided on the cover, a second three-way valve for introducing CO2 gas is provided on the base plate, a C port of the second three-way valve is connected to a CO2 gas storage tank, an aeration disk for introducing CO2 into the cavity is provided on the top surface of the base plate, a B port of the second three-way valve is connected to an air inlet of the aeration disk, and 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 one-way valve is provided between the boosting pump and the port A of the first three-way valve, a second one-way valve is provided between the boosting pump and the port A of the second three-way valve, the opening pressures of the first one-way valve and the second one-way valve are adjustable, and a pressure regulating valve is provided at the gas outlet of the CO2 gas storage tank.

[0017] Furthermore, the outer wall of the glass tube is covered with a protective cover, and a plurality of observation windows are evenly arranged on the protective cover.

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

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

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

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

[0022] By setting the experimental parameters and corresponding experimental parameters of calcium-based agents and CO2 gas, and setting several experimental parameter combinations according to the orthogonal experimental principle, the clear liquid indicators and precipitation indicators of different experimental parameter combinations are obtained. The indicators include pH value, turbidity, TDS, water content, particle size composition, liquid limit, filtration resistance, Zeta potential, carbon fixation and mineral composition changes.

[0023] By setting weights for each indicator in order to calculate the engineering performance, by converting multiple indicators into engineering performance, and converting the correlation analysis between multiple parameters into the correlation analysis between multiple parameters and one parameter, the workload of data analysis in the early stage and on-site construction is saved, and it is convenient to quickly determine the optimal combination of experimental parameters and also convenient to optimize the experimental parameter combination on-site.

[0024] A cavity for holding the mud is set up, an aeration plate for introducing CO2 gas is set on the bottom of the cavity, the aeration plate is connected to the CO2 gas storage tank, and the top surface of the cavity is connected to the aeration plate through a booster pump, so that circulating gas supply can be carried out. The CO2 gas storage tank and the booster pump work together to continuously introduce CO2 gas with a fixed flow rate and pressure into the cavity to carry out carbonization flocculation experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 It is an overall structural diagram of an experimental device for carbonization and flocculation of mud of the present invention;

[0027] Figure 2 It is a front view of an experimental device for carbonization and flocculation of mud of the present invention;

[0028] Figure 3 It is a flat view of a protective cover in an experimental device for mud carbonization and flocculation of the present invention;

[0029] Figure 4 It is a flow chart of an experimental optimization method for mud carbonization flocculation of the present invention;

[0030] In the figure: 1. sealing cover; 2. flange ring; 3. glass tube; 4. bottom plate; 5. sliding support; 501. universal wheel; 502. load-bearing bracket; 6. fastening rod; 602. nut; 7. positive and negative pressure gauge; 8. first three-way valve; 9. quick-release vacuum interface; 10. lifting ring; 11. protective cover; 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. sewage outlet; 21. aeration disk; 2101. filter membrane; 22. CO2 gas storage tank. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0034] The present invention provides an experimental device for slurry carbonization and flocculation, such as Figure 1 to Figure 2 As shown, it includes a bottom plate 4, a cover 1 and a glass tube 3, and the glass tube 3 is sealed and clamped between the bottom plate 4 and the cover 1 to form a cavity for holding the mud. Several flange holes are provided at the edges of the bottom plate 4 and the cover 1, and the bottom plate 4 and the cover 1 are sealed and fixed at both ends of the glass tube 3 by a fastening rod 6 and a nut 602. An embodiment of the present application is: a mounting groove is provided on the bottom surface of the bottom plate 4, and the lower end of the glass tube 3 is sealed and installed in the mounting groove, and the cover 1 is installed on the upper end of the glass tube 3. The fastening rod 6 is a long rod structure and has threads at both ends. During installation, the cover 1 and the flange holes on the bottom plate 4 are placed opposite each other, and the fastening rod 6 passes through the flange holes on the cover 1 and the bottom plate 4 at the same time, and nuts 602 are installed at both ends of the fastening rod 6. The two nuts 602 are respectively pressed against the top surface of the cover 1 and the bottom surface of the bottom plate 4, so that the two ends of the glass tube 3 are completely sealed.

[0035] In order to improve the sealing performance of the upper end of the glass tube 3, a flange ring 2 is sealed and installed on the upper end of the glass tube 3. A flange hole matching the cover 1 is provided on the top surface of the flange ring 2, and the sealing performance of the cavity is improved by increasing the contact area with the cover 1. An embodiment of the present application is that 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 provided with a first three-way valve 8 for discharging CO2 gas, the bottom 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 gas storage tank 22, the top surface of the bottom 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, and the CO2 gas storage tank 22 is used to continuously introduce CO2 gas into the cavity, and the CO2 gas reacts with the mud to produce a carbonization reaction, increase the mud precipitation, and absorb the CO2 gas. The surface of the aeration disc 21 is provided with a filter membrane 2101, which can ensure that the aeration disc 21 is normally introduced with CO2 gas and prevent sludge leakage.

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

[0038] like Figure 3 As shown, the outer wall of the glass tube 3 is covered with a protective cover 11 to improve the compressive strength of the glass tube 3. A plurality of observation windows 1101 are evenly arranged on the protective cover 11, and a vertical scale 1102 is provided on the protective cover 11 to facilitate observation of changes in the precipitation in the cavity and changes in the height of the clear liquid. An embodiment of the present application is: the observation window 1101 is a circular hole, and a plurality of observation windows 1101 are arranged vertically, and observation windows 1101 in different columns are arranged in a staggered manner to avoid affecting the observation of the height of the clear liquid and the precipitation.

[0039] The carbonization reaction of the sludge in the cavity cannot completely absorb the introduced CO2 gas. In order to improve the utilization rate of CO2 gas and make the sludge absorb more CO2 gas, 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, and the B port of the first three-way valve 8 is connected to the top surface of the cavity to form a circulation passage for CO2 gas, so that CO2 gas can circulate in the cavity.

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

[0041] An embodiment of the present application is as follows: the gas supply pressure of the cavity is set to 0.1 MPa, the opening pressures of the first one-way valve 14 and the second one-way valve 141 are both 0.1 MPa, the booster pump 15 is operated to make the second one-way valve 141 conductive 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 closer to the latter part of the experiment, the lower the absorption of CO2 gas by the sludge. If the liquid in the cavity cannot be discharged in time, the pressure in the cavity will gradually increase, which may easily cause the glass tube 3 to break or leak between the glass tube 3 and the bottom plate 4 and the cover 1, resulting in leakage of liquid or sludge. 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 in the cavity exceeds the threshold, the pressure reducer 12 is opened to relieve the pressure of the cavity in time. One embodiment of the present application is: the pressure reducer 12 is a pressure-controlled overflow valve with adjustable opening pressure. When the pressure at the inlet of the overflow valve exceeds the threshold, the overflow valve is turned on to discharge excess CO2; when the inlet pressure is lower than the threshold, the overflow valve is closed and CO2 does not flow.

[0043] During the mud sedimentation experiment, the flow rate of CO2 in the cavity needs to be set and kept stable to detect the effect of the flow rate on the mud sedimentation. 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 gas 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 in the cavity. One embodiment of the present application is: obtaining the sampling parameters of the first flow meter 17, dynamically adjusting the exhaust flow rate of the CO2 gas storage tank 22 according to the parameters of the first flow meter 17, and adjusting the exhaust flow rate of the CO2 gas storage tank 22 according to the sampling parameter feedback of the second flow meter 171, so as to improve the stability of the CO2 gas flow rate.

[0044] The top surface of the cover 1 is provided with a positive and negative pressure gauge 7 for detecting the pressure in the cavity and a quick-release vacuum interface 9 for extracting excess gas in the cavity. Before introducing CO2 gas into the cavity, connect the vacuum pump to the quick-release vacuum interface 9 to extract excess air in the cavity until the positive and negative pressure gauge 7 shows a negative value and the value is stable, then turn off and remove the vacuum pump; then introduce CO2 gas of preset pressure and flow into the cavity, and the positive and negative pressure gauge 7 is used to monitor the gas pressure in the cavity.

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

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

[0047] Silt sampling involves using a mud pump to pump mud into a plastic barrel at different locations and depths, using a 1cm aperture sieve set at the mouth of the plastic barrel to filter out debris such as domestic garbage or gravel in the mud, and after sampling, sealing the mouth of the barrel with plastic wrap to prevent water loss.

[0048] The pretreatment includes transporting the mud to the laboratory and then stirring the mud evenly with a constant speed mixer to prevent uneven mud properties caused by dehydration due to its own weight during transportation; dividing the mud into multiple portions in small buckets according to the mass required for the basic physical and chemical properties test and the carbonization flocculation test box model test, and sealing them with plastic wrap. Before each use, the mud in the small bucket should be stirred evenly with a constant speed mixer.

[0049] The preliminary experiments include moisture content test, particle size composition analysis, density determination, specific gravity determination, liquid and plastic limit determination, Zeta potential test, pH test and XRD test. The results of the above tests are sample parameters of sludge, which are used to characterize the basic physical and chemical properties of sludge. After the carbonization flocculation experiment, sludge is collected and the sample parameters (defined as implementation parameters) are tested using the same method. During the on-site construction process, the implementation parameters and sample parameters are compared, and the variation law of engineering performance and carbon fixation under the coupling of calcium-based agents and CO2 ventilation parameters is optimized based on the comparison results, so as to improve the accuracy of the optimal experimental parameter combination.

[0050] The parameter comparison shows the changes in the basic physical and chemical properties of the original mud without carbonization and flocculation and the mud after carbonization and flocculation, and further reveals the improvement mechanism of the mud after carbonization and flocculation, which has higher strength, better permeability and less supernatant pollution. In general, these parameters are the physical and chemical property parameters of the mud, which are strong evidence to characterize the effectiveness of this technology.

[0051] The specific process of the preliminary experiment is as follows: take out about 80g of mud, divide it into three parts, each part is 20-30g, and put it into the oven for moisture content test; take out about 20g of mud and divide it into three samples, use MasterSizer2000 laser particle size analyzer to analyze particle size composition; take out about 2000g of mud and divide it into two parts, use 500ml standard measuring cylinder to measure density; take out about 200g of mud and divide it into two parts, dry it, and use sand bath pycnometer method to measure the specific gravity of mud soil particles; take out about 2000g of mud and divide it into two parts, dry it, and use sand bath pycnometer method to measure the specific gravity of mud soil particles. The slurry was dried and divided into 6 samples of about 70g each after passing through a 0.5mm sieve. Water was added to every three soil samples according to the state close to the liquid limit, plastic limit and intermediate state, and the liquid limit and plastic limit were determined by a liquid-plastic limit combined tester; about 20g of mud was taken out and passed through a 0.45um filter membrane to obtain a clear liquid, and the Zeta potential of the mud was determined by a Zeta potential meter; about 15g of mud was taken out and divided into 3 parts, and the pH value was determined by a desktop pH meter; about 50g of mud was taken out, dried and ground to ensure that the particle size was about 40um, and the mineral composition was determined by XRD technology.

[0052] In the sludge experiment, the experimental parameters and corresponding experimental parameters of the calcium-based agent and CO2 gas were set, the experimental parameter combination of different experimental parameters was determined based on the orthogonal model experiment, and the carbonization flocculation experiment was carried out according to the experimental parameter combination.

[0053] The experimental parameters include the mass ratio of calcium-based agent, CO2 ventilation pressure, CO2 ventilation time, CO2 cycle time, CO2 cycle interval, and CO2 circulation flow rate. The experimental parameters include the mass ratio of calcium-based agent to sludge of 0.5%, 1%, 2%, 4%, 6%, 8%, and 10%, CO2 ventilation pressure set to 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, and 0.6MPa, CO2 ventilation time set to 4h, 8h, and 12h, CO2 circulation time set to 5min, CO2 circulation interval set to 4h, 6h, and 8h, and CO2 circulation flow rate set to 1L / min, 2L / min, 3L / min, and 4L / min.

[0054] Based on the orthogonal test model and the experimental parameters corresponding to the experimental parameters, several parameter combinations are determined, and each parameter combination is subjected to a carbonization flocculation experiment. An embodiment of the present application is: the parameter combination can be a calcium-based agent mass ratio of 2%, a CO2 ventilation pressure of 0.3 MPa, a CO2 ventilation time of 4 h, a CO2 circulation time of 5 min, a CO2 circulation interval of 4 h, and a CO2 circulation flow rate of 2 L / min.

[0055] The accuracy of the experimental results is improved through parallel experiments, specifically: multiple carbonization flocculation experiments are carried out for one parameter combination, and the final experimental result is output after taking the average of multiple experimental results or taking the average after removing the extreme values.

[0056] Data processing: After the carbonization flocculation experiment, 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 through the normalized values ​​and corresponding weights of the clear liquid index and sedimentation index. The carbon fixation capacity was determined based on the carbon fixation amount of the sedimentation index.

[0057] The indicators of the supernatant include pH value, turbidity and TDS. The pH value of the supernatant is measured by a benchtop pH meter, the turbidity of the supernatant is measured by a benchtop turbidity meter, and the total dissolved solids of the supernatant is measured by a TDS test pen.

[0058] The precipitation indicators include moisture content, particle size composition, liquid and plastic limits, suction resistance, Zeta potential, carbon fixation and mineral composition changes. Soil samples were collected from the upper, middle and lower positions of the lower sedimentation layer, and the moisture content was determined by drying method, the particle size composition was determined by laser particle size analyzer, the specific resistance was determined by suction bottle, the carbon fixation was determined by nitric acid acidification test, and the carbonate content was determined by XRD.

[0059] The AHP method was used to determine the weights of pH value, turbidity, TDS, water content, particle size composition, liquid and plastic limit, suction resistance, Zeta potential, carbon fixation and mineral composition changes. At the same time, the clear liquid index and precipitation index were normalized, and the engineering performance of the comprehensive index of the experiment was calculated by weighted accumulation. The total carbon fixation was calculated using the carbon fixation in the precipitation index, and the total carbon fixation was used to characterize the carbon fixation capacity.

[0060] Parameter optimization, using the Pearson method to quantitatively and qualitatively analyze the correlation between each type of experimental parameter and engineering performance, carbon fixation, based on the response surface method and qualitative analysis method to determine the change law of engineering performance and carbon fixation under the coupling of experimental parameters, dynamically adjust the parameters of each experimental parameter to form a number of experimental parameter combinations, obtain the experimental results of the experimental parameter combination according to the change law, in order to obtain the optimal experimental parameter combination.

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

[0062] The analysis results of the Pearson method were obtained, and the changing patterns of engineering performance and carbon fixation under the coupling of calcium-based agents and CO2 ventilation parameters were determined based on the response surface methodology and qualitative analysis method.

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

[0064] Based on the optimal parameter combination, on-site construction is carried out, and on-site results are obtained during on-site construction. The on-site results refer to engineering performance and carbon fixation. The on-site results are compared with the experimental results of the optimal parameter combination in the laboratory. When the ideal laboratory value is not reached, one or more parameters are adjusted according to the change law of engineering performance and carbon fixation under the coupling of calcium-based agents and CO2 ventilation parameters to improve the performance indicators during field construction. One embodiment of the present application is: the carbon fixation amount is less than the theoretical value, which may be due to air leakage (loss of carbonization pressure value), that is, the carbonization pressure is increased to achieve reverse optimization.

[0065] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation 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 flocculation, characterized in that: include, Silt 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 the calcium-based reagent and CO2 gas are set, the experimental parameter combination of different experimental parameters is determined based on the orthogonal model test, and the carbonization flocculation experiment is carried out according to the experimental parameter combination; Data processing: After the carbonization flocculation experiment, 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 through the normalized values ​​and corresponding weights of the clear liquid index and sedimentation index. The carbon fixation capacity was determined based on the carbon fixation amount of the sedimentation index. Parameter optimization, using the Pearson method to quantitatively and qualitatively analyze the correlation between each type of experimental parameter and engineering performance, carbon fixation, based on the response surface method and qualitative analysis method to determine the change law of engineering performance and carbon fixation under the coupling of experimental parameters, dynamically adjust the parameters of each experimental parameter to form a number of experimental parameter combinations, obtain the experimental results of the experimental parameter combination according to the change law, in order to obtain the optimal experimental parameter combination.

2. The experimental optimization method for slurry carbonization flocculation according to claim 1 is characterized in that: The experimental parameters include the mass ratio of calcium-based agents, 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 flocculation according to claim 1 is characterized in that: The clear liquid indicators include pH value, turbidity and TDS, and the precipitation indicators include water content, particle size composition, liquid limit, filtration resistance, Zeta potential, carbon fixation amount and mineral composition changes.

4. The experimental optimization method for slurry carbonization flocculation according to claim 1 is characterized in that: The preliminary experiments include moisture content test, particle size composition analysis, density measurement, specific gravity measurement, liquid and plastic limit measurement, Zeta potential test, pH test and XRD test, and the results of the preliminary experiments together constitute the sample parameters; According to the optimal experimental parameter combination, on-site construction is carried out, the sludge after construction is collected and pre-treated to obtain the on-site parameters, the on-site parameters and sample parameters are compared, and the experimental parameter combination is reversely optimized based on the comparison results.

5. An experimental device for carbonization and flocculation of mud, based on an experimental optimization method for carbonization and flocculation of mud according to any one of claims 1 to 4, characterized in that: The invention comprises a bottom plate (4), a sealing cover (1) and a glass tube (3), wherein a glass tube (3) is sealed between the bottom plate (4) and the sealing cover (1) to form a cavity for containing mud, wherein a first three-way valve (8) for discharging CO2 gas is provided on the sealing cover (1), wherein a second three-way valve (19) for introducing CO2 gas is provided on the bottom plate (4), wherein a C port of the second three-way valve (19) is connected to a CO2 gas storage tank (22), wherein an aeration disk (21) for introducing CO2 into the cavity is provided on the top surface of the bottom plate (4), wherein a B port of the second three-way valve (19) is connected to an air inlet of the aeration disk (21), and a booster pump (15) is connected in series between a A port of the first three-way valve (8) and a A port of the second three-way valve (19).

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

7. The experimental device for slurry carbonization and flocculation according to claim 5, characterized in that: The outer wall of the glass tube (3) is covered with a protective cover (11), and a plurality of observation windows (1101) are evenly arranged on the protective cover (11).

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

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

10. The experimental device for slurry carbonization and flocculation according to claim 5, characterized in that: The bottom surface of the bottom plate (4) is provided with a sewage outlet (20).

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