On-line test method for carbon dioxide adsorption performance of brine and application of on-line test method

Abstract

The invention discloses an on-line test method for the carbon dioxide adsorption performance of brine, and aims to evaluate the carbon capture capability of brine and other solution type adsorbents in a direct air capture technology. By constructing a small DAC system, the method can simulate atmospheric conditions, monitor the penetration time, the adsorption capacity and the removal rate of CO2 in real time, and provide a scientific basis for optimizing the performance of an adsorbent. The invention not only promotes the application of the brine in the carbon dioxide capture and storage technology, but also provides an effective technical means for the performance test of other solution type adsorbents.

Description

Technical Field

[0001] The present invention belongs to the technical field of direct air carbon capture, and in particular relates to an online testing method and application for detecting the carbon dioxide adsorption performance of brine. Background Art

[0002] As the global climate change problem becomes increasingly serious, Direct Air Capture (DAC) technology has attracted widespread attention as an effective engineering method to remove carbon dioxide (CO2) from the air. The development of DAC technology is of great significance to mitigating global warming, especially in the context of rapid global warming, the need to develop a new generation of CO2 adsorbents is becoming increasingly urgent. High-concentration waste brine produced by seawater desalination has attracted attention as an alternative absorbent for carbon dioxide capture and storage technology. In addition, bitter brine, a large amount of liquid byproduct containing high concentrations of inorganic substances produced during the salt production process, also provides new possibilities for CO2 capture and storage.

[0003] Combining brine as an adsorbent with DAC technology can not only capture CO2, but also reduce the emission of high-salinity wastewater, and has the potential for two-way governance. However, brine faces many challenges in effectively capturing and releasing CO2 from the atmosphere, mainly because the composition of high-concentration brine is complex and the CO2 concentration in the atmosphere is low (about 400 ppm). Although there are many ways to utilize brine as a resource, and even it is theoretically feasible to achieve zero emission of high-salinity wastewater through continuous CO2 mineralization, how to use brine as a solution-type adsorbent to achieve efficient CO2 capture and utilization in an atmospheric environment is still a problem that needs to be solved. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a direct air capture device system suitable for brine adsorbents.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a direct air capture device system suitable for brine adsorbent, characterized in that: the direct air capture device system comprises a gas mixing input and output module, a bubble tower temperature control adsorption module and a gas chromatography CO2 online detection response module;

[0008] The gas mixing input and output module consists of three standard gas cylinders: nitrogen, carbon dioxide and helium, a pressure reducing valve, a gas mass flow controller, a pneumatic control valve group, a gas mixing control software, a stainless steel mixing tank and a stainless steel gas pipeline.

[0009] The bubble tower temperature control adsorption module consists of a temperature controller and a stainless steel bubble tank;

[0010] The gas chromatography CO2 online detection response module consists of a water removal pipe, a sampling solenoid valve, and a gas chromatograph.

[0011] As a preferred solution of the direct air capture device system of the present invention, the gas mixing input and output module is a gas mass flow controller with a measuring range of 10 to 300 SCCM and a measuring accuracy of ±1%.

[0012] As a preferred solution of the direct air capture device system of the present invention, the temperature-controlled adsorption module of the bubble tower is a temperature controller with a temperature control range of 0 to 80°C and a temperature control accuracy of ±1°C.

[0013] As a preferred solution of the direct air capture device system of the present invention, the sampling solenoid valve of the gas chromatography CO2 online detection response module is a pneumatic six-way valve, the cycle sampling interval time is 1 to 300 seconds, and the single sampling volume is 1 mL.

[0014] Another object of the present invention is to overcome the deficiencies in the prior art and provide an online testing method for the carbon dioxide adsorption performance of a brine adsorbent, which is characterized by comprising:

[0015] Closed test system, with helium output from the gas mixing input and output module, gas flow rate 100 SCCM, purging pipeline for 5 to 10 minutes;

[0016] Set the gas mixing input and output module to output a CO2 and N2 mixing ratio of 1:99 to 99:1;

[0017] Set the temperature control temperature of the bubble tower temperature control adsorption module;

[0018] injecting liquid solutions or other additives into the bubble column;

[0019] Turn on the gas mixing input and output module to output the mixed gas of CO2 and N2;

[0020] Turn on the gas chromatography CO2 online detection response module to obtain the detection data CO2 breakthrough time, cumulative N2 and CO2 peak areas, and equilibrium adsorption time;

[0021] Calculate the CO2 adsorption capacity and CO2 removal rate;

[0022] The test system was the direct air capture device system described above.

[0023] As a preferred solution of the online testing method for carbon dioxide adsorption performance of brine adsorbent described in the present invention, the mixing ratio of CO2 and N2 is 15:85 or 30:70 or 50:50.

[0024] As a preferred solution of the online testing method for carbon dioxide adsorption performance of brine adsorbent described in the present invention, wherein: the temperature control temperature of the bubble tower temperature control adsorption module is set to 25-35°C.

[0025] As a preferred scheme of the online testing method of carbon dioxide adsorption performance of brine adsorbent described in the present invention, wherein: the liquid solution or other additives are injected into the bubbling tower, wherein the liquid solution or other additives are at least one of pure water, synthetic seawater, brine, gypsum waste liquid, and modified zeolite.

[0026] As a preferred embodiment of the online testing method for carbon dioxide adsorption performance of brine adsorbent of the present invention, the concentrations of sodium chloride, calcium chloride and magnesium chloride in the synthetic seawater are 0.464-1.856 mol / L.

[0027] As a preferred solution of the online testing method for carbon dioxide adsorption performance of brine adsorbent of the present invention, the addition amount of the gypsum waste liquid or modified zeolite is 0.2-0.6wt.% of the brine adsorbent.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention provides a small-scale direct air capture system to simulate atmospheric conditions and accurately test the performance of brine in capturing carbon dioxide. The system integrates functions such as simulated atmospheric CO2 output, liquid phase adsorption, and online detection of CO2 adsorption, aiming to evaluate the efficiency and effect of brine adsorbents under different operating conditions, collect key indicator parameters and performance data, and provide experimental basis for optimizing the adsorption characteristics of brine and DAC process.

[0030] (2) The present invention provides an innovative online testing method specifically for evaluating the performance of solution-type adsorbents such as brine in capturing carbon dioxide in direct air capture technology. This method can not only effectively optimize the adsorption characteristics of brine, but can also be widely used in the carbon capture performance testing of other solution-type adsorbents, providing a new technical means for mitigating global warming and recycling resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0032] Figure 1 This is a brine carbon capture performance testing system in an embodiment of the present invention.

[0033] Figure 2 This is the influence curve of the adsorption temperature variable on the CO2 removal rate of pure water in Example 1 of the present invention.

[0034] Figure 3 This is the effect of the adsorption gas ratio variables on the CO2 removal rate of pure water in Example 2 of the present invention.

[0035] Figure 4 This is a curve showing the effect of three salts (NaCl, CaCl2 and MgCl2) in seawater on removal rate at different concentrations in Example 3 of the present invention.

[0036] Figure 5 This is the effect of different brine on CO2 removal rate in Example 4 of the present invention (sampling from Sheyang Salt Field).

[0037] Figure 6 This is the effect of different amounts of additives on CO2 removal rate in Example 5 of the present invention. DETAILED DESCRIPTION

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0039] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0041] Unless otherwise specified, the raw materials used in the examples were purchased commercially.

[0042] The device system used in the embodiment of the present invention is as follows Figure 1 As shown, it includes a gas mixing input and output module, a bubbling tower temperature control adsorption module and a gas chromatography CO2 online detection response module;

[0043] Among them, the gas mixing input and output module is responsible for simulating the concentration of CO2 in the atmosphere and providing stable gas mixing input. It can ensure the accuracy and repeatability of CO2 concentration during the experiment and provide the necessary prerequisites for the subsequent adsorption process. The module consists of three standard gas cylinders of nitrogen, carbon dioxide and helium, a pressure reducing valve, a gas mass flow controller, a pneumatic control valve group, a gas mixing control software, a stainless steel mixing tank and a stainless steel gas pipeline;

[0044] The bubble tower temperature control adsorption module is responsible for achieving the contact between CO2 and the brine adsorbent, and consists of a temperature controller and a stainless steel bubbler;

[0045] The gas chromatography CO2 online detection response module uses gas chromatography technology to analyze the adsorbed gas to determine the concentration change of CO2. By measuring the CO2 penetration curve, key performance indicators such as the adsorption capacity and adsorption rate of the brine adsorbent can be evaluated. It consists of a water removal pipe, a sampling solenoid valve, and a gas chromatograph.

[0046] Example 1

[0047] The pipelines in the closed test system were purged with helium at a flow rate of 100 SCCM for 3 minutes to clean the pipelines, and then the mixing ratio of CO2 and N2 was set to 15:85;

[0048] The temperature of the bubble tower temperature control adsorption module was set to 25°C, 30°C, and 35°C, respectively. 200 mL of pure water was injected into the bubble tower. The gas mixing input and output module was turned on to output a mixed gas of CO2 and N2 at a flow rate of 100 SCCM. At the same time, the gas chromatography CO2 online detection response module was started to record the CO2 breakthrough time, the accumulated N2 and CO2 peak areas, and the equilibrium adsorption time.

[0049] The adsorption capacity and removal rate of CO2 were calculated according to the following formula to evaluate the performance of the adsorbent.

[0050]

[0051] Where q is the equilibrium adsorption capacity of carbon dioxide (mmol / g), C is the feed gas concentration (mmol / cm 3 ), V is the feed volume flow rate (cm 3 / min), t is the adsorption time (min), F0 and F are the inlet gas and outlet gas molar flow rates (mol / min), and m is the mass of the adsorption solvent (g).

[0052]

[0053] Where η is the CO2 removal rate (%), Cin and Cout are the CO2 concentrations for inlet and outlet air (mmol / cm 3 ), Vin and Vout are the inlet and outlet air flow rates (cm 3 / min).

[0054] Evaluation results such as Figure 2 As shown in the figure, the main effects of absorption parameters temperature and gas ratio on removal efficiency are as follows Figure 3 and Figure 4 As shown; the results show that in the temperature range of 25-35℃, the highest average removal rate was obtained at 25℃.

[0055] Example 2

[0056] The difference between this embodiment and embodiment 1 is that the mixing ratio of CO2 and N2 mixed gas is replaced with 15:85, 30:70 and 50:50 respectively, the temperature of the bubble tower temperature control adsorption module is replaced with 25°C, and the remaining steps are the same as those in embodiment 2. The results are shown in FIG. Figure 3 shown.

[0057] The experimental results show that the gas ratio has a great influence on the removal rate. Under the conditions of a total gas flow of 100 SCCM, a gas CO2 and N2 ratio of 50:50, and a temperature of 25°C, the absorption efficiency is the highest, at 58.14%. However, based on the CO2 content in the simulated air, the CO2 and N2 ratio is selected to be 15:85, corresponding to an absorption efficiency of 40.2%.

[0058] Example 3

[0059] The difference between this embodiment and embodiment 1 is that the temperature of the temperature control adsorption module of the bubbling tower is replaced with 25°C, and the injection of 200 mL of pure water into the bubbling tower is replaced with the injection of 200 mL of sodium chloride, calcium chloride, and magnesium chloride aqueous solutions into the bubbling tower, with concentrations of 0.464, 0.928, 1.393, and 1.856 mol / L, respectively. The remaining steps are the same as those in embodiment 1. The results are shown in FIG. Figure 4 shown.

[0060] The volume flow rate of the gas was 100 SCCM, the ratio of CO2 to N2 was 15:85, and the temperature was 25°C. CO2 removal efficiency using salt-based seawater, for NaCl, at a concentration of 1x, the absorption performance was about the same as when pure water was used as the solvent. However, further increasing the concentration of NaCl significantly reduced the CO2 removal efficiency. At a concentration of 4 times, the removal efficiency was 32.5%. This is due to the high salinity of the water, which results in a decrease in the Henry coefficient and diffusion coefficient. Therefore, CO2 is hardly dissolved in the solution. The reaction between sodium ions and carbonate ions or bicarbonate ions may occur. However, the effect of high salinity hinders the dissolution of CO2. Therefore, in the system, the performance of capturing CO2 using NaCl is poor.

[0061] For CaCl2, the removal efficiency increases slowly as the CaCl2 concentration increases. When the concentration is 4 times, the CO2 removal efficiency increases slightly compared to ultrapure water, reaching 43.3%. This is due to the reaction between calcium ions and carbonate ions to form calcium carbonate. With less CaCl2 in the solution, the salinity of seawater is not as low as NaCl, and more CO2 can be dissolved in the solution. As CaCO3 is formed, more CO2 can be dissolved in the solution. Due to the small concentration of CaCl2 in seawater (about 50 times lower than NaCl), this effect is quite weak.

[0062] Another set of CO2 absorption experiments was conducted by varying the concentration of MgCl2. For 1-fold MgCl2 concentration, the CO2 removal efficiency increased slightly to 41.5% compared to the case of ultrapure water. Further increasing the concentration of MgCl2 significantly increased the CO2 removal efficiency, reaching 43.8% and 45.2% for 3-fold and 4-fold MgCl2 concentrations, respectively. This is due to the rapid reaction between ions. 2 + The concentration of Ca 2+ twice as much, able to respond effectively.

[0063] Example 4

[0064] The difference between this embodiment and embodiment 3 is that: the process of injecting 200 mL of sodium chloride, calcium chloride and magnesium chloride aqueous solutions into the bubbling tower is replaced by injecting 200 mL of initial brine, saturated brine, mother liquor and bitter brine into the bubbling tower respectively, and the remaining steps are the same as those in embodiment 3, wherein the initial brine concentration is <10°Bé; 10°Bé≤saturated brine concentration≤25°Bé; mother liquor is the brine remaining after one evaporation in the salt making process, with a reference value of 20-28°Bé; bitter brine is the high-concentration brine remaining in the seawater salting process, which is the residual liquid after salting in the salt field, dark yellow in color, bitter and salty in taste, with a reference value of 24.5-32°Bé.

[0065] The results are as follows Figure 5 As shown in the experiment, the various salt components in the brine are continuously concentrated as the evaporation process proceeds. From the initial brine to the saturated brine stage, the CO2 removal rate decreases due to the increase in the concentration of sodium chloride. After the precipitation of sodium chloride crystals, the CO2 removal rate of the mother liquor increases to 40.6%. After further removal of magnesium salts, the CO2 removal rate increases to 44.8%. For the salt industry, the brine before bittern has a high utilization value, and bittern is a by-product or waste, so there is a natural advantage in further using bittern for carbon capture.

[0066] Example 5

[0067] The difference between this embodiment and embodiment 4 is that the steps of injecting 200 mL of initial brine, saturated brine, mother liquor and bittern into the bubbling tower are replaced by injecting 200 mL of bittern into the bubbling tower, and adding gypsum waste liquid or modified zeolite 0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 wt.%, respectively. The remaining steps are the same as those in embodiment 4. The results are shown in FIG. Figure 6 shown.

[0068] The experimental results show that the addition of gypsum waste liquid and modified zeolite can improve the CO2 adsorption performance of bittern. When the addition amount is 0.2% by weight, the CO2 removal rate of bittern can be increased by about 15%. When the addition amount is 0.4wt.%, the maximum CO2 removal rate can reach 74%.

[0069] Comparative Example 1

[0070] This comparative example refers to section 3.3 of the document "Experimental Study on the Absorption of Carbon Dioxide by a New Phase Change Solvent" (Gao Ge, North China Electric Power University), which provides a wet wall tower method for studying the absorption of CO2 by a solvent. Compared with the embodiment, the system with wet wall tower adsorption as the core is more complex and requires precise control of multiple parameters to maintain stable operation, while the bubble tower adsorption system of the embodiment has a simple structure and easy-to-control operating conditions; and the infrared carbon dioxide analyzer is not as good as the gas chromatograph in detecting the carbon dioxide content, which is mainly reflected in its limitations on the analysis of specific gas types, its greater influence by humidity, and its relatively weak accuracy and stability; in addition, the control system of the embodiment can observe the data curve of CO2 penetrating the adsorption solution in real time, which is more flexible than the wet wall tower method.

[0071] The present invention proposes an online testing method for the carbon dioxide adsorption performance of brine, which aims to evaluate the carbon capture capacity of brine and other solution-type adsorbents in direct air capture technology. By constructing a small DAC system, the method can simulate atmospheric conditions and monitor the penetration time, adsorption capacity and removal rate of CO2 in real time, providing a scientific basis for optimizing adsorbent performance. This invention not only promotes the application of brine in carbon dioxide capture and storage technology, but also provides an effective technical means for the performance testing of other solution-type adsorbents.

[0072] The present invention proposes an online testing method and application of brine carbon dioxide adsorption performance to fill the research gap in the application of brine in DAC technology and provide scientific basis and technical support for the application of brine in DAC technology. Through the present invention, the performance of brine as a CO2 adsorbent can be effectively evaluated and optimized, thereby promoting its application in carbon dioxide capture and storage technology and achieving the dual goals of environmental governance and resource utilization.

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A direct air capture device system suitable for brine adsorbent, characterized in that: The direct air capture device system includes a gas mixing input and output module, a bubble tower temperature control adsorption module and a gas chromatography CO2 online detection response module; The gas mixing input and output module consists of three standard gas cylinders: nitrogen, carbon dioxide and helium, a pressure reducing valve, a gas mass flow controller, a pneumatic control valve group, a gas mixing control software, a stainless steel mixing tank and a stainless steel gas pipeline. The bubble tower temperature control adsorption module consists of a temperature controller and a stainless steel bubble tank; The gas chromatography CO2 online detection response module consists of a water removal pipe, a sampling solenoid valve, and a gas chromatograph.

2. The direct air capture device system of claim 1, wherein: The gas mixing input and output module is a gas mass flow controller with a measuring range of 10-300 SCCM and a measuring accuracy of ±1%.

3. The direct air capture device system of claim 1, wherein: The temperature control adsorption module of the bubble tower is a temperature controller with a temperature control range of 0 to 80° C. and a temperature control accuracy of ±1° C.

4. The direct air capture device system of claim 1, wherein: The gas chromatography CO2 online detection response module sampling solenoid valve is a pneumatic six-way valve, the cycle sampling interval time is 1 to 300 seconds, and the single sampling volume is 1 mL.

5. An online test method for carbon dioxide adsorption performance of brine adsorbent, characterized by: include, Closed test system, with helium output from the gas mixing input and output module, gas flow rate 100 SCCM, purging pipeline for 5 to 10 minutes; Set the gas mixing input and output module to output a CO2 and N2 mixing ratio of 1:99 to 99:1; Set the temperature control temperature of the bubble tower temperature control adsorption module; injecting liquid solutions or other additives into the bubble column; Turn on the gas mixing input and output module to output the mixed gas of CO2 and N2; Turn on the gas chromatography CO2 online detection response module to obtain the detection data CO2 breakthrough time, cumulative N2 and CO2 peak areas, and equilibrium adsorption time; Calculate the CO2 adsorption capacity and CO2 removal rate; The test system is a direct air capture device system as claimed in any one of claims 1 to 4.

6. The method for online testing carbon dioxide adsorption performance of brine adsorbent according to claim 5, characterized in that: The mixing ratio of CO2 to N2 is 15:85 or 30:70 or 50:

50.

7. The method for online testing carbon dioxide adsorption performance of brine adsorbent according to claim 5, characterized in that: The temperature control temperature of the bubble tower temperature control adsorption module is set to 25-35°C.

8. The method for online testing carbon dioxide adsorption performance of brine adsorbent according to claim 5, characterized in that: The liquid solution or other additives are injected into the bubbling tower, wherein the liquid solution or other additives are at least one of pure water, synthetic seawater, brine, gypsum waste liquid, and modified zeolite.

9. The method for online testing carbon dioxide adsorption performance of brine adsorbent according to claim 8, characterized in that: The concentrations of sodium chloride, calcium chloride and magnesium chloride in the synthetic seawater are 0.464-1.856 mol / L.

10. The method for online testing carbon dioxide adsorption performance of brine adsorbent according to claim 8, characterized in that: The added amount of the gypsum waste liquid or modified zeolite is 0.2-0.6 wt.% of the brine adsorbent.

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