Method and device for measuring content of carbon dioxide in desulfurization solution

Abstract

The invention relates to a method and a device for determining the content of carbon dioxide in a desulfurization solution, and belongs to the technical field of chemical analysis. The method for determining the content of carbon dioxide in the desulfurization solution comprises the following steps: firstly, converting sulfur ions in the desulfurization solution into precipitates by using water-soluble copper salt, and then converting carbonate radicals in the desulfurization solution into carbon dioxide by using an acidic compound; and finally, determining the content of carbon dioxide in the desulfurization solution according to the amount of the gas obtained by the second mixing reaction, and the method has the advantages of high precision and good reproducibility, is convenient to operate, can effectively improve the determination efficiency, and is convenient to popularize and apply.

Description

Technical Field

[0001] The invention relates to a method and a device for determining the carbon dioxide content in a desulfurization solution, belonging to the technical field of chemical analysis. Background Art

[0002] In the gas purification process of natural gas purification plants and refineries, the desulfurization and decarbonization process usually includes the process of selectively removing acid gases (hydrogen sulfide and / or carbon dioxide) using amine liquid to obtain purified gas and rich amine liquid, and the process of recycling and regenerating the rich amine liquid to obtain lean amine liquid. Amine liquid refers to a weakly alkaline organic amine solution used to absorb hydrogen sulfide and / or carbon dioxide in the desulfurization and decarbonization process. The most commonly used amine liquid is N-methyldiethanolamine aqueous (MDEA) solution. Rich amine liquid refers to the liquid phase system after the amine liquid is used to selectively remove acid gases in the desulfurization and decarbonization process. In the desulfurization and decarbonization process, the dissolved carbon dioxide content in the rich amine liquid has an important influence on the effect of removing acid gases and energy consumption indicators such as the amine liquid circulation volume. The dissolved carbon dioxide content in the lean amine liquid can reflect the regeneration effect of the rich amine liquid. CO in the desulfurization solution (rich amine liquid and lean amine liquid) 2 The content of CO in the desulfurization solution is one of the important parameters for the operation of the reaction unit. 2 The process can be adjusted according to the content to make the desulfurization and decarbonization device operate efficiently.

[0003] In the actual production process, the carbon dioxide content in the desulfurization solution is usually determined according to the method in Section 14 (Determination of Carbon Dioxide Content in Desulfurization Solution) of the standard GB / T 35212.1-2017 "Analysis of Gases and Solutions in Natural Gas Processing Plants and Analysis and Evaluation Methods for Desulfurization, Decarbonization and Sulfur Recovery Part 1: Analysis of Gases and Solutions". However, this method is time-consuming and labor-intensive to operate, which will affect the timeliness of the detection, thereby affecting product quality or causing energy waste.

[0004] In addition, some companies use the gas volume method to determine the H in the desulfurization solution. 2 S content, the principle of the gas volume method is as follows: after the MDEA solution absorbs hydrogen sulfide and carbon dioxide, the corresponding salts are generated, and a copper sulfate-sulfuric acid mixed solution is added to the salt liquid to make the sulfide ions generate copper sulfide precipitation, and at the same time, the carbonate ions react with sulfuric acid to precipitate carbon dioxide gas, and finally the precipitated carbon dioxide gas is introduced into the gas measuring tube, the volume of carbon dioxide is measured, and the carbon dioxide content is calculated. The gas volume method is widely used because of its advantages such as simple device structure and convenient operation. At present, the gas measurement device used in the gas volume method uses a "U"-shaped connection between a measuring tube and a level bottle to calculate the volume of carbon dioxide according to the rise and fall height of the liquid level in the measuring tube. The liquid level of the measuring tube needs to be manually controlled during the test, which is cumbersome, and the accuracy of the measurement results is closely related to human factors, resulting in low accuracy and poor repeatability in the gas volume method.

[0005] There are three main problems with the gas volume method:

[0006] (1) The gas volume method is to convert CuSO 4 -H 2 SO 4 The solution is added to the desulfurization solution to be tested, and the sulfur ions react with the copper ions to generate CuS precipitation, and the carbonate ions react with the sulfuric acid to generate CO 2 However, in actual operation, the precipitated gas contains CO 2 In addition, H 2 S, and in the calculation, the evolved gas is completely regarded as CO 2 , the generated H 2 The volume of S causes the measured gas volume to be too high.

[0007] (2) When reading and recording the volume of the evolved gas in the gas volume method, it is necessary to ensure that the liquid levels of the liquid level regulating bottle and the measuring tube are level and keep the gas pressure on both sides the same. In this way, the measured gas volume is the gas volume under the atmospheric pressure of the test environment. However, in the actual experimental process, due to improper operation of the operator, the measured volume error is large.

[0008] (3) During carbon dioxide analysis, the reaction bottle needs to be shaken vigorously, which will cause a large change in the volume of the gas and cause leakage at the catheter connection, resulting in distorted measurement results. In addition, during carbon dioxide analysis, sulfuric acid and desulfurization solution are not in sufficient contact and the reaction is incomplete, resulting in poor repeatability of the results.

[0009] In addition, Chinese patent document CN115452791A discloses a method and application for online monitoring of an amine liquid desulfurization and decarbonization process system. The method provided in the patent document requires at least one Raman scattering instrument, which has a complex and large structure and is difficult to implement. Chinese patent document CN105572243A discloses a method for online monitoring of CO in a desulfurization solution. 2 and H 2 The method for detecting S content in the patent document uses a chromatograph to complete separation and detection. Although the detection result is accurate, it requires expensive and complex equipment and a special chromatographic column. In addition, the components in the desulfurization solution are complex and can easily contaminate the chromatographic column, resulting in high operating costs and difficulty in popularization and application. Summary of the invention

[0010] The purpose of the present invention is to provide a method for determining the carbon dioxide content in a desulfurization solution, which can solve the problems of poor accuracy and high operating cost in the current method for determining the carbon dioxide content in the desulfurization solution.

[0011] Another object of the present invention is to provide a device for measuring the carbon dioxide content in a desulfurization solution, which can solve the problems of poor measurement accuracy and high operating cost of the current devices for measuring the carbon dioxide content in a desulfurization solution.

[0012] In order to achieve the above purpose, the technical solution adopted by the method for determining the carbon dioxide content in the desulfurization solution of the present invention is:

[0013] A method for determining the carbon dioxide content in a desulfurization solution comprises the following steps: firstly, subjecting the desulfurization solution, sodium chloride and a desulfurizing agent to a first mixing reaction so as to convert the sulfur ions in the desulfurization solution into precipitates to obtain a mixed solution; then subjecting the mixed solution and an acidic compound to a second mixing reaction; and finally determining the carbon dioxide content in the desulfurization solution according to the amount of gas obtained in the second mixing reaction; the desulfurizing agent is a water-soluble copper salt.

[0014] The method for determining the carbon dioxide content in the desulfurization solution of the present invention first uses a water-soluble copper salt to convert the sulfide ions in the desulfurization solution into precipitates, then uses an acidic compound to convert the carbonate ions in the desulfurization solution into carbon dioxide, and finally determines the carbon dioxide content in the desulfurization solution according to the amount of gas obtained by the second mixing reaction. The method has the advantages of high precision and good reproducibility, and is easy to operate, can effectively improve the determination efficiency, and is easy to promote and apply.

[0015] Preferably, the desulfurizer is copper sulfate and / or copper sulfate hydrate. Preferably, the desulfurizer is used in the form of a desulfurizer solution. Preferably, the mass fraction of the desulfurizer in the desulfurizer solution is 20-60%. Compared with other desulfurizers (e.g., lead salts, iron salts, chromium salts, etc.), copper salts have the advantages of being non-toxic, stable, and removing sulfur ions more thoroughly; compared with other copper salts (e.g., copper chloride, etc.), using copper sulfate and / or copper sulfate hydrate can ensure that less hydrated acidic volatiles are produced during the desulfurization process, which is conducive to improving the accuracy of the determination.

[0016] Preferably, the acidic compound is sulfuric acid. Preferably, the acidic compound is used in the form of an acidic compound solution. Preferably, the mass fraction of the acidic compound solution is 75-99%. Compared with other acidic compounds (e.g., hydrochloric acid, phosphoric acid, etc.), sulfuric acid has low volatility and has little effect on the volume of generated gas.

[0017] For the convenience of addition, preferably, sodium chloride is used in the form of sodium chloride solution, and the sodium chloride solution is a saturated solution; the volume of the sodium chloride solution is 1.05 to 1.1 times the sum of the volumes of the desulfurization solution and the desulfurization agent solution. The use of saturated sodium chloride solution can prevent the carbon dioxide generated by the reaction from dissolving too much in water and affecting the accuracy of the experimental results.

[0018] In order to ensure a better sealing effect, preferably, the first mixing reaction and the second mixing reaction are carried out under magnetic stirring.

[0019] In order to ensure that the first mixing reaction and the second mixing reaction can proceed quickly, and to avoid deviations in the measurement results caused by water evaporation and droplet splashing, preferably, the speed of the magnetic stirring during the first mixing reaction is 200-300 r / min; the speed of the magnetic stirring during the second mixing reaction is 400-600 r / min.

[0020] For ease of operation and reduction of measurement cost, preferably, the amount of gas is the volume of gas. Preferably, the volume of gas is determined by liquid displacement method. Preferably, the liquid displaced by gas in the liquid displacement method is a sealing liquid, and the sealing liquid is prepared by mixing sodium chloride, HCl and water, and the mass ratio of sodium chloride, HCl and water is 26.47:(1-3):(70-73).

[0021] The technical solution adopted by the device for measuring the carbon dioxide content in the desulfurization solution of the present invention is:

[0022] A measuring device for realizing the method for measuring carbon dioxide content as described above, comprising a reaction device, a feeding device and a gas volume measuring device which are sealed and connected in sequence; the reaction device is used to provide a place for the first mixing reaction and the second mixing reaction, the feeding device is used to add an acidic compound to the reaction device, and the gas volume measuring device is used to collect and measure the volume of the gas obtained from the second mixing reaction.

[0023] The device for determining the carbon dioxide content in the desulfurization solution of the present invention has the advantages of simple structure, is suitable for large-scale application, and can reduce operating costs.

[0024] Preferably, the gas volume measuring device comprises a gas measuring tube and a balance tube; the bottom of the gas measuring tube is sealed and connected to the bottom of the balance tube, the gas measuring tube is used to collect and measure the volume of the gas obtained by the second mixing reaction, the upper end of the balance tube is open and connected to the atmosphere, the gas measuring tube and the balance tube are filled with a sealing liquid, and the balance tube is used to adjust the pressure difference between the inside and outside of the gas measuring tube. The balance tube can be used to adjust the pressure difference between the inside and outside of the gas measuring tube, thereby improving the accuracy of the result.

[0025] After the gas obtained from the second mixed reaction is collected by the gas pipe, the pressure difference between the inside and outside of the gas pipe is Δp. The calculation formula for the carbon dioxide content in the desulfurization solution is as follows:

[0026]

[0027] Wherein, X is the carbon dioxide content in the desulfurization solution, in g / L; 1.9768 is the density of carbon dioxide under standard conditions, in g / L; Δp is the pressure difference between the inside and outside of the gas measuring tube, in kPa; ΔV is the volume difference of the gas in the gas measuring tube before and after the second mixing reaction, in mL; V is the sample volume of the desulfurization solution, in mL; K pt is the temperature and pressure correction coefficient, K pt The calculation formula is as follows:

[0028]

[0029] K pt In the calculation formula, P is the ambient pressure during the test, in kpa; P 盐水 is the saturated vapor pressure of the sealing liquid at the ambient temperature during the test, in kPa; t is the ambient temperature during the test, in °C. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of a testing device used in the method for determining the carbon dioxide content in a desulfurization solution according to Example 1 of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of a three-way piston in a testing device used in a method for determining the carbon dioxide content in a desulfurization solution according to Example 1 of the present invention;

[0032] Figure 3 This is a schematic structural diagram of a valve core of a three-way piston in a testing device used in a method for determining the carbon dioxide content in a desulfurization solution according to Example 1 of the present invention;

[0033] Figure 4 This is a schematic structural diagram of the valve core hole of the three-way piston in the testing device used in the method for determining the carbon dioxide content in the desulfurization solution of Example 1 of the present invention;

[0034] Figure 5 Schematic diagram of a testing device used in the method for determining the carbon dioxide content in a desulfurization solution according to Example 3 of the present invention;

[0035] The accompanying drawings are marked as follows: 1-magnetic stirring device; 2-stirring magnet; 3-conical flask; 4-water bath; 5-thermometer; 6-feed piston; 7-constant pressure tube; 8-air guide tube; 9-three-way piston; 10-overflow tube; 11-gas measuring tube; 12-liquid regulating piston; 13-liquid accumulation bottle; 14-liquid discharge piston; 15-liquid collecting bottle; 16-liquid level regulating piston; 17-liquid level regulating bottle; 18-liquid adding tube; 19-balancing tube; 20-liquid regulating tube; 21-connecting hose; 22-length scale; 23-buffer tube; 24-liquid outlet tube; 25-volume scale. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0037] Example 1

[0038] The method for determining the carbon dioxide content in the desulfurization solution of this embodiment uses a testing device such as Figure 1 As shown in the figure, before describing the test method, the test device is introduced first.

[0039] The test device used in this embodiment includes a reaction device, a feeding device, a gas measuring tube 11, a balance tube 19 and a leveling device. The reaction device is a conical flask 3 with a ground mouth, the feeding device is a constant pressure titration funnel with a ground mouth, and the leveling device is a liquid level regulating bottle 17. The conical flask 3 is used to provide a place for the desulfurization solution and the desulfurization agent to undergo a first mixing reaction, and for the mixed solution obtained from the first mixing reaction and the acidic compound to undergo a second mixing reaction. In order to make the reaction system mix evenly, a stirring magnet 2 is placed in the conical flask 3. The test device used in this embodiment also includes a magnetic stirring device 1, and the conical flask 3 is placed on the magnetic stirring device 1. In order to regulate the temperature in the conical flask, the test device used in this embodiment also includes a water bath 4 and a thermometer 5 arranged in the water bath 4. The conical flask 3 is placed in the water bath 4, and the thermometer 5 is placed in the water bath in the water bath 4 to detect the temperature of the water bath. The conical flask 3, the constant pressure titration funnel, the water bath 4, the thermometer 5 and the magnetic stirring device 1 constitute an analytical system.

[0040] The constant pressure burette funnel comprises a liquid adding tube 18, a liquid outlet tube 24, a feed valve and a constant pressure tube 7, the upper end of the constant pressure tube 7 is connected to the atmosphere in the liquid adding tube 18, the lower end of the constant pressure tube 7 is connected to the liquid outlet tube 24 and the atmosphere inside the conical flask 3, and the feed valve is a feed piston 6. The upper end opening of the constant pressure burette funnel is connected to the upper end side wall of the gas tube 11 through the air guide tube 8, and a three-way valve is provided at the upper end connection of the air guide tube 8 and the gas tube 11. By adjusting the three-way valve, the gas tube 11 and the gas tube 8 can be connected and the gas tube 11 and the gas tube 8 can be connected to the atmosphere at the same time, or the gas tube 11 and the gas tube 8 can be connected and the gas tube 11 and the gas tube 8 can be isolated from the atmosphere at the same time. The three-way valve is a three-way piston 9, and there are T-shaped three-way air holes in the three-way piston 9, two of which are in a straight line, and the third is vertically connected to the other two holes. The three-way piston can be used not only for T-shaped three-way control, but also for linear or right-angle control. By rotating the three-way piston to different positions, the device can achieve a left-up-down three-way state, a left-down two-way state, a left-up or up-down two-way state, and a left-up-down disconnected state. The structural diagram of the three-way piston 9 is shown in FIG. Figure 2-3 As shown, the structural schematic diagram of the valve core hole in the three-way piston 9 is as follows Figure 4shown.

[0041] The bottom of the gas measuring tube 11 is sealed and connected with the bottom of the balance tube 19 and the liquid level regulating bottle 17 respectively. The gas measuring tube 11 is used to collect the gas released by the reaction during the test. The upper ends of the balance tube 19 and the liquid level regulating bottle 17 are open and connected to the atmosphere. The balance tube 19 and the gas measuring tube 11 are arranged in parallel, and the bottoms of the two are connected to form a U-shaped communicating vessel. The gas measuring tube 11, the balance tube 19 and the liquid level regulating bottle 17 are filled with a sealing liquid. The preparation method of the sealing liquid is as follows: a sodium chloride solution and a hydrochloric acid with a mass fraction of 1% are stirred and mixed, and the mass ratio of sodium chloride, HCl and water in the sealing liquid is 26.47:1:70.

[0042] In order to read and record the amount of liquid or gas in the gas measuring tube 11 and the balance tube 19 more clearly and accurately, the outer peripheral wall of the gas measuring tube 11 is provided with volume scales 25 at intervals along its axial direction, and the outer peripheral wall of the balance tube 19 is provided with length scales 22 at intervals along its axial direction; the 0 scale line of the volume scale 25 starts from the upper end of the gas measuring tube 11, and the reading gradually increases downward, and the volume corresponding to any two adjacent volume scale values ​​is 0.1mL; the 0 scale line of the length scale 22 starts from the upper end of the balance tube 19, and the reading gradually increases downward, and the length corresponding to any two adjacent length scale values ​​is 0.1mm. In order to detect more gases, the inner diameter of the gas measuring tube 11 is larger than the inner diameter of the balance tube 19. In order to ensure the sealing effect, the gas measuring tube 11 and the balance tube 19 are an integrated structure.

[0043] A buffer tube 23 is provided at the upper end of the balance tube 19, and the two are integrally formed. A liquid outlet is provided on the side wall of the buffer tube 23, and the liquid outlet of the buffer tube 23 is connected to the liquid inlet of the overflow tube 10, and the lower edge of the liquid inlet of the overflow tube 10 is located on the same horizontal plane as the 0 scale line of the volume scale on the gas measuring tube 11. The bottom liquid outlet of the overflow tube 10 is connected to a rubber tube, and the end of the rubber tube is located in the liquid accumulation bottle 13, which is used to collect excess liquid discharged from the balance tube 19. The buffer tube 23 and the overflow tube 10 together constitute an anti-backflow device to prevent the closed liquid from backflowing through the air guide tube 8 into the constant pressure titration funnel. In order to separately control the amount of liquid in the gas measuring tube 11 and the balance tube 19, a liquid regulating valve is provided at the lower end of the balance tube 19, and the liquid regulating valve is a liquid regulating piston 12.

[0044] The bottom connection of the gas measuring tube 11 and the balance tube 19 is connected with a liquid regulating tube 20, and the tail end of the liquid regulating tube 20 forms a drain pipe for discharging excess liquid in the gas measuring tube 11. A drain valve is provided on the drain pipe, and a liquid collecting bottle 15 is provided below the tail of the drain pipe for receiving liquid discharged from the drain pipe. The drain valve is a drain piston 14. The liquid regulating tube 20 is sealed and connected with the liquid level regulating bottle 17 through a connecting hose 21, which is used to achieve sealed communication between the bottom of the gas measuring tube 11 and the liquid level regulating bottle 17. A liquid level regulating valve is provided on the pipe section of the connecting hose 21 close to the liquid level regulating bottle 17, and the liquid level regulating valve is a liquid level regulating piston 16.

[0045] The method for determining the carbon dioxide content in the desulfurization solution of this embodiment specifically comprises the following steps:

[0046] (1) Insert the lower part of the constant pressure titration funnel into the upper port of the conical flask 3, the conical flask 3 and the constant pressure titration funnel are sealed and connected through the ground mouth, and sulfuric acid solution is placed in the constant pressure titration funnel; then seal the air guide tube 8 and the upper port of the constant pressure titration funnel to complete the assembly of the measuring device;

[0047] Then carry out the airtightness test, the specific method is as follows:

[0048] ① Rotate the three-way piston 9 to connect the gas measuring tube 11 with the atmosphere, raise the height of the liquid level regulating bottle 17, discharge the gas in the gas measuring tube 11, and then rotate the three-way piston 9 again to isolate the gas measuring tube 11 from the air guide tube 8 and the atmosphere, and at the same time close the liquid regulating piston 12, put down the liquid level regulating bottle 17, and observe the liquid level in the gas measuring tube 11. If the liquid level in the gas measuring tube 11 does not change, it means that the sealing of the three-way piston 9 is good. If the liquid level in the gas measuring tube 11 changes, it means that the sealing of the three-way piston 9 is poor, and it is necessary to apply grease at the connection position of the three-way piston 9 to improve the sealing;

[0049] ② After confirming that the sealing performance of the three-way piston 9 is good, rotate the three-way piston 9 to connect the gas measuring tube 11 with the atmosphere, raise the height of the liquid level regulating bottle 17, discharge the gas in the gas measuring tube 11, and then rotate the three-way piston 9 again to connect the gas measuring tube 11 with the air guide tube 8, and isolate the gas measuring tube 11 and the air guide tube 8 from the atmosphere. At the same time, close the liquid regulating piston 12, put down the liquid level regulating bottle 17, and observe the liquid level in the gas measuring tube 11. If the liquid level in the gas measuring tube 11 does not change, it means that the sealing performance of the analytical system is good. If the liquid level in the gas measuring tube 11 changes, it means that the sealing performance of the analytical system is poor, and it is necessary to apply grease to improve the sealing performance.

[0050] (2) Add the desulfurization solution, copper sulfate solution and saturated salt water (mass fraction of 26.47%) into the conical flask 3, turn on the magnetic stirring device 1, and stir the materials in the conical flask 3 at a speed of 200 r / min for 6 minutes to convert the sulfide ions in the desulfurization solution into precipitates; the volume of the saturated salt water is 1.1 times the sum of the volumes of the desulfurization solution and the copper sulfate solution; while the materials in the conical flask 3 are stirring and reacting, the temperature of the water bath in the water bath bottle 4 is controlled to be 25° C.;

[0051] (3) Assemble the constant pressure titration funnel, rotate the three-way piston 9 to connect the gas measuring tube 11 and the gas guiding tube 8 and connect the gas measuring tube 11 and the gas guiding tube 8 to the atmosphere at the same time, raise the height of the liquid level adjustment bottle 17 to make the liquid level in the gas measuring tube 11 at the 0 scale line position of the volume scale 25, then close the liquid level adjustment piston 16, rotate the three-way piston 9 to connect the gas measuring tube 11 and the gas guiding tube 8 and isolate the gas measuring tube 11 and the gas guiding tube 8 from the atmosphere at the same time, adjust the discharge piston 14 to make the liquid levels in the gas measuring tube 11 and the balance tube 19 at the same height, read and record the liquid level position V in the gas measuring tube 11 1 , then lower the height of the liquid level regulating bottle 17 and open the liquid regulating piston 12;

[0052] (4) Turn on the magnetic stirring device 1, and control the temperature of the water bath in the water bath bottle 4 so that the temperature of the material in the conical flask 3 is controlled at 25°C. At the same time, open the feed piston 6 of the constant pressure titration funnel (the constant pressure titration funnel is filled with sulfuric acid solution), add the sulfuric acid solution into the conical flask 3, and stir the material in the conical flask 3 at a speed of 400 r / min. Observe the gas volume in the gas measuring tube 11. When the gas volume in the gas measuring tube 11 no longer increases, it means that the stirring reaction has reached the end point. At this time, raise the height of the liquid level regulating bottle 17 so that the liquid in the balance tube 19 overflows into the liquid accumulation bottle 13 until the liquid level in the balance tube 19 is slightly higher than the liquid level in the gas measuring tube 11. Close the liquid level regulating piston 16, adjust the liquid discharge piston 14, and allow the liquid in the balance tube 19 to flow into the liquid collecting bottle 15 until the liquid level in the balance tube 19 is equal to the liquid level in the gas measuring tube 11. Read and record the liquid level position V in the gas measuring tube 11. 2 , and record the atmospheric pressure and temperature during the test; the temperature change in the same test experiment should not exceed 0.2℃. If the temperature change is greater than 0.2℃, the experiment needs to be repeated;

[0053] (5) Calculate the carbon dioxide content in the desulfurization solution; the calculation formula is as follows:

[0054]

[0055] In formula 1, X is the carbon dioxide content in the desulfurization solution, in g / L; 1.9768 is the density of carbon dioxide under standard conditions, in g / L; V is the sample volume of the desulfurization solution, in mL; V 1 is the liquid level position in the gas measuring tube 11 read and recorded in step (3), in mL; V 2 is the liquid level position in the gas measuring tube 11 read and recorded in step (4), in mL; K pt is the temperature and pressure correction coefficient, which is calculated as follows:

[0056]

[0057] In formula 2, P is the ambient pressure during the test, in kPa; P 盐水 is the saturated vapor pressure of the sealing liquid at the ambient temperature during the test, in kPa; t is the ambient temperature during the test, in °C.

[0058] In this embodiment, the desulfurization solution is lean amine solution, the mass fraction of copper sulfate solution is 33%, the mass fraction of sulfuric acid solution is 98%, and the amount of copper sulfate solution is determined according to the following method: slowly drop the copper sulfate solution into a mass of m 1 When no more precipitation occurs in the lean amine solution, record the mass m of copper sulfate solution added. 2 , and then calculate the amount of copper sulfate solution, the calculation method is as follows: m = 2 × (m 2 / m 1 )×m 3 , where m is the mass of copper sulfate solution added during the determination, m 2 is the mass of copper sulfate solution during the dropwise addition experiment, m 1 is the mass of lean amine solution during the dropwise addition experiment, m 3 is the mass of the desulfurization solution used in the determination. The lean amine solution used in the drop addition experiment is the same as the desulfurization solution used in the determination. The copper sulfate solution used in the drop addition experiment is the same as the copper sulfate solution used in the determination. The amount of sulfuric acid solution is determined according to the following method: slowly drop the sulfuric acid solution into a solution with a mass of n 1 When precipitation stops, record the mass of sulfuric acid solution added. 2 , and then calculate the amount of sulfuric acid solution, the calculation method is as follows: n = 2 × (n 2 / n 1 )×n 3 , where n is the mass of sulfuric acid solution added during the measurement, n 2 is the mass of sulfuric acid solution during the dropwise addition experiment, n 1 is the mass of lean amine solution during the dropwise addition experiment, n 3is the mass of the desulfurization solution used in the measurement, the lean amine solution used in the dropping experiment is the same as the desulfurization solution used in the measurement, and the sulfuric acid solution used in the dropping experiment is the same as the sulfuric acid solution used in the measurement; the ambient pressure during the test of this embodiment is 100 kPa, the ambient temperature during the test is 27°C, and the carbon dioxide content in the desulfurization solution calculated by the test is 0.82 g / L.

[0059] Example 2

[0060] The method for determining the carbon dioxide content in the desulfurization solution of this embodiment uses the testing device in Example 1 and specifically includes the following steps:

[0061] (1) Assemble the test device and conduct airtightness test;

[0062] (2) Add the desulfurization solution, copper sulfate solution and saturated salt water (mass fraction of 26.47%) into the conical flask 3, turn on the magnetic stirring device 1, and stir the materials in the conical flask 3 at a speed of 300 r / min for 4 minutes to convert the sulfide ions in the desulfurization solution into precipitates; the volume of the saturated salt water is 1.05 times the sum of the volumes of the desulfurization solution and the copper sulfate solution; while the materials in the conical flask 3 are stirring and reacting, the temperature of the water bath in the water bath bottle 4 is controlled to be 25° C.;

[0063] (3) Rotate the three-way piston 9 to connect the gas measuring tube 11 and the gas guiding tube 8 and connect the gas measuring tube 11 and the gas guiding tube 8 to the atmosphere at the same time, raise the height of the liquid level regulating bottle 17, so that the liquid level in the gas measuring tube 11 is at the 0 scale line position of the volume scale 25, then close the liquid level regulating piston 16, rotate the three-way piston 9 to connect the gas measuring tube 11 and the gas guiding tube 8 and isolate the gas measuring tube 11 and the gas guiding tube 8 from the atmosphere at the same time, and read and record the liquid level position V in the gas measuring tube 11 1 ;

[0064] (4) Turn on the magnetic stirring device 1, and control the temperature of the water bath in the water bath bottle 4 so that the temperature of the material in the conical flask 3 is controlled at 25° C. At the same time, open the feed piston 6 of the constant pressure titration funnel, add the sulfuric acid solution into the conical flask 3, and stir the material in the conical flask 3 at a speed of 600 r / min. Observe the gas volume in the gas measuring tube 11. When the gas volume in the gas measuring tube 11 no longer increases, it means that the stirring reaction has reached the end point. Read and record the liquid level position V in the gas measuring tube 11. 2 , and simultaneously record the difference Δh between the liquid level in the gas measuring tube 11 and the liquid level in the balance tube 19;

[0065] During the experiment, the atmospheric pressure and temperature of the test environment should be tested. The temperature change in the same test experiment should not exceed 0.2℃. If the temperature change is greater than 0.2℃, the experiment needs to be repeated.

[0066] (5) Calculate the carbon dioxide content in the desulfurization solution; the calculation formula is as follows:

[0067]

[0068] In formula 3, X is the carbon dioxide content in the desulfurization solution, in g / L; 1.9768 is the density of carbon dioxide under standard conditions, in g / L; K pt is the temperature and pressure correction coefficient; ΔV is the volume difference of the gas in the gas measuring tube 11 before and after the stirring reaction in step (4), in mL, and ΔV is equal to the liquid level position V in the gas measuring tube 11 read and recorded in step (4) 2 The liquid level position V in the gas measuring tube 11 read and recorded in step (3) 1 The difference; P is the ambient pressure during the test, in kPa; Δp is the pressure difference between the inside and outside of the gas measuring pipe, in kPa, which is equal to the liquid column pressure corresponding to the difference between the liquid level in the gas measuring pipe 11 and the liquid level in the balance pipe 19 in step (4); V is the sample volume of the desulfurization solution in step (2), in mL;

[0069] K pt The calculation method is as follows:

[0070]

[0071] In formula 4, P is the ambient pressure during the test, in kPa; P 盐水 is the saturated vapor pressure of the sealing liquid at the ambient temperature during the test, in kPa; t is the ambient temperature during the test, in °C.

[0072] In this embodiment, the desulfurization solution is lean amine solution, the mass fraction of copper sulfate solution is 33%, the mass fraction of sulfuric acid solution is 98%, and the amount of copper sulfate solution is determined according to the following method: slowly drop the copper sulfate solution into a mass of m 1 When no more precipitation occurs in the lean amine solution, record the mass m of copper sulfate solution added. 2 , and then calculate the amount of copper sulfate solution, the calculation method is as follows: m = 2 × (m 2 / m 1 )×m 3 , where m is the mass of copper sulfate solution added during the determination, m 2 is the mass of copper sulfate solution during the dropwise addition experiment, m 1 is the mass of lean amine solution during the dropwise addition experiment, m 3is the mass of the desulfurization solution used in the determination. The lean amine solution used in the drop addition experiment is the same as the desulfurization solution used in the determination. The copper sulfate solution used in the drop addition experiment is the same as the copper sulfate solution used in the determination. The amount of sulfuric acid solution is determined according to the following method: slowly drop the sulfuric acid solution into a solution with a mass of n 1 When precipitation stops, record the mass of sulfuric acid solution added. 2 , and then calculate the amount of sulfuric acid solution, the calculation method is as follows: n = 2 × (n 2 / n 1 )×n 3 , where n is the mass of sulfuric acid solution added during the measurement, n 2 is the mass of sulfuric acid solution during the dropwise addition experiment, n 1 is the mass of lean amine solution during the dropwise addition experiment, n 3 is the mass of the desulfurization solution used in the measurement, the lean amine solution used in the dropping experiment is the same as the desulfurization solution used in the measurement, and the sulfuric acid solution used in the dropping experiment is the same as the sulfuric acid solution used in the measurement; the ambient pressure during the test of this embodiment is 99 kPa, the ambient temperature during the test is 26°C, and the carbon dioxide content in the desulfurization solution calculated by the test is 56.26 g / L.

[0073] Example 3

[0074] The method for determining the carbon dioxide content in the desulfurization solution of this embodiment uses a testing device such as Figure 5 As shown in the figure, before describing the test method, the test device is introduced first.

[0075] The test device used in this embodiment includes a reaction device, a feeding device, a gas measuring tube 11, a balance tube 19 and a leveling device. The reaction device is a conical flask 3 with a ground mouth, the feeding device is a constant pressure titration funnel with a ground mouth, and the leveling device is a liquid accumulating bottle 13. The conical flask 3 is used to provide a place for the desulfurization solution and the desulfurization agent to undergo a first mixing reaction, and for the mixed solution obtained from the first mixing reaction and the acidic compound to undergo a second mixing reaction. In order to make the reaction system mix evenly, a stirring magnet 2 is placed in the conical flask 3. The test device used in this embodiment also includes a magnetic stirring device 1, and the conical flask 3 is placed on the magnetic stirring device 1. In order to regulate the temperature in the conical flask, the test device used in this embodiment also includes a water bath 4 and a thermometer 5 arranged in the water bath 4. The conical flask 3 is placed in the water bath 4, and the thermometer 5 is placed in the water bath in the water bath 4 to detect the temperature of the water bath. The conical flask 3, the constant pressure titration funnel, the water bath 4, the thermometer 5 and the magnetic stirring device 1 constitute an analytical system.

[0076] The constant pressure burette funnel comprises a liquid adding tube 18, a liquid outlet tube 24, a feed valve and a constant pressure tube 7, the upper end of the constant pressure tube 7 is connected to the atmosphere in the liquid adding tube 18, the lower end of the constant pressure tube 7 is connected to the liquid outlet tube 24 and the atmosphere inside the conical flask 3, and the feed valve is a feed piston 6. The upper end opening of the constant pressure burette funnel is connected to the upper end side wall of the gas tube 11 through the air guide tube 8, and a three-way valve is provided at the upper end connection of the air guide tube 8 and the gas tube 11. By adjusting the three-way valve, the gas tube 11 and the gas tube 8 can be connected and the gas tube 11 and the gas tube 8 can be connected to the atmosphere at the same time, or the gas tube 11 and the gas tube 8 can be connected and the gas tube 11 and the gas tube 8 can be isolated from the atmosphere at the same time. The three-way valve is a three-way piston 9, and there are T-shaped three-way air guide holes in the three-way piston 9, two of which are in a straight line, and the third air guide hole is vertically connected to the other two air guide holes; the three-way piston can be used not only for T-shaped three-way control, but also for linear or right-angle control. By rotating the three-way piston to different positions, the device can achieve a left-up-down three-way state, a left-down two-way state, a left-up or up-down two-way state, and a left-up-down disconnected state.

[0077] The balance tube 19 and the gas measuring tube 11 are arranged in parallel, and the bottom of the two are sealed and connected to form a U-shaped communicating vessel. The gas measuring tube 11 is used to collect the gas released by the reaction during the test, and the upper end of the balance tube 19 is open and connected to the atmosphere. In order to read and record the amount of liquid or gas in the gas measuring tube 11 and the balance tube 19 more clearly and accurately, the outer peripheral wall of the gas measuring tube 11 is provided with volume scales 25 at intervals along its axial direction, and the outer peripheral wall of the balance tube 19 is provided with length scales 22 at intervals along its axial direction; the 0 scale line of the volume scale 25 starts from the upper end of the gas measuring tube 011, and the reading gradually increases downward, and the volume corresponding to any two adjacent volume scale values ​​is 0.1mL; the 0 scale line of the length scale 22 starts from the upper end of the balance tube 19, and the reading gradually increases downward, and the length corresponding to any two adjacent length scale values ​​is 0.1mm. In order to detect more gases, the inner diameter of the gas measuring tube 11 is larger than the inner diameter of the balance tube 19. In order to ensure the sealing effect, the gas measuring tube 11 and the balance tube 19 are an integrated structure.

[0078] A buffer tube 23 is provided at the upper end of the balance tube 19, and the two are integrally formed. A liquid outlet is provided on the side wall of the buffer tube 23, and the liquid outlet of the buffer tube 23 is connected to the liquid inlet of the overflow tube 10, and the lower edge of the liquid inlet of the overflow tube 10 is located on the same horizontal plane as the 0 scale line of the volume scale on the gas measuring tube 11. The bottom liquid outlet of the overflow tube 10 is connected to a rubber tube, and the end of the rubber tube is located in the liquid accumulating bottle 13. The buffer tube 23 and the overflow tube 10 together constitute an anti-backflow device to prevent the sealing liquid from flowing back into the constant pressure titration funnel through the air guide tube 8. In order to separately regulate the amount of liquid in the gas measuring tube 11 and the balance tube 19, a liquid regulating valve is provided at the lower end of the balance tube 19, and the liquid regulating valve is a liquid regulating piston 12. The gas measuring tube 11 and the balance tube 19 are filled with a sealing liquid, and the preparation method of the sealing liquid is the same as the preparation method of the sealing liquid in Example 1. The upper ends of the balance tube 19 and the liquid accumulating bottle 13 are both open and communicated with the atmosphere.

[0079] The method for determining the carbon dioxide content in the desulfurization solution of this embodiment specifically comprises the following steps:

[0080] (1) Assemble the test device and conduct airtightness test;

[0081] (2) Add the desulfurization solution, copper sulfate solution and saturated salt water (mass fraction of 26.47%) into the conical flask 3, turn on the magnetic stirring device 1, and stir the materials in the conical flask 3 at a speed of 250 r / min for 5 minutes to convert the sulfide ions in the desulfurization solution into precipitates; the volume of the saturated salt water is 1.08 times the sum of the volumes of the desulfurization solution and the copper sulfate solution; while the materials in the conical flask 3 are stirring and reacting, the temperature of the water bath in the water bath bottle 4 is controlled to be 25° C.;

[0082] (3) Rotate the three-way piston 9 to connect the gas measuring tube 11 and the gas guiding tube 8 to the atmosphere, raise the height of the liquid effusion bottle 13, and make the liquid level in the gas measuring tube 11 located at the 0 scale line of the volume scale 25. Then rotate the three-way piston 9 to connect the gas measuring tube 11 and the gas guiding tube 8 and isolate the gas measuring tube 11 and the gas guiding tube 8 from the atmosphere at the same time, and read and record the liquid level position V in the gas measuring tube 11. 1 ;

[0083] (4) Turn on the magnetic stirring device 1, and control the temperature of the water bath in the water bath bottle 4 so that the temperature of the material in the conical flask 3 is controlled at 25° C. At the same time, open the feed piston 6 of the constant pressure titration funnel, add the sulfuric acid solution into the conical flask 3, and stir the material in the conical flask 3 at a speed of 500 r / min. Observe the gas volume in the gas measuring tube 11. When the gas volume in the gas measuring tube 11 no longer increases, it means that the stirring reaction has reached the end point. Read and record the liquid level position V in the gas measuring tube 11. 2, and simultaneously record the difference Δh between the liquid level in the gas measuring tube 11 and the liquid level in the balance tube 19;

[0084] During the experiment, the atmospheric pressure and temperature of the test environment should be tested. The temperature change in the same test experiment should not exceed 0.2℃. If the temperature change is greater than 0.2℃, the experiment needs to be repeated.

[0085] (5) Calculate the carbon dioxide content in the desulfurization solution; the calculation formula is as follows:

[0086]

[0087] In formula 5, X is the carbon dioxide content in the desulfurization solution, in g / L; 1.9768 is the density of carbon dioxide under standard conditions, in g / L; K pt is the temperature and pressure correction coefficient; ΔV is the volume difference of the gas in the gas measuring tube 11 before and after the stirring reaction in step (4), in mL, and ΔV is equal to the liquid level position V in the gas measuring tube 11 read and recorded in step (4) 2 The liquid level position V in the gas measuring tube 11 read and recorded in step (3) 1 The difference; P is the ambient pressure during the test, in kPa; Δp is the pressure difference between the inside and outside of the gas measuring pipe, in kPa, which is equal to the liquid column pressure corresponding to the difference between the liquid level in the gas measuring pipe 11 and the liquid level in the balance pipe 19 in step (4); V is the amount of desulfurization solution added in step (2), in mL;

[0088] K pt The calculation method is as follows:

[0089]

[0090] In formula 6, P is the ambient pressure during the test, in kPa; P 盐水 is the saturated vapor pressure of the sealing liquid at the ambient temperature during the test, in kPa; t is the ambient temperature during the test, in °C.

[0091] In this embodiment, the desulfurization solution is lean amine solution, the mass fraction of copper sulfate solution is 33%, the mass fraction of sulfuric acid solution is 98%, and the amount of copper sulfate solution is determined according to the following method: slowly drop the copper sulfate solution into a mass of m 1 When no more precipitation occurs in the lean amine solution, record the mass m of copper sulfate solution added. 2 , and then calculate the amount of copper sulfate solution, the calculation method is as follows: m = 2 × (m 2 / m 1 )×m 3 , where m is the mass of copper sulfate solution added during the determination, m 2is the mass of copper sulfate solution during the dropwise addition experiment, m 1 is the mass of lean amine solution during the dropwise addition experiment, m 3 is the mass of the desulfurization solution used in the determination. The lean amine solution used in the drop addition experiment is the same as the desulfurization solution used in the determination. The copper sulfate solution used in the drop addition experiment is the same as the copper sulfate solution used in the determination. The amount of sulfuric acid solution is determined according to the following method: slowly drop the sulfuric acid solution into a solution with a mass of n 1 When precipitation stops, record the mass of sulfuric acid solution added. 2 , and then calculate the amount of sulfuric acid solution, the calculation method is as follows: n = 2 × (n 2 / n 1 )×n 3 , where n is the mass of sulfuric acid solution added during the measurement, n 2 is the mass of sulfuric acid solution during the dropwise addition experiment, n 1 is the mass of lean amine solution during the dropwise addition experiment, n 3 is the mass of the desulfurization solution used in the measurement, the lean amine solution used in the dropping experiment is the same as the desulfurization solution used in the measurement, and the sulfuric acid solution used in the dropping experiment is the same as the sulfuric acid solution used in the measurement; the ambient pressure during the test of this embodiment is 100 kPa, the ambient temperature during the test is 28°C, and the carbon dioxide content in the desulfurization solution calculated by the test is 1.20 g / L.

[0092] Comparative Example 1

[0093] The method for determining the carbon dioxide content in the desulfurization solution of this comparative example specifically comprises the following steps:

[0094] (1) This step is the same as step (1) of Example 1;

[0095] (2) Add a desulfurization solution and a saturated salt water (mass fraction of 26.47%) into a conical flask 3; the desulfurization solution used in this comparative example is the same as the desulfurization solution used in Example 1, and the saturated salt water used in this comparative example is the same as the saturated salt water used in Example 1;

[0096] (3) This step is the same as step (3) of Example 1;

[0097] (4) This step is different from step (4) of Example 1 only in that in this step, the constant pressure titration funnel is filled with a mixture of sulfuric acid solution and copper sulfate solution;

[0098] (5) This step is the same as step (5) of Example 1.

[0099] Comparative Example 2

[0100] The only difference between the method for determining the carbon dioxide content in the desulfurization solution of this comparative example and the method for determining the carbon dioxide content in the desulfurization solution of Example 1 is that the sulfuric acid solution is replaced by a phosphoric acid solution in the method for determining the carbon dioxide content in the desulfurization solution of this comparative example.

[0101] Comparative Example 3

[0102] The only difference between the method for determining the carbon dioxide content in the desulfurization solution of this comparative example and the method for determining the carbon dioxide content in the desulfurization solution of Example 1 is that the sulfuric acid solution is replaced by hydrochloric acid in the method for determining the carbon dioxide content in the desulfurization solution of this comparative example.

[0103] Comparative Example 4

[0104] The only difference between the determination method of the carbon dioxide content in the desulfurization solution of this comparative example and the determination method of Example 1 is that the copper sulfate solution is replaced by a lead sulfate solution of the same mass fraction in the determination method of the carbon dioxide content in the desulfurization solution of this comparative example.

[0105] Comparative Example 5

[0106] The method for determining the carbon dioxide content in the desulfurization solution of this comparative example is carried out in accordance with Section 14 - Determination of the carbon dioxide content in the desulfurization solution of standard GB / T 35212.1-2017 "Analysis of gases and solutions in natural gas processing plants and analysis and evaluation methods for desulfurization, decarbonization and sulfur recovery Part 1: Analysis of gases and solutions".

[0107] Experimental Example 1

[0108] In order to examine the accuracy of different determination methods, the methods of Example 1 and Comparative Examples 1-5 were used to respectively determine the carbon dioxide content in the standard solution, and then the theoretical value, the measured value, and the relative error between the measured value and the theoretical value of the carbon dioxide content in the standard solution were summarized. There are four standard solutions used in the experiment, namely standard solution I, standard solution II, standard solution III and standard solution IV. The four standard solutions are all prepared by mixing methyldiethanolamine, anhydrous sodium carbonate, sodium sulfide and water. The mass ratios of methyldiethanolamine, sodium sulfide and water used in preparing standard solution I, standard solution II, standard solution III and standard solution IV are 40:20:39.995, 40:20:39.89, 40:20:37.33 and 40:20:35.97, respectively. The carbon dioxide contents in standard solution I, standard solution II, standard solution III and standard solution IV are 0.05 g / L, 1.05 g / L, 22.10 g / L and 40.05 g / L, respectively. The results obtained by different testing methods are shown in Table 1.

[0109] Table 1 Test results of standard solutions with different theoretical carbon dioxide contents using different methods and the relative errors between the measured values ​​and the theoretical values

[0110]

[0111] It can be seen from Table 1 that when the method of Example 1 is used for determination, the relative error between the measured value of carbon dioxide and the theoretical value is less than 5%, indicating that the determination method of the present invention has high accuracy.

[0112] In addition, in order to evaluate the experimental results of other salt solutions, the carbon dioxide content in standard solution I, standard solution II, standard solution III and standard solution IV was repeatedly measured according to the method of Comparative Example 4, except that the lead sulfate solution was replaced with an equal mass fraction of iron sulfate solution or chromium sulfate solution. The results showed that for the same standard solution, the difference between the measurement results when using iron sulfate solution or chromium sulfate solution and the measurement results when using lead sulfate solution was no more than 1%.

[0113] Experimental Example 2

[0114] In order to investigate the application effects of different determination methods, the methods of Example 1 and Comparative Example 5 were used to repeatedly determine the carbon dioxide content of lean amine liquid samples and rich amine liquid samples from the desulfurization device of the purification plant, and then the experimental results were summarized. The results are shown in Table 2.

[0115] Table 2 Results of repeatability tests on different samples using the method of Example 1

[0116] Sample No. Carbon dioxide content (g / L) Sample No. Carbon dioxide content (g / L) Sample 1 1.25 Sample 5 1.36 Sample 1 1.18 Sample 5 1.32 Sample 2 0.68 Sample 6 76.85 Sample 2 0.88 Sample 6 73.71 Sample 3 1.1 Sample 7 70.69 Sample 3 1.28 Sample 7 72.73 Sample 4 0.66 Sample 8 73.32 Sample 4 0.67 Sample 8 70.98

[0117] It can be seen from Table 2 that when the determination method of the present invention is used to determine the carbon dioxide content in different lean amine liquid samples and rich amine liquid samples, the difference in repeated measurement results is no more than 0.3 g / L, which is much smaller than the requirement for the repeatability test results of the gas volume method (2 g / L), and the measurement results are close to the measurement results of the method of Comparative Example 5.

[0118] In order to examine the test results of different methods, the method of Example 2-3 was used to measure the carbon dioxide content in standard solution I, standard solution II, standard solution III and standard solution IV in Experimental Example 1. The results showed that the test results using the method of Example 2 or 3 were consistent with the test results of Example 1, indicating that the method of Example 2-3 also has high accuracy.

[0119] In addition, in order to investigate the influence of different parameters on the experimental results, the method of Example 1 was repeated to measure the carbon dioxide content, except that the mass fraction of the copper sulfate solution was adjusted from 33% to 20% or 60%, or the mass fraction of the sulfuric acid solution was adjusted from 98% to 99% or 75%, or the mass ratio of sodium chloride, HCl and water in the sealing solution was adjusted from 26.47:1:70 to 26.47:3:73 or 26.47:2:71. It was found that the carbon dioxide content measured after the adjustment of the parameters was consistent with the measurement result of Example 1.

Claims

1. A method for determining the carbon dioxide content in a desulfurization solution, It is characterized in that The following steps are involved: First, a desulfurization solution, sodium chloride and a desulfurization agent are subjected to a first mixing reaction to convert sulfur ions in the desulfurization solution into precipitates to obtain a mixed solution, and then the mixed solution and an acidic compound are subjected to a second mixing reaction. Finally, the content of carbon dioxide in the desulfurization solution is determined based on the amount of gas obtained in the second mixing reaction; the desulfurization agent is a water-soluble copper salt.

2. The method for determining the carbon dioxide content in the desulfurization solution according to claim 1, It is characterized in that The desulfurizing agent is copper sulfate and / or copper sulfate hydrate.

3. The method for determining the carbon dioxide content in the desulfurization solution according to claim 2, It is characterized in that The desulfurizing agent is used in the form of a desulfurizing agent solution; the mass fraction of the desulfurizing agent in the desulfurizing agent solution is 20-60%.

4. The method for determining the carbon dioxide content in the desulfurization solution according to claim 3, It is characterized in that Sodium chloride is used in the form of sodium chloride solution; the volume of the sodium chloride solution is 1.05 to 1.1 times the sum of the volumes of the desulfurization solution and the desulfurizer solution.

5. The method for determining the carbon dioxide content in the desulfurization solution according to claim 1, It is characterized in that The acidic compound is used in the form of an acidic compound solution; the mass fraction of the acidic compound solution is 75-99%.

6. The method for determining the carbon dioxide content in the desulfurization solution according to any one of claims 1 to 5, It is characterized in that The first mixing reaction and the second mixing reaction are carried out under magnetic stirring.

7. The method for determining the carbon dioxide content in the desulfurization solution according to claim 5, It is characterized in that The rotation speed of the magnetic stirring during the first mixing reaction is 200-300 r / min; the rotation speed of the magnetic stirring during the second mixing reaction is 400-600 r / min.

8. The method for determining the carbon dioxide content in the desulfurization solution according to claim 1, 2 or 4, It is characterized in that The amount of gas is the volume of gas; the volume of gas is determined by liquid displacement method; the liquid displaced by gas in the liquid displacement method is a sealing liquid, and the sealing liquid is prepared by mixing sodium chloride, HCl and water, and the mass ratio of sodium chloride, HCl and water is 26.47:(1-3):(70-73).

9. A measuring device for realizing the method for measuring the carbon dioxide content in the desulfurization solution according to any one of claims 1 to 8, It is characterized in that It comprises a reaction device, a feeding device and a gas volume measuring device which are sealed and connected in sequence; the reaction device is used to provide a place for the first mixing reaction and the second mixing reaction, the feeding device is used to add acidic compounds to the reaction device, and the gas volume measuring device is used to collect and measure the volume of the gas obtained from the second mixing reaction.

10. The measuring device according to claim 9, It is characterized in that The gas volume measuring device includes a gas measuring tube and a balance tube; the bottom of the gas measuring tube is sealed and connected to the bottom of the balance tube, the gas measuring tube is used to collect and measure the volume of the gas obtained from the second mixing reaction, the upper end of the balance tube is open and connected to the atmosphere, the gas measuring tube and the balance tube are filled with sealing liquid, and the balance tube is used to adjust the pressure difference between the inside and outside of the gas measuring tube.

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