Determination method and application of oxidation rate of flue gas wet desulfurization oxidation reaction

Abstract

The present application proposes a method for determining the oxidation rate of a flue gas wet desulfurization oxidation reaction and its application, wherein the method for determining the oxidation rate of a flue gas wet desulfurization oxidation reaction comprises: mixing sulfite with a reaction medium and reacting in an oxygen-deficient environment to obtain a reaction liquid; extracting a first volume of the reaction liquid at a first time interval during the reaction process, and determining the concentration of sulfite in the reaction liquid; drawing a scatter plot of the reaction time and the sulfite concentration in the reaction liquid, and performing a linear fit, and taking the absolute value of the slope of the fitted straight line as the oxidation reaction rate. The method for determining the oxidation rate of a flue gas wet desulfurization oxidation reaction described in the present application controls the reaction system in an oxygen-deficient state, controls the rate-limiting step of the oxidation reaction in the oxygen diffusion process, and obtains the oxidation reaction rate of sulfite by linear fitting by measuring the sulfite content of the reaction liquid at different reaction times. The method is simple to operate and has strong feasibility.

Description

Technical Field

[0001] The present application relates to the technical field of waste gas treatment, and in particular to a method for determining the oxidation rate of a flue gas wet desulfurization oxidation reaction and its application. Background Art

[0002] In the limestone-gypsum wet desulfurization process, SO2 in the flue gas is captured by the limestone (CaCO3) slurry sprayed from the nozzle at the top of the absorption tower and falls into the bottom slurry, where it is oxidized by the blowing of oxidizing wind to obtain gypsum byproduct (CaSO4·2H2O). Slurry oxidation is mainly a liquid phase reaction process. The reaction rate of sulfite and oxygen is relatively fast. O2 must first be dissolved from the air into the liquid phase before participating in the reaction. Coal and limestone usually contain trace amounts of Mn, Fe, Co, etc., which are dissolved to generate Mn 2+ , Fe 3+ 、Co 2+ Etc. are enriched in the absorption tower and can effectively catalyze the oxidation process. The oxidation rate is usually limited by the diffusion capacity of O2 in the liquid film and cannot be accurately and effectively measured. Summary of the invention

[0003] In view of this, an object of the present application is to provide a method for determining the oxidation rate of a flue gas wet desulfurization oxidation reaction, by controlling the reaction system in an oxygen-deficient state, controlling the rate-limiting step of the oxidation reaction in the oxygen diffusion process, and by determining the sulfite content of the reaction liquid at different reaction times, the oxidation reaction rate of the sulfite is obtained by linear fitting. By adopting this determination method, the oxidation rate under different reaction media can be obtained by replacing the reaction medium; the method is simple to operate and has strong feasibility, and can be used to study the influence of changes in the operating conditions of the limestone-gypsum wet desulfurization process (such as process water, coal quality, limestone, concentration ratio, etc.) on the oxidation system, and can also be used for the research and development of additives such as catalysts or oxidants for the wet desulfurization oxidation system.

[0004] Another object of the present application is to provide a method for comparing the oxidation rates of a flue gas wet desulfurization oxidation reaction in different reaction media.

[0005] To achieve the above-mentioned purpose, the first embodiment of the present application proposes a method for determining the oxidation rate of a flue gas wet desulfurization oxidation reaction, comprising:

[0006] The sulfite is mixed with a reaction medium and reacted in an oxygen-deficient environment to obtain a reaction solution;

[0007] During the reaction, extracting a first volume of the reaction solution at first intervals to measure the concentration of sulfite in the reaction solution;

[0008] A scatter plot of the reaction time and the sulfite concentration in the reaction solution was drawn, and a linear fit was performed, and the absolute value of the slope of the fitted straight line was taken as the oxidation reaction rate.

[0009] In some embodiments, the reaction temperature and the pH of the reaction system during the reaction are kept constant.

[0010] In some embodiments, the reaction temperature is 40-50° C., the pH of the reaction system during the reaction is 5-6, and the reaction is carried out under stirring conditions.

[0011] In some embodiments, the oxygen-deficient environment has a dissolved oxygen content of less than 1 mg / L.

[0012] In some embodiments, the first time is 10-15 min, and the first volume is 5-10 mL.

[0013] In some embodiments, the method for determining the concentration of sulfite in the reaction solution is iodine titration.

[0014] In some embodiments, the reaction medium is ultrapure water or a mixed solution, and the mixed solution includes one or more of magnesium chloride, magnesium sulfate, calcium chloride, aluminum nitrate, sodium fluoride, smoke, and oil.

[0015] In some embodiments, the method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction further includes: before introducing air to start the oxidation reaction, adjusting the temperature and pH of the mixture of sulfite and reaction medium to the temperature and pH required for the reaction process, respectively.

[0016] To achieve the above-mentioned purpose, the second embodiment of the present application proposes a method for comparing the oxidation rates of a flue gas wet desulfurization oxidation reaction in different reaction media, comprising:

[0017] The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction of the embodiment of the present application is used to sequentially determine the oxidation rates of sulfite in different reaction media, and then compare the oxidation rates of sulfite in different reaction media.

[0018] The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction in the embodiment of the present application can bring the following beneficial effects: by controlling the reaction system in an oxygen-deficient state, the rate-limiting step of the oxidation reaction is controlled in the oxygen diffusion process, and by determining the sulfite content of the reaction liquid at different reaction times, the oxidation reaction rate of the sulfite is obtained through linear fitting. By adopting this determination method, the oxidation rate under different reaction media can be obtained by replacing the reaction medium; the method is simple to operate and has strong feasibility. It can be used to study the influence of changes in the operating conditions of the limestone-gypsum wet desulfurization process (such as process water, coal quality, limestone, concentration ratio, etc.) on the oxidation system, and can also be used for the research and development of additives such as catalysts or oxidants for the wet desulfurization oxidation system.

[0019] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0021] Figure 1 It is a schematic structural diagram of a system for measuring the oxidation rate of a flue gas wet desulfurization oxidation reaction according to an embodiment of the present application.

[0022] Figure 2 This is a scattered linear fitting diagram of reaction time-reaction solution sulfite concentration in Example 1.

[0023] Figure 3 This is a scattered linear fitting diagram of reaction time-reaction solution sulfite concentration in Example 2.

[0024] Figure 4 This is a scattered linear fitting diagram of reaction time-reaction solution sulfite concentration in Example 3.

[0025] Figure 5 This is a scattered linear fitting diagram of reaction time-reaction solution sulfite concentration in Example 4.

[0026] Figure 6 This is a scattered linear fitting diagram of reaction time-reaction solution sulfite concentration in Example 5.

[0027] Reference numerals:

[0028] 1-constant temperature stirring device; 2-temperature probe; 3-magnet; 4-automatic titrator; 5-acid / alkali storage; 6-weighing device; 7-solenoid valve; 8-pH composite electrode; 9-dissolved oxygen meter probe; 10-dissolved oxygen meter; 11-air pump; 12-flow meter; 13-aeration device; 14-reactor. DETAILED DESCRIPTION

[0029] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, but cannot be understood as limiting the present application.

[0030] Throughout the application, the disclosure of numerical ranges includes all values ​​within the entire range and disclosure of further subdivided ranges, including endpoints and subranges given within those ranges.

[0031] In the application, the raw materials, equipment, etc. involved, unless otherwise specified, are all raw materials and equipment that can be produced through commercial channels or known methods; the methods involved, unless otherwise specified, are all conventional methods.

[0032] The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction in the embodiment of the present application includes:

[0033] The sulfite is mixed with a reaction medium and reacted in an oxygen-deficient environment to obtain a reaction solution;

[0034] During the reaction process, a first volume of the reaction solution is extracted at a first time interval to measure the concentration of sulfite in the reaction solution;

[0035] A scatter plot of the reaction time and the sulfite concentration in the reaction solution was drawn, and a linear fit was performed. The absolute value of the slope of the fitted straight line was taken as the oxidation reaction rate.

[0036] The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction in the embodiment of the present application controls the reaction system in an oxygen-deficient state, controls the rate-limiting step of the oxidation reaction to the oxygen diffusion process, and determines the sulfite content of the reaction liquid at different reaction times, and obtains the oxidation reaction rate of the sulfite through linear fitting. By adopting this determination method, the oxidation rate under different reaction media can be obtained by replacing the reaction medium. The method is simple to operate and has strong feasibility. It can be used to study the influence of changes in the operating conditions of the limestone-gypsum wet desulfurization process (such as process water, coal quality, limestone, concentration ratio, etc.) on the oxidation system, and can also be used for the research and development of additives such as catalysts or oxidants for the wet desulfurization oxidation system.

[0037] In some embodiments, sulfites include but are not limited to one or more of calcium sulfite or sodium sulfite. In some embodiments, the reaction temperature and the pH of the reaction system during the reaction are kept constant. In the specific reaction process, the pH of the reaction system can be controlled to remain constant by dripping hydrochloric acid or sodium hydroxide. In some embodiments, the reaction temperature is 40-50°C, including but not limited to 40°C, 42°C, 45°C, 47°C or 50°C. In some embodiments, the pH of the reaction system during the reaction is 5-6, including but not limited to 5, 5.2, 5.5, 5.7 or 6.

[0038] In some embodiments, the reaction is carried out under stirring conditions, so that the sulfite and the reaction medium can be fully contacted and reacted. The stirring speed can generally be between 250-350, and the stirring speed is constant during the reaction.

[0039] In some embodiments, the dissolved oxygen content of the oxygen-deficient environment is less than 1 mg / L. By controlling the reaction system in an oxygen-deficient state, the rate-limiting step of the oxidation reaction can be controlled to the oxygen diffusion process.

[0040] In some embodiments, the first time is 10-15 minutes, including but not limited to 10 minutes, 12 minutes, 14 minutes or 15 minutes, etc.

[0041] In some embodiments, the first volume is 5-10 mL, including but not limited to 5 mL, 8 mL, or 10 mL, etc.

[0042] In some embodiments, the method for determining the concentration of sulfite in the reaction solution is iodine titration, which is a conventional method in the art and will not be described in detail herein.

[0043] In some embodiments, the reaction medium is ultrapure water or a mixed solution, and the mixed solution includes one or more of magnesium chloride, magnesium sulfate, calcium chloride, aluminum nitrate, sodium fluoride, smoke, and oil. The type of smoke is not limited, for example, it can be smoke from a thermal power plant; the type of oil is also not limited, and one or more of vegetable oil, animal oil, or mineral oil can be used. The solvent of the mixed solution is water.

[0044] In some embodiments, the method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction of the present application further includes: before introducing air to start the oxidation reaction, adjusting the temperature and pH of the mixture of sulfite and reaction medium to the temperature and pH required for the reaction process, respectively. That is, the reaction process is to first adjust the pH and temperature of the mixture after the sulfite and reaction medium are mixed to the target values ​​required for the reaction process, and then blow in an appropriate amount of air to form an oxygen-deficient environment to start the oxidation reaction.

[0045] It should be noted that the method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction in the embodiment of the present application can be implemented by a variety of reaction devices. As a possible example, the method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction in the embodiment of the present application can be implemented by the following flue gas wet desulfurization oxidation reaction oxidation rate determination system:

[0046] like Figure 1As shown, the system for measuring the oxidation rate of the flue gas wet desulfurization oxidation reaction comprises a constant temperature stirring device 1, a reactor 14, an automatic titrator 4, a weighing device 6, a dissolved oxygen meter 10 and an air pump 11. Among them, the constant temperature stirring device 1 has a temperature probe 2; the reactor 14 is arranged on the constant temperature stirring device 1, and the temperature probe 2 is arranged in the reactor 14; the automatic titrator 4 is connected to the pH composite electrode 8, and the pH composite electrode 8 extends into the reactor 14; the weighing device 6 is provided with an acid / alkali storage 5; the acid / alkali storage 5 is connected to the reactor 14 through a first pipeline, and a solenoid valve 7 is installed on the first pipeline, and the solenoid valve 7 is connected to the automatic titrator 4; the dissolved oxygen meter 10 has a dissolved oxygen meter probe 9, and the dissolved oxygen meter probe 9 extends into the reactor 14; the air pump 11 is connected to the aeration device 13 through a second pipeline, and a flow meter 12 is installed on the second pipeline, and the aeration device 13 is arranged in the reactor 14.

[0047] The reactor 14 is a beaker, a flask, or a conical flask, and a magnet 3 is arranged in the reactor 14. The constant temperature stirring device 1 is a constant temperature magnetic stirrer, the weighing device 6 is an analytical balance, the acid / alkali storage device 5 is an acid / alkali liquid bottle, and the acid / alkali liquid bottle can be a conical flask containing alkali liquid or acid, etc.; the aeration device 13 is a nozzle, a microporous aerator, and a jet aerator.

[0048] When in use, the reaction medium and sulfite are stirred and mixed in the reactor, and the temperature probe 2, dissolved oxygen meter probe 9, aeration device 13 and pH composite electrode 8 are all inserted into the reactor below the liquid level of the reaction liquid. The constant temperature stirring device can realize constant temperature and constant speed control, the automatic titrator can maintain the constant pH of the reaction system, and the dissolved oxygen meter can monitor the dissolved oxygen content of the reaction liquid. The air pump and flow meter constitute the oxidation air system, which can realize air volume control.

[0049] It should be noted that the system for measuring the oxidation rate of the wet flue gas desulfurization oxidation reaction in the above example is mainly a laboratory testing equipment. When it comes to industrialization, each functional component can be replaced or improved according to actual needs.

[0050] The method for comparing the oxidation rates of the flue gas wet desulfurization oxidation reaction in different reaction media of the embodiments of the present application comprises: adopting the method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction of the embodiments of the present application, sequentially determining the oxidation rates of sulfite in different reaction media, and then comparing the oxidation rates of sulfite in different reaction media.

[0051] The determination method and comparison method of the present application are described below in conjunction with specific examples.

[0052] The following embodiments of this application are as follows Figure 1The determination system of the oxidation rate of the wet desulfurization oxidation reaction of flue gas shown in the figure is carried out. It includes a constant temperature stirring device 1, a reactor 14, an automatic titrator 4, a weighing device 6, a dissolved oxygen meter 10 and an air pump 11. The automatic titrator 4, the weighing device 6, the dissolved oxygen meter 10 and the air pump 11 are all arranged on the periphery of the constant temperature stirring device 1, and there is a distance between them. Among them, the constant temperature stirring device 1 is a constant temperature magnetic stirrer, which has a temperature probe 2, and the temperature probe 2 extends below the reaction liquid level in the reactor 14; the reactor 14 is a beaker, which is placed on the constant temperature stirring device 1; the automatic titrator 4 is electrically connected to the pH composite electrode 8, and the end of the pH composite electrode 8 extends under the reaction liquid level of the reactor 14; the weighing device 6 is an analytical balance, and an acid / alkali storage device 5 is placed on the weighing device 6; the acid / alkali storage device 5 is an acid / alkali liquid bottle, and the acid / alkali liquid bottle can be filled with 1 mol / L of hydroxide as needed. A conical flask of sodium solution or a conical flask filled with 1 mol / L hydrochloric acid, an acid / base storage device 5 is connected to a reactor 14 through a first pipeline, and a solenoid valve 7 is installed on the first pipeline, and the solenoid valve 7 is electrically connected to an automatic titrator 4; a dissolved oxygen meter 10 has a dissolved oxygen meter probe 9, and the dissolved oxygen meter probe 9 extends below the reaction liquid level in the reactor 14; an air pump 11 is connected to an aeration device 13 through a second pipeline, and a flow meter 12 is installed on the second pipeline. The aeration device 13 is arranged below the reaction liquid level in the reactor 14, and the aeration device 13 is a microporous aerator.

[0053] Example 1

[0054] The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction in this embodiment is:

[0055] 350 mL of ultrapure water is loaded into the reactor 14 as the reaction medium, and a magnetic particle is placed. The reaction medium is controlled to be at a constant temperature of 45°C by the constant temperature stirring device 1, and is fully stirred at 300 r / min. 2.2 g of sodium sulfite is added, and then the pH of the mixture of the reaction medium and sodium sulfite is adjusted to 5.5 with 1 mol / L hydrochloric acid. The air pump 11 is turned on to introduce air into the reaction system at a flow rate of 4 L / min to start the oxidation reaction and obtain a reaction solution. During the reaction, the dissolved oxygen content in the reaction solution is measured by the dissolved oxygen meter probe 9, and the dissolved oxygen content is controlled to be always less than 0.5 mg / L, so that the reaction solution is in an oxygen-deficient state. At the same time, the pH of the reaction solution is monitored, and 1 mol / L of sodium hydroxide solution is added through the acid / base reservoir 5 to control the pH of the reaction solution to remain constant and always maintained at 5.5. Every 15 minutes, 5 mL of the reaction solution is quantitatively extracted from the reactor, and the concentration of sodium sulfite in the reaction solution is determined by the iodine titration method. A scatter plot of reaction time-reaction solution sulfite concentration is drawn and a linear fit is performed, as shown in FIG. Figure 2 As shown, the absolute value of the slope of the fitted straight line is taken as the oxidation reaction rate.

[0056] from Figure 2 It can be seen that R2 =0.97, the fitting relationship is good. The absolute value of the slope of the straight line after fitting, that is, the oxidation reaction rate is 4.77*10 -4 mol / (L·min).

[0057] Example 2

[0058] The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction in this embodiment is:

[0059] A mixed solution was prepared, wherein the solvent was ultrapure water, and the concentrations of the components were: 0.1 mmol / L aluminum nitrate, 0.5 mmol / L sodium fluoride, 0.2 g / L smoke from a thermal power plant, and 0.05 g / L No. 0 diesel. The composition of the smoke from a thermal power plant is shown in Table 1.

[0060] Table 1 Composition of smoke from thermal power plants

[0061]

[0062] 350 mL of the mixed solution was loaded into the reactor 14 as the reaction medium, and a magnetic particle was placed. The reaction medium was controlled to be at a constant temperature of 45°C by the constant temperature stirring device 1, and was fully stirred at 300 r / min. 2.2 g of sodium sulfite was added, and then the pH of the reaction medium and the sodium sulfite mixture was adjusted to 5.5 by dropping 1 mol / L of hydrochloric acid solution. The air pump 11 was turned on to introduce air into the reaction system at a flow rate of 4 L / min to start the oxidation reaction and obtain a reaction solution. During the reaction, the dissolved oxygen content in the reaction solution was measured by the dissolved oxygen meter probe 9, and the dissolved oxygen content was controlled to be always less than 0.5 mg / L, so that the reaction solution was in an oxygen-deficient state. At the same time, the pH of the reaction solution was monitored, and 1 mol / L of sodium hydroxide solution was added through the acid / base reservoir 5 to control the pH of the reaction solution to remain constant and always maintained at 5.5. Every 12 minutes, 5 mL of the reaction solution was quantitatively extracted from the reactor, and the concentration of sulfite in the reaction solution was determined by the iodine titration method. A scatter plot of reaction time-sulfite concentration in the reaction solution was drawn and a linear fit was performed, as shown in FIG. Figure 3 As shown, the absolute value of the slope of the fitted straight line is taken as the oxidation reaction rate.

[0063] from Figure 3 It can be seen that R 2 =0.99, the fitting relationship is good. The absolute value of the slope of the fitted straight line, that is, the oxidation reaction rate, is 3.72*10 -4 mol / (L·min).

[0064] Example 3

[0065] The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction in this embodiment is:

[0066] A mixed solution was prepared, wherein the solvent was ultrapure water, and the concentrations of the components were: 122 g / L magnesium chloride, 0.05 g / L magnesium sulfate, 22 g / L calcium chloride, 0.1 mmol / L aluminum nitrate, 0.5 mmol / L sodium fluoride, 0.2 g / L smoke from a thermal power plant, and 0.05 g / L No. 0 diesel. The composition of the smoke from the thermal power plant was the same as that in Example 2.

[0067] 350 mL of mixed solution was loaded into the reactor 14 as the reaction medium, and a magnetic particle was placed. The reaction medium was controlled to be at a constant temperature of 45°C by the constant temperature stirring device 1, and was fully stirred at 300 r / min. 2.34 g of calcium sulfite was added, and then the pH of the mixture of the reaction medium and calcium sulfite was adjusted to 5.5 by dropping 1 mol / L hydrochloric acid solution. The air pump 11 was turned on to introduce air into the reaction system at a flow rate of 1 L / min to start the oxidation reaction and obtain a reaction solution. During the reaction, the dissolved oxygen content in the reaction solution was measured by the dissolved oxygen meter probe 9, and the dissolved oxygen content was controlled to be always less than 0.8 mg / L, so that the reaction solution was in an oxygen-deficient state. At the same time, the pH of the reaction solution was monitored, and 1 mol / L hydrochloric acid solution was added through the acid / base reservoir 5 to control the pH of the reaction solution to remain constant and always maintained at 5.5. Every 10 minutes, 10 mL of the reaction solution was quantitatively extracted from the reactor, and the concentration of sulfite in the reaction solution was determined by the iodine titration method. A scatter plot of reaction time-sulfite concentration in the reaction solution was drawn and a linear fit was performed, as shown in FIG. Figure 4 As shown, the absolute value of the slope of the fitted straight line is taken as the oxidation reaction rate.

[0068] from Figure 4 It can be seen that R 2 =0.99, the fitting relationship is good. The absolute value of the slope of the straight line after fitting, that is, the oxidation reaction rate is 1.40*10 -4 mol / (L·min).

[0069] Example 4

[0070] The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction in this embodiment is:

[0071] A mixed solution was prepared, wherein the solvent was ultrapure water, and the concentrations of the components were: 0.1 mmol / L aluminum nitrate, 0.5 mmol / L sodium fluoride, 0.2 g / L smoke from a thermal power plant, and 0.05 g / L No. 0 diesel. The composition of the smoke from the thermal power plant was the same as that in Example 2.

[0072] 350 mL of mixed solution was loaded into the reactor 14 as the reaction medium, and a magnetic particle was placed. The reaction medium was controlled to be at a constant temperature of 45°C by the constant temperature stirring device 1, and was fully stirred at 300 r / min. 2.34 g of calcium sulfite was added, and then the pH of the mixture of the reaction medium and calcium sulfite was adjusted to 5.5 by dropping 1 mol / L of hydrochloric acid solution. The air pump 11 was turned on to introduce air into the reaction system at a flow rate of 1 L / min to start the oxidation reaction and obtain a reaction solution. During the reaction, the dissolved oxygen content in the reaction solution was measured by the dissolved oxygen meter probe 9, and the dissolved oxygen content was controlled to be always less than 0.2 mg / L, so that the reaction solution was in an oxygen-deficient state. At the same time, the pH of the reaction solution was monitored, and 1 mol / L of sodium hydroxide solution was added through the acid / base reservoir 5 to control the pH of the reaction solution to remain constant and always maintained at 5.5. Every 12 minutes, 5 mL of the reaction solution was quantitatively extracted from the reactor, and the concentration of sulfite in the reaction solution was determined by the iodine titration method. A scatter plot of reaction time-sulfite concentration in the reaction solution was drawn and a linear fit was performed, as shown in FIG. Figure 5 As shown, the absolute value of the slope of the fitted straight line is taken as the oxidation reaction rate.

[0073] from Figure 5 It can be seen that R 2 =0.98, the fitting relationship is good. The absolute value of the slope of the fitted straight line, that is, the oxidation reaction rate, is 1.21*10 -4 mol / (L·min).

[0074] Example 5

[0075] The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction in this embodiment is:

[0076] A mixed solution was prepared, wherein the solvent was ultrapure water, and the concentrations of the components were: 10.2 g / L magnesium chloride, 0.1 mmol / L aluminum nitrate, 0.5 mmol / L sodium fluoride, 0.2 g / L smoke from a thermal power plant, and 0.05 g / L No. 0 diesel. The composition of the smoke from the thermal power plant was the same as that in Example 2.

[0077] 350 mL of mixed solution was loaded into the reactor 14 as the reaction medium, and a magnetic particle was placed. The reaction medium was controlled to be at a constant temperature of 45°C by the constant temperature stirring device 1, and was fully stirred at 300 r / min. 2.34 g of calcium sulfite was added, and then the pH of the mixture of the reaction medium and calcium sulfite was adjusted to 5.5 by dropping 1 mol / L hydrochloric acid solution. The air pump 11 was turned on to introduce air into the reaction system at a flow rate of 1 L / min to start the oxidation reaction and obtain a reaction solution. During the reaction, the dissolved oxygen content in the reaction solution was measured by the dissolved oxygen meter probe 9, and the dissolved oxygen content was controlled to be always less than 0.2 mg / L, so that the reaction solution was in an oxygen-deficient state. At the same time, the pH of the reaction solution was monitored, and 1 mol / L sodium hydroxide solution was added through the acid / base reservoir 5 to control the pH of the reaction solution to remain constant and always maintained at 5.5. Every 12 minutes, 5 mL of the reaction solution was quantitatively extracted from the reactor, and the concentration of sulfite in the reaction solution was determined by the iodine titration method. A scatter plot of reaction time-sulfite concentration in the reaction solution was drawn and a linear fit was performed, as shown in FIG. Figure 6 As shown, the absolute value of the slope of the fitted straight line is taken as the oxidation reaction rate.

[0078] from Figure 6 It can be seen that R 2 =0.99, the fitting relationship is good. The absolute value of the slope of the straight line after fitting, that is, the oxidation reaction rate is 2.31*10 -4 mol / (L·min).

[0079] By comparing the oxidation reaction rate of this embodiment with the oxidation reaction rate of Example 4, it can be seen that when the reaction medium is changed under the same conditions, the fitting relationship is good, which further verifies that the method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction of the present application can be applied to the determination and comparison of sulfite reaction rates in different reaction media.

[0080] Example 6

[0081] This embodiment is basically the same as embodiment 5, except that the pH value during the reaction is 5 and the reaction temperature is 40°C.

[0082] Example 7

[0083] This embodiment is basically the same as embodiment 5, except that the pH value during the reaction is 6 and the reaction temperature is 50°C.

[0084] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0085] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for determining the oxidation rate of a flue gas wet desulfurization oxidation reaction, characterized in that: include: The sulfite is mixed with a reaction medium and reacted in an oxygen-deficient environment to obtain a reaction solution; During the reaction, extracting a first volume of the reaction solution at first intervals to measure the concentration of sulfite in the reaction solution; Draw a scatter plot of the reaction time and the sulfite concentration in the reaction solution, and perform linear fitting, and use the absolute value of the slope of the fitted straight line as the oxidation reaction rate; The dissolved oxygen content of the oxygen-deficient environment is less than 1 mg / L; The reaction temperature is 40-50°C, and the pH of the reaction system during the reaction is 5-6; The reaction temperature and the pH of the reaction system during the reaction are kept constant.

2. The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction according to claim 1, characterized in that: The reaction is carried out under stirring conditions.

3. The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction according to claim 1, characterized in that: The first time is 10-15 min, and the first volume is 5-10 mL.

4. The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction according to claim 1, characterized in that: The method for determining the concentration of sulfite in the reaction solution is iodine titration.

5. The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction according to claim 1, characterized in that: The reaction medium is ultrapure water or a mixed liquid.

6. The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction according to claim 5, characterized in that: The mixed liquid includes one or more of magnesium chloride, magnesium sulfate, calcium chloride, aluminum nitrate, sodium fluoride, smoke, and oil.

7. The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction according to claim 1, characterized in that: Also includes: Before introducing air to start the oxidation reaction, the temperature and pH of the mixture of sulfite and reaction medium are adjusted to the temperature and pH required for the reaction process, respectively.

8. A method for comparing the oxidation rates of flue gas wet desulfurization oxidation reaction in different reaction media, characterized in that: include: The method for determining the oxidation rate of the flue gas wet desulfurization oxidation reaction as described in any one of claims 1 to 7 is used to sequentially determine the oxidation rates of sulfite in different reaction media, and then compare the oxidation rates of sulfite in different reaction media.

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