A flue gas sulfur transfer agent and its preparation method and application

Abstract

The invention discloses a flue gas sulfur transfer agent and its preparation method and application, which belongs to the field of flue gas desulfurization technology, and is used to solve the technical problem of poor effect of catalytic oxygen-poor sulfur-containing flue gas desulfurization and hydrogen reduction regeneration of sulfur transfer agent in the prior art, a preparation method of flue gas sulfur transfer agent, comprising the following steps: manganese nitrate, zinc nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate and deionized water are mixed and stirred until the system dissolves, activated carbon is added to the reaction system, ultrasonically dispersed for 90 120min, and post-processed to obtain loaded carbon. The present invention is prepared based on microwave coprecipitation by loading metal on activated carbon in the form of oxide, using glucose as a soft template, and obtaining sulfur transfer agent. Not only the sulfur capacity and high temperature resistance of sulfur transfer agent are effectively improved, but also its desulfurization efficiency and recycling effect on sulfur-containing oxygen-poor flue gas are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas desulfurization, and in particular to a flue gas sulfur transfer agent, a preparation method and an application thereof. Background Art

[0002] Sulfur oxides (SO x , such as SO2, SO3) is one of the main pollutants. At present, flue gas desulfurization technologies mainly include wet desulfurization (such as limestone-gypsum method), dry adsorption (such as activated carbon adsorption) and catalytic oxidation. The catalytic oxidation desulfurization process is that SO2 reacts with an oxidant (usually oxygen) under the action of a catalyst to produce SO3.

[0003] At present, in order to reduce NOx generation, enterprises usually adopt low-oxygen combustion technology to reduce the oxygen supply, resulting in a low oxygen concentration in the flue gas and forming an oxygen-deficient environment (oxygen content ≤5vol%). During catalytic oxidation desulfurization, the catalytic oxidation of SO2 is incomplete, and SO2 cannot be effectively oxidized to SO3 or sulfate, resulting in a sharp drop in sulfur capacity. Although porous materials with high specific surface area (such as activated carbon) can increase the adsorption capacity, they have low mechanical strength and are prone to pulverization during long-term operation. Dense materials with high mechanical strength are difficult to adapt to the rapid desulfurization needs of high-sulfur concentration flue gas due to narrow pores and large mass transfer resistance. In addition, although activated carbon materials increase the adsorption capacity, they may undergo partial graphitization during the high-temperature regeneration process, resulting in micropore shrinkage or closure, hindering the diffusion of H2 to internal active sites (such as metal sulfides), so that the reduction reaction only occurs on the surface. After the carbon-containing sulfur transfer agent is reduced with H2, the internal sulfur residue is large, and the catalytic regeneration effect of the sulfur transfer agent is poor.

[0004] In view of the technical defects in this aspect, a solution is now proposed. Summary of the Invention

[0005] The object of the present invention is to provide a flue gas sulfur transfer agent and its preparation method and application, so as to solve the technical problems of poor effect of catalytic desulfurization of oxygen-depleted sulfur-containing flue gas and hydrogen reduction regeneration of sulfur transfer agents in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a flue gas sulfur transfer agent comprises the following steps:

[0008] S1. Mix manganese nitrate, zinc nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate and deionized water and stir until the system is dissolved, add activated carbon to the reaction system, ultrasonically disperse for 90-120 minutes, and post-treat to obtain loaded carbon;

[0009] S2, the loaded carbon is calcined in the absence of oxygen to obtain the loaded oxide carbon;

[0010] S3. Aluminum chloride, magnesium chloride, cerium nitrate, and deionized water are mixed and stirred until the system is dissolved, and the oxide-loaded carbon, silica sol, and glucose are added to the reaction system and stirred for 30-50 minutes to obtain a mixed solution; the mixed solution is then transferred to a microwave reactor at a temperature of 60-80° C. and kept warm for 20-30 minutes. A precipitant is added dropwise to the reactor, and the pH of the system is adjusted to 8-10. The system is kept warm for aging for 2-3 hours and post-treated to obtain a crude sulfur transfer agent;

[0011] S4. The crude sulfur transfer agent is subjected to heat treatment to prepare a sulfur transfer agent.

[0012] Furthermore, in step S1, the amount ratio of the manganese nitrate, zinc nitrate, iron nitrate, cobalt nitrate, nickel nitrate, and copper nitrate is 1 mol: 1 mol: 5 mol: 2 mol: 1 mol: 2 mol, and the amount ratio of the manganese nitrate, deionized water, and activated carbon is 1 g: 30 mL: 10-12 g. The post-treatment includes: after the reaction is completed, the temperature of the reaction system is raised to 90-100 ° C, and low-boiling substances are removed under reduced pressure to obtain loaded carbon.

[0013] Furthermore, in step S2, the oxygen-free roasting method is: placing the loaded carbon in a tube furnace, raising the temperature of the tube furnace to 450-550° C. under an inert atmosphere, keeping the temperature and roasting for 120-160 minutes, and magnetically separating and screening to obtain the loaded oxide carbon.

[0014] Furthermore, in step S3, the dosage ratio of the aluminum chloride, magnesium chloride, and cerium nitrate is 1 mol:1.2 mol:0.22 mol, the dosage ratio of the aluminum chloride, deionized water, loaded oxide carbon, silica sol, and glucose is 10 g:50 mL:7-8 g:5-6 g:8-9 g, and the precipitant is composed of urea, ammonium bicarbonate, and deionized water at a ratio of 4 g:1 g:15 mL. The post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with purified water until neutral, and then dried, and the filter cake is transferred to a drying oven at a temperature of 60-70°C and dried to constant weight to obtain a crude sulfur transfer agent.

[0015] Furthermore, in step S4, the heat treatment method is: placing the crude sulfur transfer agent in a tube furnace, under the protection of an inert atmosphere, raising the temperature of the tube furnace to 500-600°C, keeping the temperature and roasting for 3-4 hours, introducing air into the tube furnace, raising the temperature of the tube furnace to 800-850°C, keeping the temperature and roasting for 4-5 hours, cooling and discharging to obtain the sulfur transfer agent.

[0016] Furthermore, the preparation method of the activated carbon is: potassium permanganate, 20wt% hydrogen peroxide and 6mol / L nitric acid are evenly mixed to obtain an activation solution, the activation solution and activated carbon are mixed and stirred, the temperature of the reaction system is increased to 60-70°C, the reaction is kept warm for 3-4h, and post-processed to obtain activated carbon.

[0017] The synthetic reaction mechanism of activated carbon is:

[0018] During the reaction, nitric acid provides an acidic environment, and potassium permanganate and hydrogen peroxide act as oxidants. Potassium permanganate and hydrogen peroxide produce intermediates with higher oxidative activity through synergistic oxidation under acidic conditions, accelerating the oxidation reaction, oxidizing organic matter containing electron-rich groups (such as phenols, double bonds, etc.), destroying their unsaturated bonds, and generating oxygen-containing functional groups such as carboxyl and hydroxyl groups. At the same time, the oxidation reaction can also expand the original pores and increase the specific surface area, making it easier for metal ions to be loaded thereon.

[0019] Furthermore, the dosage ratio of potassium permanganate, 20wt% hydrogen peroxide and 6mol / L nitric acid is 2-3g:5-6mL:20mL, the dosage ratio of the activation solution and activated carbon is 5-7mL:1g, and the particle size of the activated carbon is 30-50μm. The post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with purified water until neutral, and the filter cake is transferred to a drying oven at a temperature of 70-80°C and dried to constant weight to obtain activated carbon.

[0020] A flue gas sulfur transfer agent is obtained by processing according to a flue gas sulfur transfer agent preparation method.

[0021] An application of a flue gas sulfur transfer agent, wherein the flue gas sulfur transfer agent prepared according to a flue gas sulfur transfer agent preparation method is applied to the desulfurization of sulfur-containing and oxygen-depleted flue gas, wherein the oxygen concentration of the sulfur-containing and oxygen-depleted flue gas is 1-7 vol%.

[0022] The present invention has the following beneficial effects:

[0023] 1. The flue gas sulfur transfer agent of the present invention is achieved by loading metals in the form of oxides on activated carbon, and then based on the microwave co-precipitation method, using glucose as a soft template to cooperate with the precipitant to promote the formation of a three-dimensional network template, and combining urea-ammonium bicarbonate precipitant to regulate surface hydroxyl groups and acidic sites, enhance chemical adsorption capacity, optimize particle size distribution and increase mesopore ratio. After high-temperature calcination, aluminum and magnesium oxides form a thermally stable spinel and a mesoporous-macroporous hierarchical structure constructed with silica sol, which is not easy to collapse during high-temperature regeneration, maintains mass transfer efficiency, inhibits the migration and sintering of active components during high-temperature processes, reduces specific surface area attenuation, and, after aerobic high-temperature calcination, promotes the combination of carbon and oxygen to form carbon dioxide, increases the exposed sites of active metals, and improves the oxidative desulfurization efficiency.

[0024] 2. The flue gas sulfur transfer agent of the present invention is to activate the activated carbon by an activation liquid. The strong oxidizing property of potassium permanganate, hydrogen peroxide and nitric acid etches the surface of the activated carbon to generate oxygen-containing functional groups such as carboxyl and hydroxyl. The introduction of the carboxyl functional group makes the surface of the activated carbon negatively charged, and the adsorption capacity of metal ions is enhanced through electrostatic action, making it easier for metal ions to anchor on the surface of the activated carbon, thereby increasing the loading amount and dispersibility. Manganese nitrate, zinc nitrate, iron nitrate, cobalt nitrate, nickel nitrate and copper nitrate loaded on the activated carbon are formed into composite oxides through high-temperature roasting. By introducing manganese, iron and copper oxides into the metal oxides, the oxygen storage capacity can promote the oxidation of SO2 to SO3 under oxygen-deficient conditions, thereby significantly improving the desulfurization efficiency. When preparing the sulfur transfer agent, cerium element is introduced therein to cooperate with the metal oxide to optimize the pore size distribution, thereby further improving the desulfurization efficiency.

[0025] 3. The flue gas sulfur transfer agent of the present invention comprises aluminum chloride and magnesium chloride which are hydrolyzed to form aluminum ions and magnesium ions, silica sol which provides a three-dimensional network skeleton, glucose which is partially carbonized under microwave heating to form a soft template to regulate the pore distribution, and its hydroxyl groups coordinate with metals such as aluminum and magnesium to inhibit particle agglomeration, urea in the precipitant which slowly decomposes into ammonia, uniformly increases the pH of the solution, and promotes the co-precipitation of metal ions in the form of hydroxides, in the precipitated particles, silica sol and glucose template synergistically form mesopores to increase their specific surface area, and calcined under an inert atmosphere, the residual carbon in glucose is partially oxidized to CO2 to form a porous structure, and metal nitrates and chlorides are used to form a porous structure. The decomposition of the oxides into oxides, Al2O3 reacts with MgO to form a MgAl2O4 spinel structure, which improves the thermal stability. After calcination in an air atmosphere, the carbon template in the crude sulfur transfer agent is completely oxidized to CO2, forming through-holes and increasing the pore size. At the same time, cerium oxide crystallizes, the grains grow, and the oxygen vacancy density increases. Transition metal oxides such as Fe, Mn, and Co form a solid solution, which enhances the redox activity and improves the oxidative desulfurization efficiency. The zinc, cobalt, and nickel oxides in the sulfur transfer agent enhance the chemical adsorption and oxidation of SO2 through Lewis acid sites to form complex sulfides, which further improves the sulfur capacity of the sulfur transfer agent. DETAILED DESCRIPTION

[0026] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] In the present invention, the silica sol is selected from Shandong Xiangzhao New Materials Co., Ltd., and its main component is silicon dioxide, with an effective component content of 99% and a solid content of 40%.

[0028] Example 1: This example provides a method for preparing a flue gas sulfur transfer agent, comprising the following steps:

[0029] Step 1: Preparation of activated carbon

[0030] Potassium permanganate, 20 wt% hydrogen peroxide, and 6 mol / L nitric acid were mixed uniformly in a ratio of 2 g: 5 mL: 20 mL to obtain an activation solution;

[0031] The activation solution and activated carbon with a particle size of 30-50 μm were added to the flask at a ratio of 5 mL:1 g and mixed. The temperature of the reaction flask was raised to 60°C and kept warm for 3 hours. The temperature of the reaction flask was lowered to room temperature and filtered. The filter cake was washed with purified water until neutral. The filter cake was transferred to a drying oven at a temperature of 70°C and dried to constant weight to obtain activated carbon.

[0032] Step 2: Preparation of loaded oxides

[0033] Weigh 17.9 g of manganese nitrate, 18.9 g of zinc nitrate, 120.9 g of ferric nitrate, 36.6 g of cobalt nitrate, 18.3 g of nickel nitrate, 37.5 g of copper nitrate, and 537 mL of deionized water, add them to a reaction flask, mix and stir until the system is dissolved, add 179 g of activated carbon to the reaction flask, ultrasonically disperse for 90 min, raise the temperature of the reaction flask to 90°C, and evaporate low-boiling substances under reduced pressure to obtain loaded carbon;

[0034] The loaded carbon was placed in a tube furnace, and the temperature of the tube furnace was raised to 450° C. in an argon atmosphere. The carbon was kept at this temperature for 120 min and subjected to magnetic separation and screening to obtain the loaded oxide carbon.

[0035] Step 3: Preparation of crude sulfur transfer agent

[0036] Weigh 26.7 g of aluminum chloride, 22.9 g of magnesium chloride, 14.3 g of cerium nitrate, and 133.5 mL of deionized water into a reaction flask, mix and stir until the system is dissolved. Then, add 18.7 g of oxide-loaded carbon, 13.4 g of silica sol, and 21.4 g of glucose into the reaction flask in sequence and stir for 30 min to obtain a mixed solution.

[0037] Urea, ammonium bicarbonate, and deionized water were mixed uniformly at a ratio of 4 g:1 g:15 mL to obtain a precipitant;

[0038] The mixed solution was transferred to a microwave reactor, the power was set to 500 W and the temperature was set to 60°C, and the mixture was kept warm for 20 minutes. A precipitant was added dropwise to the microwave reactor, the pH of the system was adjusted to 8, and the mixture was kept warm for 2 hours. The temperature of the reaction flask was lowered to room temperature, filtered, and the filter cake was washed with purified water until it was neutral and then dried. The filter cake was transferred to a drying oven at a temperature of 60°C and dried to constant weight to obtain a crude sulfur transfer agent.

[0039] Step 4: Preparation of sulfur transfer agent

[0040] The crude sulfur transfer agent was placed in a tube furnace. Under the protection of argon atmosphere, the temperature of the tube furnace was raised to 500°C and kept warm for 3 hours. Air was introduced into the tube furnace, the temperature of the tube furnace was raised to 800°C, kept warm for 4 hours, and then cooled and discharged to obtain the sulfur transfer agent.

[0041] Example 2: This example provides a method for preparing a flue gas sulfur transfer agent, comprising the following steps:

[0042] Step 1: Preparation of activated carbon

[0043] Potassium permanganate, 20 wt% hydrogen peroxide, and 6 mol / L nitric acid were mixed in a ratio of 2.5 g:5.5 mL:20 mL to obtain an activation solution;

[0044] The activation solution and activated carbon with a particle size of 30-50 μm were added to the flask at a ratio of 6 mL:1 g and mixed. The temperature of the reaction flask was raised to 65°C and kept warm for 3.5 hours. The temperature of the reaction flask was lowered to room temperature and filtered. The filter cake was washed with purified water until neutral. The filter cake was transferred to a drying oven at a temperature of 75°C and dried to constant weight to obtain activated carbon.

[0045] Step 2: Preparation of loaded oxides

[0046] Weigh 17.9 g of manganese nitrate, 18.9 g of zinc nitrate, 120.9 g of ferric nitrate, 36.6 g of cobalt nitrate, 18.3 g of nickel nitrate, 37.5 g of copper nitrate, and 537 mL of deionized water, add them to a reaction flask, mix and stir until the system is dissolved, add 196.9 g of activated carbon to the reaction flask, ultrasonically disperse for 105 min, raise the temperature of the reaction flask to 95°C, and evaporate low-boiling substances under reduced pressure to obtain loaded carbon;

[0047] The loaded carbon was placed in a tube furnace, and the temperature of the tube furnace was raised to 500° C. in an argon atmosphere. The carbon was kept at this temperature for 140 minutes and subjected to magnetic separation and screening to obtain the loaded oxide carbon.

[0048] Step 3: Preparation of crude sulfur transfer agent

[0049] Weigh 26.7 g of aluminum chloride, 22.9 g of magnesium chloride, 14.3 g of cerium nitrate, and 133.5 mL of deionized water, add them to a reaction flask, mix and stir until the system is dissolved, then add 20.1 g of oxide-loaded carbon, 14.7 g of silica sol, and 22.7 g of glucose to the reaction flask in sequence, and stir for 40 min to obtain a mixed solution;

[0050] Urea, ammonium bicarbonate, and deionized water were mixed uniformly at a ratio of 4 g:1 g:15 mL to obtain a precipitant;

[0051] The mixed solution was transferred to a microwave reactor, the power was set to 600 W and the temperature was set to 70°C, and the mixture was kept warm for 25 minutes. A precipitant was added dropwise to the microwave reactor, the pH of the system was adjusted to 9, and the mixture was kept warm for 2.5 hours. The temperature of the reaction flask was lowered to room temperature, filtered, and the filter cake was washed with purified water until it was neutral and then dried. The filter cake was transferred to a drying oven at a temperature of 65°C and dried to constant weight to obtain a crude sulfur transfer agent.

[0052] Step 4: Preparation of sulfur transfer agent

[0053] The crude sulfur transfer agent was placed in a tube furnace. Under the protection of argon atmosphere, the temperature of the tube furnace was increased to 550°C and kept warm for 3.5 hours. Air was introduced into the tube furnace, the temperature of the tube furnace was increased to 825°C, kept warm for 4.5 hours, and then cooled and discharged to obtain the sulfur transfer agent.

[0054] Example 3: This example provides a method for preparing a flue gas sulfur transfer agent, comprising the following steps:

[0055] Step 1: Preparation of activated carbon

[0056] Potassium permanganate, 20 wt% hydrogen peroxide, and 6 mol / L nitric acid were mixed uniformly in a ratio of 3 g:6 mL:20 mL to obtain an activation solution;

[0057] The activation solution and activated carbon with a particle size of 30-50 μm were added to a flask at a ratio of 7 mL:1 g and mixed. The temperature of the reaction flask was raised to 70°C and kept warm for 4 hours. The temperature of the reaction flask was lowered to room temperature and filtered. The filter cake was washed with purified water until neutral. The filter cake was transferred to a drying oven at a temperature of 80°C and dried to constant weight to obtain activated carbon.

[0058] Step 2: Preparation of loaded oxides

[0059] Weigh 17.9 g of manganese nitrate, 18.9 g of zinc nitrate, 120.9 g of ferric nitrate, 36.6 g of cobalt nitrate, 18.3 g of nickel nitrate, 37.5 g of copper nitrate, and 537 mL of deionized water into a reaction flask, mix and stir until the system is dissolved, add 214.8 g of activated carbon to the reaction flask, ultrasonically disperse for 120 min, raise the temperature of the reaction flask to 100°C, and evaporate low-boiling substances under reduced pressure to obtain supported carbon;

[0060] The loaded carbon was placed in a tube furnace, and the temperature of the tube furnace was raised to 550° C. under an argon atmosphere. The carbon was kept at this temperature for 160 min and subjected to magnetic separation and screening to obtain the loaded oxide carbon.

[0061] Step 3: Preparation of crude sulfur transfer agent

[0062] Weigh 26.7 g of aluminum chloride, 22.9 g of magnesium chloride, 14.3 g of cerium nitrate, and 133.5 mL of deionized water, add them to a reaction flask, mix and stir until the system is dissolved, then add 21.4 g of oxide-loaded carbon, 16.0 g of silica sol, and 24.0 g of glucose to the reaction flask in sequence, and stir for 50 min to obtain a mixed solution;

[0063] Urea, ammonium bicarbonate, and deionized water were mixed uniformly at a ratio of 4 g:1 g:15 mL to obtain a precipitant;

[0064] The mixed solution was transferred to a microwave reactor, the power was set to 700 W and the temperature was set to 80°C, and the mixture was kept warm for 30 minutes. A precipitant was added dropwise to the microwave reactor, the pH of the system was adjusted to 10, and the mixture was kept warm for 3 hours. The temperature of the reaction flask was lowered to room temperature, filtered, and the filter cake was washed with purified water until it was neutral and then dried. The filter cake was transferred to a drying oven at a temperature of 70°C and dried to constant weight to obtain a crude sulfur transfer agent.

[0065] Step 4: Preparation of sulfur transfer agent

[0066] The crude sulfur transfer agent was placed in a tube furnace. Under the protection of argon atmosphere, the temperature of the tube furnace was raised to 600°C and kept warm for 4 hours. Air was introduced into the tube furnace, the temperature of the tube furnace was raised to 850°C, kept warm for 5 hours, and then cooled and discharged to obtain the sulfur transfer agent.

[0067] Comparative Example 1: The difference between this comparative example and Example 3 is that step 1 is eliminated, and the activated carbon in step 1 replaces the activated carbon in step 2.

[0068] Comparative Example 2: This comparative example differs from Example 3 in that, in step 2, zinc nitrate and nickel nitrate are not added.

[0069] Comparative Example 3: The difference between this comparative example and Example 3 is that in step 3, glucose is not added.

[0070] Comparative Example 4: The difference between this comparative example and Example 3 is that in step 4, the preparation method of the sulfur transfer agent is as follows: placing the crude sulfur transfer agent in a tube furnace, under the protection of an argon atmosphere, raising the temperature of the tube furnace to 600°C, keeping the temperature and calcining for 4 hours, cooling and discharging to obtain the sulfur transfer agent.

[0071] Performance testing:

[0072] The sulfur transfer agents prepared in Examples 1-3 and Comparative Examples 1-4 were used as test samples;

[0073] Oxidative adsorption desulfurization: The test sample was placed in a quartz tube with an inner diameter of 10 mm. Quartz wool was placed at both ends of the quartz tube to prevent the test sample from blowing away. The temperature of the quartz tube was raised to 650°C. Sulfur-containing and oxygen-depleted flue gas with an oxygen content of 1 vol% was introduced into the quartz tube at a delivery rate of 70 mL / min. The desulfurization efficiency of the sulfur transfer agent was determined according to Formula 1.

[0074] Reduction regeneration: After half a cycle of oxidative adsorption desulfurization, nitrogen was introduced into the quartz tube to purge until the temperature dropped to 500°C, and hydrogen was introduced into the quartz tube at a delivery rate of 70 mL / min for 30 minutes to obtain a regenerated desulfurization transfer agent;

[0075] Cyclic test: perform oxidative adsorption desulfurization and reduction regeneration in sequence according to the above test, repeat the operation 10 times, and measure the desulfurization efficiency of the test sample at the tenth test;

[0076] Formula 1: , where C1 is the concentration of sulfur dioxide in the sulfur-containing and oxygen-depleted flue gas entering the quartz tube, C2 is the concentration of sulfur dioxide in the sulfur-containing and oxygen-depleted flue gas discharged from the quartz tube, V is the transport rate of the sulfur-containing and oxygen-depleted flue gas, and t is the transport time of the sulfur-containing and oxygen-depleted flue gas;

[0077] Determine the sulfur capacity of the test sample according to standard HG / T 5318-2018 "Test method for sulfur capacity of manganese oxide desulfurizer";

[0078] The specific test results are shown in Table 1 below.

[0079] Table 1-Performance test data of the sample

[0080]

[0081] Data Analysis:

[0082] A comparative analysis of the data in Table 1 above shows that the sulfur capacity of the sulfur transfer agent prepared by the present invention reaches 272.4 mg / g, the initial desulfurization efficiency of sulfur-containing and oxygen-depleted flue gas reaches 96.8%, the desulfurization efficiency reaches 95.9% after ten cycles, and the desulfurization efficiency retention rate reaches 99%. All performance test results are better than those of the comparative example, indicating that the present invention loads the metal on activated carbon in the form of oxides, and then based on the microwave co-precipitation method, uses glucose as a soft template to cooperate with the precipitant to promote the formation of a three-dimensional network template, combines urea-ammonium bicarbonate precipitant to regulate surface hydroxyl groups and acidic sites, enhances chemical adsorption capacity, optimizes particle size distribution and increases the mesopore ratio, and prepares the sulfur transfer agent through high-temperature calcination. This not only effectively improves the sulfur capacity and high-temperature resistance of the sulfur transfer agent, but also improves its desulfurization efficiency and recycling regeneration effect for sulfur-containing and oxygen-depleted flue gas.

[0083] The above contents are merely examples and explanations of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0084] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0085] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a flue gas sulfur transfer agent, characterized in that: The following steps are involved: S1. Mix manganese nitrate, zinc nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate and deionized water and stir until the system is dissolved, add activated carbon to the reaction system, ultrasonically disperse for 90-120 minutes, and post-treat to obtain loaded carbon; S2, the loaded carbon is calcined in the absence of oxygen to obtain the loaded oxide carbon; S3. Aluminum chloride, magnesium chloride, cerium nitrate, and deionized water are mixed and stirred until the system is dissolved, and the oxide-loaded carbon, silica sol, and glucose are added to the reaction system and stirred for 30-50 minutes to obtain a mixed solution; the mixed solution is then transferred to a microwave reactor at a temperature of 60-80° C. and kept warm for 20-30 minutes. A precipitant is added dropwise to the reactor, and the pH of the system is adjusted to 8-10. The system is kept warm for aging for 2-3 hours and post-treated to obtain a crude sulfur transfer agent; S4, the crude sulfur transfer agent is subjected to heat treatment to prepare a sulfur transfer agent; The activated carbon preparation method comprises: uniformly mixing potassium permanganate, 20wt% hydrogen peroxide and 6mol / L nitric acid to obtain an activation solution, mixing the activation solution and activated carbon, raising the temperature of the reaction system to 60-70°C, keeping the temperature for reaction for 3-4 hours, and post-treating to obtain activated carbon, wherein the amount ratio of the potassium permanganate, 20wt% hydrogen peroxide and 6mol / L nitric acid is 2-3g:5-6mL:20mL, the amount ratio of the activation solution to the activated carbon is 5-7mL:1g, and the particle size of the activated carbon is 30-50μm; The heat treatment method comprises the following steps: placing a crude sulfur transfer agent in a tube furnace, raising the temperature of the tube furnace to 500-600° C. under the protection of an inert atmosphere, keeping the temperature and roasting for 3-4 hours, introducing air into the tube furnace, raising the temperature of the tube furnace to 800-850° C., keeping the temperature and roasting for 4-5 hours, cooling and discharging the material to obtain the sulfur transfer agent.

2. The method for preparing a flue gas sulfur transfer agent according to claim 1, characterized in that: In step S1, the amount ratio of manganese nitrate, zinc nitrate, iron nitrate, cobalt nitrate, nickel nitrate, and copper nitrate is 1 mol:1 mol:5 mol:2 mol:1 mol:2 mol, and the amount ratio of manganese nitrate, deionized water, and activated carbon is 1 g:30 mL:10-12 g. The post-treatment includes: after the reaction is completed, the temperature of the reaction system is raised to 90-100° C., and low-boiling substances are distilled off under reduced pressure to obtain supported carbon.

3. The method for preparing a flue gas sulfur transfer agent according to claim 1, characterized in that: In step S2, the oxygen-free roasting method is as follows: placing the loaded carbon in a tube furnace, raising the temperature of the tube furnace to 450-550° C. in an inert atmosphere, maintaining the temperature and roasting for 120-160 minutes, and magnetically separating and screening to obtain the loaded oxide carbon.

4. The method for preparing a flue gas sulfur transfer agent according to claim 1, characterized in that: In step S3, the amount ratio of the aluminum chloride, magnesium chloride, and cerium nitrate is 1 mol:1.2 mol:0.22 mol, the amount ratio of the aluminum chloride, deionized water, loaded oxide carbon, silica sol, and glucose is 10 g:50 mL:7-8 g:5-6 g:8-9 g, and the precipitant is composed of urea, ammonium bicarbonate, and deionized water at a ratio of 4 g:1 g:15 mL. The post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with purified water until neutral, and then dried, and the filter cake is transferred to a drying oven at a temperature of 60-70 ° C. and dried to constant weight to obtain a crude sulfur transfer agent.

5. The method for preparing a flue gas sulfur transfer agent according to claim 1, characterized in that: The post-processing in the activated carbon preparation process includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with purified water until neutral, and the filter cake is transferred to a drying oven at a temperature of 70-80°C and dried to constant weight to obtain activated carbon.

6. A flue gas sulfur transfer agent, characterized in that: The flue gas sulfur transfer agent is prepared according to the preparation method of a flue gas sulfur transfer agent according to any one of claims 1-5.

7. An application of a flue gas sulfur transfer agent, characterized in that: The flue gas sulfur transfer agent prepared by the preparation method of a flue gas sulfur transfer agent according to any one of claims 1 to 5 is applied to the desulfurization of sulfur-containing and oxygen-depleted flue gas.

Images