A supported catalyst for removing COS from blast furnace gas at low temperature and a preparation method thereof

Abstract

The application discloses a supported catalyst for removing COS in blast furnace gas at low temperature and a preparation method thereof, and relates to the technical field of catalyst preparation. The catalyst comprises the following steps: chitosan oligosaccharide is dissolved in a propylene oxide aqueous solution to obtain solution A; then polymethyl methacrylate microspheres are added into a P123 solution to obtain solution B; solution B is added into solution A, stirring is carried out at a certain temperature, and the stirring is continuously carried out for a period of time to obtain solution C; solution C is placed into a hydrothermal kettle, and then placed into an oven to obtain precipitate D; precipitate D is washed to be neutral, and then placed into a vacuum freeze-drying machine to obtain material E; material E is carbonized to obtain material F; finally, material F is immersed in a mixed solution of (NH4)6Mo7O 24 4H2O and Mg(NO3)2·6H2O, and dried to obtain the catalyst. According to the method, COS can be removed at low temperature (25 DEG C) without adding a nitrogen source on the basis of dust removal of blast furnace gas.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a supported catalyst for low-temperature removal of COS from blast furnace gas and its preparation method. Background Technology

[0002] Blast furnace gas (BFG) is a large-scale byproduct generated during blast furnace ironmaking. It contains combustible components such as carbon monoxide and hydrogen, as well as pollutants like dust, carbon dioxide, hydrogen sulfide, and carbonyl sulfide. Therefore, after removing these pollutants, it is often used as fuel gas. However, it is crucial to find a suitable and effective method to remove these impurities from BFG and then utilize it as an energy source. Among these pollutants, carbonyl sulfide (COS) is a typical organic sulfur pollutant. As a sulfur-containing acidic gas, COS not only contributes to acid rain but also adversely affects industrial waste gas treatment processes. The presence of even trace amounts of COS can deactivate catalysts and corrode reaction equipment. Therefore, eliminating COS from BFG is of great significance.

[0003] Sulfides in blast furnace gas mainly exist in the form of carbonyl sulfide (COS) and hydrogen sulfide (H2S), with COS accounting for about 70%. Due to the stable chemical properties of COS, it cannot be deeply purified using simple alkaline absorption or alumina adsorption methods like H2S. Therefore, the main technical challenge in implementing fine desulfurization of blast furnace gas lies in the deep removal of COS.

[0004] Currently, common methods for COS removal include chemical absorption, adsorption, hydrogenation, and hydrolysis adsorption. Chemical absorption is difficult to implement due to the insolubility and stability of COS. Furthermore, wet absorption can corrode equipment, especially in acidic environments. Adsorption is a traditional but effective method, but the adsorbed COS can cause secondary pollution, and the regeneration process requires high temperatures and complex operations. Hydrogenation methods suffer from high temperatures, high pressures, and high costs, making their application in industrial production difficult. In contrast, hydrolysis adsorption can convert COS into easily treatable H2S and CO2 under mild reaction conditions, exhibiting high conversion efficiency.

[0005] Currently, most catalysts for removing carbonyl sulfide from blast furnace gas have adsorption temperatures above 100℃. Higher temperatures may lead to excessively rapid reaction rates, resulting in incomplete reactions and affecting removal efficiency. This can also lead to the formation of byproducts such as sulfates, further impacting removal efficiency. High temperatures also increase energy consumption and operating costs. For example, application number 202210820038.8 discloses a carbonyl sulfide catalyst composed of glacial acetic acid, isopropanol, aluminum salt, and platinum salt. This invention provides a method for treating carbonyl sulfide-containing flue gas using this catalyst. However, this catalyst is not suitable for removing carbonyl sulfide from flue gas at low temperatures. Application number 202210517243.7 discloses a carbonyl sulfide removal catalyst and its preparation method, whose components are cerium dioxide-supported potassium metal alkaline catalysts. This also fails to achieve COS removal from blast furnace gas at low temperatures. Therefore, the existing technology needs further improvement. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas. This method allows for low-temperature COS removal after blast furnace gas dust removal without the addition of an additional nitrogen source, under low-temperature conditions (25°C).

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas includes the following steps:

[0009] Step 1: Dissolve chitosan oligosaccharide in an aqueous propylene oxide solution to obtain solution A; wherein the mass-to-volume ratio of chitosan oligosaccharide to aqueous propylene oxide solution is 0.5-2.0 g / 10-25 mL, and the dissolution temperature is 60-80℃.

[0010] Step 2: Add polymethyl methacrylate microspheres to solution P123 to obtain solution B; wherein the mass ratio of polymethyl methacrylate microspheres to solution P123 is 0.1-0.7:0.1-0.4.

[0011] Step 3: Add solution B to solution A, stir at a certain temperature, adjust the pH to 3-5, and continue stirring for a period of time to obtain solution C;

[0012] Step 4: Place solution C into a hydrothermal reactor, then place it in an oven to obtain precipitate D. Wash precipitate D until neutral, then place it in a vacuum freeze dryer to obtain material E.

[0013] Step 5: Carbonize material E at a temperature of 260-360℃ for 1-3 hours and at a temperature of 700-900℃ for 1-3 hours to obtain material F;

[0014] Step 6: Prepare (NH4)6Mo7O solutions with a mass fraction of 2-11% respectively. 24 The material F is prepared by mixing 4H2O and Mg(NO3)2·6H2O with a molar concentration of 0.1-0.4 mol / L, using the mixture as an impregnation solution, immersing the material F in the impregnation solution for a period of time, and then drying it.

[0015] The conditions for COS in the blast furnace gas of the supported catalyst trailer are: temperature 25℃ and space velocity 30000 h⁻¹. -1 The simulated gas composition, by volume percentage, is: 25% CO, 400ppm COS, 10% CO2, and balanced nitrogen.

[0016] The beneficial technical effects directly brought about by the above technical solution are as follows:

[0017] This paper presents the application of a carbonyl sulfide hydrolysis catalyst supported on chitosan oligosaccharides with pyridine nitrogen and magnesium ions and hexavalent molybdenum ions in the COS catalytic hydrolysis reaction of blast furnace gas. The method utilizes the in-situ nitrogen element in chitosan oligosaccharides to prepare pyridine nitrogen-rich activated carbon material, which is then used as a support to prepare a catalyst for supporting magnesium and hexavalent molybdenum ions for COS catalytic hydrolysis in blast furnace gas. The preparation method is simple. Addressing the bottleneck problem of the current blast furnace gas desulfurization technology lacking low-temperature, high-efficiency, and long-lasting carbonyl sulfide hydrolysis catalysts, this paper proposes a catalyst based on the important role of pyridine nitrogen in the catalytic hydrolysis of carbonyl sulfide, using it as a support to load magnesium and hexavalent molybdenum ions for the catalytic hydrolysis of carbonyl sulfide.

[0018] In the preparation method of the above-mentioned supported catalyst for low-temperature removal of COS from blast furnace gas, in step one, the mass fraction of propylene oxide in the propylene oxide aqueous solution is 2-8%.

[0019] In the preparation method of the supported catalyst for low-temperature removal of COS from blast furnace gas described above, in step three, solution B is added to solution A, and the mixture is stirred at a temperature of 60-80℃ for 1-3 hours. The pH is adjusted to 3-5 by adding nitric acid, and then the mixture is stirred at a temperature of 60-80℃ for 15-17 hours to obtain solution C.

[0020] In the above-mentioned method for preparing a supported catalyst for removing COS from blast furnace gas at low temperature, in step four, the oven temperature is 110-170℃, the reaction time is 22-28h, and the reaction is carried out in a vacuum freeze dryer for 10-13h.

[0021] In the preparation method of the supported catalyst for low-temperature removal of COS from blast furnace gas, in step six, material F is placed in an impregnation solution at a temperature of 80-100°C for 1-3 hours and then dried at a temperature of 100-120°C for 11-13 hours.

[0022] The preparation method of the above-mentioned supported catalyst for low-temperature removal of COS from blast furnace gas is characterized in that the concentration of nitric acid is 0.5-2 mol / L.

[0023] Another object of the present invention is to provide a catalyst prepared by the above-described method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas, wherein the supported catalyst has a pore size of 100–120 nm and a specific surface area of ​​81.7–144.1 m². 2 / g.

[0024] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0025] (1) In terms of raw material selection, the present invention uses chitosan oligosaccharide, which is inexpensive and readily available. It is widely available and rich in nitrogen, and can provide both nitrogen and carbon sources. It is a raw material with sustainable development characteristics.

[0026] (2) In terms of preparation method, chitosan oligosaccharide is crosslinked with propylene oxide and then freeze-dried to obtain a three-dimensional ordered macroporous material in situ doped with nitrogen. Then, the obtained material is mixed with magnesium ions and hexavalent molybdenum ions using an impregnation method, thus loading the metal ions into the nitrogen-doped adsorbent material. Finally, carbonization is carried out under a nitrogen atmosphere to obtain a nitrogen-doped catalyst. This invention utilizes magnesium ions and hexavalent molybdenum ions to synergistically remove COS from blast furnace gas. This catalyst exhibits good COS removal efficiency at low temperatures. The catalyst of this invention is regenerable and has low operating costs.

[0027] (3) The embodiments of this invention studied the effects of different loading ratios of active ingredients on COS removal efficiency. The study showed that, after cross-linking, the chitosan oligosaccharide is first carbonized, and then the active metal is loaded onto it via impregnation. Further experimental confirmation revealed that 5wt% (NH4)6Mo7O 24 The catalyst exhibits the best desulfurization effect when impregnated with 4H2O and 0.2mol / L Mg(NO3)2·6H2O solutions. After the catalyst reaches its adsorption breakthrough point, the feed gas is stopped, the fixed bed is raised to a certain temperature, and air is introduced to purge the sulfurized desulfurizing agent, causing the sulfur components in its pores to be desorbed. Then, the catalyst is removed and added to 5wt% (NH4)6Mo7O. 24The sample was immersed in a solution of 4H2O and 0.2mol / L Mg(NO3)2·6H2O and stirred thoroughly. It was then heated and immersed in an oil bath at 90-180℃ for 1 hour. After filtration, it was completely dried at 120℃. The COS adsorption performance test was repeated.

[0028] In summary, the supported adsorbent prepared by this invention solves the technical problem that the prior art cannot deeply remove COS under low temperature conditions. The removal efficiency of the supported catalyst of this invention can reach 100% within 90 minutes, and it can still retain 74.4% efficiency of fresh sample after six cycles at a regeneration temperature of 90℃. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings:

[0030] Figure 1 The Fourier transform infrared spectra before and after the reaction in Example 1 of the present invention are shown below.

[0031] Figure 2 This is a comparison chart of the desulfurization effects of the supported catalyst prepared in the embodiments of the present invention and the commercially available activated carbon.

[0032] Figure 3 This is a scanning electron microscope image of the supported catalyst prepared in this invention. Detailed Implementation

[0033] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0034] All the raw materials required for this invention can be purchased through commercial channels.

[0035] The evaluation method for the removal of carbonyl sulfide by the supported catalyst of this invention is as follows:

[0036] Detection method: A fixed-bed reactor was used, and the concentration of COS at the outlet was detected by gas chromatograph (GC-9720P1us).

[0037] Experimental conditions: air velocity 30,000 h⁻¹ -1 The temperature was 25℃. The simulated gas composition was: 25% CO, 400ppm COS, 10% CO2, and balanced nitrogen. A saturator system was used for water supply, and the water content was expressed as relative humidity (RH). A water bath was used to simulate the blast furnace gas environment. A mass flow controller was used to control the total flow rate at 50mL / min.

[0038] The main technical concept of this invention is as follows: Based on a nitrogen doping strategy, a catalyst with an ordered macroporous morphology is prepared to obtain more catalytic sites and to expel hydrogen sulfide more quickly, thereby extending the catalyst's lifespan. A carbon material with pyridine nitrogen loading is synthesized using the nitrogen element inherent in chitosan oligosaccharide via freeze-drying. The key to the hydrolysis of carbonyl sulfide lies in the adsorption of carbonyl sulfide and the activation of water. On the one hand, pyridine nitrogen can combine with hydrogen atoms dissociated from water molecules, thereby activating water molecules. On the other hand, the impregnation of magnesium ions and hexavalent molybdenum ions, along with the utilization of carbon dioxide and hydrogen sulfide generated from the reaction in the blast furnace gas, achieves synergistic removal of carbonyl sulfide. The specific reaction is as follows:

[0039] COS + H2O → CO2 + H2S;

[0040] MgO + CO2 → MgCO3;

[0041] MoO3 + 3H2S → MoS2 + 3H2O;

[0042] Magnesium ions and hexavalent molybdenum ions react with carbon dioxide and hydrogen sulfide present in and produced by blast furnace gas, thus promoting the forward reaction. Furthermore, the introduction of MoO3 significantly increases the number of weakly basic sites on the catalyst, reduces the lattice oxygen content, and promotes the activation of adsorbed water, resulting in a catalyst with high antioxidant and hydrolytic performance. According to the poisoning mechanism, the deposition of sulfate species tends to reduce weakly basic sites. High-valent molybdenum readily excites H2O adsorbed on the catalyst, generating hydroxyl groups and promoting COS hydrolysis. This introduces a large number of hydroxyl groups into the material to promote carbonyl sulfide activation. Magnesium ions also promote the conversion of carbonyl sulfide to hydrogen sulfide, and the participation of pyridine nitrogen helps maintain the reaction temperature at room temperature and achieves extremely high catalytic efficiency. This modification contributes to further research on catalysts that can promote COS hydrolysis and their applications in manufacturing.

[0043] Based on the above technical concept, the present invention yields a specific technical solution: a carbonyl sulfur hydrolysis catalyst supported by chitosan oligosaccharide and pyridine nitrogen and magnesium ions and hexavalent molybdenum ions. The carbonyl sulfur hydrolysis catalyst is prepared by in-situ nitrogen doping strategy to prepare pyridine nitrogen-rich activated carbon material, and uses it as a carrier to support magnesium ions and hexavalent molybdenum ions, for use in the catalytic hydrolysis of COS in blast furnace gas.

[0044] The present invention will be further described below with reference to specific embodiments.

[0045] Example 1:

[0046] A method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas includes the following steps:

[0047] Step 1: Dissolve 0.5g of chitosan oligosaccharide in 25mL of 8% propylene oxide aqueous solution at 70℃ to obtain solution A;

[0048] Step 2: Add 0.1g of polymethyl methacrylate microspheres to 1% P123 (10mL solution) to prepare solution B;

[0049] Step 3: Add solution B to solution A, stir at 60°C for 3 hours, adjust the pH to 3 with nitric acid, and stir in a 60°C constant temperature water bath for 17 hours to obtain solution C;

[0050] Step 4: Mix solution C with 50 mL of deionized water, place it in a hydrothermal reactor, and react it in an oven at 110 °C for 26 h to obtain precipitate D; wash precipitate D until neutral, and react it in a freeze dryer for 13 h to obtain material E;

[0051] Step 5: Carbonize material E at 260℃ for 3 hours and at 600℃ for 3 hours to obtain material F;

[0052] Step 6: Add material F to 2wt% (NH4)6Mo7O 24 The catalyst was obtained by uniformly stirring in 4H2O and 0.1mol / L Mg(NO3)2·6H2O solution at 80℃ for 3h and drying at 100℃ for 13h.

[0053] The nitrogen-doped metal ion-supported adsorbent material prepared in this embodiment was tested at low temperature with a space velocity of 30,000 h⁻¹. -1 The temperature was 25°C. The simulated gas composition was: 25% CO, 400 ppm COS, 10% CO2, and balanced nitrogen. A saturator system was used to supply water, and the water content was expressed as relative humidity (RH). A water bath heating method was used to simulate the blast furnace gas environment. A mass flow controller was used to control the total flow rate at 50 mL / min. The results showed that the COS removal rate of the supported catalyst in this embodiment was consistently 100% within 70 min, and remained at 85% within 90 min.

[0054] Figure 1 The image shows the Fourier transform infrared spectra before and after the reaction in Example 1 of this invention. From the image, we can see that: 875 cm⁻¹ -1 The banding at this location can be attributed to the Mo(O) groups (six-coordinated Mo) on the surface of the modified catalyst MoO3, due to the Mo-O vibration. New functional groups, including HCO3-, are formed on the surface. - It is a basic group; Mo-O is a neutral component. 580cm -1The band at 1535 cm⁻¹ is attributed to the four-coordinated Mo(T). As the reaction proceeds, the intensity of the Mo(O)-related band decreases, while the intensity of the Mo(T)-related band increases. During hydrolysis, the acidic group weakens the hydroxyl group, inhibiting the catalytic hydrolysis activity. The Mo-O group increases the number of basic sites on the catalyst. Basic sites are the active sites for COS catalytic hydrolysis, especially weakly and moderately basic sites. -1 and 1637cm -1 The band at that location can be attributed to HCO3. - ,like Figure 1 As shown. After 5 hours of reaction, the temperature reached approximately 3000–3600 cm⁻¹. -1 The bands at 995 cm⁻¹ correspond to H₂O on the catalyst surface, indicating an increase in water content. -1 The band at that location can be attributed to HSO3 produced during COS hydrolysis. – SO4 2– The reason for this band is that the reaction product is H2S, which can be oxidized to high-valence sulfur substances. This is a key factor leading to catalyst deactivation, even for unmodified catalysts.

[0055] Example 2:

[0056] A method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas includes the following steps:

[0057] Step 1: Dissolve 1.0 g of chitosan oligosaccharide in 20 mL of 5% (w / w) propylene oxide aqueous solution at 70 °C to obtain solution A;

[0058] Step 2: Add 0.3g of polymethyl methacrylate microspheres to a 2% (w / w) solution of P123 (15mL) to prepare solution B;

[0059] Step 3: Add solution B to solution A, stir at 70°C for 2 hours, adjust the pH to 4 with nitric acid, and stir in a 70°C constant temperature water bath for 16 hours to obtain solution C;

[0060] Step 4: Mix solution C with 60 mL of deionized water, place in a hydrothermal reactor, and react in an oven at 130 °C for 24 h to obtain precipitate D; wash precipitate D until neutral, and react in a freeze dryer for 12 h to obtain material E;

[0061] Step 5: Carbonize material E at 310℃ for 2 hours and at 700℃ for 2 hours to obtain material F;

[0062] Step 6: Add material F to 5wt% (NH4)6Mo7O 24The catalyst was obtained by uniformly stirring in a solution of 4H2O and 0.2 mol / L Mg(NO3)2·6H2O at 90 °C for 2 h and then drying at 110 °C for 12 h.

[0063] The nitrogen-doped metal ion supported catalyst prepared in this embodiment was tested at low temperature using the same method as in Example 1. The results showed that the COS removal rate of the supported catalyst in this embodiment remained at 100% within 80 min, and remained at 85% within 100 min.

[0064] The scanning electron microscope image of the supported catalyst prepared in this embodiment is as follows: Figure 3 As shown.

[0065] SEM images of 3DOM scaffolds ( Figure 3 The image shows a honeycomb structure. The average macropore size is 120 nm, and the size of the small windows connecting the macropores is 25 nm. The window size can be adjusted by changing the gelation time and calcination temperature.

[0066] Example 3:

[0067] A method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas includes the following steps:

[0068] Step 1: Dissolve 1.5g of chitosan oligosaccharide in 15mL of 2% propylene oxide aqueous solution at 70℃ to obtain solution A;

[0069] Step 2: Add 0.5g of polymethyl methacrylate microspheres to a 3% (w / w) solution of P123 (20mL) to prepare solution B;

[0070] Step 3: Add solution B to solution A, stir at 80°C for 1 hour, adjust the pH to 5 with nitric acid, and stir in an 80°C constant temperature water bath for 15 hours to obtain solution C;

[0071] Step 4: Mix solution C with 70 mL of deionized water, place in a hydrothermal reactor, and react in an oven at 150 °C for 26 h to obtain precipitate D; wash precipitate D until neutral, and react in a freeze dryer for 11 h to obtain material E;

[0072] Step 5: Carbonize material E at 460℃ for 1 hour and at 900℃ for 1 hour to obtain material F;

[0073] Step 6: Add material F to 8wt% (NH4)6Mo7O 24 The catalyst was obtained by uniformly stirring in a solution of 4H2O and 0.3mol / L Mg(NO3)2·6H2O at 100℃ for 1h and then drying at 120℃ for 11h.

[0074] The nitrogen-doped metal ion supported catalyst prepared in this embodiment was tested at low temperature using the same method as in Example 1. The results showed that the COS removal rate of the supported catalyst in this embodiment remained at 100% within 60 min, and the COS removal rate remained at 85% within 80 min.

[0075] Example 4:

[0076] A method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas includes the following steps:

[0077] Step 1: Dissolve 2.0g of chitosan oligosaccharide in 10mL of 1% propylene oxide aqueous solution at 70℃ to obtain solution A;

[0078] Step 2: Add 0.5g of polymethyl methacrylate microspheres to a 4% (w / w) P123 solution (20mL) to prepare solution B;

[0079] Step 3: Add solution B to solution A, stir at 90℃ for 0.5h, adjust the pH to 6 with nitric acid, and stir in a 90℃ constant temperature water bath for 14h to obtain solution C;

[0080] Step 4: Mix solution C with 80 mL of deionized water, place in a hydrothermal reactor, and react in an oven at 170 °C for 28 h to obtain precipitate D; wash precipitate D until neutral, and react in a freeze dryer for 10 h to obtain material E;

[0081] Step 5: Carbonize material E at 410℃ for 1 hour and at 900℃ for 1 hour to obtain material F;

[0082] Step 6: Add material F to 11wt% (NH4)6Mo7O 24 The catalyst was obtained by uniformly stirring the solution of 4H2O and 0.4mol / L Mg(NO3)2·6H2O at 100℃ for 1h and drying it at 130℃ for 10h.

[0083] The nitrogen-doped metal ion supported catalyst prepared in this embodiment was tested at low temperature using the same method as in Example 1. The results showed that the carbonyl sulfide removal rate remained at 100% for 60 min, and the desulfurization efficiency remained at 80% for 70 min.

[0084] The COS removal efficiency of the supported catalyst prepared in the above embodiments and commercial activated carbon under the same conditions is as follows: Figure 2 As shown.

[0085] Comparative Example 1:

[0086] A method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas includes the following steps:

[0087] Step 1: Dissolve 1.0 g of chitosan oligosaccharide in 20 mL of 5% (w / w) propylene oxide aqueous solution at 70 °C to obtain solution A;

[0088] Step 2: Add 0.3g of polymethyl methacrylate microspheres to 15mL of 2wt% P123 solution to prepare solution B;

[0089] Step 3: Add solution B to solution A, stir at 70°C for 2 hours, adjust the pH to 4 with nitric acid, and stir in a 70°C constant temperature water bath for 16 hours to obtain solution C;

[0090] Step 4: Mix solution C with 60 mL of deionized water, place in a hydrothermal reactor, and react in an oven at 130 °C for 24 h to obtain precipitate D; wash precipitate D until neutral, and react in a freeze dryer for 12 h to obtain material E;

[0091] Step 5: Carbonize material E at 310℃ for 2 hours and at 700℃ for 2 hours to obtain the supported catalyst.

[0092] The results showed that the COS removal rate of the supported catalyst in this embodiment was 100% within 30 minutes, and remained at 80% within 40 minutes.

[0093] Comparative Example 2:

[0094] The difference from Example 2 is that glutaraldehyde was used as the crosslinking agent and F87 was used as the template agent.

[0095] The results showed that the COS removal rate of the supported catalyst in this embodiment was 100% within 45 minutes, and remained at 85% within 60 minutes.

[0096] Comparative Example 3:

[0097] A method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas includes the following steps:

[0098] Step 1: Dissolve 1.0 g of chitosan oligosaccharide in 20 mL of 5% (w / w) propylene oxide aqueous solution at 70 °C to obtain solution A;

[0099] Step 2: Add 0.3g of polymethyl methacrylate microspheres to 15mL of 2wt% g P123 solution to prepare solution B;

[0100] Step 3: Add solution B to solution A, stir at 70°C for 2 hours, adjust the pH to 4 with nitric acid, and stir in a 70°C constant temperature water bath for 16 hours to obtain solution C;

[0101] Step 4: Mix solution C with 60 mL of deionized water, place in a hydrothermal reactor, and react in an oven at 130 °C for 24 h to obtain precipitate D; wash precipitate D until neutral, and react in a freeze dryer for 12 h to obtain material E;

[0102] Step 5: Carbonize material E at 310℃ for 2 hours and at 700℃ for 2 hours to obtain material F;

[0103] Step 6: Add material F to 5wt% (NH4)6Mo7O 24 The catalyst was obtained by uniformly stirring the solution in 4H2O at 90°C for 2 hours and drying it at 110°C for 12 hours.

[0104] The results showed that the COS removal rate of the supported catalyst in this embodiment was 100% within 55 minutes, and remained at 80% within 70 minutes.

[0105] Comparative Example 4:

[0106] A method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas includes the following steps:

[0107] Step 1: Dissolve 1.0 g of chitosan oligosaccharide in 20 mL of 5% (w / w) propylene oxide aqueous solution at 70 °C to obtain solution A;

[0108] Step 2: Add 0.3g of polymethyl methacrylate microspheres to a 2% (w / w) solution of P123 (15mL) to prepare solution B;

[0109] Step 3: Add solution B to solution A, stir at 70°C for 2 hours, adjust the pH to 4 with nitric acid, and stir in a 70°C constant temperature water bath for 16 hours to obtain solution C;

[0110] Step 4: Mix solution C with 60 mL of deionized water, place in a hydrothermal reactor, and react in an oven at 130 °C for 24 h to obtain precipitate D; wash precipitate D until neutral, and react in a freeze dryer for 12 h to obtain material E;

[0111] Step 5: Carbonize material E at 310℃ for 2 hours and at 700℃ for 2 hours to obtain material F;

[0112] Step 6: Stir material F uniformly in 0.2 mol / L Mg(NO3)2·6H2O solution at 90℃ for 2 h, and dry at 110℃ for 12 h to obtain the supported catalyst.

[0113] The results showed that the COS removal rate of the supported catalyst in this embodiment was 100% within 50 minutes, and remained at 80% within 60 minutes.

[0114] Any parts not mentioned in this invention can be achieved by referring to existing technologies.

[0115] Those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of protection claimed in this application.

Claims

1. A method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas, characterized in that, Includes the following steps: Step 1: Dissolve chitosan oligosaccharide in an aqueous propylene oxide solution to obtain solution A; wherein the mass-to-volume ratio of chitosan oligosaccharide to aqueous propylene oxide solution is 0.5-2.0 g / 10-25 mL, and the dissolution temperature is 60-80℃. Step 2: Add polymethyl methacrylate microspheres to solution P123 to obtain solution B; wherein the mass ratio of polymethyl methacrylate microspheres to solution P123 is 0.1-0.7:0.1-0.

4. Step 3: Add solution B to solution A, stir at a certain temperature, adjust the pH to 3-5, and continue stirring for a period of time to obtain solution C; Step 4: Place solution C into a hydrothermal reactor, then place it in an oven to obtain precipitate D. Wash precipitate D until neutral, then place it in a vacuum freeze dryer to obtain material E. Step 5: Carbonize material E at a temperature of 260-360℃ for 1-3 hours and at a temperature of 700-900℃ for 1-3 hours to obtain material F; Step 6: Prepare (NH4)6Mo7O solutions with a mass fraction of 2-11% respectively. 24 The material F is prepared by mixing 4H2O and Mg(NO3)2·6H2O with a molar concentration of 0.1-0.4 mol / L, using the mixture as an impregnation solution, and then immersing the material F in the impregnation solution for a period of time and drying it. The conditions for removing COS from blast furnace gas using the supported catalyst are: temperature 25℃ and space velocity 30000 h⁻¹. -1 The simulated gas composition, by volume percentage, is: 25% CO, 400ppm COS, 10% CO2, and balanced nitrogen.

2. The method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas according to claim 1, characterized in that: In step one, the mass fraction of propylene oxide in the aqueous solution is 2-8%.

3. The method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas according to claim 1, characterized in that: In step three, solution B is added to solution A and stirred at 60–80 °C for 1–3 hours. The pH is adjusted to 3–5 by adding nitric acid, and then the temperature is maintained at 60–80 °C and stirred for 15–17 hours to obtain solution C.

4. The method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas according to claim 1, characterized in that: In step four, the oven temperature is 110–170℃, the reaction time is 22–28 h, and the product is dried in a vacuum freeze dryer for 10–13 h.

5. The method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas according to claim 1, characterized in that: In step six, material F is placed in an impregnation solution at a temperature of 80–100°C for 1–3 hours and then dried at a temperature of 100–120°C for 11–13 hours.

6. The method for preparing a supported catalyst for low-temperature removal of COS from blast furnace gas according to claim 3, characterized in that: The concentration of nitric acid is 0.5–2 mol / L.

7. A supported catalyst for low-temperature removal of COS from blast furnace gas, characterized in that, It is prepared using the preparation method described in any one of claims 1 to 6, wherein the supported catalyst has a pore size of 100–120 nm and a specific surface area of ​​81.7–144.1 m². 2 / g.

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