High-stability hydrolysis catalyst for removing carbonyl sulfide in blast furnace gas at low temperature as well as preparation method and application of high-stability hydrolysis catalyst

Abstract

The invention discloses a high-stability hydrolysis catalyst for removing carbonyl sulfide in blast furnace gas at a low temperature as well as a preparation method and application of the high-stability hydrolysis catalyst, and belongs to the technical field of carbonyl sulfide removal. The preparation method comprises the following steps: preparing MgO nanoparticles; the preparation method comprises the following steps: dissolving Nd (NO3) 3.6 H2O and Al (NO3) 3.9 H2O in deionized water, uniformly stirring at normal temperature until the Nd (NO3) 3.6 H2O and the Al (NO3) 3.9 H2O are completely dissolved, then adding MgO nanoparticles into the mixed solution, ultrasonically stirring, oscillating and dehydrating the obtained mixture to obtain white powder, drying and roasting to obtain the product. The preparation method is simple, the prepared catalyst has a large specific surface area, many alkaline active sites and good photocatalytic characteristics, compared with an existing COS removal technology and an existing photo-thermal concerted catalytic hydrolysis technology, COS can be efficiently removed at a low temperature, reaction energy consumption is reduced, and the method is suitable for industrial production. The method has a wide application prospect in efficient removal of COS.

Description

Technical Field

[0001] The present invention relates to the technical field of carbonyl sulfide removal, and specifically relates to a hydrolysis catalyst with high stability for removing carbonyl sulfide from blast furnace gas at low temperature, and its preparation method and application. Background Art

[0002] The iron and steel industry is an important basic industrial sector and the material basis for the development of the national economy and national defense construction. With the global attention to green and low-carbon development, the iron and steel industry is also undergoing transformation and upgrading to reduce environmental pollution and resource consumption. Blast furnace gas, a by-product of the iron and steel industry, is a secondary energy source generated during the iron and steel smelting process. The pollutant component COS (carbonyl sulfide) contained in it has high chemical stability and is difficult to remove. Direct emission will cause environmental pollution. COS is prone to chemical reactions in the stratosphere and troposphere to form sulfate aerosol particles, affecting the atmospheric radiation balance. In addition, in industrial production, trace amounts of COS can also cause catalyst deactivation. Therefore, removing COS from blast furnace gas is of great significance.

[0003] At present, the research on COS removal methods mainly focuses on catalytic hydrogenation and catalytic hydrolysis. The catalytic hydrogenation method requires high-temperature conditions and has many side reactions, and the cost of the reactant hydrogen is high. Compared with the catalytic hydrogenation method, the advantage of the catalytic hydrolysis method is that its reaction conditions are mild, the energy consumption is low, its economy is good, and it is suitable for industrial desulfurization.

[0004] However, the traditional thermal catalytic hydrolysis for removing COS also has certain limitations. For example, the hydrolysis catalyst is prone to poisoning and deactivation, and only relying on heating to supply the energy required by the reaction system leads to a high reaction temperature and high energy consumption. At present, the adsorption temperature of most hydrolysis catalysts for removing COS from blast furnace gas is above 100°C. Under relatively high-temperature conditions, the reaction rate may be too fast, resulting in incomplete reaction, weakening the removal effect, generating reaction by-products such as sulfates, affecting the removal efficiency, and increasing the energy consumption and operation cost of the equipment under high-temperature conditions.

[0005] For example, in Chinese Patent, publication number: CN115445602B, a catalyst for hydrolyzing organic sulfur in blast furnace gas and its preparation and application method are disclosed. The catalyst is an Al2O3-ZrO2 composite material loaded with MoO3 and Cs2O. The prepared catalyst can carry out COS catalytic hydrolysis reaction under the conditions of 100-400°C and 0.1-7 MPa. The catalyst invented in this patent has a relatively high use temperature and is not suitable for low-temperature hydrolysis to remove COS from blast furnace gas.

[0006] Chinese Patent, Publication No.: CN118874499A, discloses a COS hydrolysis catalyst, its preparation method and application. The catalyst of this invention uses sulfates or sulfuric acid - acidified metal oxides as active ingredients, and uses Al2O3, TiO2, SiO2 - Al2O3 or cordierite as the catalyst carrier. The hydrolysis effect of COS is good, which solves the technical problem that the catalyst in the COS hydrolysis of blast furnace gas is prone to form sulfates or be poisoned by hydrogen chloride gas and deactivate. However, the operating temperature of the catalyst of this patent invention is between 80 and 180 °C, and it still cannot meet the low - temperature use requirements.

[0007] Therefore, it is extremely crucial to explore a technology for low - temperature and efficient removal of COS with reduced energy consumption. In recent years, the photo - thermal synergistic catalysis technology has received extensive attention. Compared with single thermal catalysis and photocatalysis, the synergistic effect of the photochemical reaction and the thermal reaction can endow the catalyst with higher catalytic activity. Introducing the photo - thermal synergistic catalysis technology into the low - temperature hydrolysis removal of COS is a potential alternative to the traditional thermal - catalytic hydrolysis method. Summary of the Invention

[0008] In view of this, the present invention provides a highly stable low - temperature hydrolysis catalyst for removing carbonyl sulfide from blast furnace gas, its preparation method and application.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A preparation method of a highly stable low - temperature hydrolysis catalyst for removing carbonyl sulfide from blast furnace gas, comprising the following steps:

[0011] (1) Dissolve MgCl2·6H2O in deionized water to obtain a uniformly transparent solution, then add an aqueous NaOH solution to the solution, stir, and let it stand to obtain a precipitate.

[0012] (2) Wash, dry, and anneal the precipitate obtained in step (1) to obtain MgO nanoparticles.

[0013] (3) Dissolve Nd(NO3)3·6H2O and Al(NO3)3·9H2O in deionized water, stir evenly at room temperature until completely dissolved to obtain a mixed solution, then add the MgO nanoparticles obtained in step (2) to the mixed solution, and stir ultrasonically to obtain a mixture.

[0014] (4) Oscillate and dehydrate the mixture obtained in step (3) to obtain a white powder, dry it, and calcine it to obtain an Al - and Nd - co - doped modified MgO material, that is, the above - mentioned highly stable low - temperature hydrolysis catalyst for removing carbonyl sulfide from blast furnace gas, denoted as Al - Nd / MgO.

[0015] Further, in step (1), the molar volume ratio of MgCl2·6H2O, deionized water and NaOH aqueous solution is (0.1 - 0.3) mol : 200 mL : (30 - 35) mL, the concentration of the NaOH aqueous solution is 0.8 - 1.0 mol / L, the above stirring speed is 70 r / min, the stirring time is 6 h, and the standing time is 10 h.

[0016] Further, in step (2), the precipitate is washed alternately with ethanol and deionized water for multiple times, the drying temperature is 80 - 120 °C, the drying time is 12 h, the annealing temperature is 700 °C, the annealing time is 3 h, and the particle size of the MgO nanoparticles is 10 - 25 nm.

[0017] The beneficial effects of adopting the above further technical solutions: It provides a catalyst based on nano-MgO that plays an important role in the catalytic hydrolysis of carbonyl sulfide. Its preparation method is simple, and the prepared nano-MgO has abundant basic active sites, good photocatalytic properties and adsorption capacity.

[0018] Further, in step (3), the mass volume ratio of Nd(NO3)3·6H2O, Al(NO3)3·9H2O, MgO nanoparticles and deionized water is 0.53 g : 0.75 - 2.21 g : 2 g : 10 mL.

[0019] Further, in step (3), Nd(NO3)3·6H2O and Al(NO3)3·9H2O are dissolved in deionized water and stirred at room temperature for 0.5 h until completely dissolved, and the stirring speed is 75 r / min; the power of the ultrasonic stirring is 50 - 100 W, the frequency of the ultrasonic stirring is 20 - 40 kHz, and the time of the ultrasonic stirring is 1 - 2 h.

[0020] Further, in step (4), the above dehydration method is to transfer the mixture to a 70 °C constant temperature water bath and continuously oscillate for 5 h for dehydration, the oscillation frequency is 80 times / min, the drying temperature is 80 - 100 °C, the drying time is 12 h, and the roasting is carried out by heating to 400 - 600 °C at a heating rate of 5 °C / min, and the holding roasting time is 3 h.

[0021] The beneficial effects of adopting the above further technical solutions: The Al-Nd / MgO catalyst is prepared by impregnating Al and Nd active components on nano-MgO. The active components of the synthesized catalyst are evenly dispersed. The co-doping of Al and Nd increases the number of basic active sites on the catalyst surface and improves the photocatalytic performance of the catalyst, making the catalyst have excellent catalytic activity.

[0022] The present invention also provides a highly stable hydrolysis catalyst for low-temperature removal of carbonyl sulfide in blast furnace gas prepared by the above preparation method, which comprises Al2O3, Nd2O3 and MgO. Al2O3 and Nd2O3 are loaded on MgO. The loading ratio of Al2O3 is 5wt%, 8wt% or 15wt%, and the loading ratio of Nd2O3 is 10wt%. The loading ratio refers to the mass ratio of Al2O3 or Nd2O3 to MgO.

[0023] The present invention also provides an application of the above preparation method or the above hydrolysis catalyst in the low-temperature removal of carbonyl sulfide in blast furnace gas.

[0024] Furthermore, the application of the above hydrolysis catalyst in the low-temperature removal of carbonyl sulfide in blast furnace gas comprises the following steps:

[0025] Fill the hydrolysis catalyst Al-Nd / MgO into a U-shaped quartz tube, connect the U-shaped quartz tube to a fixed-bed continuous-flow reactor, adjust the reaction temperature through the temperature control device of the fixed-bed continuous-flow reactor, externally connect an ultraviolet lamp to the fixed-bed continuous-flow reactor, introduce blast furnace gas containing COS into the fixed-bed continuous-flow reactor, and use N2 as the balance gas. Under the irradiation of the ultraviolet light of the externally connected ultraviolet lamp of the fixed-bed continuous-flow reactor, and under the action of the hydrolysis catalyst Al-Nd / MgO, carry out the reaction of photo-thermal synergistic catalysis and thermal catalytic hydrolysis of COS.

[0026] Furthermore, the concentration of COS in the above blast furnace gas is 150mg / m 3 , the flow rate of the above N2 is 170mL / min, and the reaction space velocity is 20000h -1 ; the reaction temperature of the above fixed-bed continuous-flow reactor is 25 - 60°C, and the power of the above ultraviolet lamp is 9W.

[0027] Advantages of the present invention:

[0028] (1) Based on the synthesis principle of MgO, the present invention first synthesizes MgO nanoparticles by the precipitation method, and then prepares a MgO catalyst Al-Nd / MgO co-doped and modified with bimetallic oxides Al2O3 and Nd2O3 with uniformly dispersed active components by the impregnation method. The high specific surface area of nano-MgO enables it to provide abundant basic active sites and conditions for the uniform dispersion of active components on the carrier surface; the unsaturated atoms and defect structures on the surface contribute to the separation and transport of photo-generated carriers, thus effectively promoting the progress of the photocatalytic reaction. The prepared catalyst has abundant basic active sites and good photocatalytic properties. Applying this invention to the photo-thermal synergistic catalytic hydrolysis of COS can effectively reduce the reaction temperature and energy consumption. The catalyst has high catalytic activity and stability, effectively prolongs the service life of the catalyst, and reduces the cost.

[0029] (2) The preparation method of the Al-Nd / MgO catalyst is simple. The raw material, nano-MgO, is green, environmentally friendly and inexpensive. Its sufficient reaction sites and natural structural defects endow it with special photocatalytic activity and the ability to adsorb, hydrolyze and transform COS.

[0030] (3) Based on the technology of thermocatalytic hydrolysis of carbonyl sulfide, the present invention introduces ultraviolet light and adopts a photo-thermal synergistic technology to catalyze the hydrolysis of COS, achieving high conversion rate of COS and high selectivity for H2S at a relatively low reaction temperature. The Al-Nd / MgO catalyst co-doped with Al and Nd is prepared by the impregnation method, and the Al5-Nd 10 / MgO calcined at 500 °C is selected as the optimal catalyst. During the thermal reaction (T) at 60 °C, the COS conversion rate remains at about 65%. During the photo-thermal reaction (PT) at 60 °C, the COS conversion rate increases to about 96%, and the H2S selectivity is close to 100%. During the photo-thermal reaction (PT) at 45 °C, the COS conversion rate remains at about 78% for 85 h before showing a slow downward trend, demonstrating the high stability of the Al-Nd / MgO catalyst.

[0031] (4) The MgO catalyst Al-Nd / MgO co-doped with Al and Nd in the present invention exhibits obvious stability and photo-induced thermocatalytic effect. This is because the co-doping of Al and Nd increases the number of basic active sites on the surface of MgO, and the Nd2O3 / MgO heterojunction formed by Nd doping under ultraviolet light irradiation promotes the separation of photo-generated electron-hole pairs. The holes react with H2O molecules adsorbed on the surface of MgO to generate highly reactive oxidizing species, hydroxyl radicals ·OH, for the hydrolysis reaction of COS, improving the hydrolysis activity of the catalyst for COS.

[0032] In summary, the preparation method of the present invention is simple, the active components have a high dispersion on the MgO carrier, the prepared catalyst has a large specific surface area and a large number of basic active sites, as well as good photocatalytic characteristics, significantly improving the absorption intensity of the catalyst for ultraviolet light, and enabling the catalyst to obtain better photo-thermal synergistic catalytic hydrolysis performance of COS. Compared with the existing COS removal technologies, the photo-thermal synergistic catalytic hydrolysis technology is more conducive to the efficient removal of COS at a relatively low temperature, reducing the reaction energy consumption, and has a wide application prospect in the efficient removal of COS. Description of the Drawings

[0033] Figure 1 It is a diagram of the experimental device for photo-thermal synergistic catalytic hydrolysis of COS.

[0034] Figure 2 It is the COS conversion rate of the Al5-Nd 10 / MgO catalyst sample during the photo-thermal (PT) and thermal (T) reaction processes at different temperatures.

[0035] Figure 3 H2S selectivity of Al5-Nd 10 / MgO catalyst samples during photothermal (PT) and thermal (T) reactions.

[0036] Figure 4 For Al5-Nd at different temperatures 10 Conversion rate of COS catalytic hydrolysis of / MgO catalyst samples under two on-off lamp cycles.

[0037] Figure 5 For Al5-Nd 10 / MgO catalyst samples were tested for the stability of photothermal (PT) and thermal (T) catalytic hydrolysis of COS at a reaction temperature of 45 °C.

[0038] Figure 6 COS conversion rates of Al-Nd / MgO and MgO catalyst samples during photothermal (PT) and thermal (T) reactions at a reaction temperature of 60 °C. Specific implementation mode

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] Example 1

[0041] A preparation method of a hydrolysis catalyst for highly stable low-temperature removal of carbonyl sulfide in blast furnace gas, characterized by comprising the following steps:

[0042] (1) Dissolve 0.1 mol of MgCl2·6H2O in 200 mL of deionized water to obtain a uniform and transparent solution, then slowly add 30 mL of a 1.0 mol / L NaOH aqueous solution to the solution, stir for 6 h, the stirring speed is 70 r / min, and let it stand for 10 h to obtain a precipitate;

[0043] (2) Wash the precipitate obtained in step (1) alternately with ethanol and deionized water for multiple times, dry it in a hot air oven at 80 °C for 12 h, and anneal it at 700 °C for 3 h to obtain MgO nanoparticles with a particle size of 10-25 nm;

[0044] (3) Dissolve 0.53 g of Nd(NO3)3·6H2O and 0.75 g of Al(NO3)3·9H2O in 10 mL of deionized water, stir at room temperature for 0.5 h until completely dissolved, with a stirring speed of 75 r / min to obtain a mixed solution. Then add 2 g of the MgO nanoparticles obtained in step (2) to the mixed solution, and perform ultrasonic stirring. The power of ultrasonic stirring is 80 W, the frequency of ultrasonic stirring is 40 kHz, and the time of ultrasonic stirring is 1 h to obtain a mixture;

[0045] (4) Transfer the mixture obtained in step (3) to a 70 °C constant temperature water bath and continuously oscillate for 5 h to dehydrate, with an oscillation frequency of 80 times / min to obtain a white powder. Dry it at 100 °C for 12 h, heat it to 500 °C at a heating rate of 5 °C / min, and keep the heat treatment time for 3 h to obtain an Al and Nd co-doped modified MgO material, that is, a high-stability low-temperature hydrolysis catalyst for removing carbonyl sulfide in blast furnace gas, denoted as Al5-Nd 10 / MgO.

[0046] Al5-Nd 10 / MgO includes Al2O3, Nd2O3 and MgO. Al2O3 and Nd2O3 are loaded on MgO. The loading ratio of Al2O3 is 5 wt%, and the loading ratio of Nd2O3 is 10 wt%. The loading ratio refers to the mass ratio of Al2O3 or Nd2O3 to MgO.

[0047] Example 2

[0048] A preparation method of a high-stability low-temperature hydrolysis catalyst for removing carbonyl sulfide in blast furnace gas, characterized by comprising the following steps:

[0049] (1) Dissolve 0.1 mol of MgCl2·6H2O in 200 mL of deionized water to obtain a uniformly transparent solution. Then slowly add 30 mL of a 1.0 mol / L NaOH aqueous solution to the solution, stir for 6 h, with a stirring speed of 70 r / min, and let it stand for 10 h to obtain a precipitate;

[0050] (2) Wash the precipitate obtained in step (1) alternately with ethanol and deionized water for multiple times, dry it in a hot air oven at 80 °C for 12 h, and anneal it at 700 °C for 3 h to obtain MgO nanoparticles with a particle size of 10 - 25 nm;

[0051] (3) Dissolve 0.53 g of Nd(NO3)3·6H2O and 1.16 g of Al(NO3)3·9H2O in 10 mL of deionized water, stir at room temperature for 0.5 h until completely dissolved, with a stirring speed of 75 r / min to obtain a mixed solution. Then add 2 g of the MgO nanoparticles obtained in step (2) to the mixed solution, and perform ultrasonic stirring. The power of ultrasonic stirring is 80 W, the frequency of ultrasonic stirring is 40 kHz, and the time of ultrasonic stirring is 1 h to obtain a mixture;

[0052] (4) Transfer the mixture obtained in step (3) to a 70°C constant temperature water bath and continuously oscillate for 5 h for dehydration, with an oscillation frequency of 80 times / min to obtain a white powder. Dry it at 100°C for 12 h, heat it to 500°C at a heating rate of 5°C / min, and keep the temperature for 3 h for roasting to obtain an Al- and Nd-codoped modified MgO material, that is, a high-stability low-temperature hydrolysis catalyst for removing carbonyl sulfide in blast furnace gas, denoted as Al8-Nd 10 / MgO.

[0053] Al8-Nd 10 / MgO includes Al2O3, Nd2O3 and MgO. Al2O3 and Nd2O3 are loaded on MgO. The loading ratio of Al2O3 is 8 wt%, and the loading ratio of Nd2O3 is 10 wt%. The loading ratio refers to the mass ratio of Al2O3 or Nd2O3 to MgO.

[0054] Example 3

[0055] A preparation method of a high-stability low-temperature hydrolysis catalyst for removing carbonyl sulfide in blast furnace gas, characterized by comprising the following steps:

[0056] (1) Dissolve 0.1 mol of MgCl2·6H2O in 200 mL of deionized water to obtain a uniformly transparent solution. Then slowly add 30 mL of a 1.0 mol / L NaOH aqueous solution to the solution, stir for 6 h, with a stirring speed of 70 r / min, and let it stand for 10 h to obtain a precipitate;

[0057] (2) Wash the precipitate obtained in step (1) alternately with ethanol and deionized water for multiple times, dry it in an 80°C hot air oven for 12 h, and anneal it at 700°C for 3 h to obtain MgO nanoparticles with a particle size of 10 - 25 nm;

[0058] (3) Dissolve 0.53 g of Nd(NO3)3·6H2O and 2.21 g of Al(NO3)3·9H2O in 10 mL of deionized water, stir at room temperature for 0.5 h until completely dissolved, with a stirring speed of 75 r / min to obtain a mixed solution. Then add 2 g of the MgO nanoparticles obtained in step (2) to the mixed solution, and perform ultrasonic stirring. The power of ultrasonic stirring is 80 W, the frequency is 40 kHz, and the time is 1 h to obtain a mixture.

[0059] (4) Transfer the mixture obtained in step (3) to a 70 °C constant temperature water bath and continuously oscillate for 5 h to dehydrate, with an oscillation frequency of 80 times / min to obtain a white powder. Dry at 100 °C for 12 h, heat up to 500 °C at a heating rate of 5 °C / min, and the holding roasting time is 3 h to obtain an Al and Nd co-doped modified MgO material, that is, a high-stability low-temperature hydrolysis catalyst for removing carbonyl sulfide in blast furnace gas, denoted as Al 15 -Nd 10 / MgO.

[0060] Al 15 -Nd 10 / MgO includes Al2O3, Nd2O3 and MgO. Al2O3 and Nd2O3 are loaded on MgO. The loading ratio of Al2O3 is 15 wt%, and the loading ratio of Nd2O3 is 10 wt%. The loading ratio refers to the mass ratio of Al2O3 or Nd2O3 to MgO.

[0061] Example 4

[0062] The application of the hydrolysis catalyst in the low-temperature removal of carbonyl sulfide in blast furnace gas includes the following steps:

[0063] Load 0.2 g of the hydrolysis catalyst Al5-Nd 10 / MgO into a U-shaped quartz tube, connect the U-shaped quartz tube to a fixed-bed continuous-flow reactor, adjust the reaction temperature to 25 °C through the temperature control device of the fixed-bed continuous-flow reactor, externally connect an ultraviolet lamp to the fixed-bed continuous-flow reactor, with the power of the ultraviolet lamp being 9 W. Pass the blast furnace gas containing COS into the fixed-bed continuous-flow reactor, the COS inlet concentration is 150 mg / m 3 , and use N2 as the balance gas, with the flow rate of N2 being 170 mL / min, and the reaction space velocity being 20000 h -1 . Under the irradiation of the ultraviolet light of the externally connected ultraviolet lamp of the fixed-bed continuous-flow reactor, carry out the photo-thermal synergistic catalytic hydrolysis reaction of COS under the action of the hydrolysis catalyst Al5-Nd 10 / MgO.

[0064] Example 5

[0065] Application of hydrolysis catalyst in low-temperature removal of carbonyl sulfide from blast furnace gas, comprising the following steps:

[0066] Load 0.2 g of the hydrolysis catalyst Al5-Nd 10 / MgO prepared in Example 1 into a U-shaped quartz tube, connect the U-shaped quartz tube to a fixed-bed continuous-flow reactor, adjust the reaction temperature to 40 °C through the temperature control device of the fixed-bed continuous-flow reactor, externally connect an ultraviolet lamp to the fixed-bed continuous-flow reactor, the power of the ultraviolet lamp is 9 W, introduce the blast furnace gas containing COS into the fixed-bed continuous-flow reactor, the inlet concentration of COS is 150 mg / m 3 , and use N2 as the balance gas, the flow rate of N2 is 170 mL / min, the reaction space velocity is 20000 h -1 , under the irradiation of the ultraviolet light of the ultraviolet lamp externally connected to the fixed-bed continuous-flow reactor, carry out the photo-thermal synergistic catalytic hydrolysis reaction of COS under the action of the hydrolysis catalyst Al5-Nd 10 / MgO.

[0067] Example 6

[0068] Application of hydrolysis catalyst in low-temperature removal of carbonyl sulfide from blast furnace gas, comprising the following steps:

[0069] Load 0.2 g of the hydrolysis catalyst Al5-Nd 10 / MgO prepared in Example 1 into a U-shaped quartz tube, connect the U-shaped quartz tube to a fixed-bed continuous-flow reactor, adjust the reaction temperature to 60 °C through the temperature control device of the fixed-bed continuous-flow reactor, externally connect an ultraviolet lamp to the fixed-bed continuous-flow reactor, the power of the ultraviolet lamp is 9 W, introduce the blast furnace gas containing COS into the fixed-bed continuous-flow reactor, the inlet concentration of COS is 150 mg / m 3 , and use N2 as the balance gas, the flow rate of N2 is 170 mL / min, the reaction space velocity is 20000 h -1 , under the irradiation of the ultraviolet light of the ultraviolet lamp externally connected to the fixed-bed continuous-flow reactor, carry out the photo-thermal synergistic catalytic hydrolysis reaction of COS under the action of the hydrolysis catalyst Al5-Nd 10 / MgO.

[0070] Comparative Example 1

[0071] Application of hydrolysis catalyst in low-temperature removal of carbonyl sulfide from blast furnace gas, comprising the following steps:

[0072] Load 0.2 g of the hydrolysis catalyst Al5-Nd 10The Al5-Nd / MgO was filled into a U-shaped quartz tube, and the U-shaped quartz tube was connected to a fixed-bed continuous-flow reactor. The reaction temperature was adjusted to 25 °C through the temperature control device of the fixed-bed continuous-flow reactor. The blast furnace gas containing COS was introduced into the fixed-bed continuous-flow reactor, and the inlet concentration of COS was 150 mg / m 3 , and N2 was used as the balance gas with a flow rate of 170 mL / min. The reaction space velocity was 20,000 h -1 , and the thermal catalytic hydrolysis reaction of COS was carried out under the action of the hydrolysis catalyst Al5-Nd 10 / MgO.

[0073] Comparative Example 2

[0074] The application of the hydrolysis catalyst in the low-temperature removal of carbonyl sulfide from blast furnace gas includes the following steps:

[0075] 0.2 g of the hydrolysis catalyst Al5-Nd 10 / MgO prepared in Example 1 was filled into a U-shaped quartz tube, and the U-shaped quartz tube was connected to a fixed-bed continuous-flow reactor. The reaction temperature was adjusted to 40 °C through the temperature control device of the fixed-bed continuous-flow reactor. The blast furnace gas containing COS was introduced into the fixed-bed continuous-flow reactor, and the inlet concentration of COS was 150 mg / m 3 , and N2 was used as the balance gas with a flow rate of 170 mL / min. The reaction space velocity was 20,000 h -1 , and the thermal catalytic hydrolysis reaction of COS was carried out under the action of the hydrolysis catalyst Al5-Nd 10 / MgO.

[0076] Comparative Example 3

[0077] The application of the hydrolysis catalyst in the low-temperature removal of carbonyl sulfide from blast furnace gas includes the following steps:

[0078] 0.2 g of the hydrolysis catalyst Al5-Nd 10 / MgO prepared in Example 1 was filled into a U-shaped quartz tube, and the U-shaped quartz tube was connected to a fixed-bed continuous-flow reactor. The reaction temperature was adjusted to 60 °C through the temperature control device of the fixed-bed continuous-flow reactor. The blast furnace gas containing COS was introduced into the fixed-bed continuous-flow reactor, and the inlet concentration of COS was 150 mg / m 3 , and N2 was used as the balance gas with a flow rate of 170 mL / min. The reaction space velocity was 20,000 h -1 , and the thermal catalytic hydrolysis reaction of COS was carried out under the action of the hydrolysis catalyst Al5-Nd 10 / MgO.

[0079] Effect Experiment

[0080] In order to study Al5-Nd10 The response ability of the Al5-Nd / MgO photocatalyst to ultraviolet light was evaluated. A switch-on and switch-off experiment was designed at 25 - 60 °C. Two switch-on and switch-off cycles of switch-on - switch-off - switch-on - switch-off were used to simulate the photo-thermal (PT) and thermal (T) catalytic processes, and the catalytic hydrolysis conversion rate of COS was evaluated. The specific implementation methods refer to Experiment 1, Experiment 2, and Experiment 3. The catalyst stability test refers to Experiment 4 and 5.

[0081] Experiment 1

[0082] Under the reaction conditions in Example 4, the catalytic hydrolysis conversion rate of COS of the Al5-Nd / MgO catalyst sample was evaluated at a reaction temperature of 25 °C under two switch-on and switch-off cycles. 10 Under the reaction conditions in Example 4, the catalytic hydrolysis conversion rate of COS of the Al5-Nd / MgO catalyst sample was evaluated at a reaction temperature of 25 °C under two switch-on and switch-off cycles.

[0083] Experiment 2

[0084] Under the reaction conditions in Example 4, the catalytic hydrolysis conversion rate of COS of the Al5-Nd / MgO catalyst sample was evaluated at a reaction temperature of 40 °C under two switch-on and switch-off cycles. 10 Under the reaction conditions in Example 4, the catalytic hydrolysis conversion rate of COS of the Al5-Nd / MgO catalyst sample was evaluated at a reaction temperature of 40 °C under two switch-on and switch-off cycles.

[0085] Experiment 3

[0086] Under the reaction conditions in Example 4, the catalytic hydrolysis conversion rate of COS of the Al5-Nd / MgO catalyst sample was evaluated at a reaction temperature of 60 °C under two switch-on and switch-off cycles. 10 Under the reaction conditions in Example 4, the catalytic hydrolysis conversion rate of COS of the Al5-Nd / MgO catalyst sample was evaluated at a reaction temperature of 60 °C under two switch-on and switch-off cycles.

[0087] Experiment 4

[0088] Under the reaction conditions in Example 4, the stability test of the photo-thermal (PT) catalytic hydrolysis of carbonyl sulfide was carried out at a reaction temperature of 45 °C.

[0089] Experiment 5

[0090] Under the reaction conditions in Example 4, the illumination of the ultraviolet lamp was removed, and the stability test of the thermal (T) catalytic hydrolysis of carbonyl sulfide was carried out at a reaction temperature of 45 °C.

[0091] Figure 2 COS conversion rates of the Al5-Nd / MgO catalyst sample during the photo-thermal (PT) and thermal (T) reaction processes at different temperatures. As 10 can be seen, at different reaction temperature points, the COS conversion rate during the photo-thermal reaction (PT) process is always higher than that during the thermal (T) reaction process. The COS conversion rate is the highest under the photo-thermal reaction conditions at 60 °C, reaching 96%, indicating that the catalyst has high catalytic activity under photo-thermal reaction conditions, and the introduction of ultraviolet light enhances its catalytic activity. Figure 2 COS conversion rates of the Al5-Nd / MgO catalyst sample during the photo-thermal (PT) and thermal (T) reaction processes at different temperatures. As

[0092] Figure 3 The H2S selectivity of the Al5-Nd 10 / MgO catalyst samples during the photothermal (PT) and thermal (T) reaction processes at different temperatures. It can be Figure 3 seen that the selectivity of H2S is the highest under the photothermal reaction conditions at 60 °C, reaching 98.5%, which also indicates that the catalyst has high catalytic activity under the photothermal reaction conditions.

[0093] Figure 4 The catalytic hydrolysis conversion rate of COS by the Al5-Nd 10 / MgO catalyst samples under two on-off lamp cycle periods at different temperatures. It can be Figure 4 seen that when ultraviolet light illumination (turning on the lamp) is introduced and the catalyst is placed under the photothermal reaction conditions, the hydrolysis conversion rate of COS rises rapidly and then remains stable; while when the ultraviolet lamp is turned off and it returns to the thermal reaction conditions, the hydrolysis conversion rate of COS drops rapidly. The experiment shows that introducing ultraviolet light on the basis of simple thermal catalytic hydrolysis has a significant promoting effect on the hydrolysis of COS, and this effect can be demonstrated in a short time.

[0094] Figure 5 The stability test of the Al5-Nd 10 / MgO catalyst samples for the co-catalytic hydrolysis of COS by photothermal (PT) and thermal (T) catalysis at a reaction temperature of 45 °C. The experiment shows that the introduction of ultraviolet light helps to improve the hydrolysis stability of the catalyst and effectively extends the service life of the catalyst. Under the photothermal reaction conditions, the conversion rate of COS maintains at about 78% for 85 h before showing a slow downward trend.

[0095] Figure 6 The COS conversion rates of Al-Nd / MgO and MgO during the photothermal (PT) and thermal (T) reaction processes at a reaction temperature of 60 °C. The experiment shows that the Al5-Nd 10 / MgO material has the best effect on the co-catalytic hydrolysis of COS by photothermal at 60 °C.

[0096] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation method of a hydrolysis catalyst for removing carbonyl sulfide in blast furnace gas at low temperature with high stability, characterized in that, It includes the following steps: (1) Dissolve MgCl2·6H2O in deionized water to obtain a homogeneous and transparent solution, then add an aqueous NaOH solution to the solution, stir, and let it stand to obtain a precipitate. (2) Wash, dry, and anneal the precipitate obtained in step (1) to obtain MgO nanoparticles. (3) Dissolve Nd(NO3)3·6H2O and Al(NO3)3·9H2O in deionized water, stir evenly at room temperature until completely dissolved to obtain a mixed solution, then add the MgO nanoparticles obtained in step (2) to the mixed solution, and stir ultrasonically to obtain a mixture. (4) Oscillate and dehydrate the mixture obtained in step (3) to obtain a white powder, dry it, and calcine it to obtain an Al- and Nd-codoped MgO material, that is, the high-stability low-temperature hydrolysis catalyst for removing carbonyl sulfide in blast furnace gas, denoted as Al-Nd / MgO.

2. The preparation method of a hydrolysis catalyst for highly stably removing carbonyl sulfide in blast furnace gas at low temperature according to claim 1, characterized in that In step (1), the molar volume ratio of MgCl2·6H2O, deionized water, and the aqueous NaOH solution is (0.1 - 0.3) mol: 200 mL: (30 - 35) mL, the concentration of the aqueous NaOH solution is 0.8 - 1.0 mol / L, the stirring speed is 70 r / min, the stirring time is 6 h, and the standing time is 10 h.

3. The preparation method of a hydrolysis catalyst for highly stable low-temperature removal of carbonyl sulfide in blast furnace gas according to claim 1, characterized in that, In step (2), wash the precipitate alternately with ethanol and deionized water for multiple times, the drying temperature is 80 - 120 °C, the drying time is 12 h, the annealing temperature is 700 °C, the annealing time is 3 h, and the particle size of the MgO nanoparticles is 10 - 25 nm.

4. The preparation method of a hydrolysis catalyst for highly stable low-temperature removal of carbonyl sulfide from blast furnace gas according to claim 1, characterized in that, In step (3), the mass-volume ratio of Nd(NO3)3·6H2O, Al(NO3)3·9H2O, MgO nanoparticles, and deionized water is 0.53 g: (0.75 - 2.21) g: 2 g: 10 mL.

5. The preparation method of a hydrolysis catalyst for highly stable low-temperature removal of carbonyl sulfide in blast furnace gas according to claim 1, characterized in that, In step (3), dissolve Nd(NO3)3·6H2O and Al(NO3)3·9H2O in deionized water, stir at room temperature for 0.5 h until completely dissolved, and the stirring speed is 75 r / min; the power of ultrasonic stirring is 50 - 100 W, the frequency of ultrasonic stirring is 20 - 40 kHz, and the time of ultrasonic stirring is 1 - 2 h.

6. The preparation method of a hydrolysis catalyst for highly stable low-temperature removal of carbonyl sulfide in blast furnace gas according to claim 1, characterized in that, In step (4), the dehydration method is to transfer the mixture to a 70 °C constant temperature water bath and continuously oscillate it for 5 h to dehydrate, the oscillation frequency is 80 times / min, the drying temperature is 80 - 100 °C, the drying time is 12 h, and the calcination is carried out by heating at a heating rate of 5 °C / min to 400 - 600 °C, and the holding calcination time is 3 h.

7. A highly stable hydrolysis catalyst for removing carbonyl sulfide from blast furnace gas at low temperature prepared by the preparation method according to any one of claims 1-6, characterized in that, It includes Al2O3, Nd2O3, and MgO. Al2O3 and Nd2O3 are loaded on MgO. The loading ratio of Al2O3 is 5 wt%, 8 wt%, or 15 wt%, and the loading ratio of Nd2O3 is 10 wt%. The loading ratio refers to the mass ratio of Al2O3 or Nd2O3 to MgO.

8. Use of the preparation method according to any one of claims 1 - 6 or the hydrolysis catalyst according to claim 7 in the low-temperature removal of carbonyl sulfide in blast furnace gas.

9. Use of the hydrolysis catalyst according to claim 8 in the low-temperature removal of carbonyl sulfide in blast furnace gas, characterized in that, It includes the following steps: The hydrolysis catalyst Al-Nd / MgO was loaded into a U-shaped quartz tube, and the U-shaped quartz tube was connected to a fixed-bed continuous-flow reactor. The reaction temperature was adjusted by the temperature control device of the fixed-bed continuous-flow reactor. An ultraviolet lamp was externally connected to the fixed-bed continuous-flow reactor. The blast furnace gas containing COS was introduced into the fixed-bed continuous-flow reactor, and N2 was used as the balance gas. Under the irradiation of the ultraviolet light of the externally connected ultraviolet lamp of the fixed-bed continuous-flow reactor, and under the action of the hydrolysis catalyst Al-Nd / MgO, the photo-thermal synergistic catalysis and thermal catalytic hydrolysis reaction of COS were carried out.

10. Use of the hydrolysis catalyst according to claim 9 in the low-temperature removal of carbonyl sulfide from blast furnace gas, characterized in that, The concentration of COS in the blast furnace gas is 150 mg / m 3 , the flow rate of N2 is 170 mL / min, and the reaction space velocity is 20000 h -1 ; the reaction temperature of the fixed-bed continuous-flow reactor is 25 - 60 °C, and the power of the ultraviolet lamp is 9 W.

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