A high sulfur capacity, regenerable activated carbon-based desulfurization catalyst, its preparation method and application

Abstract

The present invention belongs to the technical field of desulfurization, and specifically discloses a high-sulfur-capacity, regenerable activated-carbon-based desulfurization catalyst, its preparation method and application. The preparation method includes steps such as the preparation of modified activated carbon, the preparation of modified attapulgite, the preparation of pretreated fly ash, the preparation of a composite support, the loading of iron, the loading of manganese, the loading of cerium, etc. The prepared activated-carbon-based desulfurization catalyst has a high sulfur capacity, high desulfurization accuracy, good cyclic regeneration performance, and has good industrial application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of desulfurization, and particularly relates to a high sulfur capacity, regenerable activated carbon-based desulfurization catalyst, its preparation method and application. Background Art

[0002] The rapid development of the industrial economy has led to a sharp increase in the emissions of various pollutants including sulfur-containing pollutants, bringing potential safety and environmental hazards. For example, sulfur-containing gases such as hydrogen sulfide (H2S) and sulfur dioxide (SO2) are not only highly toxic and corrosive, but also cause environmental problems such as acid rain and photochemical smog, and accelerate equipment aging. With the tightening of global environmental protection regulations, the industrial field has an increasingly urgent need for efficient desulfurization technologies.

[0003] The sources of sulfide pollution are diverse. Taking hydrogen sulfide gas as an example, hydrogen sulfide mostly comes from certain chemical reactions and the decomposition of proteins in nature. It is also a component or impurity of some natural substances and widely exists in nature. In addition, hydrogen sulfide emissions also occur in production processes such as mining and non-ferrous metal smelting. For sulfide pollution, a variety of desulfurization processes have been developed in industry, including: wet desulfurization (i.e., using liquid absorption), dry desulfurization (i.e., using powder absorbents or catalysts, etc.), and semi-dry desulfurization; according to the desulfurization object, desulfurization also includes the removal of organic sulfur and the removal of inorganic sulfur. In the prior art, dry desulfurization has been widely used; among them, dry desulfurization includes chemical reaction desulfurization and physical adsorption desulfurization. Chemical reaction desulfurization removes sulfides by chemical reactions, and its desulfurization has the characteristics of high desulfurization accuracy and large sulfur capacity; physical adsorption desulfurization mainly removes sulfides by the polarity of the adsorbent, and there are certain requirements for the polarity of sulfides for desulfurization by polar adsorption. Sulfides with low polarity cannot be adsorbed and removed.

[0004] For dry desulfurization, various types of desulfurizers / desulfurization catalysts have been applied. For example, patent document CN119869528A provides a marine biomass desulfurization catalyst and its preparation method. The catalyst contains a carbon source carrier made from marine biomass and a metal active component, and the mass ratio of the metal active component to the carbon source carrier is 1:1 to 3; the mesoporous specific surface area and mesoporous pore volume of the catalyst are respectively in the range of 85 - 100 m 2 / g, 0.150 - 0170 cm 3 / g; for another example, patent document CN119303632A provides a high-temperature resistant desulfurization catalyst and its preparation method, which contains the following components in weight percentages: cobalt phthalocyanine 30-35%, Fe-PBTCA-EDTMP 10-15%, manganese sulfate monohydrate 10-15%, 2,4-dinitrophenol 5-10%, tannin extract 15-20%, sodium metavanadate 4-10%, ammonium phosphate 4-10%, ammonia-ammonium chloride solution 4-8%; for another example, patent document CN119075974A provides modified halloysite, an oxidative desulfurization catalyst and its preparation method and application. By electrostatically anchoring and loading tungsten oxide inside the inner cavity of HNT, excellent catalytic performance can be achieved with a low loading amount of tungsten oxide, and efficient oxidative desulfurization can be realized in fuel.

[0005] In fact, no matter which method is adopted, from the perspective of performance indicators, the desulfurization performance of the desulfurization catalyst itself is nothing more than sulfur capacity, desulfurization accuracy, and regeneration performance. Providing an efficient and cost-effective desulfurizer has very important practical significance. For example, patent document CN118454685A provides a composite activated carbon desulfurizer and its preparation method and application, which uses activated carbon and rectorite as the main carriers, and sequentially impregnates and loads active components such as iron, zinc, and bismuth, and can be obtained through simple impregnation and loading; through the above technical solution, good desulfurization effect and cyclic regeneration performance are achieved, but the above performance still needs to be further improved.

[0006] Aiming at the deficiencies of the existing technology, the present invention hopes to propose a high-sulfur-capacity, regenerable activated carbon-based desulfurization catalyst and its preparation method and application. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a high-sulfur-capacity, regenerable activated carbon-based desulfurization catalyst and its preparation method and application, with high sulfur capacity, high desulfurization accuracy, and good cyclic regeneration performance.

[0008] To achieve the above purpose, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a preparation method of a high-sulfur-capacity, regenerable activated carbon-based desulfurization catalyst, including the following steps:

[0010] (1) Preparation of modified activated carbon;

[0011] (2) Preparation of modified attapulgite: Wash attapulgite with water and then dry it. Subsequently, add the dried attapulgite to a sodium hydroxide solution, stir, wash to neutrality, and dry to obtain pre-modified attapulgite; then add the obtained pre-modified attapulgite to water, stir evenly, add polyethylene glycol, stir evenly again, and then perform drying and calcination treatments; after calcination is completed, perform grinding and sieving treatments to obtain modified attapulgite;

[0012] (3)Preparation of pretreated fly ash: Grind the fly ash and then conduct calcination treatment. After the treatment is completed, add it to hydrochloric acid solution for further treatment; after the treatment is completed, filter, wash, and dry it to obtain pretreated fly ash;

[0013] (4)Preparation of composite support: Add the modified activated carbon obtained in step (1), the modified attapulgite obtained in step (2), and the pretreated fly ash obtained in step (3) to water in sequence. After stirring, conduct centrifugation and drying treatment to obtain the composite support;

[0014] (5)Loading of iron: Add the composite support obtained in step (4) to ferric nitrate solution, oscillate and impregnate it, and then conduct drying and calcination treatment to obtain the catalyst with primary loading;

[0015] (6)Loading of manganese: Add the catalyst with primary loading obtained in step (5) to manganese nitrate solution, oscillate and impregnate it, and then conduct drying and calcination treatment to obtain the catalyst with secondary loading;

[0016] (7)Loading of cerium: Add the catalyst with secondary loading obtained in step (6) to cerium nitrate solution, oscillate and impregnate it, then dry it and extrude it into pellets, and then conduct calcination treatment to obtain the activated carbon-based desulfurization catalyst.

[0017] Preferably as the technical solution of the present invention, in step (1), the preparation of the modified activated carbon includes the following steps: Wash and dry the rice husk and then conduct carbonization treatment. After cooling, grind it to 80 - 150 meshes; then immerse it in potassium hydroxide solution for 8 - 24 h, and then conduct microwave activation treatment under a nitrogen flow rate of 0.1 - 0.5 L / min. After the treatment is completed, conduct washing and drying treatment in sequence to obtain the modified activated carbon;

[0018] Among them, the carbonization treatment temperature is 390 - 420 °C, and the carbonization time is 20 - 60 min;

[0019] Among them, the dosage ratio of rice husk to potassium hydroxide solution is 1:6 - 10 mL;

[0020] Among them, the concentration of potassium hydroxide is 40 - 60 wt%, the microwave power is 550 - 750 W, and the irradiation time is 20 - 40 min.

[0021] Preferably as the technical solution of the present invention, in step (2), the concentration of sodium hydroxide solution is 3 - 5.5 mol / L; the dosage ratio of attapulgite to sodium hydroxide solution is 1 g:5 - 8 mL, the stirring treatment temperature during the preparation of the pre-modified attapulgite is 75 - 90 °C, and the stirring treatment time is 1 - 4 h; the mass ratio of the pre-modified attapulgite, water, and polyethylene glycol is 1:0.75 - 0.9:0.015 - 0.025; the calcination time is 330 - 380 °C, and the calcination temperature is 3 - 8 h;

[0022] The grinding and sieving mesh number is 100 - 150 meshes.

[0023] As a preference of the technical solution of the present invention, in step (3), grind to a mesh number of 80 - 120 meshes; the calcination temperature is 550 - 660 °C, and the calcination treatment time is 5 - 8 h;

[0024] The concentration of the hydrochloric acid solution is 1 - 1.2 mol / L, and the dosage ratio of fly ash to the hydrochloric acid solution is 1 g : 6 - 10 mL; the treatment temperature of fly ash in the hydrochloric acid solution is 75 - 85 °C, and the treatment time is 1 - 4 h.

[0025] As a preference of the technical solution of the present invention, in step (4), the mass ratio of modified activated carbon, modified attapulgite, pretreated fly ash, and water is 1 : 2 - 3 : 1.2 - 1.5 : 8 - 12; the stirring treatment temperature is 25 - 35 °C, and the treatment time is 1 - 4 h.

[0026] As a preference of the technical solution of the present invention, in step (5), the concentration of the ferric nitrate solution is 1 - 1.5 mol / L, and the mass ratio of the composite support to the ferric nitrate solution is 1 : 4 - 5; the calcination temperature is 500 - 530 °C, and the calcination treatment time is 0.5 - 4 h.

[0027] As a preference of the technical solution of the present invention, in step (6), the concentration of the manganese nitrate solution is 0.8 - 1.2 mol / L, and the mass ratio of the primary loaded catalyst to the manganese nitrate solution is 1 : 2.5 - 4.5, the calcination temperature is 590 - 620 °C, and the calcination treatment time is 0.5 - 4 h.

[0028] As a preference of the technical solution of the present invention, in step (7), the concentration of the cerium nitrate solution is 0.5 - 0.8 mol / L, and the mass ratio of the secondary loaded catalyst to the cerium nitrate solution is 1 : 1 - 2; the calcination temperature is 490 - 520 °C, and the calcination treatment time is 0.5 - 4 h.

[0029] In the second aspect, the present invention also claims the activated carbon - based desulfurization catalyst prepared by the above - mentioned method.

[0030] In the third aspect, the present invention also provides the application of the above - mentioned activated carbon - based desulfurization catalyst in the desulfurization field.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) An activated carbon - based desulfurization catalyst provided by the present invention uses activated carbon, attapulgite, and fly ash as raw materials for the composite support. By loading iron, manganese, and cerium, the desulfurization capacity of the catalyst is high, the desulfurization precision is high, and the regenerated desulfurization performance is excellent; the raw materials are common, especially the use of fly ash and rice husk has the significance of ecological protection.

[0033] (2) The preparation method of the activated carbon-based desulfurization catalyst provided by the present invention mainly adopts impregnation, and the preparation process is simple.

[0034] (3) For the activated carbon-based desulfurization catalyst provided by the present invention, it is proposed to use activated carbon, attapulgite, and fly ash as raw materials to prepare three carriers. Among them, the activated carbon is prepared from rice husk, an agricultural and forestry by-product, through carbonization and activation treatment. During the activation treatment, microwave activation is used to improve the structure of the activated carbon and enhance its activity, which not only improves the compounding efficiency with fly ash and attapulgite but also enhances the loading effect of the activated carbon itself and the final desulfurization effect.

[0035] During the preparation of modified attapulgite, sodium hydroxide is first used for modification, and then polyethylene glycol is used for modification. The purpose of such treatment is as follows: Alkali modification with sodium hydroxide increases the interlayer distance of attapulgite on the one hand through cation exchange, and on the other hand, more silanol groups will be exposed after aluminum ions are replaced, which is beneficial to improving the adsorption of polyethylene glycol and the subsequent modification effect of polyethylene glycol; the introduction of polyethylene glycol is beneficial to further enriching the pore size distribution of attapulgite and improving its compounding efficiency with fly ash and attapulgite.

[0036] During the preparation of modified fly ash, a process method of first high-temperature calcination and then hydrochloric acid treatment is adopted. Among them, high-temperature calcination is beneficial to partially destroying the structure of fly ash, enriching the structure, and improving the reaction activity, which is beneficial to subsequent carrier compounding; further hydrochloric acid can further increase the specific surface area of fly ash, which is beneficial to the loading of subsequent active components.

[0037] (4) For the activated carbon-based desulfurization catalyst provided by the present invention, the applicant proposes to compound modified activated carbon, modified attapulgite, and pre-modified fly ash into a ternary composite carrier. Compared with single carriers or binary composite carriers, its desulfurization effect has been significantly improved. The reason may be that the multi-level pore structure compounding improves the loading efficiency of iron, manganese, and cerium on the one hand, and thus improves the desulfurization effect; on the other hand, the stability of the multi-level compounding of the composite carrier ensures the improvement of the recycling performance of the desulfurizer.

[0038] (5) For the composite usage amount of the modified activated carbon, modified attapulgite, and pre-modified fly ash provided by the present invention, the applicant has repeatedly optimized it. Finally, it is selected that the usage amount of modified attapulgite is the largest, followed by pre-modified fly ash, and the usage amount of modified activated carbon is the smallest. Such a usage combination can make the prepared desulfurizer have the best effect. The reason is that: the modified attapulgite with the largest usage amount can provide the basic framework of the carrier, ensuring the high-temperature resistance and impact resistance of the desulfurization catalyst, and at the same time ensuring the high loading of metal active components based on its excellent adsorption; the composition of fly ash is relatively complex. After calcination and acid treatment, acidic sites may be generated, which helps to increase the acidic sites of the desulfurizer. At the same time, the potential metal content in fly ash is beneficial to providing potential active sites and improving the desulfurization accuracy; activated carbon has rich active sites and high sulfur capacity, and a small amount of use can ensure the basic performance of the desulfurizer.

[0039] (6) For the activated carbon-based desulfurization catalyst provided by the present invention, the composite use of iron, manganese, and cerium has a better desulfurization effect compared with the combination of two-element active components.

[0040] In short, the desulfurization catalyst provided by the present invention can achieve a very good desulfurization effect, and has good recycling performance, and has great potential for industrial use. Detailed Embodiments

[0041] The embodiments of the present invention are described in detail below. All embodiments are exemplary and are intended to explain the present invention and should not be construed as a limitation to the present invention.

[0042] Unless otherwise specified, the chemical reagents and production equipment involved in the present invention are all purchased from the market.

[0043] Among them, attapulgite is purchased from Shanghai Yuanye Bio-Technology Co., Ltd., with a particle size of about 150 mesh.

[0044] Polyethylene glycol is PEG-400, and the manufacturer is Dow Chemical.

[0045] Fly ash is purchased from Yiran Mineral Products Processing Factory, Lingshou County, Hebei Province, and the total mass fraction of Al2O3 and SiO2 ≥ 80%.

[0046] At the same time, it should be noted that the treatment processes such as filtration, drying, and impregnation mentioned in the present invention are all mature processes or equipment, and the present invention does not specifically describe them, and it is subject to the implementation by those skilled in the art. Example 1

[0047] A preparation method of a high-sulfur-capacity and regenerable activated carbon-based desulfurization catalyst includes the following steps:

[0048] (1)Preparation of modified activated carbon: Wash and dry rice husks, then carbonize them (400 °C, 30 min). After cooling, grind them to 100 mesh. Subsequently, immerse them in a 50 wt% potassium hydroxide solution for 12 h, and then perform microwave activation treatment (650 W, irradiation time 25 min) under a nitrogen flow rate of 0.25 L / min. After the treatment is completed, wash and dry them in sequence to obtain modified activated carbon. Among them, the dosage ratio of rice husks to potassium hydroxide solution is 1:8 mL;

[0049] (2)Preparation of modified attapulgite: Wash attapulgite with water and then dry it. Subsequently, according to the dosage ratio of 1 g:7 mL, add the dried attapulgite to a 5 mol / L sodium hydroxide solution, stir (85 °C, 2 h), then wash it to neutrality and dry it to obtain pre-modified attapulgite. Subsequently, add the obtained pre-modified attapulgite to water, stir evenly, then add polyethylene glycol, stir evenly again, and then perform drying and calcination treatment (350 °C, 4.5 h). After the calcination is completed, grind and sieve it through 150 mesh to obtain modified attapulgite. Among them, the mass ratio of pre-modified attapulgite, water, and polyethylene glycol is 1:0.8:0.02;

[0050] (3)Preparation of pretreated fly ash: Grind fly ash to 100 mesh and then perform calcination treatment (590 °C, 6 h). After the treatment is completed, add it to a 1.1 mol / L hydrochloric acid solution for further treatment (80 °C, 2 h). After the treatment is completed, filter, wash, and dry it in sequence to obtain pretreated fly ash;

[0051] (4)Preparation of composite support: According to the mass ratio of 1:2.5:1.25:10, add the modified activated carbon prepared in step (1), the modified attapulgite prepared in step (2), and the pretreated fly ash prepared in step (3) to water in sequence, stir (30 °C, 2.5 h), and then perform centrifugation and drying treatment to obtain a composite support;

[0052] (5)Loading of iron: Add the composite support obtained in step (4) to a 1.25 mol / L iron nitrate solution, oscillate and immerse it (80 °C, 6 h), and then perform drying and roasting treatment (520 °C, 2 h) to obtain a once-loaded catalyst. Among them, the mass ratio of the composite support to the iron nitrate solution is 1:4.5;

[0053] (6)Loading of manganese: Add the once-loaded catalyst obtained in step (5) to a 1.0 mol / L manganese nitrate solution, oscillate and immerse it (80 °C, 5.5 h), and then perform drying and roasting treatment (600 °C, 2.5 h) to obtain a twice-loaded catalyst. Among them, the mass ratio of the once-loaded catalyst to the manganese nitrate solution is 1:3.5;

[0054] (7)Loading of cerium: The secondary-loaded catalyst obtained in step (6) was added to a 0.7 mol / L cerium nitrate solution, and oscillating impregnation was carried out (80 °C, 6 h). Then, after drying, it was extruded into pellets, and then subjected to calcination treatment (500 °C, 2 h) to obtain the activated carbon-based desulfurization catalyst. Example 2

[0055] A preparation method of a high sulfur capacity and regenerable activated carbon-based desulfurization catalyst includes the following steps:

[0056] (1)Preparation of modified activated carbon: Rice husks were washed, dried, and then carbonized (390 °C, 35 min). After cooling, they were ground to 100 mesh. Subsequently, they were immersed in a 50 wt% potassium hydroxide solution for 16 h, and then subjected to microwave activation treatment (650 W, irradiation time 25 min) under a nitrogen flow rate of 0.3 L / min. After the treatment was completed, they were successively washed and dried to obtain modified activated carbon. Among them, the dosage ratio of rice husks to the potassium hydroxide solution was 1:9 mL;

[0057] (2)Preparation of modified attapulgite: Attapulgite was washed with water and then dried. Subsequently, according to the dosage ratio of 1 g:8 mL, the dried attapulgite was added to a 4.5 mol / L sodium hydroxide solution, and after stirring treatment (85 °C, 2 h), it was washed to neutrality and dried to obtain pre-modified attapulgite. Subsequently, the obtained pre-modified attapulgite was added to water, stirred evenly, then polyethylene glycol was added, and after stirring evenly again, it was dried and calcined (345 °C, 5 h). After the calcination was completed, it was ground and sieved through 150 mesh to obtain modified attapulgite. Among them, the mass ratio of pre-modified attapulgite, water, and polyethylene glycol was 1:0.8:0.025;

[0058] (3)Preparation of pretreated fly ash: Fly ash was ground to 100 mesh and then calcined (590 °C, 6 h). After the treatment was completed, it was added to a 1.15 mol / L hydrochloric acid solution for further treatment (80 °C, 2 h). After the treatment was completed, it was filtered, washed, and dried to obtain pretreated fly ash;

[0059] (4)Preparation of composite support: According to the mass ratio of 1:2.5:1.3:10, the modified activated carbon prepared in step (1), the modified attapulgite prepared in step (2), and the pretreated fly ash prepared in step (3) were successively added to water, stirred (35 °C, 2.5 h), and then centrifuged and dried to obtain a composite support;

[0060] (5)Loading of iron: The composite support obtained in step (4) was added to a 1.3 mol / L iron nitrate solution, and oscillating impregnation was carried out (80 °C, 6 h). Subsequently, it was dried and calcined (525 °C, 2 h) to obtain a primary-loaded catalyst. Among them, the mass ratio of the composite support to the iron nitrate solution was 1:4.5;

[0061] (6) Loading of manganese: The catalyst with the first loading obtained in step (5) was added to a 1.0 mol / L manganese nitrate solution, and impregnated by shaking (80 °C, 6 h), followed by drying and calcination (600 °C, 2.5 h) to obtain the catalyst with the second loading; wherein, the mass ratio of the catalyst with the first loading to the manganese nitrate solution was 1:3;

[0062] (7) Loading of cerium: The catalyst with the second loading obtained in step (6) was added to a 0.7 mol / L cerium nitrate solution, and impregnated by shaking (80 °C, 5 h), then dried and extruded into pellets, and then calcined (500 °C, 2 h) to obtain the activated carbon-based desulfurization catalyst. Example 3

[0063] A preparation method of a high sulfur capacity and regenerable activated carbon-based desulfurization catalyst includes the following steps:

[0064] (1) Preparation of modified activated carbon: The rice husks were washed, dried and then carbonized (405 °C, 25 min), cooled and ground to 100 mesh; then placed in a 45 wt% potassium hydroxide solution and impregnated for 10 h, and then microwave-activated (600 W, irradiation time 30 min) under a nitrogen flow rate of 0.3 L / min. After the treatment was completed, it was successively washed and dried to obtain the modified activated carbon; wherein, the dosage ratio of the rice husks to the potassium hydroxide solution was 1:8 mL;

[0065] (2) Preparation of modified attapulgite: The attapulgite was washed with water and then dried. Subsequently, according to the dosage ratio of 1 g:8 mL, the dried attapulgite was added to a 4.8 mol / L sodium hydroxide solution, stirred (85 °C, 2 h), washed to neutrality and dried to obtain the pre-modified attapulgite; then the obtained pre-modified attapulgite was added to water, stirred evenly, polyethylene glycol was added, stirred evenly again, and then dried and calcined (350 °C, 4.5 h); after the calcination was completed, it was ground and sieved through 150 mesh to obtain the modified attapulgite; wherein, the mass ratio of the pre-modified attapulgite, water and polyethylene glycol was 1:0.85:0.02;

[0066] (3) Preparation of pretreated fly ash: The fly ash was ground to 100 mesh and then calcined (590 °C, 6 h). After the treatment was completed, it was added to a 1.05 mol / L hydrochloric acid solution for further treatment (80 °C, 2 h); after the treatment was completed, it was filtered, washed and dried to obtain the pretreated fly ash;

[0067] (4) Preparation of composite support: According to the mass ratio of 1:2.8:1.25:10, the modified activated carbon obtained in step (1), the modified attapulgite obtained in step (2), and the pretreated fly ash obtained in step (3) are successively added to water. After stirring (30°C, 3 h), it is centrifuged and dried to obtain the composite support;

[0068] (5) Loading of iron: The composite support obtained in step (4) is added to a 1.3 mol / L iron nitrate solution, and oscillated and impregnated (80°C, 6 h). Subsequently, it is dried and calcined (510°C, 2.5 h) to obtain the once-loaded catalyst; wherein, the mass ratio of the composite support to the iron nitrate solution is 1:4.5;

[0069] (6) Loading of manganese: The once-loaded catalyst obtained in step (5) is added to a 1.1 mol / L manganese nitrate solution, and oscillated and impregnated (80°C, 5.5 h). Subsequently, it is dried and calcined (595°C, 3 h) to obtain the twice-loaded catalyst; wherein, the mass ratio of the once-loaded catalyst to the manganese nitrate solution is 1:3.5;

[0070] (7) Loading of cerium: The twice-loaded catalyst obtained in step (6) is added to a 0.75 mol / L cerium nitrate solution, and oscillated and impregnated (80°C, 6 h). Then it is dried and extruded into pellets, and then calcined (500°C, 2 h) to obtain the activated carbon-based desulfurization catalyst. Comparative Example 1

[0071] Compared with Example 1, Comparative Example 1 omits the polyethylene glycol modification of attapulgite, and the rest are the same. Specifically, in this comparative example, a preparation method of a high sulfur capacity and regenerable activated carbon-based desulfurization catalyst is provided, including the following steps:

[0072] (1) Preparation of modified activated carbon: The rice husks are washed, dried and then carbonized (400°C, 30 min), cooled and ground to 100 meshes; then placed in a 50 wt% potassium hydroxide solution and impregnated for 12 h, and then microwave-activated (650 W, irradiation time 25 min) under a nitrogen flow rate of 0.25 L / min. After the treatment is completed, it is washed and dried successively to obtain the modified activated carbon; wherein, the dosage ratio of rice husks to the potassium hydroxide solution is 1:8 mL;

[0073] (2) Preparation of modified attapulgite: The attapulgite is washed with water and then dried. Subsequently, according to the dosage ratio of 1 g:7 mL, the dried attapulgite is added to a 5 mol / L sodium hydroxide solution, stirred (85°C, 2 h), washed to neutral and dried, ground and sieved through 150 meshes to obtain the modified attapulgite;

[0074] (3) Preparation of pretreated fly ash: The fly ash was ground to 100 mesh and then calcined (590 °C, 6 h). After the treatment was completed, it was added to a 1.1 mol / L hydrochloric acid solution for further treatment (80 °C, 2 h). After the treatment was completed, it was filtered, washed, and dried to obtain pretreated fly ash;

[0075] (4) Preparation of the composite support: According to the mass ratio of 1:2.5:1.25:10, the modified activated carbon prepared in step (1), the modified attapulgite prepared in step (2), and the pretreated fly ash prepared in step (3) were successively added to water. After stirring (30 °C, 2.5 h), it was centrifuged and dried to obtain the composite support;

[0076] (5) Loading of iron: The composite support obtained in step (4) was added to a 1.25 mol / L iron nitrate solution, and oscillated and impregnated (80 °C, 6 h). Subsequently, it was dried and calcined (520 °C, 2 h) to obtain a once-loaded catalyst; among them, the mass ratio of the composite support to the iron nitrate solution was 1:4.5;

[0077] (6) Loading of manganese: The once-loaded catalyst obtained in step (5) was added to a 1.0 mol / L manganese nitrate solution, and oscillated and impregnated (80 °C, 5.5 h). Subsequently, it was dried and calcined (600 °C, 2.5 h) to obtain a twice-loaded catalyst; among them, the mass ratio of the once-loaded catalyst to the manganese nitrate solution was 1:3.5;

[0078] (7) Loading of cerium: The twice-loaded catalyst obtained in step (6) was added to a 0.7 mol / L cerium nitrate solution, and oscillated and impregnated (80 °C, 6 h). Then it was dried and extruded into pellets, and then calcined (500 °C, 2 h) to obtain the activated carbon-based desulfurization catalyst. Comparative Example 2

[0079] Compared with Example 1, the calcination treatment of fly ash was omitted in Comparative Example 2, and the rest were the same. Specifically, in this comparative example, a preparation method of a high sulfur capacity and regenerable activated carbon-based desulfurization catalyst is provided, including the following steps:

[0080] (1) Preparation of modified activated carbon: The rice husks were washed, dried, and then carbonized (400 °C, 30 min). After cooling, they were ground to 100 mesh. Subsequently, they were immersed in a 50 wt% potassium hydroxide solution for 12 h, and then microwave-activated (650 W, irradiation time 25 min) under a nitrogen flow rate of 0.25 L / min. After the treatment was completed, they were washed and dried successively to obtain modified activated carbon; among them, the dosage ratio of rice husks to the potassium hydroxide solution was 1:8 mL;

[0081] (2) Preparation of modified attapulgite: Wash the attapulgite with water and then dry it. Subsequently, add the dried attapulgite to a 5 mol / L sodium hydroxide solution according to the dosage ratio of 1 g:7 mL, stir (at 85 °C for 2 h), wash until neutral and dry to obtain pre-modified attapulgite. Then add the obtained pre-modified attapulgite to water, stir evenly, add polyethylene glycol, stir evenly again, and then perform drying and calcination treatment (at 350 °C for 4.5 h). After calcination, grind and screen through 150 meshes to obtain modified attapulgite. Among them, the mass ratio of pre-modified attapulgite, water, and polyethylene glycol is 1:0.8:0.02;

[0082] (3) Preparation of pretreated fly ash: Grind the fly ash to 100 meshes and then add it to a 1.1 mol / L hydrochloric acid solution for treatment (at 80 °C for 2 h). After treatment, filter, wash, and dry to obtain pretreated fly ash;

[0083] (4) Preparation of composite support: Add the modified activated carbon prepared in step (1), the modified attapulgite prepared in step (2), and the pretreated fly ash prepared in step (3) to water in sequence according to the mass ratio of 1:2.5:1.25:10, stir (at 30 °C for 2.5 h), and then perform centrifugation and drying treatment to obtain a composite support;

[0084] (5) Loading of iron: Add the composite support obtained in step (4) to a 1.25 mol / L iron nitrate solution, oscillate and impregnate (at 80 °C for 6 h), and then perform drying and calcination treatment (at 520 °C for 2 h) to obtain a once-loaded catalyst. Among them, the mass ratio of the composite support to the iron nitrate solution is 1:4.5;

[0085] (6) Loading of manganese: Add the once-loaded catalyst obtained in step (5) to a 1.0 mol / L manganese nitrate solution, oscillate and impregnate (at 80 °C for 5.5 h), and then perform drying and calcination treatment (at 600 °C for 2.5 h) to obtain a twice-loaded catalyst. Among them, the mass ratio of the once-loaded catalyst to the manganese nitrate solution is 1:3.5;

[0086] (7) Loading of cerium: Add the twice-loaded catalyst obtained in step (6) to a 0.7 mol / L cerium nitrate solution, oscillate and impregnate (at 80 °C for 6 h), then dry and extrude into pellets, and then perform calcination treatment (at 500 °C for 2 h) to obtain the activated carbon-based desulfurization catalyst. Comparative Example 3

[0087] Compared with Example 1, the use of modified activated carbon is omitted in Comparative Example 3, and the rest are the same. Specifically, in this comparative example, a preparation method of a high sulfur capacity and regenerable activated carbon-based desulfurization catalyst is provided, including the following steps:

[0088] (1)Preparation of modified attapulgite: Wash the attapulgite with water and then dry it. Subsequently, add the dried attapulgite to a 5 mol / L sodium hydroxide solution according to a dosage ratio of 1 g:7 mL, stir (at 85 °C for 2 h), wash until neutral, and dry to obtain pre-modified attapulgite. Then add the obtained pre-modified attapulgite to water, stir evenly, add polyethylene glycol, stir evenly again, and then perform drying and calcination treatment (at 350 °C for 4.5 h). After calcination, grind and sieve through 150 meshes to obtain modified attapulgite. Among them, the mass ratio of pre-modified attapulgite, water, and polyethylene glycol is 1:0.8:0.02;

[0089] (2)Preparation of pretreated fly ash: Grind the fly ash to 100 meshes and then perform calcination treatment (at 590 °C for 6 h). After the treatment is completed, add it to a 1.1 mol / L hydrochloric acid solution for further treatment (at 80 °C for 2 h). After the treatment is completed, filter, wash, and dry to obtain pretreated fly ash;

[0090] (3)Preparation of composite support: Add the modified attapulgite prepared in step (1) and the pretreated fly ash prepared in step (2) to water in a mass ratio of 2.5:1.25:10, stir (at 30 °C for 2.5 h), and then perform centrifugation and drying to obtain a composite support;

[0091] (4)Loading of iron: Add the composite support obtained in step (3) to a 1.25 mol / L iron nitrate solution, oscillate and impregnate (at 80 °C for 6 h), and then perform drying and calcination treatment (at 520 °C for 2 h) to obtain a once-loaded catalyst. Among them, the mass ratio of the composite support to the iron nitrate solution is 1:4.5;

[0092] (5)Loading of manganese: Add the once-loaded catalyst obtained in step (4) to a 1.0 mol / L manganese nitrate solution, oscillate and impregnate (at 80 °C for 5.5 h), and then perform drying and calcination treatment (at 600 °C for 2.5 h) to obtain a twice-loaded catalyst. Among them, the mass ratio of the once-loaded catalyst to the manganese nitrate solution is 1:3.5;

[0093] (6)Loading of cerium: Add the twice-loaded catalyst obtained in step (5) to a 0.7 mol / L cerium nitrate solution, oscillate and impregnate (at 80 °C for 6 h), then dry and extrude into pellets, and then perform calcination treatment (at 500 °C for 2 h) to obtain the activated carbon-based desulfurization catalyst. Comparative Example 4

[0094] Compared with Example 1, the use of modified attapulgite is omitted in Comparative Example 4, and the rest are the same. Specifically, in this comparative example, a preparation method of a high sulfur capacity and regenerable activated carbon-based desulfurization catalyst is provided, including the following steps:

[0095] (1)Preparation of modified activated carbon: Wash and dry rice husks, then carbonize them (400 °C, 30 min), cool and grind to 100 mesh; then immerse them in a 50 wt% potassium hydroxide solution for 12 h, and then carry out microwave activation treatment (650 W, irradiation time 25 min) under a nitrogen flow rate of 0.25 L / min. After the treatment is completed, wash and dry them in sequence to obtain modified activated carbon; among them, the dosage ratio of rice husks to potassium hydroxide solution is 1:8 mL;

[0096] (2)Preparation of pretreated fly ash: Grind fly ash to 100 mesh and then carry out calcination treatment (590 °C, 6 h). After the treatment is completed, add it to a 1.1 mol / L hydrochloric acid solution for further treatment (80 °C, 2 h); after the treatment is completed, filter, wash and dry it to obtain pretreated fly ash;

[0097] (3)Preparation of composite support: According to the mass ratio of 1:1.25:10, add the modified activated carbon prepared in step (1) and the pretreated fly ash prepared in step (2) to water in sequence, stir (30 °C, 2.5 h), and then carry out centrifugation and drying treatment to obtain a composite support;

[0098] (4)Loading of iron: Add the composite support obtained in step (3) to a 1.25 mol / L iron nitrate solution, oscillate and immerse it (80 °C, 6 h), and then carry out drying and calcination treatment (520 °C, 2 h) to obtain a once-loaded catalyst; among them, the mass ratio of the composite support to the iron nitrate solution is 1:4.5;

[0099] (5)Loading of manganese: Add the once-loaded catalyst obtained in step (4) to a 1.0 mol / L manganese nitrate solution, oscillate and immerse it (80 °C, 5.5 h), and then carry out drying and calcination treatment (600 °C, 2.5 h) to obtain a twice-loaded catalyst; among them, the mass ratio of the once-loaded catalyst to the manganese nitrate solution is 1:3.5;

[0100] (6)Loading of cerium: Add the twice-loaded catalyst obtained in step (5) to a 0.7 mol / L cerium nitrate solution, oscillate and immerse it (80 °C, 6 h), then dry and extrude it into pellets, and then carry out calcination treatment (500 °C, 2 h) to obtain the activated carbon-based desulfurization catalyst. Comparative Example 5

[0101] Compared with Example 1, the use of pretreated fly ash is omitted in Comparative Example 5, and the rest are the same. Specifically, in this comparative example, a preparation method of a high sulfur capacity and regenerable activated carbon-based desulfurization catalyst is provided, including the following steps:

[0102] (1)Preparation of modified activated carbon: Wash and dry rice husks, then carbonize them (400 °C, 30 min), cool and grind to 100 mesh; then immerse them in a 50 wt% potassium hydroxide solution for 12 h, and then perform microwave activation treatment (650 W, irradiation time 25 min) under a nitrogen flow rate of 0.25 L / min. After the treatment is completed, wash and dry them in sequence to obtain modified activated carbon; among them, the dosage ratio of rice husks to potassium hydroxide solution is 1:8 mL;

[0103] (2)Preparation of modified attapulgite: Wash attapulgite with water and then dry it. Subsequently, add the dried attapulgite to a 5 mol / L sodium hydroxide solution according to the dosage ratio of 1 g:7 mL, stir (85 °C, 2 h), wash to neutrality and dry to obtain pre-modified attapulgite; then add the obtained pre-modified attapulgite to water, stir evenly, add polyethylene glycol, stir evenly again, and then perform drying and calcination treatment (350 °C, 4.5 h); after the calcination is completed, grind and sieve through 150 mesh to obtain modified attapulgite; among them, the mass ratio of pre-modified attapulgite, water, and polyethylene glycol is 1:0.8:0.02;

[0104] (3)Preparation of composite support: Add the modified activated carbon prepared in step (1) and the modified attapulgite prepared in step (2) to water in sequence according to the mass ratio of 1:2.5:10, stir (30 °C, 2.5 h), and then perform centrifugation and drying treatment to obtain a composite support;

[0105] (4)Loading of iron: Add the composite support obtained in step (3) to a 1.25 mol / L iron nitrate solution, oscillate and immerse (80 °C, 6 h), and then perform drying and calcination treatment (520 °C, 2 h) to obtain a once-loaded catalyst; among them, the mass ratio of the composite support to the iron nitrate solution is 1:4.5;

[0106] (5)Loading of manganese: Add the once-loaded catalyst obtained in step (4) to a 1.0 mol / L manganese nitrate solution, oscillate and immerse (80 °C, 5.5 h), and then perform drying and calcination treatment (600 °C, 2.5 h) to obtain a twice-loaded catalyst; among them, the mass ratio of the once-loaded catalyst to the manganese nitrate solution is 1:3.5;

[0107] (6)Loading of cerium: Add the twice-loaded catalyst obtained in step (5) to a 0.7 mol / L cerium nitrate solution, oscillate and immerse (80 °C, 6 h), then dry and extrude into pellets, and then perform calcination treatment (500 °C, 2 h) to obtain the activated carbon-based desulfurization catalyst.

[0108] The performance of the activated carbon-based desulfurization catalysts prepared in Example 1 and Comparative Examples 1-5 was tested. The specific method is as follows: In a fixed bed, 3 g of each desulfurizer obtained in Example 1 and Comparative Examples 1-3 was loaded. Under normal pressure, the temperature was raised to 200 °C, and a mixed gas (hydrogen sulfide 2000 ppm, methanethiol 600 ppm, hydrogen content 25%, water vapor content 8%, and the balance being nitrogen) was introduced at a space velocity of 3500 h -1 for desulfurization. The desulfurizer deactivated by breakthrough was regenerated by washing with water, then ultrasonically vibrated in deionized water for 15 min, dried, and reserved. After 60 cycles of use, the desulfurization performance was tested again. The test results are shown in Tables 1 and 2. Among them, the desulfurization accuracy refers to the sulfur content of the desulfurized tail gas before the sulfur content penetrates during the desulfurization process; the breakthrough sulfur capacity refers to the capacity of sulfur that can be absorbed by a unit volume of desulfurizer to ensure the process purification index; the sulfur content of the mixed gas after desulfurization was detected according to GB / T 28727-2012.

[0109] Table 1 Initial desulfurization results

[0110]

[0111] Table 2 Desulfurization results after 60 cycles

[0112]

[0113] As can be seen from Table 1, the desulfurizer provided by the present invention has a high sulfur capacity and desulfurization accuracy; as can be seen from Table 2, after 60 cycles of use, a high sulfur capacity is still maintained, indicating good performance in cyclic regeneration and use.

[0114] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of a high sulfur capacity and regenerable activated carbon-based desulfurization catalyst, characterized in that, It includes the following steps: (1) Preparation of modified activated carbon; (2) Preparation of modified attapulgite: Wash the attapulgite with water and then dry it. Subsequently, add the dried attapulgite into a sodium hydroxide solution, stir it, wash it until neutral, and dry it to obtain pre-modified attapulgite; Subsequently, add the obtained pre-modified attapulgite into water, stir evenly, then add polyethylene glycol, stir evenly again, and then perform drying and calcination treatments; After the calcination is completed, perform grinding and sieving treatments to obtain modified attapulgite; (3) Preparation of pretreated fly ash: Grind the fly ash and then perform calcination treatment. After the treatment is completed, add it into a hydrochloric acid solution for further treatment; After the treatment is completed, perform filtration, washing, and drying treatments to obtain pretreated fly ash; (4) Preparation of composite support: Sequentially add the modified activated carbon prepared in step (1), the modified attapulgite prepared in step (2), and the pretreated fly ash prepared in step (3) into water, stir, and then perform centrifugation and drying treatments to obtain a composite support; (5) Loading of iron: Add the composite support obtained in step (4) into a ferric nitrate solution, oscillate and impregnate it, and then perform drying and roasting treatments to obtain a once-loaded catalyst; (6) Loading of manganese: Add the once-loaded catalyst obtained in step (5) into a manganese nitrate solution, oscillate and impregnate it, and then perform drying and roasting treatments to obtain a twice-loaded catalyst; (7) Loading of cerium: Add the twice-loaded catalyst obtained in step (6) into a cerium nitrate solution, oscillate and impregnate it, then dry it and perform extrusion molding, and then perform roasting treatment to obtain an activated carbon-based desulfurization catalyst; Among them, in step (1), the preparation of the modified activated carbon includes the following steps: Wash and dry the rice husk, then perform carbonization treatment, cool it, and grind it to 80 - 150 meshes; Subsequently, immerse it in a potassium hydroxide solution for 8 - 24 h, and then perform microwave activation treatment under a nitrogen flow rate of 0.1 - 0.5 L / min. After the treatment is completed, perform washing and drying treatments in sequence to obtain modified activated carbon; Among them, the carbonization treatment temperature is 390 - 420 °C, and the carbonization time is 20 - 60 min; Among them, the dosage ratio of rice husk to potassium hydroxide solution is 1:6 - 10 mL; Among them, the concentration of potassium hydroxide is 40 - 60 wt%, the microwave power is 550 - 750 W, and the irradiation time is 20 - 40 min; Among them, in step (2), the concentration of the sodium hydroxide solution is 3 - 5.5 mol / L; the dosage ratio of attapulgite to sodium hydroxide solution is 1 g:5 - 8 mL, the stirring treatment temperature during the preparation process of the pre-modified attapulgite is 75 - 90 °C, and the stirring treatment time is 1 - 4 h; the mass ratio of pre-modified attapulgite, water, and polyethylene glycol is 1:0.75 - 0.9:0.015 - 0.025; the calcination time is 330 - 380 °C, and the calcination temperature is 3 - 8 h; The grinding and sieving mesh number is 100 - 150 meshes; Among them, in step (3), grind it to 80 - 120 meshes; the calcination temperature is 550 - 660 °C, and the calcination treatment time is 5 - 8 h; The concentration of the hydrochloric acid solution is 1 to 1.2 mol / L, and the dosage ratio of fly ash to the hydrochloric acid solution is 1 g: 6 to 10 mL; the temperature for treating fly ash in the hydrochloric acid solution is 75 to 85 °C, and the treatment time is 1 to 4 h; Among them, in step (4), the mass ratio of the modified activated carbon, the modified attapulgite, the pretreated fly ash, and water is 1: 2 to 3: 1.2 to 1.5: 8 to 12; the stirring treatment temperature is 25 to 35 °C, and the treatment time is 1 to 4 h; Among them, in step (5), the concentration of the iron nitrate solution is 1 to 1.5 mol / L, and the mass ratio of the composite support to the iron nitrate solution is 1: 4 to 5; the calcination temperature is 500 to 530 °C, and the calcination treatment time is 0.5 to 4 h.

2. The preparation method according to claim 1, characterized in that In step (6), the concentration of the manganese nitrate solution is 0.8 to 1.2 mol / L, and the mass ratio of the primary loaded catalyst to the manganese nitrate solution is 1: 2.5 to 4.5, the calcination temperature is 590 to 620 °C, and the calcination treatment time is 0.5 to 4 h.

3. The preparation method according to claim 1, characterized in that, In step (7), the concentration of the cerium nitrate solution is 0.5 to 0.8 mol / L, and the mass ratio of the secondary loaded catalyst to the cerium nitrate solution is 1: 1 to 2; the calcination temperature is 490 to 520 °C, and the calcination treatment time is 0.5 to 4 h.

4. An activated carbon-based desulfurization catalyst prepared by the method according to any one of claims 1 to 3.

5. Use of the activated carbon-based desulfurization catalyst according to claim 4 in the field of desulfurization.

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