阅读说明：本技术 克劳斯尾气加氢脱硫催化剂及其制备方法、应用 (Claus tail gas hydrodesulfurization catalyst and preparation method and application thereof ) 是由 卓润生 刘兵 孙秋实 王钦 肖可 刘新生 于 2020-12-08 设计创作，主要内容包括：本发明公开了一种克劳斯尾气加氢脱硫催化剂及其制备方法、应用,克劳斯尾气加氢脱硫催化剂由复合载体和活性组分组成,其中按最终克劳斯尾气加氢脱硫催化剂的重量为基准,活性组分的重量百分比为6％～26％,复合载体由通过涂覆或通过表面沉积的方式负载于载体基体上的TiO-2和载体基体组成,所述复合载体为壳层结构,外层为TiO-2层,内层为载体基体；该克劳斯尾气加氢脱硫催化剂的比表面积：300～450m～2/g,孔容：0.5～0.7g/mL,孔径：6～20nm；利用涂覆或表面沉积的方法,将TiO-2在载体基体的表面形成一层0.1～0.5mm的保护层,TiO-2和载体基体是分布不均的,既不影响载体基体的性质同时也可以增强载体基体的水热稳定性以及活性组分的分散性,且具有TiO-2的高催化活性和良好的疏水性能。(The invention discloses a Claus tail gas hydrodesulfurization catalyst and a preparation method and application thereof, wherein the Claus tail gas hydrodesulfurization catalyst consists of a composite carrier and an active component, and the weight of the final Claus tail gas hydrodesulfurization catalyst isThe weight percentage of the active component is 6 percent to 26 percent by taking as a reference, the composite carrier is prepared by coating or carrying TiO on a carrier matrix in a surface deposition mode 2 And a carrier matrix, wherein the composite carrier is of a shell structure, and the outer layer is TiO 2 A layer, the inner layer being a carrier matrix; the specific surface area of the claus tail gas hydrodesulfurization catalyst is as follows: 300 to 450m 2 Per g, pore volume: 0.5-0.7 g/mL, pore diameter: 6-20 nm; by coating or surface deposition of TiO 2 Forming a 0.1-0.5 mm protective layer and TiO on the surface of the carrier substrate 2 The carrier matrix is not uniformly distributed, the hydrothermal stability of the carrier matrix and the dispersibility of active components can be enhanced without influencing the properties of the carrier matrix, and the TiO-based composite material has the advantages of 2 High catalytic activity and good hydrophobic properties.)

1. A Claus tail gas hydrodesulfurization catalyst is characterized by comprising a composite carrier and active components, wherein the weight percentage of the active components is 6-26% based on the weight of the final Claus tail gas hydrodesulfurization catalyst, and the composite carrier is TiO loaded on a carrier matrix in a coating or surface deposition manner₂And a carrier matrix, wherein the composite carrier is of a shell structure, and the outer layer is TiO₂A layer, the inner layer being a carrier matrix;

the active components are oxides of VIB group metal elements and oxides of VIII group metal elements;

the specific surface area of the claus tail gas hydrodesulfurization catalyst is as follows: 300 to 450m²Per g, pore volume: 0.5-0.7 g/mL, pore diameter: 6-20 nm.

2. The claus tail gas hydrodesulfurization catalyst of claim 1 wherein the TiO is₂The thickness of the layer is 0.1 to 0.5 mm.

3. The claus tail gas hydrodesulfurization catalyst of claim 1 wherein the support matrix is γ -Al₂O₃Or silica or molecular sieves.

4. The claus tail gas hydrodesulfurization catalyst of claim 1 wherein the support matrix has a specific surface area greater than 300m²Per g, pore volume is more than 0.50cm³(iv)/g, average crush strength greater than 50N/particle.

5. The claus tail gas hydrodesulfurization catalyst of claim 1 wherein the weight of the final claus tail gas hydrodesulfurization catalyst is based on 5 to 20% by weight of the group VIB metal element oxide and 1 to 6% by weight of the group VIII metal element oxide.

6. A method of preparing a Claus tail gas hydrodesulphurisation catalyst according to any of claims 1-5, comprising the steps of:

preparation of composite Carrier

Coating the surface of the dried carrier substrate with TiO₂The powder or surface deposit being able to be hydrolysed or calcined to produce TiO₂Drying the titanium-containing compound solution for 6-12 hours at a drying temperature of 100-130 ℃, and then roasting at a roasting temperature of 450-550 ℃ for 2-8 hours to obtain a composite carrier;

preparation of the precursor

Soaking a solution containing VIB group metal elements on a composite carrier, and then drying for 6-12 hours at the drying temperature of 100-130 ℃, and then roasting at the temperature of 400-550 ℃ for 2-8 hours to obtain a precursor;

preparation of Claus tail gas hydrodesulfurization catalyst

And (2) soaking the solution containing the VIII group metal element on the precursor, drying for 6-12 hours at the drying temperature of 100-130 ℃, and roasting at the roasting temperature of 400-550 ℃ for 2-8 hours to obtain the Claus tail gas hydrodesulfurization catalyst.

7. The production method according to claim 6, wherein the volume ratio of the support substrate to the titanium-containing compound solution is 1.5: 1, depositing for 3-5 hours, wherein the temperature of a titanium-containing compound solution is 30-80 ℃; the volume ratio of the composite carrier to the solution containing the VIB group metal elements is 1:1, the dipping time is 1-2 hours, and the temperature of the solution containing the titanium compound is 20-30 ℃; the volume ratio of the solution containing the VIII group metal elements to the precursor is 1:1, the dipping time is 1-2 hours, and the temperature of the solution containing the VIII group metal elements is 2-30 ℃.

8. The method of claim 6, wherein the carrier matrix is prepared by: mixing aluminum hydroxide, a binder and a pore-expanding agent to obtain a mixture A, kneading the mixture A, forming a rolling ball, drying, and roasting at 450-650 ℃ to obtain the gamma-Al with the diameter of 1.9-2.5 mm₂O₃A spherical carrier.

9. The method of claim 8, wherein the carrier matrix is prepared by: the binder is one of nitric acid, acetic acid or oxalic acid; the pore-enlarging agent is one of polyethylene glycol, polyvinyl alcohol, sesbania powder or citric acid.

10. Use of a claus tail gas hydrodesulphurisation catalyst prepared by a process according to any one of claims 6 to 9 for the low temperature hydrodesulphurisation of a claus tail gas.

Technical Field

The invention belongs to the technical field of hydrodesulfurization, and particularly relates to a Claus tail gas hydrodesulfurization catalyst, a preparation method thereof and application of the Claus tail gas hydrodesulfurization catalyst prepared by the method in low-temperature hydrodesulfurization of Claus tail gas.

Background

Along with the strictness of environmental regulations, the requirements on the emission standards of sulfur-containing compounds in petroleum processing and petrochemical plants are more and more strict, in order to meet the environmental protection requirements and protect the environment, the total sulfur recovery rate of sulfur recovery devices of oil refineries and natural gas purification plants must reach more than 99.7%, and in order to meet the total sulfur recovery rate, the Claus tail gas is generally treated by adopting a reduction absorption method in the prior art, and the main process comprises the following steps: 1. carrying out hydrodesulfurization, and carrying out hydrogenation reaction on sulfides such as sulfur dioxide in the Claus tail gas to generate hydrogen sulfide; 2. organic sulfur compounds (COS and CS)₂) Hydrolyzing to hydrogen sulfide and carbon dioxide; 3. cooling the gas obtained after the hydro-hydrolysis to about 40 ℃ to remove most of water vapor; 4. the residual gas contacts with alcohol amine solution in an absorption tower, and is discharged after hydrogen sulfide is removed. In the reduction absorption method, the hydrogenation of sulfur dioxide and the hydrolysis of organic sulfide are key steps, and the main chemical reactions involved are as follows: SO (SO)₂+3H₂＝H₂S+2H₂O，COS+H₂O＝CO₂+H₂S，CS₂+2H₂O＝CO₂+2H₂And S. Catalysts are required to accelerate the reaction rate during the hydrogenation of sulfur dioxide and the hydrolysis reaction of organic sulfides. One of the key technologies influencing the total sulfur recovery rate of the process is to adopt a high-activity sulfur-containing compound hydrogenation catalyst which has good hydrothermal stability, excellent hydrogenation activity and COS and CS₂Excellent hydrolysis activity. In the preparation process of the hydrogenation catalyst, alumina is mainly selected as a carrier to impregnate Mo/W, Co/Ni and other active components and auxiliaries.

Japanese patent JP06127907 discloses a process and catalyst for hydrotreating a tail gas containing sulfur Claus, wherein two catalysts are loaded into the same reactor, and the upper part of the catalyst is MoO₃/TiO₂Catalyst of which MoO₃The content reaches 16 percent; the lower part is Co-Mo/Al₂O₃Catalyst of which MoO₃The content of (A) is up to 13%, and the CoO content is 3.5%. International Shell corporation's Chinese application CN1230134 discloses a sulfur tail gas hydrogenation catalyst which is SiO₂And Al₂O₃Is used as carrier, contains silicon oxide more than 25%, and Ni and Mo as active components, and is required to be mixed with COS and CS₂Hydrolytic agent (K/TiO)₂) The reactor is used together with the reactor. The above patent is to separate the hydrolysis catalyst and the hydrogenation catalyst, which not only complicates the loading and use of the catalysts, but also makes it difficult to make the service lives of the two types of catalysts uniform.

The Claus tail gas hydrogenation catalysts disclosed in Chinese patents CN1498674, CN1621134 and CN1936768 use Co and Mo as active components and SiO₂The modified alumina is used as a carrier. The Claus tail gas hydrogenation catalysts related to the patents have the use temperature of 280-330 ℃, higher temperature and larger energy consumption.

The low-temperature Claus tail gas hydrogenation catalyst disclosed in Chinese patents CN101108349A and CN101108348 comprises NiO 20-60%, chromium oxide, copper oxide and ferric oxide 0-5%, and the rest alumina, and is prepared by adopting coprecipitation technology, SO₂100% conversion toH₂The minimum reaction temperature of S is 210 ℃, and other sulfides such as CS₂The conversion temperatures of COS and S are not examined, and the Ni content of the catalyst in the patent is too high, so the cost is high.

In conclusion, in the current industrial catalyst production, gamma-Al₂O₃As a traditional hydrodesulfurization catalyst carrier, the catalyst has the function of an inert carrier and the promotion function on the formation of an active phase due to the large specific surface and a proper pore structure, and is widely applied to production. gamma-Al₂O₃The promotion effect of the carrier on the active phase is mainly to promote the transfer of electrons from the metal or sulfide to the active sites of the carrier lattice acceptors, the transfer of the electrons is beneficial to the adsorption of adsorbates, and the hydrogenation reaction of the metal or sulfide is promoted; but gamma-Al₂O₃The hydrothermal stability under the condition of high-temperature water vapor is poor.

Disclosure of Invention

For gamma-Al₂O₃The invention provides a Claus tail gas hydrodesulfurization catalyst, which has good hydrodesulfurization activity and excellent stability under the condition of water vapor.

The technical scheme of the invention is as follows: a Claus tail gas hydrodesulfurization catalyst comprises a composite carrier and an active component, wherein the weight percentage of the active component is 6-26% based on the weight of the final Claus tail gas hydrodesulfurization catalyst, the composite carrier is TiO loaded on a carrier substrate in a coating or surface deposition mode₂And a carrier matrix; the composite carrier is of a shell structure, and the outer layer is TiO₂A layer, the inner layer is a carrier matrix, and the outer layer is TiO₂The thickness of the layer is 0.1-0.5 mm; the pore volume of the Claus tail gas hydrodesulfurization catalyst should be greater than 0.5cm³A specific surface area of more than 300m²Per g, pore diameterThe pore volume between 7 nm and 9nm is more than 80%, the pore diameter is 6 nm to 10nm, and the appearance of the carrier is spherical with the diameter of 2 mm to 3 mm;

the active components are oxides of VIB group metal elements and oxides of VIII group metal elements.

The specific surface area of the claus tail gas hydrodesulfurization catalyst is as follows: 300 to 450m²Per g, pore volume: 0.5-0.7 g/mL, pore diameter: 6 to 20nm

Wherein, the carrier matrix is alumina, and the alumina accounts for 95-99.9% (m/m), preferably 96-98% (m/m) of the composite carrier; TiO 2₂0.1-5%, preferably 2-4% (m/m) of the composite carrier.

The active component is molybdenum oxide (tungsten oxide) accounting for 5-20% (m/m), preferably 9-15% (m/m) of the Claus tail gas hydrodesulfurization catalyst; cobalt oxide (nickel oxide) accounts for 1-6%, preferably 2-5% (m/m) of the claus tail gas hydrodesulfurization catalyst.

The claus tail gas hydrodesulfurization catalyst can be in the shape of a bar, a sphere, a clover and the like, and the diameter of the sphere is 0.5-10 mm.

The VIB group metal elements are tungsten and molybdenum, preferably molybdenum, and the solution of the VIB group metal elements is all water-soluble molybdenum salts such as ammonium molybdate, ammonium paramolybdate, sodium molybdate and the like; the VIII group metal elements are cobalt and nickel, preferably cobalt, and the solution of the VIII group metal elements is all water-soluble cobalt salts such as cobalt acetate, cobalt nitrate, cobalt chloride and the like and organic cobalt complexes.

Compared with the prior art, the invention has the beneficial effects that: by coating or surface deposition of TiO₂Forming a 0.1-0.5 mm protective layer and TiO on the surface of the carrier substrate₂The carrier matrix is not uniformly distributed, the hydrothermal stability of the carrier matrix and the dispersibility of active components can be enhanced without influencing the properties of the carrier matrix, and the TiO-based composite material has the advantages of₂High catalytic activity and good hydrophobic property, thereby improving the stability, catalytic activity and activity of the Claus tail gas hydrodesulfurization catalyst on COS and CS₂The hydrolysis performance of (2).

The invention also discloses a preparation method of the Claus tail gas hydrodesulfurization catalyst, which comprises the following steps:

1. selecting proper aluminum hydroxide, adding a binder and a pore-expanding agent in a proportioning amount, mixing, kneading the mixture, forming a rolling ball, drying the ball at 100-120 ℃ for 4-6 hours, and roasting the ball at 450-650 ℃ for 4-8 hours to obtain the gamma-Al with the diameter of 1.9-2.5 mm₂O₃A carrier precursor;

2. alumina with proper specific surface area and pore diameter is selected as a carrier matrix and TiO₂Powder, adhesive, mother ball of alumina, rolling ball shaping, TiO₂The thickness of the shell layer is controlled to be 0.1-0.5 mm, the shell layer is dried for 4-6 hours at the temperature of 100-120 ℃, and is roasted for 4-8 hours at the temperature of 450-600 ℃ to prepare the TiO-doped titanium dioxide₂Al of shell structure₂O₃And (3) a carrier.

Or selecting tetrabutyl titanate and isopropanol solution to slowly hydrolyze tetrabutyl titanate into TiO₂And depositing on the surface of the alumina ball to form a shell structure. Dissolving tetrabutyl titanate in isopropanol, placing alumina balls in isopropanol solution of tetrabutyl titanate, heating and stirring at 60-90 ℃ until the solution is completely volatilized, and controlling TiO by the amount of tetrabutyl titanate₂The thickness of the shell layer is 0.1-0.5 mm. Drying for 4-6 hours at the temperature of 100-120 ℃, roasting for 4-8 hours at the temperature of 450-600 ℃, and preparing the TiO-containing material₂Al of shell structure₂O₃And (3) a carrier.

Titanium dioxide is deposited on the surface of the alumina ball by selecting titanyl oxalate amine aqueous solution to form a shell layer structure. Placing the alumina ball in titanyl oxalate amine water solution, and controlling TiO quantity by titanyl oxalate amine quantity₂The thickness of the shell layer is 0.01-0.8 mm. Drying for 4-6 hours at the temperature of 100-120 ℃, roasting for 4-8 hours at the temperature of 450-600 ℃, and preparing the TiO-containing material₂Al of shell structure₂O₃And (3) a carrier.

And adopting an impregnation method to impregnate the ammonium molybdate aqueous solution and the cobalt acetate aqueous solution step by step. Firstly, soaking an ammonium paramolybdate aqueous solution on a composite carrier, drying for 4-8 hours at 100-120 ℃, and roasting for 3-6 hours at 450-600 ℃ to prepare a catalyst precursor containing molybdenum oxide. Cobalt acetate aqueous solution is dipped on a catalyst precursor containing oxidation, dried for 4-8 hours at the temperature of 100-120 ℃, and roasted for 3-6 hours at the temperature of 450-600 ℃ to prepare the grayish blue hydrodesulfurization catalyst.

Prevulcanisation of

And after the test device is qualified by testing density, carrying out conventional presulfurization on the catalyst. The vulcanization conditions are as follows: the pressure is 0.1MPa, and the volume space velocity is 1000h^-1The sulfidation gas used was 2% (v/v) H₂S and the balance being H₂And (4) mixing the gases. And (3) a vulcanization step: and (3) heating the nitrogen, adjusting the amount of the nitrogen according to the airspeed, heating to 220 ℃ at the speed of 30 ℃/h, cutting off the nitrogen, switching to the sulfuration gas, adjusting the amount of the nitrogen, continuously heating to 250 ℃, keeping the temperature for 5h, ending sulfuration after the balance of hydrogen sulfide at the inlet and the outlet of the reactor, and switching to the reaction gas.

Reaction gas composition:

CS₂:0.5％(v/v)，H₂O:20％(v/v)，SO₂:2.0％(v/v)，H₂8.0% (v/v), the balance being nitrogen. With 3H₂+SO₂→H₂S+2H₂O，CS₂+2H₂O→CO₂+2H₂S is an index reaction, and SO of the catalyst is considered₂Hydrogenation activity and CS₂The hydrolytic activity of (1). The gas volume space velocity is 1000h^-1The reaction temperature was 220 ℃ and 240 ℃.

Catalyst activity evaluation device:

the evaluation of the catalyst activity was carried out on a micro-reactor, which was made of a stainless steel tube with an inner diameter of 20mm and a reactor furnace using an electrical heating method. The loading of the catalyst is 3g, and inert ceramic balls with the same particle size are loaded on the upper part and the lower part of the catalyst for mixing and preheating. The inlet and outlet gases of the reactor were analyzed by a gas chromatograph, GC-2014, Shimadzu, at a column temperature of 120 ℃ and a thermal conductivity detector with hydrogen as carrier gas.

According to the above evaluation method, the reaction evaluation time was 8 hours, the results were measured every hour, and the analysis results were averaged.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are described in detail and completely, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Example 1

This example provides a catalyst suitable for low temperature claus tail gas hydrodesulfurization, which uses TiO₂The modified active alumina is a carrier, and molybdenum oxide and cobalt oxide are loaded on the composite titanium dioxide alumina carrier with a shell structure.

The specific preparation method of the carrier is as follows:

crushing 10g of sesbania powder and 20g of polyethylene glycol (the number average molecular weight is 1800) on a crusher to obtain powder with the particle size of less than 150 meshes, putting the powder into 600mL of deionized water, and stirring the materials into colloid at the temperature of 30-60 ℃ to obtain the spray adhesive. 10g of citric acid or acetic acid (concentration: 100%) and 15g of nitric acid (concentration: 71%) were mixed with the acid and stirred at 25 ℃ for 3 hours to obtain a kneaded gum. 500g of pseudo-boehmite powder is put into a kneading machine, the rotating speed is 30r/min, 150g of kneading gum is poured into the kneading machine for 1 hour in twice to obtain homogenized powder, the powder is put into a grinder to be ground, and then the powder with the particle size below 150 meshes is obtained. And (2) feeding the powder into a shaping machine to perform ball mixing, spraying spray glue while using high-efficiency spray, running for 3 hours, screening qualified balls with the diameter of 1.9-2.9 mm, shaping the qualified balls for 6 hours, aging for 8 hours, drying for 4 hours at 100 ℃, and roasting for 4 hours at 600 ℃ to obtain the spherical alumina balls A.

Rolling ball forming method-0.1 mm TiO₂Preparing a shell structure:

30g of titanium dioxide powder, 5g of polyvinyl alcohol are uniformly mixed, 20g of deionized water is placed into a small kneader to be kneaded for 1 hour to obtain homogenized powder, the powder is put into a crusher to be crushed, and then the powder is powder with the particle size below 150 meshes. Feeding the powder and the alumina balls A into a shaping machine for mixed ball manufacturing and forming, operating for 3h, screening qualified balls with the diameter of 2-3 mm, shaping the qualified balls for 4 h, aging for 8 h, drying for 4 h at 100 ℃, and roasting for 4 h at 550 ℃ to obtain 0.1mm TiO₂The alumina composite carrier with a shell structure.

The specific preparation method of the catalyst comprises the following steps:

100g of the above composite carrier was dried at 120 ℃ for 4 hours, and the water absorption rate of the carrier was determined to be 0.625mL of carrier/mL of water. Preparing 100mL of cobalt acetate aqueous solution, wherein the concentration of the cobalt acetate is 136g/L, and 100mL of ammonium molybdate aqueous solution, wherein the concentration of the ammonium molybdate is 170 g/L.

60mL of an ammonium paramolybdate aqueous solution was measured by a measuring cylinder, and 79g of the dried composite carrier was immersed in the mixed aqueous solution, and was aged for 4 hours after being immersed for 3 hours in molybdenum oxide at room temperature. The resultant solid was dried at 120 ℃ for 6 hours and then calcined at 500 ℃ for 4 hours to obtain a cobalt oxide-supported catalyst precursor.

The catalyst precursor loaded with cobalt oxide obtained in the above step was immersed in an aqueous solution of cobalt acetate, immersed and aged at room temperature for 3 hours in equal volume, and the aged solid was dried at 120 ℃ for 6 hours and then calcined at 500 ℃ for 4 hours to obtain a grayish blue catalyst sample of this example.

In this example, the catalyst was determined to have TiO content, based on the total weight of the catalyst taken as 100%₂The weight ratio of the active alumina composite carrier of the shell structure is 86.2%, the weight ratio of the cobalt oxide is 4.0%, and the weight ratio of the molybdenum oxide is 9.8%. Specific surface area 289m of the catalyst sample²(ii)/g, average crush strength 90N/particle.

Example 2:

the specific preparation method of the carrier is as follows:

the alumina rolling ball method was the same as in example 1.

Surface deposition method-0.1 mm TiO₂Preparing a shell structure:

200g of dried alumina spheres A were taken and placed in a reactor. 100g of tetrabutyltitanate solution and 200g of isopropanol were mixed and the mixture was poured into the surface deposition solution. And adding the surface deposition solution into a reactor containing an alumina carrier, wherein the reaction temperature is 80 ℃, and the stirring speed is 40r/min until the reaction solution is completely reacted. Screening qualified balls with the diameter of 2-3 mm, aging for 8 hours, drying for 4 hours at 100 ℃, roasting for 4 hours at 600v to obtain the spherical TiO-containing balls₂Alumina carrier with shell structure.

The catalyst was prepared in the same manner as in example 1.

In this example, the catalyst was determined to have TiO content, based on the total weight of the catalyst taken as 100%₂The weight ratio of the active alumina composite carrier of the shell structure is 86.3%, the weight ratio of the cobalt oxide is 3.8%, and the weight ratio of the molybdenum oxide is 9.9%. Specific surface area of catalyst sample 278m²(iv)/g, average crush strength 89N/grain.

Example 3:

the specific preparation method of the carrier is as follows:

crushing 10g of sesbania powder and 20g of polyethylene glycol (the number average molecular weight is 1800) on a crusher to obtain powder below 150 meshes, putting the powder into 600mL of deionized water, and stirring the materials into colloid at the temperature of 30-60 ℃ to obtain the spray adhesive. 10g of citric acid or acetic acid (concentration: 100%) and 15g of nitric acid (concentration: 71%) were mixed with the acid and stirred at 25 ℃ for 3 hours to obtain a kneaded gum. 500g of alumina powder is put into a kneading machine, the rotating speed is 30r/min, 150g of kneading gum is poured into the kneading machine for 1 hour in two times to obtain homogenized powder, the powder is put into a pulverizer to be pulverized, and then the powder with the particle size below 150 meshes is obtained. And (2) feeding the powder into a shaping machine to perform ball mixing, molding, spraying spray glue by using high-efficiency spray, operating for 2.5 hours, screening qualified balls with the diameter of 1.7-2.7 mm, shaping the qualified balls for 6 hours, aging for 8 hours, drying for 4 hours at 100 ℃, and roasting for 4 hours at 600 ℃ to obtain spherical alumina balls B.

Rolling ball forming method-0.3 mm TiO₂Preparing a shell structure:

60g of titanium dioxide powder, 10g of polyvinyl alcohol are uniformly mixed, 40g of deionized water is placed into a small kneader to be kneaded for 1 hour to obtain homogenized powder, the powder is put into a crusher to be crushed, and then the powder is powder with the particle size below 150 meshes. Feeding the powder and the alumina balls B into a shaping machine for mixing, forming, molding, operating for 3h, screening qualified balls with the diameter of 2-3 mm, shaping the qualified balls for 4 h, aging for 8 h, drying for 4 h at 100 ℃, and roasting for 4 h at 550 ℃ to obtain 0.3mm TiO₂The alumina composite carrier with a shell structure.

The preparation method of the catalyst and the carrier prepared in this example were the same as in example 1.

In this example, the catalyst was determined to have TiO content, based on the total weight of the catalyst taken as 100%₂The weight ratio of the active alumina composite carrier of the shell structure is 86.1 percent, the weight ratio of the cobalt oxide is 3.9 percent, and the weight ratio of the molybdenum oxide is 10.0 percent. Specific surface area of catalyst sample 258m²(iv)/g, average crush strength 102N/grain.

Example 4:

the specific preparation method of the carrier is as follows:

the alumina rolling ball method was the same as in example 3.

Surface deposition method-0.3 mm TiO₂Preparing a shell structure:

200g of dried alumina carrier B were taken and placed in a reactor. 150g of tetrabutyltitanate solution and 200g of isopropanol were mixed and the mixture was allowed to stand until the surface deposition solution was obtained. And adding the surface deposition solution into a reactor containing an alumina carrier, wherein the reaction temperature is 80 ℃, and the stirring speed is 40r/min until the reaction solution is completely reacted. Screening qualified balls with the diameter of 2-3 mm, aging for 8 hours, drying for 4 hours at 100 ℃, and roasting for 4 hours at 600 ℃ to obtain the balls with TiO₂Alumina carrier with shell structure.

The preparation method of the catalyst and the carrier prepared in this example were the same as in example 1.

In this example, the catalyst was determined to have TiO content, based on the total weight of the catalyst taken as 100%₂The weight ratio of the active alumina composite carrier of the shell structure is 86.3%, the weight ratio of the cobalt oxide is 3.8%, and the weight ratio of the molybdenum oxide is 9.9%. Specific surface area 266m of the catalyst sample²(iv)/g, average crush strength 104N/grain.

Example 5:

the specific preparation method of the carrier is as follows:

crushing 10g of sesbania powder and 20g of polyethylene glycol (the number average molecular weight is 1800) on a crusher to obtain powder below 150 meshes, putting the powder into 600mL of deionized water, and stirring the materials into colloid at the temperature of 30-60 ℃ to obtain the spray adhesive. 10g of citric acid or acetic acid (concentration: 100%) and 15g of nitric acid (concentration: 71%) were mixed with the acid and stirred at 25 ℃ for 3 hours to obtain a kneaded gum. 500g of alumina powder is put into a kneading machine, the rotating speed is 30r/min, 150g of kneading gum is poured into the kneading machine for 1 hour in two times to obtain homogenized powder, the powder is put into a pulverizer to be pulverized, and then the powder with the particle size below 150 meshes is obtained. And (2) feeding the powder into a shaping machine to perform ball mixing and forming, spraying spray glue by using high-efficiency spray, operating for 2 hours, screening qualified balls with the diameter of 1.5-2.5 mm, shaping the qualified balls for 6 hours, aging for 8 hours, drying for 4 hours at 100 ℃, and roasting for 4 hours at 600 ℃ to obtain spherical alumina balls C.

Rolling ball forming method-0.5 mm TiO₂Preparing a shell structure:

taking 90g of titanium dioxide powder, 30g of polyvinyl alcohol, uniformly mixing and 60g of deionized water, putting into a small kneader for kneading for 1 hour to obtain homogenized powder, putting the powder into a crusher for crushing, and then putting the powder below 150 meshes. Feeding the powder and the alumina balls C into a shaping machine for mixing, making and forming, operating for 3h, screening qualified balls with the diameter of 2-3 mm, shaping the qualified balls for 4 h, aging for 8 h, drying for 4 h at 100 ℃, and roasting for 4 h at 550 ℃ to obtain 0.5mm TiO₂The alumina composite carrier with a shell structure.

The preparation method of the catalyst and the carrier prepared in this example were the same as in example 1.

In this example, the catalyst was determined to have TiO content, based on the total weight of the catalyst taken as 100%₂The weight ratio of the active alumina composite carrier of the shell structure is 86.2%, the weight ratio of the cobalt oxide is 4.0%, and the weight ratio of the molybdenum oxide is 9.8%. Specific surface area 243m of catalyst sample²(ii)/g, average crush strength 125N/grain.

Example 6:

the specific preparation method of the carrier is as follows:

the alumina rolling ball method was the same as in example 5.

Surface deposition method of-0.5 mm TiO₂Preparing a shell structure:

200g of dried alumina spheres C were taken and placed in a reactor. 200g of tetrabutyltitanate solution and 200g of isopropanol were mixed and the mixture was poured into the surface deposition solution. And adding the surface deposition solution into a reactor containing an alumina carrier, wherein the reaction temperature is 80 ℃, and the stirring speed is 40r/min until the reaction solution is completely reacted. Screening qualified balls with the diameter of 2-3 mm, aging for 8 hours, drying for 4 hours at 100 ℃, and roasting for 4 hours at 600 ℃ to obtain the balls with TiO₂Alumina carrier with shell structure.

In this example, the catalyst was determined to have TiO content, based on the total weight of the catalyst taken as 100%₂The weight ratio of the active alumina composite carrier of the shell structure is 86.1 percent, the weight ratio of the cobalt oxide is 3.9 percent, and the weight ratio of the molybdenum oxide is 10 percent. Specific surface area of catalyst sample 240m²(ii)/g, average crush strength 130N/particle.

Example 7:

the specific preparation method of the carrier is as follows:

the alumina rolling ball method was the same as in example 5.

Surface deposition method of-0.5 mm TiO₂Preparing a shell structure:

200g of dried alumina spheres C were taken and placed in a reactor. 30g of ammonium titanyl oxalate was mixed with 100mL of deionized water and allowed to stand until the surface deposition solution. Adding the surface deposition solution into a reactor containing an alumina carrier to obtain a reaction solutionIs completely absorbed. Screening qualified balls with the diameter of 2-3 mm, aging for 8 hours, drying for 4 hours at 100 ℃, and roasting for 4 hours at 600 ℃ to obtain the balls with TiO₂Alumina carrier with shell structure.

In this example, the catalyst was determined to have TiO content, based on the total weight of the catalyst taken as 100%₂The weight ratio of the active alumina composite carrier of the shell structure is 86.1 percent, the weight ratio of the cobalt oxide is 4.0 percent, and the weight ratio of the molybdenum oxide is 9.9 percent. Specific surface area 248m of catalyst sample²(iv)/g, average crush strength of 122N/grain.

Table one, summary of physical Properties of catalysts of examples

Evaluation results were as follows:

TABLE II, evaluation results of catalysts TABLE

As can be seen from the results in Table II, in the present invention, when the thickness of the titanium dioxide shell layer is 0.5mm and the reaction temperature is 240 ℃, the hydrogenation activity of sulfur dioxide is more than 99% and the hydrolysis activity of organic sulfur is more than 99% (i.e., sulfur-containing compounds other than hydrogen sulfide are not detected by chromatography); the shell thickness of the titanium dioxide is more than 0.3mm, and the hydrogenation activity of sulfur dioxide of the catalyst is more than 97 percent and the hydrolysis activity of organic sulfur is more than 99 percent at the reaction temperature of 240 ℃.

In summary, compared with the existing claus tail gas hydrogenation catalyst, the catalyst disclosed by the invention has higher activity and better stability. In addition, the catalyst disclosed by the invention has the advantages of simple and easily-obtained production raw materials and simple preparation process, can be efficiently, stably and economically produced by using the existing production line, and can effectively replace the existing traditional Claus tail gas hydrodesulfurization catalyst.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.