A claus tail gas hydrogenation catalyst, its preparation method and application

Abstract

The application provides a Claus tail gas hydrogenation catalyst and a preparation method and application thereof, and belongs to the technical field of sulfur recovery, and the Claus tail gas hydrogenation catalyst comprises an aluminum-titanium-silicon-based composite carrier and an active component, wherein the aluminum-titanium-silicon-based composite carrier comprises Al2O3, nano TiO2 and SiO2, the aluminum-titanium-silicon-based composite carrier further comprises an antioxidant, and the aluminum-titanium-silicon-based composite carrier is prepared by means of kneading; wherein the active component comprises an oxide of a group VIII metal, an oxide of a group VIB metal and an oxide of a rare earth metal, the rare earth metal is kneaded into the composite carrier in the form of an oxide, and cobalt and molybdenum are loaded on the carrier by means of impregnation. The catalyst has the characteristics of high low-temperature activity and strong oxidation resistance, simultaneously has the function of catalyzing CO conversion, and is suitable for being widely applied to a hydrogenation reactor of a sulfur recovery device in the petroleum refining, coal chemical industry and the like, and is especially suitable for treating acid gas with a high CO2 content.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sulfur recovery, in particular to a Claus tail gas hydrogenation catalyst, a preparation method thereof, and application in sulfur recovery tail gas treatment, especially treatment of acidic gas with high CO2 content. BACKGROUND

[0002] Sulfur recovery refers to the conversion of sulfides in toxic sulfur-containing gas (acidic gas) containing hydrogen sulfide into elemental sulfur. Sulfur recovery usually adopts the Claus sulfur production process, which has two steps of high-temperature thermal reaction in a sulfur production furnace and low-temperature catalytic reaction in a converter in industry. Due to the limitation of Claus method thermodynamic equilibrium and reversible reaction, the conversion rate cannot be high enough, so that the Claus tail gas usually contains a small amount of hydrogen sulfide and other sulfur-containing compounds, such as sulfur dioxide, carbon disulfide, carbonyl sulfur and Sx, etc. Direct incineration cannot meet the current national tail gas emission standard, so it is necessary to remove hydrogen sulfide and sulfur-containing compounds before incineration.

[0003] The Claus tail gas is treated by a hydrogenation reactor, sulfur dioxide is hydrogenated and reduced, and organic sulfur is hydrolyzed into hydrogen sulfide. This process requires a high-efficiency hydrogenation catalyst specially used for tail gas treatment. The gas passing through the hydrogenation reactor is selectively absorbed by a solvent to remove hydrogen sulfide therefrom. After treatment, the sulfur content is extremely low, and the gas can be burned and released into the atmosphere. However, in the acidic gas entering the sulfur recovery device, the CO2 content in part of the acidic gas is too high, such as the CO2 content in the acidic gas of the low-temperature methanol washing device of Qilu Branch of Sinopec is as high as 80%. In the acidic gas reaction furnace, CO2 can be reduced by hydrogen sulfide and sulfur to CO, which makes the CO content in the Claus tail gas relatively high. If it is not treated, the CO content in the tail gas finally burned and released into the atmosphere is too high to meet the current national emission standard. The high CO2 content in the acidic gas also leads to an increase in the organic sulfur content in the Claus tail gas. The Claus tail gas entering the hydrogenation reactor also contains part of oxygen. Therefore, it is necessary to develop a Claus tail gas hydrogenation catalyst with high low-temperature activity and strong oxidation resistance, which has the functions of high-efficiency catalysis of sulfur dioxide hydrogenation, organic sulfur hydrolysis and CO conversion, and is of great significance to the SO2 and CO standard emission of the sulfur recovery device.

[0004] Chinese patent application with publication number CN100591418C discloses a preparation method of a Claus sulfur recovery device tail gas hydrogenation catalyst. The catalyst is a nickel-based catalyst prepared by co-precipitation method. The main active component is nickel oxide with a content of 20.1%-60%, the auxiliary active component is any one, any two or any three of chromium oxide, copper oxide and magnesium oxide with a content of 0%-10%, and the rest is aluminum oxide. Although the catalyst has good low-temperature activity, it has poor oxidation resistance and does not have the function of catalyzing CO conversion.

[0005] Chinese patent application CN101879451A discloses a preparation method of a low-temperature Claus tail gas hydrogenation catalyst, the carrier of the catalyst is made of silicon-modified aluminum titanium silicon composite dry glue, binder, pore-expanding agent and auxiliary agent, the active component is ternary active component composed of molybdenum or tungsten and cobalt, nickel, the catalyst has good low-temperature activity, but is not suitable for treating oxygen-containing Claus tail gas, and the catalytic CO conversion function is not mentioned.

[0006] Chinese patent application CN1268719C discloses a preparation method of a Claus tail gas hydrogenation catalyst, the carrier of the catalyst is silicon oxide-modified alumina carrier, the active component is cobalt and molybdenum, a stable solution is prepared by using a stabilizer, and the catalyst is prepared by using a kneading method to extrude into a strip, the catalyst has high organic sulfur hydrolysis activity and CS2 and COS hydrolysis activity, and good stability, but poor oxidation resistance, and the catalytic CO conversion function is not mentioned.

[0007] In summary, the current Claus tail gas hydrogenation catalyst cannot have the multifunction of catalyzing sulfur dioxide hydrogenation, organic sulfur hydrolysis and CO conversion.

[0008] Therefore, the present application is proposed. SUMMARY

[0009] The low-temperature active component is added to improve the low-temperature catalytic activity of the catalyst, and the antioxidant is added to improve the oxidation resistance of the catalyst, the catalyst has the characteristics of high low-temperature activity and strong oxidation resistance, and has the multifunctional catalytic properties of catalyzing sulfur dioxide hydrogenation, organic sulfur hydrolysis and CO conversion (CO is converted into CO2), and can be widely applied to a sulfur recovery device Claus tail gas hydrogenation reactor in the petroleum refining and coal chemical industry, and the catalytic effect is better for the acidic gas with high CO2 content.

[0010] One of the purposes of the present application is to provide a Claus tail gas hydrogenation catalyst.

[0011] The second purpose of the present application is to provide a preparation method of the Claus tail gas hydrogenation catalyst.

[0012] The third purpose of the present application is to provide an application of the Claus tail gas hydrogenation catalyst.

[0013] In order to achieve the above purposes of the present application, the following technical solutions are adopted:

[0014] In a first aspect, the present application provides a Claus tail gas hydrogenation catalyst, comprising an aluminum titanium silicon-based composite carrier, and an active component,

[0015] The aluminum titanium silicon-based composite carrier comprises Al2O3, nano TiO2 and SiO2, and further comprises an antioxidant,

[0016] The weight percentage of Al2O3 is 47% to 88%, the weight percentage of nano TiO2 is 10% to 40%, the weight percentage of SiO2 is 1% to 10%, and the weight percentage of antioxidant is 1% to 3%, based on the weight of the aluminum-titanium-silicon-based composite carrier.

[0017] The active component includes an oxide of a Group VIII metal, an oxide of a Group VIB metal, and an oxide of a rare earth metal,

[0018] The weight percentage of the oxide of the Group VIII metal is 1% to 3%, the weight percentage of the oxide of the Group VIB metal is 5% to 15%, and the weight percentage of the oxide of the rare earth metal is 5% to 10%, based on the weight of the Claus tail gas hydrogenation catalyst.

[0019] I. Carrier

[0020] The carrier of the present application is an aluminum-titanium-silicon-based composite carrier, which is mainly composed of Al2O3, nano TiO2, and SiO2. The weight percentage of Al2O3 is 47% to 88%, such as 48%, 50%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 75%, 80%, 85%, but not limited thereto; the weight percentage of nano TiO2 is 10% to 40%, such as 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, but not limited thereto; and the weight percentage of SiO2 is 1% to 10%, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, but not limited thereto.

[0021] The source of Al2O3 is not particularly limited, and pseudo-boehmite can be used as a raw material.

[0022] The source of nano TiO2 is not particularly limited, and can be obtained from the market or prepared by oneself. Preferably, the average particle size of nano TiO2 is 10 to 50 nm.

[0023] The source of SiO2 is not particularly limited, and diatomite can be used as a raw material.

[0024] In the preparation process of the carrier of the present application, an appropriate amount of a pore-expanding agent, a binder, and an antioxidant are added, and an aluminum-titanium-silicon-based composite carrier is prepared by kneading.

[0025] In some embodiments, the antioxidant is an oxide of iron (Fe2O3).

[0026] The weight percentage of the antioxidant is 1% to 3%, and preferably 1%, based on the weight of the carrier.

[0027] II. Active component

[0028] The Group VIII metal is one selected from cobalt and nickel, preferably cobalt, and a salt of the Group VIII metal (cobalt) can be used as a raw material and loaded on the carrier by a solution impregnation method. The cobalt salt can be cobalt acetate, cobalt nitrate, cobalt chloride, or any other water-soluble cobalt salt.

[0029] The Group VIB metal is one selected from tungsten and molybdenum, preferably molybdenum, and a salt or oxide of the Group VIB metal (molybdenum) can be used as a raw material and loaded on the carrier by a solution impregnation method. The molybdenum salt can be ammonium heptamolybdate, ammonium molybdate, ammonium paramolybdate, sodium molybdate, or any other water-soluble molybdenum salt, and the molybdenum oxide can be molybdenum trioxide.

[0030] The rare earth metal is one or more selected from La and Nd, preferably La and Nd. The rare earth metal is added to the carrier in the form of an oxide by a kneading method.

[0031] The oxide of the Group VIII metal (e.g., CoO) accounts for 1% to 3% of the weight of the catalyst, such as 1%, 2%, or 3%, but is not limited thereto; the oxide of the Group VIB metal (e.g., MoO3) accounts for 5% to 15% of the weight of the catalyst, such as 6%, 8%, 10%, or 12%, but is not limited thereto; and the oxide of the rare earth metal (e.g., the sum of La and Nd oxides) accounts for 5% to 10% of the weight of the catalyst, such as 6%, 7%, 8%, or 9%, but is not limited thereto.

[0032] In a second aspect, the present application provides a preparation method of the Claus tail gas hydrogenation catalyst, comprising the following steps:

[0033] (1) Knead pseudo-boehmite, nano-TiO2, diatomite, an oxide of a rare earth metal, a pore-expanding agent, a binder, an antioxidant source, and water together, and then extrude, dry, and calcine to obtain an aluminum-titanium-silicon-based composite carrier modified by the oxide of the rare earth metal;

[0034] (2) Prepare an impregnation solution by mixing a salt of a Group VIII metal, a salt or oxide of a Group VIB metal, and a complexing agent with water, impregnate the aluminum-titanium-silicon-based composite carrier modified by the oxide of the rare earth metal, and then dry and calcine to obtain the Claus tail gas hydrogenation catalyst.

[0035] Step (1):

[0036] The carrier is prepared by an extrusion molding method.

[0037] In some embodiments, the specific surface area of the pseudo-boehmite is ≥ 260 m 2 / g, preferably ≥ 300 m 2 / g.

[0038] In some embodiments, the nano-TiO2 is prepared by the following method:

[0039] For example,Figure 1 As shown, metatitanic acid is added to 98% concentrated sulfuric acid in a mass ratio of metatitanic acid: concentrated sulfuric acid = 1:4-6 (such as 1:5), heated and stirred until the metatitanic acid is completely dissolved, heating is stopped, impurities in the solution are removed by adsorption (such as activated carbon adsorption) and filtration (such as filter paper filtration), an appropriate amount of deionized water is added for dilution to obtain a mixed solution, the concentration of metatitanic acid in the mixed solution is 35-600 g / L, an appropriate amount of urea is added to the solution, heating is continued to hydrolyze the urea, the reaction is ended after the precipitation is complete, the precipitate is washed, dried at 110-130 °C for 3-5 h, calcined at 400-700 °C for 3-6 h, and ground after cooling to obtain a nano-TiO2 powder with an average particle size of 10-50 nm.

[0040] In some embodiments, the oxide of the rare earth metal is one or more selected from the group consisting of oxides of La and Nd, and preferably La2O3 and Nd2O3 in a mass ratio of 1:1.

[0041] In some embodiments, the pore-expanding agent is one or more selected from the group consisting of polyethylene glycol, polyethylene oxide, and sesbania powder, and preferably polyethylene glycol with a number average molecular weight of 200-600.

[0042] In some embodiments, the binder is one or more selected from the group consisting of concentrated sulfuric acid, citric acid, and carboxymethyl cellulose, and preferably concentrated sulfuric acid.

[0043] In some embodiments, the antioxidant source is a soluble salt of iron, such as ferrous sulfate.

[0044] In some embodiments, the calcination temperature of step (1) is 400-700 °C, and preferably 500 °C; and / or

[0045] The calcination time is 4-7 h, and preferably 5 h.

[0046] Step (2):

[0047] The relevant description of the salt of the Group VIII metal, the salt of the Group VIB metal, or the oxide is as in the first aspect.

[0048] The active components, cobalt and molybdenum, are loaded on the carrier using an impregnation method with a complexing agent.

[0049] In some embodiments, the complexing agent is one or more selected from the group consisting of ethylene glycol, citric acid, and phosphoric acid, and preferably a combination of ethylene glycol and citric acid in a mass ratio of 1:1.

[0050] The catalyst is prepared using an equal-volume impregnation method, specifically: the catalyst carrier is soaked in deionized water at room temperature, after soaking for a period of time, the volume of deionized water reduced is recorded, which is the volume impregnated into the catalyst carrier, and the same volume of impregnation solution is used for impregnation, which is the equal-volume impregnation method.

[0051] In some embodiments, the impregnation time is 30 min to 3 h, preferably 1 to 2 h.

[0052] In some embodiments, the calcination temperature of step (2) is 300 to 500°C; and / or

[0053] The calcination time is 2 to 6 h.

[0054] The shape of the prepared catalyst can be strip-shaped, spherical, clover-shaped, four-leaf clover-shaped, etc., preferably clover-shaped or four-leaf clover-shaped.

[0055] In one embodiment of the preparation method of the Claus tail gas hydrogenation catalyst, as shown in the example, the method comprises the following steps: Figure 2 as shown in the example, the method comprises the following steps:

[0056] 1. Preparation of the carrier:

[0057] Pseudo-boehmite (specific surface area ≥ 300 m 2 / g), nano-TiO2, diatomite, oxide of rare earth metal, FeSO4, pore-expanding agent, binder, water are added into a kneader for kneading, after kneading is completed, a three-leaf clover-shaped or four-leaf clover-shaped hole plate with a diameter of ф3 mm is used for extruding into a strip, drying at 110 to 150°C for 2 to 4 h, calcination at 400 to 700°C for 4 to 7 h, to prepare an oxide of rare earth metal modified aluminum-titanium-silicon-based composite carrier. The specific surface area of the carrier is determined by N2 adsorption method and should be greater than 260 m 2 / g.

[0058] 2. Preparation of the catalyst

[0059] Ammonium heptamolybdate, cobalt nitrate are added into deionized water for stirring until completely dissolved, to prepare a mixed solution, a complexing agent is added into deionized water, to prepare a complexing solution, the two solutions are mixed and constant volume is prepared into an active component impregnation solution, a certain amount of the above impregnation solution is taken, impregnation of the carrier of step 1 at room temperature for 1 to 2 h, drying at 110 to 150°C for 2 to 6 h, calcination at 300 to 500°C for 2 to 6 h, to obtain the catalyst of the present application.

[0060] The rare earth metal in the active component of the catalyst is added into the aluminum-titanium-silicon-based composite carrier in the form of oxide by kneading, the active components of cobalt and molybdenum are loaded on the carrier by impregnation, the antioxidant Fe2O3 in the carrier is added in the form of FeSO4, MoO3 is added in the form of molybdenum trioxide or ammonium heptamolybdate, CoO is added in the form of cobalt carbonate or cobalt nitrate, and the rare earth metal is added in the form of La2O3 or Nd2O3, in the obtained catalyst, the content of the rare earth metal oxide is 5 to 10%, the content of MoO3 is 5 to 15%, and the content of CoO is 1 to 3%, based on the weight of the catalyst.

[0061] In a third aspect, the present application provides a use of the Claus tail gas hydrogenation catalyst in sulfur recovery tail gas treatment.

[0062] The catalyst can be widely applied to a hydrogenation reactor in a sulfur recovery tail gas treatment device in the petroleum refining, coal chemical industry and the like, and is particularly suitable for treating acidic gas with a high CO2 content.

[0063] Advantages:

[0064] The carrier of the catalyst prepared by the present application is an aluminum-titanium-silicon-based composite carrier, wherein the titanium component is added in the form of nano-sized TiO2 particles. Compared with the commonly used industrial-grade TiO2, the nano-sized TiO2 can more effectively improve the catalytic performance of the catalyst. The average particle size of the industrial-grade TiO2 is generally 200-300 nm, while the average particle size of the nano-sized TiO2 particles is only 10-50 nm. The carrier prepared by using the nano-sized TiO2 particles has a smaller pore size and is more easily adsorbed with sulfur dioxide, carbon disulfide, carbonyl sulfur and Sx and the like in the Claus tail gas, and has higher adsorption performance. In addition, compared with the commonly used industrial-grade TiO2, the nano-sized TiO2 is not easy to form water droplets on the surface of the carrier, effectively preventing the inhibition of the water droplets on the performance of the catalyst.

[0065] In the preparation process, low-temperature catalytic active components are added, so that the catalyst can have the functions of catalyzing the hydrogenation of sulfur dioxide, the hydrolysis of organic sulfur and the conversion of CO under low-temperature conditions. Rare earth metals are added as active components to improve the catalytic activity and thermal stability of the catalyst. In addition, antioxidants are added in the carrier to improve the antioxidant capacity of the catalyst. The catalyst can be used in a hydrogenation reactor of a sulfur recovery device, is suitable for treating acidic gas with a high CO2 content in the petroleum refining, coal chemical industry and the like, effectively reduces the content of SO2 and CO in the flue gas, meets the current national environmental protection emission standards, and has significant economic and social benefits.

[0066] The application has been described in detail in the foregoing, but the above-described embodiments are merely illustrative in nature and are not intended to limit the present application. In addition, the present application is not limited by any theory described in the foregoing prior art or summary of the application or in the following examples. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 The preparation flowchart of the nano TiO2 of one embodiment of the present application.

[0068] Figure 2 The preparation flowchart of the Claus tail gas hydrogenation catalyst of one embodiment of the present application.

[0069] Figure 3 The schematic diagram of the sulfur micro-reaction evaluation device in the activity evaluation of the catalyst of the embodiment of the present application.

[0070] Figure: 1-hydrogen; 2-oxygen; 3-hydrogen sulfide; 4-sulfur dioxide; 5-nitrogen; 6-carbon disulfide; 7-carbon monoxide; 8-water; 9-mass flow meter; 10-mixing tank; 11-reactor; 12-sulfur accumulator; 13-cold trap; 14-water pump; 15-automatic control system; 16-alkali solution tank; 17-tail gas exhaust. DETAILED DESCRIPTION

[0071] The application will be further described in conjunction with the following examples. It should be noted that the following examples are provided for illustration only and are not intended to limit the scope of the present application.

[0072] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, methods in the art.

[0073] Example

[0074] Example 1

[0075] Metatitanic acid is added to 98% concentrated sulfuric acid in a mass ratio of metatitanic acid: concentrated sulfuric acid = 1:5, heated and stirred until the metatitanic acid is completely dissolved, heating is stopped, and an appropriate amount of deionized water is added to dilute the solution to obtain a mixed solution with a metatitanic acid concentration of 300 g / L. An appropriate amount of urea is added to the solution to adjust the pH of the solution to 8.5-9.0, and heating is continued to hydrolyze the urea. After the precipitation is complete, the reaction is stopped, the precipitate is washed, dried at 120°C for 4 h, calcined at 500°C for 5 h, and ground after cooling to obtain a nano-TiO2 powder with a particle size distribution of 10-20 nm.

[0076] Take 218 g of pseudoboehmite (specific surface area of 300 m 2 / g), 20 g of diatomite, 51 g of nano-TiO2 powder, 9 g of lanthanum trioxide, 9 g of neodymium trioxide, 5 g of sesbania powder, 30 g of concentrated sulfuric acid, and 4.7 g of ferrous sulfate dissolved in 275 ml of deionized water, mix uniformly, extrude into a strip on an extruder, dry at 130°C for 4 h, and calcine at 500°C for 5 h to prepare an aluminum-titanium-silicon-based composite carrier modified with La2O3 and Nd2O3.

[0077] Take 6 ml of citric acid in 100 ml of deionized water, mix 14.7 g of cobalt nitrate and 30 g of molybdenum trioxide uniformly, add the citric acid-containing aqueous solution, stir until completely dissolved, and make up to volume to obtain an active component impregnation solution. The carrier is impregnated with the impregnation solution for 2 h, dried at 130°C for 2 h, and calcined at 500°C for 5 h to prepare a catalyst. The catalyst thus prepared contains 6% of rare earth metal oxides, 10% of MoO3, and 2% of CoO by mass of the catalyst.

[0078] Comparative Example 1: Compared with Example 1, the ferrous sulfate in Example 1 was removed.

[0079] Comparative Example 2: Compared with Example 1, the ferrous sulfate in Example 1 was replaced with manganese sulfate 5.17g (the form of existence in the carrier after calcination was MnO).

[0080] Comparative Example 3: Compared with Example 1, the nano-TiO2 powder in Example 1 was removed.

[0081] Comparative Example 4: Compared with Example 1, the nano-TiO2 powder in Example 1 was replaced with industrial TiO2 powder (purchased from Zibo Feian Chemical Co., Ltd., Shandong Province, R-618).

[0082] Comparative Example 5: Compared with Example 1, the nano-TiO2 in Example 1 was replaced with TiO2 powder obtained by directly calcining metatitanic acid at 500℃.

[0083] Comparative Example 6: Compared with Example 1, the concentration of metatitanic acid in the preparation method of nano-TiO2 in Example 1 was changed to 10g / L.

[0084] Comparative Example 7: Compared with Example 1, the calcination temperature of nano-TiO2 in Example 1 was changed to 350℃.

[0085] Example 2:

[0086] Metatitanic acid was added to 98% concentrated sulfuric acid in a mass ratio of metatitanic acid: concentrated sulfuric acid = 1:5, heated and stirred until the metatitanic acid was completely dissolved, the heating was stopped, and the appropriate amount of deionized water was added to dilute to obtain a mixed solution, the concentration of metatitanic acid in the mixed solution was 50g / L, the appropriate amount of urea was added to the solution until the pH of the solution was 8.5-9.0, the urea was continuously hydrolyzed, the precipitation was completed, and the reaction was stopped, the precipitate was washed, dried at 110℃ for 5h, calcined at 400℃ for 4h, and then ground to obtain nano-TiO2 powder.

[0087] Take 186g of pseudoboehmite (specific surface area is 300m 2 / g), 20g of diatomite, 43g of nano-TiO2 powder, 15g of lanthanum trioxide, 15g of neodymium trioxide, 5g of sesbania powder, 30g of concentrated sulfuric acid, and 10.5g of ferrous sulfate were dissolved in 275ml of deionized water to mix uniformly, extruded into a strip on an extruder, dried at 130℃ for 4h, and calcined at 500℃ for 5h to prepare an aluminum-titanium-silicon-based composite carrier modified by La2O3 and Nd2O3.

[0088] Take 6ml citric acid in 100ml deionized water, mix 22.1g of cobalt nitrate, 45g of molybdenum trioxide uniformly, add the aqueous solution containing sulfuric acid, stir until completely dissolved, after constant volume, the active component impregnation solution is obtained. Impregnate the carrier with the impregnation solution for 2h, dry at 130℃ for 2h, calcine at 400℃ for 5h, prepare the catalyst. The rare earth metal oxide content in the catalyst prepared in this way is 10% of the mass of the catalyst, the MoO3 content is 15% of the mass of the catalyst, and the CoO content is 3% of the mass of the catalyst.

[0089] Comparative Example 8: Compared with Example 2, the cobalt nitrate in Example 2 is removed.

[0090] Comparative Example 9: Compared with Example 2, the molybdenum trioxide in Example 2 is removed.

[0091] Example 3:

[0092] Add metatitanic acid to 98% concentrated sulfuric acid in a mass ratio of metatitanic acid: concentrated sulfuric acid = 1:5, heat and stir until the metatitanic acid is completely dissolved, stop heating, add an appropriate amount of deionized water to dilute to obtain a mixed solution, make the concentration of metatitanic acid in the mixed solution 300g / L, add an appropriate amount of urea to the solution until the pH of the solution is 8.5-9.0, continue to heat to hydrolyze the urea, and end the reaction after the precipitation is complete, wash the precipitate, dry at 120℃ for 4h, calcine at 500℃ for 5h, and grind after cooling to obtain nano-TiO2 powder.

[0093] Take 218g of pseudoboehmite (specific surface area 300m 2 / g), 20g of diatomite, 47.5g of nano-TiO2 powder, 7.5g of lanthanum trioxide, 7.5g of neodymium trioxide, 5g of sesbania powder, 30g of concentrated sulfuric acid, and 4.6g of ferrous sulfate dissolved in 275ml of deionized water, mix uniformly, extrude into a strip on an extruder, dry at 130℃ for 4h, calcine at 500℃ for 5h, and prepare an aluminum titanium silicon-based composite carrier modified with La2O3 and Nd2O3.

[0094] Take 6ml citric acid in 100ml deionized water, mix 22.1g of cobalt nitrate, 45g of molybdenum trioxide uniformly, add the aqueous solution containing sulfuric acid, stir until completely dissolved, after constant volume, the active component impregnation solution is obtained. Impregnate the carrier with the impregnation solution for 2h, dry at 130℃ for 2h, calcine at 500℃ for 7h, prepare the catalyst. The rare earth metal oxide content in the catalyst prepared in this way is 5% of the mass of the catalyst, the MoO3 content is 13% of the mass of the catalyst, and the CoO content is 1% of the mass of the catalyst.

[0095] Comparative Example 10: Compared with Example 3, the lanthanum trioxide and neodymium trioxide in Example 3 are removed.

[0096] Comparative Example 11: Compared with Example 3, lanthanum trioxide and neodymium trioxide in Example 3 were replaced by equal mass of lanthanum trioxide.

[0097] Example 4:

[0098] Metatitanic acid was added to 98% concentrated sulfuric acid in a mass ratio of metatitanic acid: concentrated sulfuric acid = 1:5, and heated and stirred until the metatitanic acid was completely dissolved. Heating was stopped, and an appropriate amount of deionized water was added to dilute the mixture to obtain a mixed solution with a metatitanic acid concentration of 300 g / L. An appropriate amount of urea was added to the solution until the solution pH was 8.5-9.0. Heating was continued to hydrolyze the urea, and the reaction was ended after the precipitation was complete. The precipitate was washed, dried at 120°C for 4 h, calcined at 500°C for 5 h, and ground after cooling to obtain a nano-TiO2 powder.

[0099] 220 g of pseudoboehmite (specific surface area 300 m 2 / g), 20 g of diatomite, 50 g of nano-TiO2 powder, 12 g of lanthanum trioxide, 12 g of neodymium trioxide, 5 g of sesbania powder, 30 g of concentrated sulfuric acid, and 4.8 g of ferrous sulfate were dissolved in 275 ml of deionized water to obtain a mixture, which was extruded into a shape on an extruder, dried at 130°C for 4 h, and calcined at 500°C for 5 h to prepare an aluminum-titanium-silicon-based composite carrier modified by La2O3 and Nd2O3.

[0100] 7.4 g of cobalt nitrate and 24 g of molybdenum trioxide were mixed uniformly in 100 ml of deionized water containing a sulfuric acid aqueous solution, and stirred until completely dissolved to obtain an active component impregnation solution. The carrier was impregnated with the impregnation solution for 2 h, dried at 130°C for 2 h, and calcined at 500°C for 6 h to prepare a catalyst. The catalyst thus prepared contained 8% of rare earth metal oxides, 8% of MoO3, and 1% of CoO by mass of the catalyst.

[0101] Example 5:

[0102] Metatitanic acid was added to 98% concentrated sulfuric acid in a mass ratio of metatitanic acid: concentrated sulfuric acid = 1:5, and heated and stirred until the metatitanic acid was completely dissolved. Heating was stopped, and an appropriate amount of deionized water was added to dilute the mixture to obtain a mixed solution with a metatitanic acid concentration of 300 g / L. An appropriate amount of urea was added to the solution until the solution pH was 8.5-9.0. Heating was continued to hydrolyze the urea, and the reaction was ended after the precipitation was complete. The precipitate was washed, dried at 120°C for 4 h, calcined at 500°C for 5 h, and ground after cooling to obtain a nano-TiO2 powder.

[0103] 220 g of pseudoboehmite (specific surface area 300 m 2 / g), 20g diatomite, 45g nano-TiO2 powder, 10.5g lanthanum trioxide, 10.5g neodymium trioxide, 5g sesbania powder, 30g concentrated sulfuric acid, 4.6g ferrous sulfate were dissolved in 275ml deionized water and uniformly mixed, extruded into a strip on an extruder, dried at 130°C for 4h, and calcined at 500°C for 5h to prepare the La2O3 and Nd2O3 modified aluminum-titanium-silicon-based composite carrier.

[0104] 6ml citric acid was taken in 100ml deionized water, 14.7g cobalt nitrate, 33g molybdenum trioxide were uniformly mixed, and added to the aqueous solution containing sulfuric acid, stirred until completely dissolved, and then diluted to obtain the active component impregnation solution. The carrier was impregnated with the impregnation solution for 2h, dried at 130°C for 2h, and calcined at 700°C for 6h to prepare the catalyst. The rare earth metal oxide content in the catalyst prepared in this way was 7% of the mass of the catalyst, the MoO3 content was 11% of the mass of the catalyst, and the CoO content was 2% of the mass of the catalyst.

[0105] Example 6:

[0106] Metatitanic acid was added to 98% concentrated sulfuric acid in a mass ratio of metatitanic acid: concentrated sulfuric acid = 1:5, heated and stirred until the metatitanic acid was completely dissolved, heating was stopped, and the appropriate amount of deionized water was added to dilute it to obtain a mixed solution with a metatitanic acid concentration of 300g / L. The appropriate amount of urea was added to the solution until the pH of the solution was 8.5-9.0, the urea was hydrolyzed by continuing to heat, the precipitation was completed, and the reaction was stopped. The precipitate was washed, dried at 120°C for 4h, calcined at 500°C for 5h, and ground after cooling to obtain nano-TiO2 powder.

[0107] 225g pseudoboehmite (specific surface area 300m 2 / g), 20g diatomite, 45g nano-TiO2 powder, 10.5g lanthanum trioxide, 10.5g neodymium trioxide, 5g sesbania powder, 30g concentrated sulfuric acid, 4.6g ferrous sulfate were dissolved in 275ml deionized water and uniformly mixed, extruded into a strip on an extruder, dried at 130°C for 4h, and calcined at 500°C for 5h to prepare the La2O3 and Nd2O3 modified aluminum-titanium-silicon-based composite carrier.

[0108] 6ml citric acid was taken in 100ml deionized water, 14.7g cobalt nitrate, 33g molybdenum trioxide were uniformly mixed, and added to the aqueous solution containing sulfuric acid, stirred until completely dissolved, and then diluted to obtain the active component impregnation solution. The carrier was impregnated with the impregnation solution for 2h, dried at 130°C for 2h, and calcined at 700°C for 6h to prepare the catalyst. The rare earth metal oxide content in the catalyst prepared in this way was 7% of the mass of the catalyst, the MoO3 content was 11% of the mass of the catalyst, and the CoO content was 2% of the mass of the catalyst.

[0109] Table 1 shows the active component content in each embodiment.

[0110] Table 1 shows the active component content in each embodiment.

[0111]

[0112] Performance test

[0113] According to GB-T34233-2017 Low Temperature Sulfur Tail Gas Hydrogenation Catalyst Activity Test Method, the catalysts prepared in Examples 1-6 and Comparative Examples 1-11 were evaluated for activity on a sulfur micro-reaction evaluation device (as shown in Figure 3 The reactor of the micro-reaction device was made of a stainless steel tube with an inner diameter of 20 mm, and was heated using a thermostat. The catalyst loading was 10 ml, and quartz sand of the same particle size was loaded in the upper part for mixing and preheating. The reaction gas volume composition was H2S 1%, SO2 0.6%, CS2 0.6%, H2 10%, water 30%, O2 0.02-1%, CO 0.02-3%, and the rest was nitrogen. The reaction conditions were a volume space velocity of 1200 h -11 -1, a reaction temperature of 200°C, and a pressure of 0.1 MPa.

[0114] The SO2 hydrogenation conversion rate of the catalyst was calculated according to the following formula:

[0115]

[0116] Where: M0, M1 represent the volume concentration of SO2 at the inlet and outlet of the reactor, respectively.

[0117] The organic sulfur hydrolysis rate of the catalyst was calculated according to the following formula:

[0118]

[0119] Where: C0, C1 are the volume concentrations of CS2 at the inlet and outlet of the reactor, respectively.

[0120] The CO conversion rate of the catalyst was calculated according to the following formula:

[0121]

[0122] Where: N0, N1 represent the volume concentration of CO at the inlet and outlet of the reactor, respectively.

[0123] The catalysts prepared in Examples 1-6 and Comparative Examples 1-11 were evaluated for activity using the above method, and the evaluation results are shown in Table 2.

[0124] Table 2 Catalyst activity evaluation results

[0125]

[0126] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit the present application. Even though the present application has been described in detail with reference to the foregoing embodiments, it is to be understood that modifications and / or equivalent arrangements can be made to the technical solutions described in the foregoing embodiments without departing from the spirit and scope of the present application as defined in the appended claims.

Claims

1. A Claus tail gas hydrogenation catalyst characterized in that, The active component comprises an oxide of a Group VIII metal, an oxide of a Group VIB metal and an oxide of a rare earth metal, The active component comprises an oxide of a Group VIII metal, an oxide of a Group VIB metal and an oxide of a rare earth metal, The active component comprises an oxide of a Group VIII metal, an oxide of a Group VIB metal and an oxide of a rare earth metal, The active component comprises an oxide of a Group VIII metal, an oxide of a Group VIB metal and an oxide of a rare earth metal, The active component comprises an oxide of a Group VIII metal, an oxide of a Group VIB metal and an oxide of a rare earth metal, The preparation method of the Claus tail gas hydrogenation catalyst comprises the following steps: The active component comprises an oxide of a Group VIII metal, an oxide of a Group VIB metal and an oxide of a rare earth metal, The preparation method of the nano-TiO2 is as follows: The metatitanic acid is added to the concentrated sulfuric acid in a mass ratio of metatitanic acid: concentrated sulfuric acid = 1:4-6, heated and stirred until the metatitanic acid is completely dissolved, heating is stopped, water is added for dilution to obtain a mixed solution, the concentration of the metatitanic acid in the mixed solution is 35-600 g / L, urea is added to the solution until the pH of the solution is 8.5-9.0, heating is continued until the urea is hydrolyzed and the precipitation is complete, the reaction is ended, the precipitate is washed, dried at 110-130°C for 3-5 h, calcined at 400-700°C for 3-6 h, and ground after cooling to obtain a nano-TiO2 powder with an average particle size of 10-50 nm. The oxide of the rare earth metal in step (1) is La2O3 and Nd2O3 in a mass ratio of 1:1; and / or 2. The Claus tail gas hydrogenation catalyst according to claim 1, characterized in that The pore-expanding agent is one or more selected from polyethylene glycol, polyethylene oxide and sesbania powder; and / or The binder is one or more selected from concentrated sulfuric acid, citric acid and carboxymethyl cellulose. The pore-expanding agent is polyethylene glycol with a number average molecular weight of 200-600; and / or 3. The Claus tail gas hydrogenation catalyst according to claim 2, characterized in that The binder is concentrated sulfuric acid. The calcination temperature in step (1) is 400-700°C; and / or 4. The Claus tail gas hydrogenation catalyst according to claim 1, characterized in that, The calcination time is 4-7 h. The calcination temperature in step (1) is 500°C; and / or 5. The Claus tail gas hydrogenation catalyst according to claim 4, characterized in that, The calcination time is 5 h. The impregnation time in step (2) is 1-2 h; 6. The Claus tail gas hydrogenation catalyst according to claim 1, characterized in that, The calcination temperature in step (2) is 300-500°C; and / or The calcination time is 2-6 h. ​ 7. Use of the Claus tail gas hydrogenation catalyst according to any one of claims 1 to 6 in the treatment of sulfur recovery tail gas.

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