Sulfur recovery catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of catalysts, and particularly discloses a sulfur recovery catalyst and a preparation method and application thereof. The catalyst is pure titanium dioxide, the pore volume of the catalyst is 0.2-0.5 mLg <-1 >, and the specific surface area of the catalyst is 200-250 m < 2 > g <-1 >. The preparation method comprises the following steps: 1) mixing tetrabutyl titanate with ethanol to obtain a solution A; 2) mixing a hydrochloric acid solution with ethanol to obtain a solution B; (3) simultaneously pouring the solution B and the solution A into a rotary liquid membrane reactor, performing high-speed nucleation cycle mixing for 3-5 minutes, continuously pouring into a container, stirring, performing aging polymerization reaction to obtain gel, and drying; the invention relates to a preparation method of a catalyst, which comprises the following steps of 1, preparing gel, 2, preparing the gel, 3, preparing the gel, 4, mixing the dried gel with a binder, carrying out extrusion molding, and drying, and 5, roasting the molded body obtained in the step 4 to obtain the catalyst.When the catalyst is used for sulfur recovery, the activity stability is good, the organic sulfur hydrolysis activity gt is 95%, and the Claus activity gt is 80%.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a sulfur recovery catalyst and its preparation method, as well as the application of the catalyst in sulfur recovery. Background Technology

[0002] Natural gas purification plants, oil refineries, and coal chemical plants commonly employ the Claus sulfur recovery process to recover sulfur from acidic gases containing hydrogen sulfide. This technology can generally recover 90% of the sulfur from acidic gases. 97% of the hydrogen sulfide is recovered and converted into sulfur. The tail gas after sulfur recovery typically contains 0.5% sulfur by volume. 2% hydrogen sulfide, 0.01 0.5% organic sulfur, 0.02 0.1% elemental sulfur and 0.2% elemental sulfur. Even with only 1% sulfur dioxide, reducing hydrogen sulfide emissions and recovering sulfur resources are crucial from environmental, public health, and economic perspectives. Currently, the Claus process is the most widely used technology for H2S elimination and sulfur resource recovery. However, due to thermodynamic limitations, 3% to 5% of hydrogen sulfide remains in Claus tail gas. Therefore, the subsequent treatment of Claus tail gas is becoming increasingly important.

[0003] In Claus exhaust gas treatment technologies, selective oxidation of hydrogen sulfide has advantages such as low investment cost and no thermodynamic equilibrium limitations. The reaction process of selective oxidation of hydrogen sulfide is as follows: H₂S + 1 / 2O₂ → 1 / nS n +H2O However, side reactions are always inevitable during the reaction process, such as the oxidation of elemental sulfur or the excessive oxidation of hydrogen sulfide to sulfur dioxide, which reduces the conversion rate and selectivity of the reaction. Therefore, it is crucial to prepare and screen catalysts with high conversion rates and selectivity by regulating the catalyst. Summary of the Invention

[0004] In view of the above, the purpose of this invention is to provide a sulfur recovery catalyst, its preparation method and application. The catalyst uses pure titanium dioxide as a component, has high catalytic activity and good stability, and its preparation method is simple, which is conducive to its industrial application.

[0005] The first aspect of the present invention provides a sulfur recovery catalyst, which is pure titanium dioxide with a pore volume of 0.2-0.5 mL. g -1 Specific surface area is 200-250 m² 2 g -1 .

[0006] A second aspect of the present invention provides a method for preparing the above-mentioned sulfur recovery catalyst, the method comprising: 1) Tetrabutyl titanate was mixed with ethanol to obtain solution A; 2) Mix hydrochloric acid solution with ethanol to obtain solution B; 3) Pour solutions B and A into a rotating liquid film reactor simultaneously, mix at high speed for 3-5 minutes, then continue to pour into a container and stir to age and polymerize the gel, which is then dried. 4) Mix the dried gel with the binder, extrude it into shape, and then dry it; 5) The molded body obtained in step 4) is calcined to obtain the catalyst.

[0007] The third aspect of the present invention provides the application of the above-described sulfur recovery catalyst and the sulfur recovery catalyst prepared by the above-described preparation method in sulfur recovery.

[0008] Compared with the prior art, the present invention has the following beneficial effects: 1. The catalyst of the present invention has good activity stability, with organic sulfur hydrolysis activity >95% and Claus activity >80%.

[0009] 2. The catalyst of the present invention is prepared by using tetrabutyl titanate as the main raw material, adding ethanol as a solvent, and adding hydrochloric acid solution as a hydrolysis inhibitor. The preparation process is free of secondary pollution, the catalyst preparation method is simple and has a large specific surface area, which is beneficial for practical application in industrial production.

[0010] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0011] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0012] According to a first aspect of the present invention, a sulfur recovery catalyst is provided, the catalyst being pure titanium dioxide with a pore volume of 0.2-0.5 mL. g -1 Specific surface area is 200-250 m² 2 g -1 .

[0013] Preferably, the catalyst has a pore volume of 0.2-0.4 mL. g -1 Specific surface area is 210-240 m² 2 g -1.

[0014] According to a second aspect of the present invention, the present invention provides a method for preparing the above-described sulfur recovery catalyst, the method comprising: 1) Tetrabutyl titanate was mixed with ethanol to obtain solution A; 2) Mix hydrochloric acid solution with ethanol to obtain solution B; 3) Pour solutions B and A into a rotating liquid film reactor simultaneously, mix at high speed for 3-5 minutes, then continue to pour into a container and stir to age and polymerize the gel, which is then dried. 4) Mix the dried gel with the binder, extrude it into shape, and then dry it; 5) The molded body obtained in step 4) is calcined to obtain the catalyst.

[0015] According to the present invention, in step 1), the mass ratio of tetrabutyl titanate to ethanol can be 1:1. 0.5-2.

[0016] In step 2) of this invention, the molar concentration of the hydrochloric acid solution can be 1-3 M, and the mixing ratio of the hydrochloric acid solution and ethanol can be 5-30 mL. 30-60 g.

[0017] According to the present invention, in step 3), the temperature of the aging polymerization reaction can be 20-40 °C, and the reaction time can be 3-5 h; the drying temperature can be 110-130 °C, and the drying time can be 8-16 h.

[0018] In this invention, the adhesive can be any commonly used adhesive in the prior art, such as at least one selected from nitric acid, acetic acid, oxalic acid, and citric acid. Furthermore, based on the weight of the dried gel, the amount of adhesive used can be 4-15 wt%.

[0019] According to the present invention, step 4) may include: dissolving the adhesive in deionized water, and adding the dried gel while continuously stirring. The molded body can be a shape conventionally used in the art, such as a strip of 3-10 mm, a sphere, etc., which can be selected as needed. The drying conditions after molding may include drying at 100-180 °C for 6-12 h.

[0020] In step 5) of the present invention, the calcination conditions may include: heating to 350-650 ℃ at a heating rate of 1-5 ℃ / min in an air atmosphere and holding at that temperature for 3-6 h.

[0021] Preferably, the calcination conditions may include: heating to 600°C at a heating rate of 2°C / min in an air atmosphere and holding at that temperature for 5 hours.

[0022] According to a third aspect of the present invention, the present invention provides the application of the above-described sulfur recovery catalyst and the sulfur recovery catalyst prepared by the above-described preparation method in sulfur recovery.

[0023] The catalyst of this invention is used for the recovery of sulfides from acidic gases and their conversion to sulfur. The reaction conditions can be: a reaction temperature of 280 °C and a mass hourly space velocity of 2500 h⁻¹. -1 The reaction pressure is 0.1 MPa.

[0024] The substances and parameters not limited in this invention can be selected according to existing technology, which is a conventional technical means in this field.

[0025] The present invention will be further described below with reference to embodiments. However, the invention is not limited to these embodiments.

[0026] The experimental methods and data for each embodiment and comparative example were obtained through the following methods: Pore ​​volume of the catalyst: determined by low-pressure mercury intrusion porosimetry.

[0027] Specific surface area of ​​the catalyst: determined by BET gas adsorption method.

[0028] Catalyst activity evaluation: The activity evaluation test of the sulfur recovery catalyst was conducted on a 10 mL micro-reactor for sulfur recovery. The reactor was made of stainless steel tubing with an inner diameter of 20 mm and placed in a constant temperature chamber. The catalyst loading was 10 mL, and the top was filled with quartz sand of the same particle size for mixing and preheating. The contents of HS, SO2, COS, and CS2 in the reactor inlet and outlet gases were analyzed online using a Shimadzu GC-2014 gas chromatograph. Sulfides were analyzed using a GDX-301 support, and O2 content was analyzed using a 5A molecular sieve. The column temperature was 120 ℃, a thermal conductivity detector was used, hydrogen was used as the carrier gas, and the post-column flow rate was 25 mL / min.

[0029] With 2H2S+SO 2→ S x The +2H2O reaction was used as the index reaction to evaluate the Claus activity of the catalyst. The inlet gas composition was 2% H2S, 1% SO2, 3000 ppm O2, 30% H2O, and the remainder was N2. The gas hourly space velocity was 2500 h⁻¹. -1 The reaction temperature is 280℃. Calculate the Claus conversion of the catalyst using the following formula:

[0030] Where M0 and M1 represent the volume concentrations of H2S and SO2 at the inlet and outlet, respectively. Sampling and analysis are performed hourly, and the results are averaged over 10 hours.

[0031] The activity of the catalyst in the hydrolysis of organic sulfur was investigated using the reaction CS2 + 2H2O → CO2 + 2H2S as the index reaction. The inlet gas composition was 2% H2S, 0.6% CS2, 1% SO2, 3000 ppm O2, 30% H2O, and the remainder was N2. The gas hourly space velocity was 2500 h⁻¹. -1 The reaction temperature is 280 ℃. Calculate the CS2 hydrolysis rate of the catalyst using the following formula:

[0032] Wherein, C0 and C1 are the volume concentrations of CS2 at the inlet and outlet, respectively. Sampling and analysis were performed hourly, and the results were averaged over 10 hours.

[0033] Critical aging of catalysts: The activity evaluation process of sulfur recovery catalysts usually lasts only 10 hours. For fresh catalysts, 10 hours of continuous operation has little impact on the performance of the catalyst. In order to examine the effect of operating time on the performance of the catalyst and evaluate the stability of the catalyst, a certain treatment is generally carried out on the catalyst by artificial harsh aging in order to simulate the condition of the catalyst after a long period of use in a short time. The performance of the catalyst after 3 years of use can be simulated by conducting experiments according to harsh aging conditions. Critical aging conditions: (1) Calcination of catalyst at 550 ℃ for 2 h; (2) Space velocity of 1000 h⁻¹ -1 Temperature 260 ℃, gas composition SO2 Air Water vapor = 1 2.5 6.5 Treat the catalyst for 2 hours.

[0034] Example 1

[0035] Step A: Accurately weigh 100 g of tetrabutyl titanate and 100 g of ethanol and add them to a beaker. Stir until a clear solution is obtained to prepare solution A.

[0036] Step B: Mix 12 mL of 1.5 M hydrochloric acid solution and 50 g of ethanol solution to prepare solution B.

[0037] Step C: Pour solutions B and A into a rotating liquid film reactor simultaneously and mix at high speed for 3-5 minutes.

[0038] Step D: Pour the mixed solution from step C into a container and stir. Let it age at 30 °C for 4 h to allow the polymerization reaction to proceed. Then, dry the resulting gel at 120 °C for 12 h.

[0039] Step E: Dissolve 10 g of nitric acid in 80 mL of deionized water, add it to 100 g of dried gel while stirring continuously, mix the materials evenly in an extruder and extrude them to obtain long strips, and dry the long strips at 120 ℃ for 8 h. Step F: The strip is heated to 400 °C in air at a heating rate of 2 °C / min and held at that temperature for 5 h to obtain sulfur recovery catalyst 1.

[0040] Example 2

[0041] Step A: Accurately weigh 100 g of tetrabutyl titanate and 100 g of ethanol and add them to a beaker. Stir until a clear solution is obtained to prepare solution A.

[0042] Step B: Mix 12 mL of 1.5 M hydrochloric acid solution and 50 g of ethanol solution to prepare solution B.

[0043] Step C: Pour solutions B and A into a rotating liquid film reactor simultaneously and mix at high speed for 3-5 minutes.

[0044] Step D: Pour the mixed solution from step C into a container and stir. Let it age at 30 °C for 4 h to allow the polymerization reaction to proceed. Then, dry the resulting gel at 120 °C for 12 h.

[0045] Step E: Dissolve 10 g of nitric acid in 80 mL of deionized water, add it to 100 g of dried gel while stirring continuously, mix the materials evenly in an extruder and extrude them to obtain long strips, and dry the long strips at 120 ℃ for 8 h. Step F: The strip is heated to 500 °C in air at a heating rate of 2 °C / min and held at that temperature for 5 h to obtain sulfur recovery catalyst 2.

[0046] Example 3

[0047] Step A: Accurately weigh 100 g of tetrabutyl titanate and 100 g of ethanol and add them to a beaker. Stir until a clear solution is obtained to prepare solution A.

[0048] Step B: Mix 12 mL of 1.5 M hydrochloric acid solution and 50 g of ethanol solution to prepare solution B.

[0049] Step C: Pour solutions B and A into a rotating liquid film reactor simultaneously and mix at high speed for 3-5 minutes.

[0050] Step D: Pour the mixed solution from step C into a container and stir. Let it age at 30 °C for 4 h to allow the polymerization reaction to proceed. Then, dry the resulting gel at 120 °C for 12 h.

[0051] Step E: Dissolve 10 g of nitric acid in 80 mL of deionized water, add it to 100 g of dried gel while stirring continuously, mix the materials evenly in an extruder and extrude them to obtain long strips, and dry the long strips at 120 ℃ for 8 h. Step F: The strip is heated to 600 °C in air at a heating rate of 2 °C / min and held at that temperature for 5 h to obtain sulfur recovery catalyst 3.

[0052] Example 4

[0053] Step A: Accurately weigh 100 g of tetrabutyl titanate and 100 g of ethanol and add them to a beaker. Stir until a clear solution is obtained to prepare solution A.

[0054] Step B: Mix 6 mL of 1.5 M hydrochloric acid solution and 50 g of ethanol solution to prepare solution B.

[0055] Step C: Pour solutions B and A into a rotating liquid film reactor simultaneously and mix at high speed for 3-5 minutes.

[0056] Step D: Pour the mixed solution from step C into a container and stir. Let it age at 30 °C for 4 h to allow the polymerization reaction to proceed. Then, dry the resulting gel at 120 °C for 12 h.

[0057] Step E: Dissolve 10 g of nitric acid in 80 mL of deionized water, add it to 100 g of dried gel while stirring continuously, mix the materials evenly in an extruder and extrude them to obtain long strips, and dry the long strips at 120 ℃ for 8 h. Step F: The strip is heated to 600 °C in air at a heating rate of 2 °C / min and held at that temperature for 5 h to obtain sulfur recovery catalyst 4.

[0058] Example 5

[0059] Step A: Accurately weigh 100 g of tetrabutyl titanate and 100 g of ethanol and add them to a beaker. Stir until a clear solution is obtained to prepare solution A.

[0060] Step B: Mix 18 mL of 1.5 M hydrochloric acid solution and 50 g of ethanol solution to prepare solution B.

[0061] Step C: Pour solutions B and A into a rotating liquid film reactor simultaneously and mix at high speed for 3-5 minutes.

[0062] Step D: Pour the mixed solution from step C into a container and stir. Let it age at 30 °C for 4 h to allow the polymerization reaction to proceed. Then, dry the resulting gel at 120 °C for 12 h.

[0063] Step E: Dissolve 10 g of nitric acid in 80 mL of deionized water, add it to 100 g of dried gel while stirring continuously, mix the materials evenly in an extruder and extrude them to obtain long strips, and dry the long strips at 120 ℃ for 8 h. Step F: The strip is heated to 600 °C in air at a heating rate of 2 °C / min and held at that temperature for 5 h to obtain sulfur recovery catalyst 5.

[0064] Example 6

[0065] Step A: Accurately weigh 100 g of tetrabutyl titanate and 100 g of ethanol and add them to a beaker. Stir until a clear solution is obtained to prepare solution A.

[0066] Step B: Mix 24 mL of 1.5 M hydrochloric acid solution and 50 g of ethanol solution to prepare solution B.

[0067] Step C: Pour solutions B and A into a rotating liquid film reactor simultaneously and mix at high speed for 3-5 minutes.

[0068] Step D: Pour the mixed solution from step C into a container and stir. Let it age at 30 °C for 4 h to allow the polymerization reaction to proceed. Then, dry the resulting gel at 120 °C for 12 h.

[0069] Step E: Dissolve 10 g of nitric acid in 80 mL of deionized water, add it to 100 g of dried gel while stirring continuously, mix the materials evenly in an extruder and extrude them to obtain long strips, and dry the long strips at 120 ℃ for 8 h. Step F: The strip is heated to 600 °C in air at a heating rate of 2 °C / min and held at that temperature for 5 h to obtain sulfur recovery catalyst 6.

[0070] Comparative Example 1

[0071] Step A: Accurately weigh 100 g of anatase metatitanic acid, and simultaneously weigh 2.5 g of nitric acid and dilute it with 11.0 mL of deionized water.

[0072] Step B: Mix the diluted nitric acid solution with 100 g of anatase-type metatitanic acid, stir at 30 °C for 4 h, and then dry the resulting mixture at 120 °C for 12 h.

[0073] Step C: Dissolve 10 g of nitric acid in 80 mL of deionized water, add it to 100 g of dried gel while stirring continuously, mix the materials evenly in an extruder and extrude them to obtain long strips, and dry the long strips at 120 ℃ for 8 h. Step D: The strip is heated to 600 ℃ in air at a heating rate of 2 ℃ / min and held at that temperature for 5 h to obtain sulfur recovery catalyst D1.

[0074] The physical parameters and catalytic performance of the catalysts prepared in each embodiment and comparative example are shown in Table 1. The catalytic performance of each catalyst was tested after a harsh aging treatment.

[0075] Table 1

[0076] As shown in Table 1, the catalyst of the present invention exhibits higher Claus conversion and CS2 hydrolysis rate in the sulfur recovery reaction at low temperature, and the catalyst also has better stability.

[0077] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A sulfur recovery catalyst, characterized in that, The catalyst is pure titanium dioxide with a pore volume of 0.2-0.5 mL. g -1 Specific surface area is 200-250 m² 2 g -1 .

2. The sulfur recovery catalyst according to claim 1, wherein, The catalyst has a pore volume of 0.2-0.4 mL. g -1 Specific surface area is 210-240 m² 2 g -1 .

3. The method for preparing the sulfur recovery catalyst according to claim 1 or 2, characterized in that, The preparation method of this catalyst includes: 1) Tetrabutyl titanate was mixed with ethanol to obtain solution A; 2) Mix hydrochloric acid solution with ethanol to obtain solution B; 3) Pour solutions B and A into a rotating liquid film reactor simultaneously, mix at high speed for 3-5 minutes, then continue to pour into a container and stir to age and polymerize the gel, which is then dried. 4) Mix the dried gel with the binder, extrude it into shape, and then dry it; 5) The molded body obtained in step 4) is calcined to obtain the catalyst.

4. The method for preparing the sulfur recovery catalyst according to claim 3, wherein, In step 1), the mass ratio of tetrabutyl titanate to ethanol is 1:

1. 0.5-2.

5. The method for preparing the sulfur recovery catalyst according to claim 3, wherein, In step 2), the molar concentration of the hydrochloric acid solution is 1-3 M, and the mixing ratio of the hydrochloric acid solution to ethanol is 5-30 mL. 30-60 g.

6. The method for preparing the sulfur recovery catalyst according to claim 3, wherein, In step 3), the aging polymerization reaction is carried out at a temperature of 20-40 ℃ for 3-5 h; the drying temperature is 110-130 ℃ for 8-16 h.

7. The method for preparing the sulfur recovery catalyst according to claim 3, wherein, The binder is selected from at least one of nitric acid, acetic acid, oxalic acid and citric acid, and the amount of the binder is 4-15 wt% based on the weight of the dried gel.

8. The method for preparing the sulfur recovery catalyst according to claim 3 or 7, wherein, Step 4) includes: dissolving the adhesive in deionized water and adding the dried gel while stirring continuously; drying conditions include: drying at 100-180 ℃ for 6-12 h.

9. The method for preparing the sulfur recovery catalyst according to claim 3, wherein, In step 5), the calcination conditions include: heating to 350-650 ℃ at a heating rate of 1-5 ℃ / min in an air atmosphere, and holding at that temperature for 3-6 h.

10. The application of the sulfur recovery catalyst according to claim 1 or 2, or the sulfur recovery catalyst prepared by any one of claims 3-9, in sulfur recovery.

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