Organic sulfur hydrolysis catalyst, preparation method and application

Abstract

The application discloses an organic sulfur hydrolysis catalyst, a preparation method and application, and adds a water-soluble titanium-containing compound and a surfactant to obtain titanium-containing pseudo-boehmite; finally, the titanium-containing pseudo-boehmite is formed to obtain the organic sulfur hydrolysis catalyst; and in the carbonization method reaction process, the pH is slowly changed by adjusting the flow of the CO2, the pH change value of the mixed solution is less than 1 in 30 min, and the final pH value of the reaction solution is controlled to be 7.0-9.5. In the preparation of the pseudo-boehmite, the titanium element is highly dispersed in the pseudo-boehmite powder by adding the titanium element and the surfactant and controlling the pH change rate, the catalyst fully plays the hydrolysis effect of each titanium active site on the organic sulfur, and a higher organic sulfur hydrolysis rate is realized under the condition that the titanium content is lower.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to an organic sulfur hydrolysis catalyst, its preparation method, and its application. Background Technology

[0002] The main components of acid gas are hydrogen sulfide, carbon dioxide, and hydrocarbons. In the main combustion furnace of the sulfur recovery unit, it burns with air, undergoing a thermochemical reaction at high temperatures to produce elemental sulfur, sulfur dioxide, and organic sulfur. Among these, organic sulfur has the greatest impact on subsequent treatment processes, directly affecting the sulfur dioxide emissions from the unit's tail gas. The organic sulfur hydrolysis process has always been a key research focus in sulfur recovery. To address the organic sulfur hydrolysis problem, domestic and international researchers have proposed using alumina-supported titanium dioxide catalysts and titanium-based sulfur recovery catalysts in the first-stage Claus reactor, and alkaline earth-titanium-aluminum catalysts in the second-stage Claus reactor. Mature products on the market include catalysts such as CT6-7, CT6-8, CT6-17, CRS-31, and S-7001. However, existing organic sulfur hydrolysis catalyst products have at least the following problems:

[0003] (1) For alumina-supported catalysts, the titanium dioxide loading is low and the organic sulfur hydrolysis rate is less than 80%, which cannot meet the current technical requirements of production units for ultra-low sulfur dioxide emissions.

[0004] (2) For titanium-based catalysts, the titanium dioxide content is more than 85%, resulting in high product cost, high bulk density, and excessive initial investment;

[0005] (3) The organic sulfur hydrolysis rate of the alkaline earth-titanium aluminum catalyst in the secondary Claus reactor is only 60%, and there is a large room for improvement in the organic sulfur hydrolysis rate. Summary of the Invention

[0006] Based on the above background technology, the present invention provides an organic sulfur hydrolysis catalyst, preparation method and application to solve the above problems. In the preparation of boehmite, by adding titanium and surfactant and controlling the pH change rate, titanium can be highly dispersed in boehmite powder. The catalyst fully utilizes the hydrolysis effect of each titanium active site on organic sulfur and achieves a high organic sulfur hydrolysis rate under the condition of low titanium content.

[0007] This invention is achieved through the following technical solution:

[0008] A method for preparing an organic sulfur hydrolysis catalyst involves using a carbonization method to prepare boehmite. A water-soluble titanium-containing compound and a surfactant are added, and titanium-containing boehmite is obtained through a CO2 carbonization process (e.g., by adding a water-soluble titanium-containing compound and a surfactant to a sodium aluminate solution and obtaining titanium-containing boehmite through a CO2 carbonization process). Finally, the titanium-containing boehmite is shaped to obtain the organic sulfur hydrolysis catalyst. During the carbonization reaction, the pH is slowly changed by adjusting the CO2 flow rate, with the pH change of the mixed solution being less than 1 over 30 minutes, and the final pH of the reaction solution is controlled to be 7.0-9.5.

[0009] Further optionally, the catalyst contains 5%-30% titanium (calculated as oxides).

[0010] Further optionally, the surfactant includes sodium dodecyl sulfate and / or ethanol dodecyl stearate.

[0011] Further optionally, the amount of surfactant added is 0.1%-1% based on the total mass of the solid raw materials.

[0012] Further, alternatively, the titanium-containing compound is used to formulate a titanium-containing aqueous solution.

[0013] Further optionally, the titanium-containing aqueous solution is prepared using one or more of titanium tetrachloride, titanium oxysulfate, and titanium sulfate.

[0014] Alternatively, the aluminum source for the pseudoboehmite may be a water-soluble alkali metal aluminate.

[0015] Further, alternatively, the method of slowly changing the pH by adjusting the CO2 flow rate includes: introducing CO2 gas into the reaction solution, monitoring the pH value of the mixed solution, reducing the CO2 flow rate when the pH value drops to 8, and allowing the pH value to drop from 8 to 7 in 1 hour; stopping the introduction of carbon dioxide gas when the pH value drops to 7, and carrying out the aging reaction under the conditions of stirring and reaction temperature.

[0016] An organic sulfur hydrolysis catalyst was prepared using the method described above.

[0017] An application of an organic sulfur hydrolysis catalyst for the hydrolysis of organic sulfur compounds such as CS2; the organic sulfur hydrolysis catalyst is prepared using the above-mentioned method for preparing an organic sulfur hydrolysis catalyst.

[0018] The present invention has the following advantages and beneficial effects:

[0019] The organic sulfur hydrolysis catalyst, preparation method, and application provided by this invention utilize a carbonization method to prepare boehmite. During this process, titanium and a surfactant are added, and the pH is slowly changed by adjusting the CO2 flow rate. The pH change in the mixed solution is less than 1 within half an hour. This slow pH change allows for hydrophobic interactions between titanium ions and the surfactant, as well as the attraction between the surfactant's cationic and anionic ions and titanium ions. This reduces the aggregation of titanium ions on the boehmite surface and increases their dispersion, resulting in high dispersion of titanium in the boehmite powder. The titanium-containing boehmite powder is then shaped to prepare an organic sulfur hydrolysis catalyst for sulfur recovery. This catalyst fully utilizes the hydrolysis effect of each titanium active site on organic sulfur, achieving a high organic sulfur hydrolysis rate even with low titanium content. Due to the low titanium content and high utilization rate, the catalyst cost can be significantly reduced. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 This is a TEM characterization image of catalyst sample 1.

[0022] Figure 2 This is a TEM characterization image of control sample 2. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0024] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the invention.

[0025] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] Example 1

[0027] This embodiment provides an organic sulfur hydrolysis catalyst, which is prepared by the following method:

[0028] A mixed solution of sodium aluminate and titanium sulfate was prepared, with a sodium aluminate concentration of 1 mol / L and a titanium sulfate concentration of 0.034 mol / L, denoted as solution A (the titanium content (based on oxides) in the solution was 5% wt). Sodium dodecyl sulfate was added to solution A, making its mass 0.1% of the solute in solution A, denoted as solution B. The self-assembly of the surfactant was utilized to largely inhibit the aggregation of titanium ions, improve their dispersion, and provide more reactive sites on the catalyst surface. Solution B was heated and stirred in a water bath at 80°C at a stirring speed of 500 rpm to serve as the reaction solution.

[0029] CO2 gas was introduced into the reaction solution at a flow rate of 0.5 L / min per liter of solution B. The pH of the mixed solution was monitored. When the pH dropped to 8, the CO2 flow rate was adjusted to 100 mL / min per liter of solution B to slowly decrease the pH. The time from 8 to 7 was 1 hour. When the pH of the solution dropped to 7, the introduction of carbon dioxide gas was stopped. Then, the stirring speed and water bath temperature were kept constant for 6 hours of aging. After washing and drying, the titanium-containing pseudoboehmite sample was obtained.

[0030] After pulverizing 500 kg of titanium-containing pseudoboehmite sample and rapidly desulfurizing it, it was sphericalized. During the sphericalization process, an appropriate amount of water was sprayed as a binder to control the size of the spherical particles between 3-6 mm. After sphericalization, the sample was aged, dried at 120℃ for 2 h, and calcined at 600℃ for 1 h to obtain catalyst sample 1.

[0031] Example 2

[0032] This embodiment provides an organic sulfur hydrolysis catalyst, which is prepared by the following method:

[0033] A mixed solution of sodium aluminate and titanium sulfate was prepared, with a sodium aluminate concentration of 0.5 mol / L and a titanium sulfate concentration of 0.136 mol / L, denoted as solution A (the titanium content (based on oxides) in the solution was 30% wt). Ethanol dodecyl stearate was added to solution A, making it 1% of the solute mass in solution A, denoted as solution B. The self-assembly of the surfactant was utilized to largely inhibit the aggregation of titanium ions, improving their dispersion and providing more reactive sites on the catalyst surface. Solution B was heated and stirred in a 90°C water bath at a stirring speed of 500 rpm to serve as the reaction solution.

[0034] CO2 gas was introduced into the reaction solution at a flow rate of 0.5 L / min per liter of solution B. The pH of the mixed solution was monitored. When the pH dropped to 8, the CO2 flow rate was adjusted to 100 mL / min per liter of solution B to slowly decrease the pH. The time from 8 to 7 was 1 hour. When the pH of the solution dropped to 7, the introduction of carbon dioxide gas was stopped. Then, the stirring speed and water bath temperature were kept constant for 6 hours of aging. After washing and drying, the titanium-containing pseudoboehmite sample was obtained.

[0035] After pulverizing 500 kg of titanium-containing boehmite sample and rapidly desulfurizing it, the sample was sphericalized. During the sphericalization process, an appropriate amount of water was sprayed as a binder to control the size of the spherical particles between 3-6 mm. The spherical sample was then aged, dried at 120℃ for 2 h, and calcined at 500℃ for 1 h to obtain catalyst sample 2.

[0036] Example 3

[0037] This embodiment provides an organic sulfur hydrolysis catalyst, which is prepared by the following method:

[0038] A mixed solution of sodium aluminate and titanium sulfate was prepared, with a sodium aluminate concentration of 0.75 mol / L and a titanium sulfate concentration of 0.084 mol / L, denoted as solution A (the titanium content (based on oxides) in the solution was 15% wt). Ethanol dodecyl stearate was added to solution A, making the ethanol dodecyl stearate content 0.5% of the solute in solution A, denoted as solution B. The self-assembly of the surfactant was utilized to largely inhibit the aggregation of titanium ions, improve their dispersion, and provide more reactive sites on the catalyst surface. Solution B was heated and stirred in a 70°C water bath at a stirring speed of 500 rpm to serve as the reaction solution.

[0039] CO2 gas was introduced into the reaction solution at a flow rate of 0.5 L / min per liter of solution B. The pH of the mixed solution was monitored. When the pH dropped to 8, the CO2 flow rate was adjusted to 100 mL / min per liter of solution B to slowly decrease the pH. The time from 8 to 7 was 1 hour. When the pH of the solution dropped to 7, the introduction of carbon dioxide gas was stopped. Then, the stirring speed and water bath temperature were kept constant for 6 hours of aging. After washing and drying, the titanium-containing pseudoboehmite sample was obtained.

[0040] After pulverizing 500 kg of titanium-containing boehmite sample and rapidly desulfurizing it, the sample was sphericalized. During the sphericalization process, an appropriate amount of water was sprayed as a binder to control the size of the spherical particles between 3-6 mm. The spherical sample was then aged, dried at 120℃ for 2 h, and calcined at 400℃ for 1 h to obtain catalyst sample 3.

[0041] Comparison document 1

[0042] This comparative case provides an organic sulfur hydrolysis catalyst, prepared using the method described in Example 1, with the difference being the pH control method. The specific pH control method is shown below:

[0043] CO2 gas was introduced into the mixed solution at a flow rate of 0.5 L / min. The pH value of the mixed solution was monitored, and the introduction of CO2 gas was stopped when the pH value of the solution dropped to 7.

[0044] The obtained sample was the control sample 1.

[0045] Comparison document 2

[0046] This comparative case provides an organic sulfur hydrolysis catalyst, which is prepared using the method described in Example 1, except that: no surfactant is added, and solution B is directly heated and stirred in a water bath at 90°C to serve as the reaction solution.

[0047] The obtained sample was control sample 2.

[0048] Comparison document 3

[0049] This comparative case provides an organic sulfur hydrolysis catalyst, which is prepared using the method of Example 1, except that the pH control method is the same as that of Comparative Example 1, and no surfactant is added.

[0050] The obtained sample was control sample 3.

[0051] Table 1 shows a comparison of the organic sulfur hydrolysis activities of the catalyst samples obtained in Examples 1 and 2, the catalyst samples obtained in Comparative Examples 1-3, and the commercial titanium-based catalyst sample CRS-31.

[0052] The test conditions for the hydrolytic activity of organosulfur compounds were: reaction temperature 320℃ and space velocity 5000 h⁻¹. -1 The catalyst loading is 20 mL, the catalyst particle size is 1.5-2.5 mm, and the gas composition is H2S 4%, SO2 2.5%, CS2 1%, CO2 20%, H2O 25%, O2 0.2%, and N2 is the balance gas.

[0053] TEM characterization images of catalyst sample 1 and control sample 2 are shown below. Figure 1 and Figure 2 As shown in the TEM image, the titanium oxides on the surface of boehmite are well separated in the presence of surfactant; in the absence of surfactant, the titanium oxides aggregate on the surface of boehmite, thereby reducing the hydrolysis activity of the catalyst.

[0054] Table 1 Comparison of CS2 hydrolysis rates

[0055]

[0056] Note: The titanium content is (titanium: (aluminum + titanium)) × 100%.

[0057] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an organic sulfur hydrolysis catalyst, characterized in that, In the preparation of pseudoboehmite using the carbonization method, water-soluble titanium-containing compounds and surfactants are added, and titanium-containing pseudoboehmite is obtained through a CO2 carbonization process. Finally, the titanium-containing pseudoboehmite is shaped to obtain an organic sulfur hydrolysis catalyst. During the carbonization reaction, the pH is slowly changed by adjusting the CO2 flow rate, with the pH change of the mixed solution being less than 1 over 30 minutes, and the final pH of the reaction solution is controlled to be 7.0-9.

5. The specific method for slowly changing the pH by adjusting the CO2 flow rate includes: introducing CO2 gas into the reaction solution, monitoring the pH of the mixed solution, and when the pH drops to 8, reducing the CO2 flow rate so that the pH drops from 8 to 7 within 1 hour; when the pH drops to 7, stopping the introduction of carbon dioxide gas, and maintaining stirring and reaction temperature conditions to carry out the aging reaction.

2. The method for preparing an organic sulfur hydrolysis catalyst according to claim 1, characterized in that, Based on oxides, the titanium content in the catalyst is 5%-30%.

3. The method for preparing an organic sulfur hydrolysis catalyst according to claim 1, characterized in that, The surfactant includes sodium dodecyl sulfate and / or ethanol dodecyl stearate.

4. The method for preparing an organic sulfur hydrolysis catalyst according to claim 1, characterized in that, The amount of surfactant added is 0.1%-1% based on the total mass of solid raw materials.

5. The method for preparing an organic sulfur hydrolysis catalyst according to claim 1, characterized in that, The titanium-containing compound is used to prepare a titanium-containing aqueous solution.

6. The method for preparing an organic sulfur hydrolysis catalyst according to claim 5, characterized in that, The titanium-containing aqueous solution is prepared using one or more of titanium tetrachloride, titanium oxysulfate, and titanium sulfate.

7. The method for preparing an organic sulfur hydrolysis catalyst according to claim 1, characterized in that, The aluminum source for pseudoboehmite is a water-soluble alkali metal aluminate.

8. An organic sulfur hydrolysis catalyst, characterized in that, It was prepared using the method described in any one of claims 1 to 7 for the preparation of an organic sulfur hydrolysis catalyst.

9. The application of an organic sulfur hydrolysis catalyst, characterized in that, For use in the hydrolysis of organic sulfur CS2, wherein the organic sulfur includes CS2; the organic sulfur hydrolysis catalyst is prepared by the method for preparing an organic sulfur hydrolysis catalyst according to any one of claims 1 to 7.

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