Preparation method of solid-supported low-carbon hydrocarbon alkali-free deodorization catalyst

Abstract

This invention discloses a method for preparing a supported low-carbon hydrocarbon deodorization catalyst. The method includes: (1) preparing a catalyst containing M... 2+ and M' 3+ (1) Add molecular sieve to the solution and stir evenly; (2) React the obtained suspension with a mixed solution of NaOH and Na2CO3 or a weak alkaline solution under stirring; (3) Obtain the composite carrier by drying and calcination; (4) Prepare a cobalt salt solution and transfer Co to the cobalt salt solution by ion exchange. 2+ (5) After filtration and drying, Co molecular sieve solid alkali is obtained; (6) Co molecular sieve solid alkali, ammonium phthalate sulfonate, urea, ammonium molybdate, and phthalic anhydride are added in proportion and ground evenly; (7) The obtained material is heated under an inert atmosphere to react and obtain the catalyst product. In the catalyst prepared by this invention, sulfonated cobalt phthalocyanine is combined with molecular sieve through chemical bonds, the active component has a stronger binding force and a longer service life.

Description

Technical Field

[0001] This invention belongs to the field of petrochemicals and relates to a method for preparing a catalyst suitable for alkali-free deodorization of low-carbon hydrocarbons, specifically a method for preparing a supported catalyst for alkali-free deodorization processes of C3-C8 hydrocarbons. Background Technology

[0002] The most widely used technology in the deodorization of low-carbon hydrocarbons is the Merox extraction oxidation process. Its basic principle is to absorb thiols with an alkaline solution to generate sodium thiolate, which is then oxidized to disulfide and alkali by air under the action of a water-soluble cobalt phthalocyanine catalyst. The two are then separated to remove the disulfide and regenerate the alkaline solution. The main problems with this technology are the relatively large amount of alkaline residue discharged, the difficulty in treating the residue, and the resulting environmental issues; additionally, water-soluble cobalt phthalocyanine is prone to agglomeration and deactivation, leading to high operating costs.

[0003] To address this issue, UOP proposed a fixed-bed mercaptan removal process. The core of this process involves dispersing and loading the cobalt phthalocyanine active component and a solid alkali onto a porous support, achieving one-step catalytic oxidation to remove mercaptan. US Patent USP2988500 discloses a supported cobalt phthalocyanine catalyst, which loads cobalt phthalocyanine onto activated carbon and catalytically oxidizes mercaptan under the action of a soluble base reagent.

[0004] Chinese patent CN1200958A discloses a catalyst in which a complex is supported on the surface of a solid alkaline oxide. The complex is formed by cobalt sulfonate phthalocyanine or cobalt carboxylate phthalocyanine with anionic groups and cobalt quaternary ammonium salt phthalocyanine with positive ionic groups. The catalyst does not require the addition of an external alkali solution during the oxidation reaction and has a certain degree of improved activity and stability.

[0005] The preparation methods of this type of catalyst mostly adopt the loading method, and the drying is usually carried out at room temperature or low temperature after loading. Therefore, the loading stability of the active component is not good. At higher space velocities or with the extension of reaction time, some of the active components will fall off, resulting in a decrease in catalytic activity or even deactivation. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a method for preparing a supported, alkali-free deodorization catalyst for low-carbon hydrocarbons. This catalyst can remove thiols from low-carbon hydrocarbons under alkali-free conditions, and the active components are bonded to the support, making them less prone to detachment and deactivation during the reaction. This significantly improves catalyst stability and reduces operating costs.

[0007] The present invention provides a method for preparing a supported low-carbon hydrocarbon alkali-free deodorization catalyst, comprising the following:

[0008] (1) Prepare a solution of M at a certain concentration 2+ and M'3+ The microporous molecular sieve is added to the above mixed solution and stirred until homogeneous;

[0009] (2) React the suspension obtained in step (1) with a mixed solution of NaOH and Na2CO3 or a weak alkaline solution under stirring for a period of time;

[0010] (3) The material obtained in step (2) is filtered, washed, dried and calcined to obtain a composite carrier;

[0011] (4) Prepare a cobalt-containing solution and remove Co through ion exchange. 2+ The components are transferred to the composite carrier obtained in step (3);

[0012] (5) The material obtained in step (4) is filtered and dried to obtain Co molecular sieve solid alkali;

[0013] (6) Add a certain amount of ammonium phthalate sulfonate, urea, ammonium molybdate, and phthalic anhydride to the Co molecular sieve and solid alkali obtained in step (5) in a certain proportion, and grind them evenly;

[0014] (7) The material obtained in step (6) is placed in a reactor and heated to 80℃~160℃ under an inert atmosphere for 3h~8h. Then, the temperature is raised to 180℃~300℃ and reacted for 3h~8h to obtain the catalyst product.

[0015] Furthermore, the stirring time in step (1) is generally 10 min to 180 min, preferably 60 min to 120 min.

[0016] Further, in the mixed solution of step (1), M is a Group IIA or Group IIB element, and M' is a Group IIIA or Group VIII element; preferably, M is at least one divalent metal selected from Mg, Ca, Ba, and Zn, and M' is at least one trivalent metal selected from Al, Fe, Co, and Ni. Containing M 2+ and M' 3+ The mixed solution can be a nitrate solution or a hydrochloride solution of M and M'. Containing M 2+ and M' 3+ The concentrations of the mixed solutions are typically 0.1 mol / L (saturation concentration) and 0.02 mol / L (saturation concentration). M 2+ and M' 3+ The molar ratio is generally 0.5 to 30.

[0017] Furthermore, in step (2), the molar ratio of NaOH to Na2CO3 in the mixed solution is 1:3 to 30:1. The weak alkaline solution is selected from at least one of ammonia water (dilute ammonia water) and dimethylamine. In step (2), when the pH value reaches 9 to 10, stirring is stopped, and the solution is allowed to stand for 10 to 180 minutes, preferably 60 to 120 minutes.

[0018] Furthermore, the filtration, washing, drying, and calcination described in step (3) can be performed under conventional operating conditions in the art. The calcination conditions are as follows: the temperature is generally 400–900℃, preferably 500–800℃, and the calcination time is 4–10 h, preferably 6–8 h. The heating rate is 3–20℃ / min, preferably 5–10℃ / min.

[0019] Furthermore, the cobalt salt solution in step (4) is selected from at least one of Co(NO3)2, Co(AC)2, or CoCl2 solution. The operating conditions for the ion exchange in step (4) are: temperature from room temperature to 200°C, preferably 80 to 150°C, and exchange time from 12 to 36 hours, preferably 18 to 26 hours.

[0020] Furthermore, the filtration, washing, drying and calcination described in step (5) can be performed under conventional operating conditions in the art, and will not be described in detail here.

[0021] Furthermore, the mixing and grinding described in step (6) are performed using conventional methods in the art.

[0022] The second aspect of the present invention also provides a supported low-carbon hydrocarbon alkali-free deodorization catalyst, which is obtained by the preparation method described above.

[0023] Further, the catalyst comprises, by weight, 35%-65% molecular sieve, 10%-55% xMO·yM'₂O₃, and 5%-25% sulfonated cobalt phthalocyanine; M is at least one divalent metal selected from Mg, Ca, Ba, and Zn, and M' is at least one trivalent metal selected from Al, Fe, Co, and Ni, with x:y = 0.5-30; the molecular sieve is at least one selected from Y-type molecular sieve, X-type molecular sieve, MCM-41 molecular sieve, Al / MCM-48 molecular sieve, and SBA-15 molecular sieve. The silica-alumina molar ratio of the molecular sieve is 0.5-200, preferably 1-50.

[0024] The supported alkali-free deodorization catalyst provided by this invention can catalytically oxidize thiols to disulfides under alkaline conditions. Compared with conventional processes, it consumes no alkali solution, fundamentally solving the environmental problem of waste alkali discharge. Furthermore, this catalyst uses a supported method to combine cobalt phthalocyanine with mesoporous molecular sieves, effectively reducing the problem of cobalt phthalocyanine catalyst aggregation and deactivation.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The supported alkali-free deodorization catalyst prepared by the method of this invention uses microporous or mesoporous molecular sieves with suitable pore structures as the basic support, and metal oxides MO and M'2O3 as solid bases. Simultaneously, the active component cobalt phthalocyanine is synthesized and immobilized in situ onto the Co molecular sieve and solid base, thereby obtaining the low-carbon hydrocarbon deodorization catalyst. Compared with catalysts in the prior art, the alkali-free deodorization catalyst prepared by the method of this invention exhibits higher binding strength of the active component.

[0027] 2. In the catalyst preparation method provided by the present invention, the mesoporous molecular sieve is first impregnated with a mixed solution containing M(NO3)2 and M'(NO3)3, and then calcined to obtain the catalyst.

[0028] 3. The catalyst provided by this invention forms a Co-molecular sieve through ion exchange and then forms sulfonated cobalt phthalocyanine through in-situ synthesis. Compared with similar supported catalysts, sulfonated cobalt phthalocyanine is chemically bonded to the molecular sieve, and therefore undergoes virtually no freeing, shedding, or aggregation during the catalytic reaction, thus avoiding deactivation and resulting in a longer service life. Detailed Implementation

[0029] The following detailed description of the supported alkali-free desulfurization catalyst and its preparation method according to the present invention is provided in conjunction with specific embodiments. Unless otherwise specified, all percentages mentioned in the embodiments are mass percentages.

[0030] Example 1

[0031] 105g of Zn(NO3)2·6H2O and 20g of Al(NO3)3·9H2O were dissolved in 500mL of deionized water. 22.8g of SBA-15 molecular sieve (silicon-to-aluminum molar ratio of 30) was added and stirred to prepare a suspension. While continuously stirring, 1mol / L ammonia solution was simultaneously added dropwise to the same reactor, maintaining the pH at 10, and the reaction was carried out at room temperature for 3 hours. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 95℃, and then calcined in a muffle furnace at 700℃ for 4 hours to obtain the catalyst composite support.

[0032] Prepare a 0.2 mol / L Co(AC)₂ solution, and slowly add 27 mL of the Co(AC)₂ solution dropwise into the reaction vessel. Stir at room temperature for 2 h, then raise the temperature to 85 °C and maintain it for 12 h. Cool the reaction vessel to room temperature. After filtration, washing with deionized water, and drying at 180 °C, obtain the Co molecular sieve solid alkali sample.

[0033] Weigh out 6.5g of ammonium phthalate sulfonate, 16.2g of urea, 0.06g of ammonium molybdate, and 0.1g of phthalic anhydride, mix them with the Co molecular sieve solid alkali sample, and grind them evenly.

[0034] The above materials were placed in a reactor and heated to 120°C under an inert atmosphere for 8 hours. The temperature was then increased to 200°C and reacted for 5 hours to obtain a supported catalyst.

[0035] Example 2

[0036] 115g Ni(NO3)2·6H2O and 20g Al(NO3)3·9H2O were mixed and dissolved in 500mL deionized water. 33.5g HY molecular sieve (silicon-to-aluminum molar ratio of 2) was added and stirred to prepare a suspension. While continuously stirring, a 1mol / L mixed solution of NaOH and Na2CO3 (NaOH to Na2CO3 molar ratio 1:1) was simultaneously added dropwise to the same reactor, maintaining the pH at 10, and the reaction was carried out at room temperature for 5 hours. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 80℃, and then calcined in a muffle furnace at 650℃ for 8 hours to obtain the catalyst composite support.

[0037] A 0.2 mol / L Co(AC)₂ solution was prepared, and 54 mL of the solution was slowly added dropwise to the reaction vessel. The mixture was stirred at room temperature for 2 hours, then heated to 85°C and maintained at that temperature for 20 hours. The reaction vessel was then cooled to room temperature. After filtration, washing with deionized water, and drying at 190°C, a Co(Y) molecular sieve solid alkali sample was obtained.

[0038] Weigh out 12.8g of ammonium phthalate sulfonate, 32.4g of urea, 0.11g of ammonium molybdate, and 0.2g of phthalic anhydride, mix them with the Co molecular sieve solid alkali sample, and grind them evenly.

[0039] The above materials were placed in a reactor and heated to 150°C under an inert atmosphere for 5 hours. The temperature was then increased to 240°C and reacted for 5 hours to obtain a supported catalyst.

[0040] Example 3

[0041] 58g of Mg(NO3)2·6H2O and 20g of Al(NO3)3·9H2O were dissolved in 300mL of deionized water. 14.3g of SBA-15 molecular sieve (silicon-to-aluminum molar ratio of 30) was added and stirred to prepare a suspension. While continuously stirring, 1mol / L ammonia solution was simultaneously added dropwise to the same reactor, maintaining the pH at 10, and the reaction was carried out at room temperature for 4 hours. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 90℃, and then calcined in a muffle furnace at 700℃ for 5 hours to obtain the catalyst composite support.

[0042] A 0.2 mol / L Co(NO3)2 solution was prepared, and 27 mL of the solution was slowly added dropwise to the reaction vessel. The mixture was stirred at room temperature for 5 h, then heated to 120 °C and maintained at that temperature for 24 h. The reaction vessel was then cooled to room temperature. After filtration, washing with deionized water, and drying at 200 °C, a Co(Y) molecular sieve solid alkali sample was obtained.

[0043] Weigh out 6.5g of ammonium phthalate sulfonate, 16.2g of urea, 0.06g of ammonium molybdate, and 0.1g of phthalic anhydride, mix them with the Co molecular sieve solid alkali sample, and grind them evenly.

[0044] The above materials were placed in a reactor and heated to 130°C under an inert atmosphere for 5 hours. The temperature was then increased to 230°C and reacted for 6 hours to obtain a supported catalyst.

[0045] Example 4

[0046] 56g of Mg(NO3)2·6H2O and 20g of Al(NO3)3·9H2O were dissolved in 300mL of deionized water. 21.1g of HY molecular sieve (silicon-to-aluminum molar ratio of 2) was added and stirred to prepare a suspension. While continuously stirring, a 1mol / L mixed solution of NaOH and Na2CO3 (NaOH to Na2CO3 molar ratio 1:2) was simultaneously added dropwise to the same reactor, maintaining the pH at 10, and the reaction was carried out at room temperature for 4.5h. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 80℃, and then calcined in a muffle furnace at 650℃ for 6h to obtain the catalyst composite support.

[0047] A 0.2 mol / L CoCl2 solution was prepared, and 55 mL of the solution was slowly added dropwise to the reaction vessel. The mixture was stirred at room temperature for 5 h, then heated to 120 °C and maintained at that temperature for 28 h. The reaction vessel was then cooled to room temperature. After filtration, washing with deionized water, and drying at 150 °C, a Co(Y) molecular sieve solid alkali sample was obtained.

[0048] Weigh out 12.8g of ammonium phthalate sulfonate, 32.4g of urea, 0.11g of ammonium molybdate, and 0.2g of phthalic anhydride, mix them with the Co molecular sieve solid alkali sample, and grind them evenly.

[0049] The above materials were placed in a reactor and heated to 160°C under an inert atmosphere for 6 hours. The temperature was then increased to 260°C and reacted for 4 hours to obtain a supported catalyst.

[0050] Example 5

[0051] 30g of Mg(NO3)2·6H2O and 8g of Al(NO3)3·9H2O were dissolved in 200mL of deionized water. 17.1g of HY molecular sieve (silicon-to-aluminum molar ratio of 2) was added and stirred to prepare a suspension. While continuously stirring, 0.5mol / L ammonia solution was simultaneously added dropwise to the same reactor, maintaining the pH at 9, and the reaction was carried out at room temperature for 3 hours. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 100℃, and then calcined in a muffle furnace at 500℃ for 8 hours to obtain the catalyst composite support.

[0052] Prepare a 0.2 mol / L Co(AC)₂ solution, and slowly add 55 mL of the solution dropwise into the reaction vessel. Stir at room temperature for 2 h, then raise the temperature to 150 °C and maintain it for 18 h. Cool the reaction vessel to room temperature. After filtration, washing with deionized water, and drying at 150 °C, obtain the Co(Y) molecular sieve solid alkali sample.

[0053] Weigh out 12.8g of ammonium phthalate sulfonate, 32.4g of urea, 0.11g of ammonium molybdate, and 0.2g of phthalic anhydride, mix them with the Co molecular sieve solid alkali sample, and grind them evenly.

[0054] The above materials were placed in a reactor and heated to 130°C under an inert atmosphere for 5 hours. The temperature was then increased to 240°C and reacted for 6 hours to obtain a supported catalyst.

[0055] Example 6

[0056] 5g of Cr(NO3)3·9H2O and 8g of Mg(NO3)2·9H2O were dissolved in 200mL of deionized water. 14.8g of HY molecular sieve (silicon-to-aluminum molar ratio of 2) was added and stirred to prepare a suspension. While continuously stirring, 0.8mol / L ammonia solution was simultaneously added dropwise to the same reactor, maintaining the pH at 11, and the reaction was carried out at room temperature for 4 hours. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 90℃, and then calcined in a muffle furnace at 800℃ for 5 hours to obtain the catalyst composite support.

[0057] A 0.2 mol / L Co(AC)₂ solution was prepared, and 55 mL of the solution was slowly added dropwise to the reaction vessel. The mixture was stirred at room temperature for 2 h, then heated to 110 °C and maintained at that temperature for 22 h. The reaction vessel was then cooled to room temperature. After filtration, washing with deionized water, and drying at 190 °C, a Co(Y) molecular sieve solid alkali sample was obtained.

[0058] Weigh out 12.8g of ammonium phthalate sulfonate, 32.4g of urea, 0.11g of ammonium molybdate, and 0.2g of phthalic anhydride, mix them with the Co molecular sieve solid alkali sample, and grind them evenly.

[0059] The above materials were placed in a reactor and heated to 170°C under an inert atmosphere for 10 hours. The temperature was then increased to 270°C and reacted for 8 hours to obtain a supported catalyst.

[0060] Comparative Example 1

[0061] An alkali-free desulfurization catalyst was prepared using the method disclosed in CN1200958A. The catalyst composition was 54% molecular sieve, 18% solid alkali, and 28% cobalt phthalocyanine. The molecular sieve and solid alkali were the same as in Example 5.

[0062] Comparative Example 2

[0063] An alkali-free desulfurization catalyst was prepared using the method disclosed in CN1978058A. The catalyst composition was 57% molecular sieve, 9% solid alkali, and 34% cobalt phthalocyanine. The molecular sieve and solid alkali were the same as in Example 6.

[0064] Table 1 Catalyst Composition (wt%)

[0065]

[0066]

[0067] Desulfurization evaluation experiments were conducted on the catalysts prepared in Examples 1-6 and Comparative Examples 1-2. The experimental feedstock properties were: sulfur content 12000 μg / g, mercaptan sulfur content 11500 μg / g. A fixed-bed reactor with top feed was used; the reaction conditions were: volume hourly space velocity (VHSV) 1 h⁻¹. -1 The reaction temperature was 25℃ and the reaction pressure was 1.5MPa. The experimental results are listed in Table 2.

[0068] Table 2 Evaluation Results (Sampling Time: 10h)

[0069] catalyst Sulfur content of raw materials, μg / g Product thiol sulfur, μg / g Example 1 12000 ＜2 Example 2 12000 ＜2 Example 3 12000 ＜2 Example 4 12000 ＜2 Example 5 12000 ＜2 Example 6 12000 ＜2 Comparative Example 1 12000 ＜2 Comparative Example 2 12000 ＜2

[0070] Table 3. Stability Tests (Product Thiol Sulfur, μg / g)

[0071] Sampling time 48h 96h 144h 192h Example 1 ＜2 ＜2 3 5 Example 2 ＜2 ＜2 ＜2 3 Example 3 ＜2 ＜2 ＜2 2 Example 4 ＜2 ＜2 ＜2 ＜2 Example 5 ＜2 ＜2 ＜2 ＜2 Example 6 ＜2 ＜2 ＜2 ＜2 Comparative Example 1 ＜2 ＜2 7 19 Comparative Example 2 ＜2 ＜2 8 48

Claims

1. A method for preparing a supported low-carbon hydrocarbon alkali-free deodorization catalyst, comprising the following: (1) Prepare a solution of a certain concentration containing M 2+ and M' 3+ The microporous molecular sieve is added to the above mixed solution and stirred until homogeneous; (2) React the suspension obtained in step (1) with a mixed solution of NaOH and Na2CO3 or a weak alkaline solution under stirring for a period of time; (3) The material obtained in step (2) is filtered, washed, dried and calcined to obtain a composite carrier; (4) Prepare a cobalt salt solution and remove Co through ion exchange. 2+ The components are transferred to the composite carrier obtained in step (3); (5) The material obtained in step (4) is filtered and dried to obtain Co molecular sieve solid alkali; (6) Add a certain amount of ammonium phthalate sulfonate, urea, ammonium molybdate and phthalic anhydride to the Co molecular sieve solid alkali obtained in step (5) in proportion, and grind evenly; (7) The material obtained in step (6) is placed in a reactor and heated to 80℃~160℃ under an inert atmosphere for 3h~8h. Then the temperature is raised to 180℃~300℃ and reacted for 3h~8h to obtain the catalyst product. in, M is a Group IIA or Group IIB element, and M' is a Group IIIA or Group VIII element; the silicon-to-aluminum molar ratio of the molecular sieve is 0.5 to 200.

2. The preparation method according to claim 1, characterized in that, The stirring time in step (1) is 10 min to 180 min.

3. The preparation method according to claim 1, characterized in that, M is selected from at least one divalent metal from Mg, Ca, Ba, and Zn, and M' is selected from at least one trivalent metal from Al, Fe, Co, and Ni.

4. The preparation method according to claim 1, characterized in that, The M-containing 2+ and M' 3+ The mixed solution is a nitrate solution or hydrochloride solution of M and M'; containing M 2+ and M' 3+ The concentrations of the mixed solutions are 0.1 mol / L (saturation concentration) and 0.02 mol / L (saturation concentration), respectively; M 2+ and M' 3+ The molar ratio is 0.5~30.

5. The preparation method according to claim 1, characterized in that, In step (2), the molar ratio of NaOH to Na2CO3 in the mixed solution is 1:3 to 30:1; the weak alkaline solution is selected from at least one of dilute ammonia water and dimethylamine.

6. The preparation method according to claim 1, characterized in that, In step (2), stop stirring when the pH of the suspension is 9-10 and let it stand for 10-180 minutes.

7. The preparation method according to claim 1, characterized in that, The calcination conditions in step (3) are: temperature of 400~900℃ and calcination time of 4-10h.

8. The preparation method according to claim 1, characterized in that, The cobalt salt solution in step (4) is selected from at least one of Co(NO3)2 solution, Co(AC)2 solution or CoCl2 solution.

9. The preparation method according to claim 1, characterized in that, The operating conditions for ion exchange in step (4) are: temperature from room temperature to 200℃, and exchange time from 12 to 36 hours.

10. The supported low-carbon hydrocarbon alkali-free deodorization catalyst obtained by any of the preparation methods described in claims 1-9.

11. The alkali-free deodorizing catalyst according to claim 10, characterized in that, The catalyst comprises, by weight, 35%-65% molecular sieve, 10%-55% xMO▪yM'2O3, and 5%-25% sulfonated cobalt phthalocyanine; wherein M is selected from at least one divalent metal of Mg, Ca, Ba, and Zn, and M' is selected from at least one trivalent metal of Al, Fe, Co, and Ni, and x:y = 0.5~30.

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