Regeneration method of inactivated benzene hydrogenation catalyst

Abstract

The invention relates to a regeneration method of a deactivated benzene hydrogenation catalyst, which comprises the following steps: purging the deactivated benzene hydrogenation catalyst in an inert atmosphere at 130-300 DEG C for 1-8 hours so as to remove materials such as benzene attached to the surface, thereby obtaining a debenzolized catalyst; soaking the debenzolized catalyst in polyhydric alcohol for 2 to 30 hours under the conditions that the temperature is 100 to 300 DEG C and the pressure is 0.1 to 3 MPa; and after soaking is finished, cooling, emptying the polyol, washing the catalyst with a solvent, and then purging with high-temperature inert gas to remove the solvent. According to the method, surface deposited silicon is selectively removed from an industrial hydrodesulfurization deactivated catalyst through a glycerol depolymerization process, and the activity and physical properties of the catalyst are recovered. The method provides a new technical means for regeneration of the industrial catalyst, and realizes reutilization of the catalyst deactivated due to silicon poisoning.

Description

Technical Field

[0001] This invention relates to the field of catalyst regeneration, and more specifically to a method for regenerating a deactivated benzene hydrogenation catalyst. Background Technology

[0002] During hydrodesulfurization, silicon compounds (such as polydimethylsiloxane, PDMS) in coking crude benzene can deposit on the catalyst surface. These silicon compounds decompose into lighter siloxane fragments at high temperatures and undergo condensation reactions on the alumina (Al₂O₃) surface of the catalyst, forming a difficult-to-remove silicon species (such as SiO₂) deposition layer. This deposition clogs the catalyst's pores, reduces its specific surface area and the accessibility of active sites, ultimately leading to catalyst deactivation. Summary of the Invention

[0003] To address the above-mentioned technical problems, the inventors of this disclosure conducted in-depth research on the mechanism of hydrogenation catalyst poisoning through repeated experiments, and obtained a method for treating catalysts deactivated by silicon poisoning, and completed this disclosure based on this method.

[0004] The main objective of this disclosure is to provide a method for regenerating a deactivated benzene hydrogenation catalyst.

[0005] According to one embodiment of this disclosure, a method for regenerating a deactivated benzene hydrogenation catalyst is provided, the method comprising: S1: The deactivated benzene hydrogenation catalyst is purged in an inert atmosphere at 130-300℃ for 1-8 hours to remove the benzene adhering to the surface and obtain the benzene-free catalyst. S2: The benzene-free catalyst is soaked in a polyol at 100 to 300°C and 0.1 to 3 MPa for 2 to 30 hours; S3: After soaking, cool down, vent the polyol, wash the catalyst with solvent, and then purge with high-temperature inert gas to remove the solvent.

[0006] By utilizing the chemical properties of polyols at high temperatures, deposited silicon compounds can be converted into soluble or volatile products for easy removal.

[0007] According to one embodiment of the present invention, the deactivated benzene hydrogenation catalyst refers to a NiMo-based catalyst or a CoMo catalyst deactivated due to silicon poisoning.

[0008] According to one embodiment of the present invention, wherein, In step S1, the inert atmosphere is a nitrogen atmosphere, which refers to nitrogen with an oxygen content of no more than 5%.

[0009] According to one embodiment of the present invention, wherein, In step S1, the benzene removal temperature is 200-300℃; the time is 2-8 hours; the inert atmosphere pressure is 0.1-3 MPa; and the space velocity is 1000-1500 Nm. 3 / h·m 3 -cat.

[0010] Under these conditions, it can be ensured that benzene compounds are removed as much as possible.

[0011] According to one embodiment of the present invention, wherein, The polyol in step S2 is selected from one or more of glycerol, ethylene glycol, and 1,2,4-butanetriol.

[0012] When using glycerol, under high temperature (around 260°C) and certain pressure (e.g., 2.5 MPa), glycerol, as a polyol, can chemically react with silicon compounds on the catalyst surface. The hydroxyl groups (-OH) in the glycerol molecule can react with the silicon-oxygen bonds (Si-O-Si), breaking the silicon-oxygen bonds and forming intermediate products such as methoxysilanes (Si-O-CH3). These intermediate products further decompose at high temperature, generating soluble or volatile silicon compounds, which then detach from the catalyst surface.

[0013] According to one embodiment of the present invention, in step S3, the solvent is methanol or ethanol.

[0014] According to one embodiment of the present invention, in step S3, the temperature is lowered to 90-110°C, and the high-temperature inert gas is nitrogen gas at 100-200°C.

[0015] According to one embodiment of the present invention, in step S3, the catalyst is washed with methanol three or more times.

[0016] Beneficial effects This invention utilizes a polyol depolymerization process to selectively remove deposited silicon from the surface of deactivated Ni-Mo or Co-Mo-based hydrodesulfurization catalysts in industrial applications, thereby restoring the catalyst's activity and physical properties. This method provides a novel technological approach for the regeneration of industrial catalysts, enabling the reuse of catalysts deactivated due to silicon poisoning. Attached Figure Description

[0017] Figure 1 This is a flowchart of a method for treating silicon in a benzene hydrogenation catalyst according to one embodiment of the present disclosure.

[0018] Figure 2 This is a schematic diagram of a device for processing silicon in a benzene hydrogenation catalyst according to an embodiment of the present disclosure. In the diagram, E-4 represents a methanol feed pump and E-5 represents a glycerol feed pump. Detailed Implementation

[0019] As used in this disclosure, the term "benzene hydrogenation catalyst" refers to a NiMo-based or CoMo-based catalyst used in the main reactor during the production of crude benzene hydrogenation refining. "Deactivated catalyst" / "deactivated benzene hydrogenation catalyst" refers to a NiMo-based or CoMo-based catalyst whose hydrogenation and impurity removal capabilities have decreased after long-term operation and thus cannot achieve the desired performance.

[0020] "Silicon content in the benzene hydrogenation CoMo catalyst" refers to the total amount of silicon in all organosilicon and inorganic silicon in the "benzene hydrogenation CoMo catalyst". "Silicon content in new catalysts": The silicon content in the new CoMo catalyst, as analyzed by atomic absorption spectroscopy (AAS), is generally between 800-1000 ppm.

[0021] “cat” refers to a catalyst.

[0022] Example 1: S1: Weigh 300g of deactivated CoMo catalyst, analyze the silicon content in the catalyst by atomic absorption spectrometry (AAS), and record the data 1.1.

[0023] S2: Place the deactivated catalyst in a fixed-bed reactor and seal it.

[0024] S3: Use high-temperature nitrogen gas to purge benzene from the catalyst. Nitrogen temperature: 150℃, pressure: 0.4MPa, space velocity: ≥1200Nm 3 / h·m 3 -cat, purging time 4h.

[0025] S4: After purging is complete, seal the gas inlet and outlet of the fixed bed and start injecting glycerol until the glycerol completely covers the hydrogenation catalyst. S5: Introduce nitrogen gas to raise the pressure of the fixed-bed reactor to 2.5 MPa, and simultaneously raise the temperature to 260℃.

[0026] S6: The reaction time is 4 hours.

[0027] S7: After the reaction is complete, open the exhaust port and reduce the pressure to atmospheric pressure. When the temperature drops to about 100℃, open the discharge port to release the glycerol from the reactor.

[0028] S8: Pass in excess methanol for washing, with a minimum of 750ml each time.

[0029] S9: Repeat the washing operation three times to ensure complete washing of glycerin. Collect the methanol solution using a collection tank.

[0030] S10: After washing, purge with nitrogen gas at 100°C or higher for 2 hours.

[0031] S11: Remove the hydrogenation catalyst and analyze the silicon content in the catalyst by atomic absorption spectroscopy (AAS), and record the data 1.2.

[0032] S12: Calculate the silicon reduction rate.

[0033] Reduction rate 1 = (Data 1.1 - Data 1.2) / Data 1.1 * 100% Activity recovery 1 = (Data 1.1 - Data 1.2) / (Data 1.1 - Silicon content of new catalyst) * 100% The results are listed in Table 1 below.

[0034] Example 2 S1: Weigh 300g of deactivated CoMo catalyst and analyze the silicon content in the CoMo catalyst by atomic absorption spectrometry (AAS). Record the data in 2.1.

[0035] S2: Place the deactivated catalyst in a fixed-bed reactor and seal it.

[0036] S3: Use high-temperature nitrogen gas to purge benzene from the catalyst. Nitrogen temperature: 150℃, pressure: 0.4MPa, space velocity: ≥1200Nm 3 / h·m 3 -cat, purging time 4h.

[0037] S4: Inject 500ml of heated ethylene glycol (100℃), introduce nitrogen gas to raise the pressure of the fixed-bed reactor to 2.2MPa, and simultaneously raise the temperature to 240℃.

[0038] S5: The reaction time is 4 hours, which allows ethylene glycol to fully polymerize and silicon to fully dissolve in the ethylene glycol solution.

[0039] S6: Keep the temperature above 100℃, and while depressurizing, use nitrogen to purge away most of the ethylene glycol.

[0040] S7: Dissolve the residual ethylene glycol in methanol solution, drain, and repeat three times.

[0041] S8: Purge the catalyst surface with nitrogen gas at around 100°C for 2 hours to remove methanol.

[0042] S9: Remove the hydrogenation catalyst and analyze the silicon content in the catalyst by atomic absorption spectroscopy (AAS), and record the data 2.2.

[0043] S10: Calculate the silicon reduction rate.

[0044] Reduction rate 2 = (Data 2.1 - Data 2.2) / Data 2.1 * 100% Activity recovery 2 = (Data 2.1 - Data 2.2) / (Data 2.1 - Silicon content of the new CoMo catalyst) * 100% The results are listed in Table 1 below.

[0045] Example 3 S1: Weigh 300g of deactivated CoMo catalyst, analyze the silicon content in the catalyst by atomic absorption spectrometry (AAS), and record the data in 3.1.

[0046] S2: Place the deactivated catalyst in a fixed-bed reactor and seal it.

[0047] S3: Use high-temperature nitrogen gas to purge benzene from the catalyst. Nitrogen temperature: 150℃, pressure: 0.4MPa, space velocity: ≥1200Nm 3 / h·m 3 -cat, purging time 4h.

[0048] S4: Inject 500ml of heated 1,2,4-butanetriol (100℃), introduce nitrogen gas to raise the pressure of the fixed-bed reactor to 2.2MPa, and simultaneously raise the temperature to 240℃.

[0049] S5: The reaction time is 4 hours to allow silicon to dissolve completely.

[0050] S6: Keep the temperature above 100℃, and while depressurizing, use nitrogen to purge away most of the 1,2,4-butanetriol.

[0051] S7: Dissolve the remaining 1,2,4-butanetriol in methanol solution, drain, and repeat three times.

[0052] S8: Purge the catalyst surface with nitrogen gas at around 100°C for 2 hours to remove methanol.

[0053] S9: Remove the hydrogenation catalyst and analyze the silicon content in the catalyst by atomic absorption spectrometry (AAS), and record the data 3.2.

[0054] S10: Calculate the silicon reduction rate.

[0055] Reduction rate 3 = (Data 3.1 - Data 3.2) / Data 3.1 * 100% Activity recovery 3 = (Data 3.1 - Data 3.2) / (Data 3.1 - Silicon content of new catalyst) * 100% The results are listed in Table 1 below.

[0056] Example 4 S1: Weigh 500g of deactivated CoMo catalyst and analyze the silicon content in the catalyst by atomic absorption spectrometry (AAS). Record the data as 4.1.

[0057] S2: Place the deactivated catalyst in a fixed-bed reactor and seal it.

[0058] S3: Use high-temperature nitrogen gas to purge benzene from the catalyst. Nitrogen temperature: 150℃, pressure: 0.4MPa, space velocity: ≥1200Nm 3 / h·m 3 -cat, purging time 4h.

[0059] S4: After purging is complete, seal the gas inlet and outlet of the fixed bed and start injecting glycerol until the glycerol completely covers the hydrogenation catalyst; S5: Introduce nitrogen gas to raise the pressure of the fixed-bed reactor to 2.5 MPa, and simultaneously raise the temperature to 260℃. S6: The reaction time is 4 hours.

[0060] S7: After the reaction is complete, open the exhaust port to release the pressure to atmospheric pressure. When the temperature drops to about 100℃, open the discharge port to release the glycerol in the reactor.

[0061] S8: Pass in excess ethanol for washing, with each pass being approximately 750 ml.

[0062] S9: Repeat the washing operation three times to ensure complete washing of the glycerin. Collect the ethanol solution using a collection tank.

[0063] S10: Purge the catalyst surface with nitrogen gas at around 100°C for 2 hours to remove ethanol.

[0064] S11: Remove the hydrogenation catalyst and observe its surface morphology using an electron microscope (SEM); analyze the silicon content in the catalyst using atomic absorption spectrometry (AAS) and record the data 4.2.

[0065] S12: Calculate the silicon reduction rate.

[0066] Reduction rate 4 = (Data 4.1 - Data 4.2) / Data 4.1 * 100% Activity recovery 4 = (Data 4.1 - Data 4.2) / (Data 4.1 - Silicon content of new catalyst) * 100% The results are listed in Table 1 below.

[0067] Example 5 S1: Weigh 300g of deactivated CoMo catalyst and analyze the silicon content in the catalyst by atomic absorption spectrometry (AAS). Record the data in 5.1.

[0068] S2: Place the deactivated catalyst in a fixed-bed reactor and seal it.

[0069] S3: Use high-temperature nitrogen gas to purge benzene from the catalyst. Nitrogen temperature: 150℃, pressure: 0.4MPa, space velocity: ≥1200Nm 3 / h·m 3 -cat, purging time 4h.

[0070] S4: Inject 500ml of heated ethylene glycol (100℃), introduce nitrogen gas to raise the pressure of the fixed-bed reactor to 2.2MPa, and simultaneously raise the temperature to 240℃.

[0071] S5: The reaction time is 4 hours to allow silicon to dissolve completely.

[0072] S6: Keep the temperature above 100℃, and while depressurizing, use nitrogen to purge away most of the ethylene glycol.

[0073] S7: Dissolve the residual ethylene glycol in an ethanol solution, drain it, and repeat three times.

[0074] S8: Purge the catalyst surface with nitrogen gas at around 100°C for 2 hours to remove ethanol.

[0075] S9: Remove the hydrogenation catalyst and observe its surface morphology using an electron microscope (SEM); analyze the silicon content in the catalyst using atomic absorption spectroscopy (AAS) and record the data (5.2).

[0076] S10: Calculate the silicon reduction rate.

[0077] Reduction rate 5 = (Data 5.1 - Data 5.2) / Data 5.1 * 100% Activity recovery 5 = (Data 5.1 - Data 5.2) / (Data 5.1 - Silicon content of the new CoMo catalyst) * 100% The results are listed in Table 1 below.

[0078] Example 6 S1: Weigh 300g of deactivated CoMo catalyst and analyze the silicon content in the catalyst by atomic absorption spectrometry (AAS). Record the data as 6.1.

[0079] S2: Place the deactivated catalyst in a fixed-bed reactor and seal it.

[0080] S3: Use high-temperature nitrogen gas to purge benzene from the catalyst. Nitrogen temperature: 150℃, pressure: 0.4MPa, space velocity: ≥1200Nm 3 / h·m 3 -cat, purging time 4h.

[0081] S4: Inject 500ml of heated 1,2,4-butanetriol (100℃), introduce nitrogen gas to raise the pressure of the fixed-bed reactor to 2.2MPa, and simultaneously raise the temperature to 240℃.

[0082] S5: The reaction time is 4 hours, which allows 1,2,4-butanetriol to fully condense and silicon to fully dissolve in the polymer.

[0083] S6: Keep the temperature above 100℃, and while depressurizing, use nitrogen to purge away most of the 1,2,4-butanetriol.

[0084] S7: Dissolve the remaining 1,2,4-butanetriol in ethanol solution, drain, and repeat three times.

[0085] S8: Purge the catalyst surface with nitrogen gas at around 100°C for 2 hours to remove ethanol.

[0086] S9: Remove the hydrogenation catalyst and observe its surface morphology using an electron microscope (SEM); analyze the silicon content in the catalyst using atomic absorption spectroscopy (AAS) and record the data (6.2).

[0087] S10: Calculate the silicon reduction rate.

[0088] Reduction rate 6 = (Data 6.1 - Data 6.2) / Data 6.1 * 100% Activity recovery 6 = (Data 6.1 - Data 6.2) / (Data 6.1 - Silicon content of new catalyst) * 100% The results are listed in Table 1 below.

[0089] Table 1. Comparison of silicon reduction rates.

[0090]

[0091] As can be seen from Table 1, the deposited silicon in the catalyst can be removed and the catalyst activity can be restored by using polyols.

[0092] Experimental Example 1 According to one embodiment of this disclosure, such as Figure 1 As shown, a method for treating silicon in a benzene hydrogenation catalyst is provided, the method comprising: In a 100,000-ton-capacity benzene hydrogenation plant, the CoMo catalyst in the main reactor had been in use for 5 years and was no longer effective in removing impurities during hydrogenation. The hydrogenation catalyst was removed from the main reactor in batches of 1000 kg and placed in a high-temperature, high-pressure reactor. First, the catalyst was purged with 300°C nitrogen gas for 4 hours to remove benzene from the catalyst.

[0093] After purging, the catalyst was soaked in 5000 kg of glycerol at a temperature of 280°C and a pressure of 2.5 MPa for 24 hours. After soaking, the glycerol was vented, and excess glycerol was dissolved by rinsing with methanol. Finally, high-temperature nitrogen was used to remove methanol, yielding a regenerated and activated hydrogenation catalyst. Based on the residual thiophene value in pure benzene, the hydrogenation efficiency was restored to 93%; based on the product's standard service life, the service life was approximately 65% ​​of that of a new catalyst.

[0094] Experimental Example 2 In a 100,000-ton-capacity benzene hydrogenation unit, the CoMo catalyst in the main reactor had been in use for eight years and was no longer effective in removing impurities during hydrogenation. The plant had a backup hydrogenation reactor. The main reactor was switched out, and circulating nitrogen was used to continuously purge it for 5 hours at 280°C and 2.5 MPa to evaporate the residual benzene in the main reactor.

[0095] After purging, the catalyst was immersed in a circulating solution of 5 times its volume of glycerol (catalyst 22m). 3 110m of glycerol 3 Soaking temperature 280℃, pressure 2.5MPa, soaking time 24h.

[0096] After soaking, drain the glycerol and rinse with a methanol-water solution to dissolve excess glycerol. Finally, purge with high-temperature nitrogen gas to remove methanol.

[0097] The silicon content in the catalyst was analyzed by atomic absorption spectrometry (AAS).

[0098] Before treatment: 26990ppm, after treatment: 8700ppm, silicon reduction rate: 67.7%.

[0099] The treated catalyst can operate stably on the unit with hydrogenation efficiency within an acceptable range, but the catalyst life is reduced to about 70% of that of a new catalyst.

[0100] Experimental Example 3 In a 150,000-ton-capacity benzene hydrogenation unit, the CoMo catalyst in the main reactor had been in use for four years. Due to the long-term use of crude benzene with a high silicon content, the catalyst could no longer achieve the desired hydrogenation and impurity removal effect. The plant discarded the upper 10 tons of hydrogenation catalyst in the main reactor. In the lower part, circulating nitrogen was used to continuously purge for 5 hours at 280°C and 2.5 MPa to evaporate the residual benzene in the main reactor.

[0101] After purging, the catalyst was immersed in a circulating solution of 5 times its volume of glycerol (catalyst 21m). 3 110m of glycerol 3 Soaking temperature 280℃, pressure 2.5MPa, soaking time 24h.

[0102] After soaking, drain the glycerol and rinse with a methanol-water solution to dissolve excess glycerol. Finally, purge with high-temperature nitrogen gas to remove methanol.

[0103] The silicon content in the catalyst was analyzed by atomic absorption spectrometry (AAS).

[0104] Before treatment: 32730ppm, after treatment: 9300ppm, silicon reduction rate: 70.3%.

[0105] Adding 10 tons of new hydrogenation catalyst allows for continuous operation for three years, with a service life of approximately 80% of that of replacing all catalysts.

[0106] The processing device used in the above experimental embodiments is as follows: Figure 2 As shown.

[0107] Finally, it should be noted that the above describes a method for removing deposited silicon from a benzene hydrogenation catalyst and restoring its activity, as provided by this invention, and provides a detailed description. Specific embodiments have been used to illustrate the process and implementation of this invention. The descriptions of the above embodiments are merely for the purpose of helping to understand the method and its central idea. It should be pointed out that those skilled in the art can make several improvements and modifications to this invention without departing from the principles of this invention, and these improvements and modifications also fall under the protection of the claims of this invention.

Claims

1. A method for regenerating a deactivated benzene hydrogenation catalyst, the method comprising: S1: The deactivated benzene hydrogenation catalyst is purged in an inert atmosphere at 130-300℃ for 1-8 hours to remove the benzene adhering to the surface and obtain the benzene-free catalyst. S2: The benzene-free catalyst is soaked in a polyol at 100 to 300°C and 0.1 to 3 MPa for 2 to 30 hours; S3: After soaking, cool down, vent the polyol, wash the catalyst with solvent, and then purge with high-temperature inert gas to remove the solvent.

2. The method according to claim 1, wherein, The deactivated benzene hydrogenation catalyst refers to a NiMo-based catalyst or a CoMo-based catalyst that is deactivated due to silicon poisoning.

3. The method according to claim 1, wherein, In step S1, the inert atmosphere is a nitrogen atmosphere, which refers to nitrogen with an oxygen content of no more than 5%.

4. The method according to claim 1, wherein, In step S1, the benzene removal temperature is 200-300℃; the time is 2-8 hours; the inert atmosphere pressure is 0.1-3 MPa; and the space velocity is 1000-1500 Nm. 3 / h·m 3 -cat.

5. The method according to claim 1, wherein, The polyol in step S2 is selected from one or more of glycerol, ethylene glycol, and 1,2,4-butanetriol.

6. The method according to claim 1, wherein, In step S3, the solvent is methanol or ethanol.

7. The method according to claim 1, wherein, In step S3, the temperature is lowered to 90-110°C, and the high-temperature inert gas is nitrogen gas at 100-200°C.

8. The method according to claim 1, wherein, In step S3, the catalyst is washed with methanol more than three times.

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