Process for the regeneration of deactivated hydrogenation catalysts

Abstract

The application discloses a regeneration method of inactivated hydrogenation catalyst, which comprises the following steps: (1) calcining alkali metal poisoned hydrogenation catalyst in an inert atmosphere; (2) impregnating the catalyst obtained in step (1) with an organic acid solution and then drying; and (3) washing the catalyst obtained in step (2) with a buffer solution, and then drying and calcining to obtain a final regenerated hydrogenation catalyst. The regeneration method can remove alkali metal impurities adsorbed on the surface acid sites of the catalyst in a targeted manner, and restores the catalyst activity to the maximum extent.

Description

Technical Field

[0001] This invention relates to a method for regenerating a deactivated hydrogenation catalyst, and more particularly to a method for regenerating an abnormally deactivated hydrogenation catalyst. Background Technology

[0002] During hydrogenation reactions, the activity of hydrogenation catalysts typically decreases gradually with prolonged operation, eventually leading to deactivation. Many factors contribute to catalyst deactivation, one of the main ones being coke deposition. Coke typically deposits on the catalyst surface, clogging pores and covering active sites, thus reducing reaction activity. In addition, deactivated catalysts also suffer from severe transition metal (nickel, vanadium, and iron) impurity deposition, which can account for more than 20% of the weight of the deactivated catalyst.

[0003] CN201911361889.5 discloses a method for hydrotreating heavy oil. The heavy oil feedstock is contacted with hydrogen in a hydrotreating reactor to complete the hydrotreating process. The hydrotreating reactor is filled with a regenerator obtained by regenerating a deactivated hydrotreating catalyst. The regeneration process of the regenerator is as follows: the deactivated hydrotreating catalyst is carbonized and desulfurized, then impregnated with an acidic solution containing a complexing agent, and then impregnated with an alkaline solution and treated under an ammonia atmosphere to effectively remove metallic impurities such as nickel, vanadium and iron.

[0004] The catalyst regeneration method described in the aforementioned patent is for catalysts that have become deactivated due to conventional reasons such as carbon buildup and transition metal deposition. This deactivation can often be adjusted by increasing the reaction temperature during the reaction process. However, when the reaction cycle is nearing its end and further temperature increases are no longer possible, existing regeneration methods are required to regenerate the catalyst. In actual operation, there is also a phenomenon where catalysts suddenly deactivate within the normal operating cycle due to improper operating conditions or fluctuations in reactant materials. Existing technologies do not provide solutions for how to regenerate or whether such abnormally deactivated hydrogenation catalysts can be regenerated. A detailed analysis of the causes of deactivation is needed to provide relevant solutions. Summary of the Invention

[0005] The inventors encountered a situation where a hydrogenation catalyst underwent abnormal deactivation. The catalyst experienced severe deactivation shortly after starting operation, and even increasing the temperature could not restore its activity, forcing the refining plant to shut down. Through in-depth research, the inventors discovered that the cause of catalyst deactivation was not carbon buildup or transition metal deposition, but rather a significant increase in the alkali metal content of the deactivated catalyst, stemming from improper raw material control during industrial applications. Further research revealed that the rapid deactivation of the hydrogenation catalyst due to alkali metal impurities was caused by these impurities occupying acidic sites on the catalyst surface.

[0006] Based on the above research results, this invention proposes a method for regenerating deactivated hydrogenation catalysts. The regeneration method can specifically remove alkali metal impurities adsorbed on acidic sites on the catalyst surface and restore catalyst activity to the greatest extent.

[0007] This invention provides a method for regenerating a deactivated hydrogenation catalyst, comprising the following steps: (1) The alkali metal poisoned hydrogenation catalyst was calcined in an inert atmosphere; (2) Impregnate the catalyst obtained in step (1) with an organic acid solution and then dry it; (3) The catalyst obtained in step (2) is rinsed with a buffer solution, dried and calcined to obtain the final regenerated hydrogenation catalyst.

[0008] In the method of the present invention, the alkali metal poisoned hydrogenation catalyst mentioned in step (1) refers to a catalyst that is partially deactivated or fails to meet the reaction requirements due to alkali metal deposition during the hydrogenation process. The catalyst includes a support and an active metal component. The support is generally at least one of alumina, amorphous silica-alumina and molecular sieve. The active metal component is generally a Group VIB metal and / or a Group VIII metal, wherein the Group VIB metal is at least one of Mo and W, and the Group VIII metal is at least one of Ni and Co.

[0009] In the method of the present invention, in step (1), based on the mass of the alkali metal deposition deactivated catalyst after removing sulfur and carbon, the alkali metal content in the alkali metal poisoned hydrogenation catalyst is 0.2wt%-8.0wt%, preferably 0.3wt%-5.0wt%, further preferably 0.5wt%-3.0wt%, and even more preferably 1wt%-2.0wt%; the alkali metal includes one or more of lithium, sodium and potassium.

[0010] In the method of the present invention, the inert atmosphere in step (1) is a nitrogen atmosphere or an inert gas atmosphere, and the inert gas atmosphere is one or more of argon atmosphere, helium atmosphere and neon atmosphere.

[0011] In the method of the present invention, the roasting temperature in step (1) is 400~800℃, preferably 500~700℃, and the time is 1~3h.

[0012] In the method of the present invention, the molar ratio of the organic acid contained in the organic acid solution in step (2) to the group VIB metal and group VIII metal (calculated as elemental metal) in the alkali metal poisoning hydrogenation catalyst is 0.03~0.6, preferably 0.05~0.5.

[0013] In the method of the present invention, the organic acid solution in step (2) contains a solute organic acid and a solvent. The organic acid is an organic acid with less than 10 carbon atoms, preferably an α-hydroxy acid, such as one or more of malic acid, citric acid, salicylic acid, glycolic acid, tartaric acid or lactic acid; the solvent is an alcohol and / or ketone, such as one or more of methanol, ethanol, propanol, butanol, ethylene glycol and acetone, preferably one or more of methanol, ethanol, propanol and acetone.

[0014] In the method of the present invention, the impregnation in step (2) is saturated impregnation or supersaturated impregnation, a technique well known to those skilled in the art.

[0015] In the method of the present invention, the drying process described in step (2) is well known to those skilled in the art, and the drying temperature is 60~140℃ and the drying time is 2~8h.

[0016] In the method of the present invention, the buffer solution in step (3) is an aqueous solution containing ammonium salt, wherein the concentration of ammonium ions is 0.003~0.04 mol / 100g; the ammonium salt is one or more of ammonium carbonate, ammonium bicarbonate, triammonium phosphate, diammonium phosphate, monoammonium phosphate, ammonium acetate and ammonium formate.

[0017] In the method of the present invention, the buffer solution in step (3) is slightly acidic / neutral with a pH value of 6.0~7.0. Depending on the required pH value of the buffer solution, acetic acid and / or ammonia can be used to adjust the pH value.

[0018] In the method of the present invention, the specific operation process of washing in step (3) is as follows: spray the catalyst obtained in step (2) with a buffer solution, and repeat the above steps 1 to 10 times according to the difference in alkali metal content until the alkali metal content is less than 0.1 wt%; wherein, the volume of the buffer solution used for each washing is 120% to 1000% of the saturated water absorption (volume) of the catalyst obtained in step (2).

[0019] In the method of the present invention, the drying temperature in step (3) is 90~150℃ and the drying time is 2~8h.

[0020] In the method of the present invention, the calcination in step (3) is carried out in an oxygen-containing atmosphere, wherein the oxygen content of the oxygen-containing atmosphere is 15v%~100v%, preferably an air atmosphere.

[0021] In the method of the present invention, the calcination temperature in step (3) is 380~530℃ and the time is 2~6h, the purpose of which is to oxidize and burn off the sulfides and carbides on the catalyst.

[0022] The present invention provides a regenerated hydrogenation catalyst obtained by the above method.

[0023] Compared with the prior art, the present invention has the following advantages: This invention creatively proposes a method for regenerating deactivated hydrogenation catalysts due to alkali metal poisoning. The method first involves high-temperature treatment of the catalyst under an inert atmosphere and suitable temperature conditions. This helps the sulfide-state active metal wafers adhere more firmly to the alumina support. Simultaneously, the carbon deposited on the catalyst surface during calcination forms water-insoluble carbides, such as CoMoSxCy or MoSxCy, with the active metal components, preventing the loss of active metals during subsequent ammonium salt washing. Then, organic acids, especially α-hydroxy acids, are introduced onto the surface of the deactivated catalyst to interact with the alkali metal impurities, thereby weakening the adsorption strength between the alkali metals and acidic sites. This facilitates the removal of alkali metal impurities by subsequent buffer solution washing, exposing the acidic sites of the catalyst and restoring its activity. Detailed Implementation

[0024] The following examples further illustrate the solution and effects of the present invention, but do not constitute a limitation on the present invention.

[0025] In this invention, the relative desulfurization activity is calculated according to the following formula: Relative desulfurization activity % = [1 / (S)] p ) 0.65 -1 / (S f ) 0.65 ] / [1 / (S pr ) 0.65 -1 / (S f ) 0.65 ]*100% Wherein: S f Sulfur content of crude oil, mg / kg; S pr The sulfur content of the reference hydrogenated oil, in mg / kg; S p The sulfur content of the oil produced by hydrogenation of fresh catalyst, in mg / kg.

[0026] The alkali metal poisoned hydrogenation catalyst used in the examples and comparative examples was a commercially available FHUDS-7 hydrogenation catalyst, which was applied to a deactivated hydrogenation catalyst obtained from a refinery. The alkali metal poisoned hydrogenation catalyst had a sulfur content of 8.4 wt%, a carbon content of 6.5 wt%, and, based on the mass of the catalyst after sulfur and carbon removal, an alkali metal impurity content (as oxides) of 1.8 wt%, a Group VIB Mo content (as oxides) of 21.6 wt%, and a Group VIII Ni content (as oxides) of 3.8 wt%.

[0027] Example 1 117.6 g of the above-mentioned alkali metal poisoned catalyst was taken, and the saturated water absorption of the catalyst was measured to be 40 mL / 100 g catalyst. The catalyst was calcined at 600 °C for 2 h in a nitrogen atmosphere and then allowed to cool to room temperature. 6.6 g of citric acid was dissolved in ethanol and diluted to 70 mL, and supersaturated and impregnated onto the catalyst. After vacuum drying at 100 °C for 4 h, the catalyst was washed with 230 mL of diammonium phosphate / acetic acid buffer solution with a pH of 6.5 and an ammonium ion concentration of 0.006 mol / 100 g. After washing three times, the alkali metal impurity content on the catalyst was 0.03 wt%. After drying at 120 °C for 4 h, it was calcined at 450 °C for 4 h in an air atmosphere to obtain the regenerated finished catalyst R-1.

[0028] Example 2 117.6 g of the above-mentioned alkali metal poisoned catalyst was taken, and the saturated water absorption of the catalyst was measured to be 40 mL / 100 g catalyst. The catalyst was calcined at 500 °C for 2 h in an argon atmosphere and then allowed to cool to room temperature. 9.2 g of malic acid was dissolved in ethanol and diluted to 65.8 mL, which was then supersaturated and impregnated onto the catalyst. After vacuum drying at 120 °C for 4 h, the catalyst was washed with 280 mL of ammonium formate / ammonia buffer solution with a pH of 6.8 and an ammonium ion concentration of 0.015 mol / 100 g. After washing three times, the alkali metal impurity content on the catalyst was 0.02 wt%. After drying at 120 °C for 3 h, it was calcined at 420 °C for 3 h in an air atmosphere to obtain the regenerated finished catalyst R-2.

[0029] Example 3 117.6 g of the above-mentioned alkali metal poisoned catalyst was taken, and the saturated water absorption of the catalyst was measured to be 40 mL / 100 g catalyst. The catalyst was calcined at 550 °C for 3 h in a nitrogen atmosphere and then allowed to cool to room temperature. 3.9 g of tartaric acid was dissolved in ethanol and diluted to 61 mL, which was then supersaturated and impregnated onto the catalyst. After vacuum drying at 110 °C for 3 h, the catalyst was washed with 190 mL of ammonium bicarbonate / acetic acid buffer solution with a pH of 6.3 and an ammonium ion concentration of 0.01 mol / 100 g. After washing three times, the alkali metal impurity content on the catalyst was 0.04 wt%. After drying at 120 °C for 3 h, the catalyst was calcined at 490 °C for 3 h in an air atmosphere to obtain the regenerated finished catalyst R-3.

[0030] Example 4 117.6 g of the above-mentioned alkali metal poisoned catalyst was taken, and the saturated water absorption of the catalyst was measured to be 40 mL / 100 g catalyst. The catalyst was calcined at 650 °C for 2 h in a helium atmosphere and then allowed to cool to room temperature. 7.1 g of salicylic acid was dissolved in acetone and diluted to 75 mL, which was then supersaturated and impregnated onto the catalyst. After vacuum drying at 90 °C for 4 h, the catalyst was washed with 300 mL of ammonium bicarbonate / acetic acid buffer solution with a pH of 6.6 and an ammonium ion concentration of 0.03 mol / 100 g. After washing three times, the alkali metal impurity content on the catalyst was 0.03 wt%. After drying at 120 °C for 3 h, the catalyst was calcined at 510 °C for 3 h in an air atmosphere to obtain the regenerated finished catalyst R-4.

[0031] Comparative Example 1 The preparation method of Example 1 was followed, but the alkali metal poisoned hydrogenation catalyst was calcined in air. 117.6 g of the above alkali metal poisoned hydrogenation catalyst was taken and calcined in air at 600°C for 2 h, then allowed to cool to room temperature. 6.6 g of citric acid was dissolved in ethanol and diluted to 70 mL, then supersaturated and impregnated onto the catalyst. After vacuum drying at 100°C for 4 h, 230 mL of a diammonium phosphate / acetic acid buffer solution with a pH of 6.5 and an ammonium ion concentration of 0.006 mol / 100 g was used to wash the catalyst. After three washes, the alkali metal impurity content on the catalyst was 0.03 wt%. After drying at 120°C for 4 h, it was calcined in air at 450°C for 4 h to obtain the regenerated finished catalyst D-1.

[0032] Comparative Example 2 The preparation method of Example 1 was followed, but the alkali metal poisoned hydrogenation catalyst was not calcined in an inert atmosphere. 117.6 g of the above alkali metal poisoned hydrogenation catalyst was taken for later use. 6.6 g of citric acid was dissolved in ethanol and diluted to 70 mL, then supersaturated and impregnated onto the catalyst. After vacuum drying at 100 °C for 4 h, the catalyst was washed with 230 mL of a diammonium phosphate / acetic acid buffer solution with a pH of 6.5 and an ammonium ion concentration of 0.006 mol / 100 g. After washing three times, the alkali metal impurity content on the catalyst was 0.05 wt%. After drying at 120 °C for 4 h, it was calcined at 450 °C for 4 h in air to obtain the regenerated finished catalyst D-2.

[0033] Comparative Example 3 The preparation method of Example 1 was followed, but the alkali metal poisoned hydrogenation catalyst was not impregnated with acid solution after calcination in an inert atmosphere. 117.6 g of the above alkali metal poisoned catalyst was taken, and the saturated water absorption of the catalyst was measured to be 40 mL / 100 g catalyst. The catalyst was calcined at 600 °C for 2 h in a nitrogen atmosphere and then allowed to cool to room temperature. 230 mL of a diammonium phosphate / acetic acid buffer solution with a pH of 6.5 and an ammonium ion concentration of 0.006 mol / 100 g was used to wash the catalyst. After three washes, the alkali metal impurity content on the catalyst was 0.42 wt%. After drying at 120 °C for 4 h, it was calcined at 450 °C for 4 h in an air atmosphere to obtain the regenerated finished catalyst D-3.

[0034] Comparative Example 4 The preparation method of Example 1 was followed, but the alkali metal poisoned hydrogenation catalyst was washed with dilute nitric acid with a pH of 3. 117.6 g of the above alkali metal poisoned catalyst was taken, and the saturated water absorption of the catalyst was measured to be 40 mL / 100 g catalyst. The catalyst was calcined at 600 °C for 2 h in a nitrogen atmosphere and then allowed to cool to room temperature. 6.6 g of citric acid was dissolved in ethanol and diluted to 70 mL, then supersaturated and impregnated onto the catalyst. After vacuum drying at 100 °C for 4 h, the catalyst was washed with 230 mL of dilute nitric acid solution with a pH of 3. After three washes, the alkali metal impurity content on the catalyst was 0.03 wt%. After drying at 120 °C for 4 h, it was calcined at 450 °C for 4 h in an air atmosphere to obtain the regenerated finished catalyst D-4.

[0035] Example 5 The catalysts obtained in the examples and comparative examples were subjected to activity evaluation tests in a 10 mL reaction apparatus. The feedstock was atmospheric diesel oil with a sulfur content of 1.9 wt%, a nitrogen content of 290 ng / μL, and a final boiling point of 367°C.

[0036] Before the reaction begins, the catalyst needs to be pre-sulfurized. The sulfiding agent is conventional straight-run diesel fuel with 1.5 v% DMDS added. The sulfidation operating conditions are: sulfidation pressure 6.4 MPa, liquid hourly space velocity (LHSV) 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio was 400:1. The catalyst in the reactor was completely wetted at 140℃, then the temperature was increased to 320℃ at a rate of 1℃ / min and held at this temperature for 10 hours to complete sulfidation. The reaction operating conditions were as follows: reaction pressure 6.4 MPa, reaction temperature 360℃, and liquid hourly space velocity (LISH) 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio was 400:1. After initial activity stabilization for 24 hours, the product properties were analyzed. The properties and relative desulfurization activity of the catalyst are listed in Table 1.

[0037] Table 1. Catalyst properties and desulfurization activity in the examples and comparative examples

[0038] *Based on the fresh agent, its desulfurization activity is set to 100%.

Claims

1. A method for regenerating a deactivated hydrogenation catalyst, characterized in that: Includes the following: (1) The alkali metal poisoned hydrogenation catalyst was calcined in an inert atmosphere; (2) Impregnate the catalyst obtained in step (1) with an organic acid solution and then dry it; (3) The catalyst obtained in step (2) is rinsed with a buffer solution, dried and calcined to obtain the final regenerated hydrogenation catalyst; The buffer solution mentioned in step (3) is an aqueous solution containing ammonium salt; the ammonium salt is one or more of ammonium carbonate, ammonium bicarbonate, triammonium phosphate, diammonium phosphate, monoammonium phosphate, ammonium acetate, and ammonium formate; The buffer solution mentioned in step (3) is slightly acidic / neutral with a pH value of 6.0~7.

0.

2. The method according to claim 1, characterized in that: In step (1), the mass of the alkali metal poisoning hydrogenation catalyst after removing sulfur and carbon is used as the basis, and the alkali metal content in the alkali metal poisoning hydrogenation catalyst is 0.2wt%-8.0wt%; the alkali metal includes one or more of lithium, sodium and potassium.

3. The method according to claim 2, characterized in that: In step (1), the mass of the alkali metal poisoning hydrogenation catalyst after removing sulfur and carbon is used as the basis, and the alkali metal content in the alkali metal poisoning hydrogenation catalyst is 0.3wt%-5.0wt%.

4. The method according to claim 2, characterized in that: In step (1), the mass of the alkali metal poisoning hydrogenation catalyst after removing sulfur and carbon is used as the basis, and the alkali metal content in the alkali metal poisoning hydrogenation catalyst is 0.5wt%-3.0wt%.

5. The method according to claim 2, characterized in that: In step (1), the mass of the alkali metal poisoning hydrogenation catalyst after removing sulfur and carbon is used as the basis, and the alkali metal content in the alkali metal poisoning hydrogenation catalyst is 1wt%-2.0wt%.

6. The method according to claim 1, characterized in that: The inert atmosphere mentioned in step (1) is a nitrogen atmosphere or an inert gas atmosphere, wherein the inert gas atmosphere is one or more of argon atmosphere, helium atmosphere and neon atmosphere.

7. The method according to claim 1, characterized in that: The roasting temperature in step (1) is 400~800℃ and the time is 1~3h.

8. The method according to claim 7, characterized in that: The roasting temperature in step (1) is 500~700℃.

9. The method according to claim 1, characterized in that: The organic acid in the organic acid solution in step (2) contains a molar ratio of Group VIB metals and Group VIII metals in the alkali metal poisoning hydrogenation catalyst of 0.03 to 0.6, wherein the Group VIB metals and Group VIII metals are calculated as elemental metals.

10. The method according to claim 9, characterized in that: The molar ratio of the organic acid in the organic acid solution to the group VIB metal and group VIII metal in the alkali metal poisoning hydrogenation catalyst in step (2) is 0.05 to 0.5, wherein the group VIB metal and group VIII metal are calculated as elemental metals.

11. The method according to claim 1, characterized in that: The organic acid solution in step (2) contains a solute organic acid and a solvent. The organic acid is an organic acid with less than 10 carbon atoms; the solvent is an alcohol and / or a ketone.

12. The method according to claim 11, characterized in that: The organic acid solution in step (2) contains a solute organic acid and a solvent. The organic acid is an α-hydroxy acid, and the solvent is one or more of methanol, ethanol, propanol, butanol, ethylene glycol, and acetone.

13. The method according to claim 11, characterized in that: The organic acid solution in step (2) contains a solute organic acid and a solvent. The organic acid is one or more of malic acid, citric acid, salicylic acid, glycolic acid, tartaric acid or lactic acid; the solvent is one or more of methanol, ethanol, propanol and acetone.

14. The method according to claim 1, characterized in that: The impregnation described in step (2) is saturated impregnation or supersaturated impregnation.

15. The method according to claim 1, characterized in that: The drying process in step (2) is carried out at a temperature of 60~140℃ for 2~8 hours.

16. The method according to claim 1, characterized in that: In step (3), an aqueous solution containing ammonium salt is used, wherein the concentration of ammonium ions is 0.003~0.04 mol / 100g.

17. The method according to claim 1, characterized in that: The specific operation process of rinsing in step (3) is as follows: spray the catalyst obtained in step (2) with a buffer solution, and repeat the above steps 1 to 10 times according to the difference in alkali metal content, until the alkali metal content is less than 0.1 wt%.

18. The method according to claim 1, characterized in that: The drying temperature in step (3) is 90~150℃ and the drying time is 2~8h.

19. The method according to claim 1, characterized in that: The roasting in step (3) is carried out in an oxygen-containing atmosphere, the oxygen content of which is 15v%~100v.

20. The method according to claim 19, characterized in that: In step (3), the oxygen-containing atmosphere is an air atmosphere.

21. The method according to claim 1, characterized in that: In step (3), the roasting temperature is 380~530℃ and the time is 2~6h.

22. A regenerated hydrogenation catalyst obtained by the method according to any one of claims 1-21.

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