Regeneration method of inactivated hydrogenation catalyst

Abstract

The invention discloses a regeneration method of an inactivated hydrogenation catalyst. The regeneration method comprises the following steps: (1) roasting an alkali metal poisoning hydrogenation catalyst in an inert atmosphere; (2) impregnating the catalyst obtained in the step (1) with an organic acid solution, and then drying; and (3) flushing the catalyst obtained in the step (2) by adopting a buffer solution, drying and roasting to obtain the final regenerated hydrogenation catalyst. According to the regeneration method, alkali metal impurities adsorbed on acid sites on the surface of the catalyst can be removed in a targeted manner, and the activity of the catalyst is recovered to the maximum extent.

Description

Technical Field

[0001] The present invention relates to a method for regenerating a deactivated hydrogenation catalyst, and particularly to a method for regenerating an abnormally deactivated hydrogenation catalyst. Background Art

[0002] During the hydrogenation reaction process, under normal circumstances, the activity of the hydrogenation catalyst gradually decreases with the extension of the operation time and finally deactivates. There are many factors causing catalyst deactivation, and one of the main factors is coke deposition. Coke is usually deposited on the catalyst surface, blocking the pores and covering the active sites of the catalyst, thereby reducing the reaction activity. In addition, there are serious deposits of transition metal (such as nickel, vanadium, and iron) impurities in the deactivated catalyst, and the transition metal deposits can account for more than 20% of the weight of the deactivated catalyst.

[0003] CN201911361889.5 discloses a heavy oil hydrotreating method. The heavy oil raw material contacts with hydrogen in a hydrotreating reactor to complete the hydrotreating process. The hydrotreating reactor is filled with a regenerant obtained by regenerating a deactivated hydrotreating catalyst. The regeneration process of the regenerant is as follows: The deactivated hydrotreating catalyst is subjected to carbon burning and desulfurization, then impregnated with an acidic solution containing a complexing agent, and then impregnated with an alkali solution and treated in an ammonia-containing atmosphere to effectively remove metal impurities such as nickel, vanadium, and iron.

[0004] The catalyst regeneration method involved in the above patent is for catalysts deactivated due to conventional reasons such as carbon deposition and transition metal deposition. This kind of deactivation can often be adjusted by increasing the reaction temperature during the reaction process. Generally, when the reaction cycle is about to end and the reaction temperature cannot be increased for adjustment anymore, the existing regeneration method in the prior art needs to be used to regenerate the catalyst. During the actual operation process, there is also a phenomenon of sudden deactivation of the catalyst that occurs within the normal operation cycle due to improper operating conditions and fluctuations in reaction raw materials. For how to regenerate and whether it can be regenerated for this kind of abnormally deactivated hydrogenation catalyst, the prior art does not give relevant solutions, and specific analysis of the deactivation reasons is required to provide relevant solutions. Summary of the Invention

[0005] The inventor has encountered such a situation of abnormal deactivation of a hydrogenation catalyst. The hydrotreating catalyst shows serious deactivation soon after operation, and even the activity of the catalyst cannot be restored by increasing the temperature. The refining enterprise is forced to stop production for treatment. Through in-depth research, the inventor found that the reason for the catalyst deactivation is not carbon deposition and transition metal deposition. The main factor leading to its deactivation is that the content of alkali metals in the deactivated catalyst has increased significantly. The cause is improper control of raw materials during industrial application. Further research found that the reason for the rapid deactivation of the hydrogenation catalyst caused by alkali metal impurities is that the alkali metal impurities will occupy the acidic sites on the catalyst surface.

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

[0007] The present invention provides a method for regenerating a deactivated hydrogenation catalyst, comprising the following contents: (1) calcining the alkali metal poisoning hydrogenation catalyst in an inert atmosphere; (2) impregnating the catalyst obtained in step (1) with an organic acid solution, and then drying; (3) The catalyst obtained in step (2) is rinsed with a buffer solution, and then dried and calcined to obtain a final regenerated hydrogenation catalyst.

[0008] In the method of the present invention, the alkali metal poisoning hydrogenation catalyst 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 comprises a carrier and an active metal component. The carrier is generally at least one of alumina, amorphous silica-alumina and molecular sieves. The active metal component is generally a VIB group metal and / or a VIII group metal, wherein the VIB group metal is at least one of Mo and W, and the VIII group 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 deposited deactivated catalyst after the removal of sulfur and carbon, the alkali metal content in the alkali metal poisoned hydrogenation catalyst is 0.2wt%-8.0wt%, preferably 0.3wt%-5.0wt%, more 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 an argon atmosphere, a helium atmosphere and a neon atmosphere.

[0011] In the method of the present invention, the calcination temperature in step (1) is 400-800° C., preferably 500-700° C., and the calcination time is 1-3 h.

[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 the Group VIII metal (calculated as metal elements) in the alkali metal poisoning hydrogenation catalyst is 0.03 to 0.6, preferably 0.05 to 0.5.

[0013] In the method of the present invention, in step (2), the organic acid solution 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 a 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, which is well known to those skilled in the art.

[0015] In the method of the present invention, the drying treatment in step (2) is well known to those skilled in the art. The drying temperature is 60~140°C, 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 an ammonium salt, wherein the concentration of ammonium ions is 0.003~0.04mol / 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, and the pH value is 6.0~7.0. According to the different required pH values of the buffer solution, acetic acid and / or ammonia water can be used to adjust the pH value.

[0018] In the method of the present invention, the specific operation process of the washing in step (3) is as follows: spray the catalyst obtained in step (2) with the buffer solution, and repeat the above steps 1~10 times according to the difference in alkali metal content until the alkali metal content is lower than 0.1wt%; wherein, the volume of the buffer solution used for each washing is 120%~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°C, 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, and 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°C, and the time is 2~6h, aiming to oxidize and burn out 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: For a hydrogenation catalyst deactivated by alkali metal poisoning, the present invention creatively proposes a regeneration method for the deactivated hydrogenation catalyst. First, the catalyst is heat-treated under an inert atmosphere and appropriate temperature conditions in the method of the present invention, which helps the sulfided active metal wafers to adhere more firmly to the alumina support. At the same time, the carbon deposited on the catalyst surface under the roasting action will also form carbides that are insoluble in water with the active metal components, such as CoMoSxCy or MoSxCy, etc., to avoid the loss of active metal caused by subsequent flushing with ammonium salt solution. Then, by introducing an organic acid, especially α-hydroxy acid, to the surface of the deactivated catalyst, an interaction is generated with the alkali metal impurities on the catalyst, thereby weakening the adsorption strength between the alkali metal and the acidic sites, facilitating the removal of alkali metal impurities by subsequent washing with a buffer solution, thereby exposing the acidic sites of the catalyst and restoring the activity of the catalyst. Specific Embodiments

[0024] The following further illustrates the solutions and effects of the present invention through examples, but does not constitute a limitation to the present invention.

[0025] In the present 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% Where: S f is the sulfur content of the feedstock oil, mg / kg; S pr is the sulfur content of the hydrogenated product oil of the reference agent, mg / kg; S p is the sulfur content of the hydrogenated product oil of the fresh catalyst, mg / kg.

[0026] The alkali metal-poisoned hydrogenation catalyst used in the examples and comparative examples is a deactivated hydrogenation catalyst obtained by applying a commercially available hydrogenation catalyst with the brand number FHUDS-7 to a certain refinery. The sulfur content of the alkali metal-poisoned hydrogenation catalyst is 8.4 wt%, the carbon content is 6.5 wt%, based on the mass of the catalyst after burning off sulfur and carbon, the alkali metal impurity content (calculated as the oxide) is 1.8 wt%, the content of Group VIB metal Mo (calculated as the oxide) is 21.6 wt%, and the content of Group VIII metal Ni (calculated as the oxide) is 3.8 wt%.

[0027] Example 1 Take 117.6 g of the above alkali metal poisoned catalyst, and measure that the saturated water absorption of the catalyst is 40 mL / 100 g of catalyst. Place the catalyst in a nitrogen atmosphere and calcine it at 600 °C for 2 h, then let it stand and cool to room temperature. Dissolve 6.6 g of citric acid in ethanol and dilute it to 70 mL, and supersaturate it on the catalyst. After vacuum drying at 100 °C for 4 h, select 230 mL of diammonium phosphate / acetic acid buffer solution with a pH value of 6.5 and an ammonium ion concentration of 0.006 mol / 100 g solution to wash the above catalyst. After washing three times, the alkali metal impurity content on the catalyst is 0.03 wt%. After drying at 120 °C for 4 h, place it in an air atmosphere and calcine it at 450 °C for 4 h to obtain the regenerated finished catalyst R-1.

[0028] Example 2 Take 117.6 g of the above alkali metal poisoned catalyst, and measure that the saturated water absorption of the catalyst is 40 mL / 100 g of catalyst. Place the catalyst in an argon atmosphere and calcine it at 500 °C for 2 h, then let it stand and cool to room temperature. Dissolve 9.2 g of malic acid in ethanol and dilute it to 65.8 mL, and supersaturate it on the catalyst. After vacuum drying at 120 °C for 4 h, select 280 mL of ammonium formate / ammonia buffer solution with a pH value of 6.8 and an ammonium ion concentration of 0.015 mol / 100 g solution to wash the above catalyst. After washing three times, the alkali metal impurity content on the catalyst is 0.02 wt%. After drying at 120 °C for 3 h, place it in an air atmosphere and calcine it at 420 °C for 3 h to obtain the regenerated finished catalyst R-2.

[0029] Example 3 Take 117.6 g of the above alkali metal poisoned catalyst, and measure that the saturated water absorption of the catalyst is 40 mL / 100 g of catalyst. Place the catalyst in a nitrogen atmosphere and calcine it at 550 °C for 3 h, then let it stand and cool to room temperature. Dissolve 3.9 g of tartaric acid in ethanol and dilute it to 61 mL, and supersaturate it on the catalyst. After vacuum drying at 110 °C for 3 h, select 190 mL of ammonium bicarbonate / acetic acid buffer solution with a pH value of 6.3 and an ammonium ion concentration of 0.01 mol / 100 g solution to wash the above catalyst. After washing three times, the alkali metal impurity content on the catalyst is 0.04 wt%. After drying at 120 °C for 3 h, place it in an air atmosphere and calcine it at 490 °C for 3 h to obtain the regenerated finished catalyst R-3.

[0030] Example 4 Take 117.6 g of the above alkali metal-poisoned catalyst, and measure that the saturated water absorption of this catalyst is 40 mL / 100 g of catalyst. Place this catalyst in a helium atmosphere and calcine it at 650 °C for 2 h, then let it stand and cool to room temperature. Dissolve 7.1 g of salicylic acid in acetone and dilute it to 75 mL, and supersaturate it on the catalyst. After vacuum drying at 90 °C for 4 h, select 300 mL of ammonium bicarbonate / acetic acid buffer solution with a pH value of 6.6 and an ammonium ion concentration of 0.03 mol / 100 g solution to rinse the above catalyst. After rinsing three times, the alkali metal impurity content on the catalyst is 0.03 wt%. After drying at 120 °C for 3 h, place it in an air atmosphere and calcine it at 510 °C for 3 h to obtain the regenerated finished catalyst R-4.

[0031] Comparative Example 1 According to the preparation method of Example 1, but the alkali metal-poisoned hydrogenation catalyst is calcined in an air atmosphere. Take 117.6 g of the above alkali metal-poisoned hydrogenation catalyst, place this catalyst in an air atmosphere and calcine it at 600 °C for 2 h, then let it stand and cool to room temperature. Dissolve 6.6 g of citric acid in ethanol and dilute it to 70 mL, and supersaturate it on the catalyst. After vacuum drying at 100 °C for 4 h, select 230 mL of diammonium phosphate / acetic acid buffer solution with a pH value of 6.5 and an ammonium ion concentration of 0.006 mol / 100 g solution to rinse the above catalyst. After rinsing three times, the alkali metal impurity content on the catalyst is 0.03 wt%. After drying at 120 °C for 4 h, place it in an air atmosphere and calcine it at 450 °C for 4 h to obtain the regenerated finished catalyst D-1.

[0032] Comparative Example 2 According to the preparation method of Example 1, but the alkali metal-poisoned hydrogenation catalyst is not calcined in an inert atmosphere. Take 117.6 g of the above alkali metal-poisoned hydrogenation catalyst for standby. Dissolve 6.6 g of citric acid in ethanol and dilute it to 70 mL, and supersaturate it on the catalyst. After vacuum drying at 100 °C for 4 h, select 230 mL of diammonium phosphate / acetic acid buffer solution with a pH value of 6.5 and an ammonium ion concentration of 0.006 mol / 100 g solution to rinse the above catalyst. After rinsing three times, the alkali metal impurity content on the catalyst is 0.05 wt%. After drying at 120 °C for 4 h, place it in an air atmosphere and calcine it at 450 °C for 4 h to obtain the regenerated finished catalyst D-2.

[0033] Comparative Example 3 According to the preparation method of Example 1, but the alkali metal poisoned hydrogenation catalyst is not impregnated with an acid solution after calcination in an inert atmosphere. Take 117.6 g of the above-mentioned alkali metal poisoned catalyst, and measure that the saturated water absorption of the catalyst is 40 mL / 100 g of catalyst. Place the catalyst in a nitrogen atmosphere and calcine it at 600 °C for 2 h, then let it stand and cool to room temperature. Select 230 mL of diammonium phosphate / acetic acid buffer solution with a pH value of 6.5 and an ammonium ion concentration of 0.006 mol / 100 g solution to rinse the above catalyst. After rinsing three times, the alkali metal impurity content on the catalyst is 0.42 wt%. After drying at 120 °C for 4 h, place it in an air atmosphere and calcine it at 450 °C for 4 h to obtain the regenerated finished catalyst D-3.

[0034] Comparative Example 4 According to the preparation method of Example 1, but the alkali metal poisoned hydrogenation catalyst is rinsed with dilute nitric acid with a pH value of 3. Take 117.6 g of the above-mentioned alkali metal poisoned catalyst, and measure that the saturated water absorption of the catalyst is 40 mL / 100 g of catalyst. Place the catalyst in a nitrogen atmosphere and calcine it at 600 °C for 2 h, then let it stand and cool to room temperature. Dissolve 6.6 g of citric acid in ethanol and dilute it to 70 mL, and supersaturate it on the catalyst. After vacuum drying at 100 °C for 4 h, select 230 mL of dilute nitric acid solution with a pH value of 3 to rinse the above catalyst. After rinsing three times, the alkali metal impurity content on the catalyst is 0.03 wt%. After drying at 120 °C for 4 h, place it in an air atmosphere and calcine it at 450 °C for 4 h to obtain the regenerated finished catalyst D-4.

[0035] Example 5 The catalysts obtained in the examples and comparative examples were subjected to an activity evaluation test in a 10 mL reaction device. The feedstock oil is the third side stream diesel with a sulfur content of 1.9 wt%, a nitrogen content of 290 ng / μL, and an end boiling point of 367 °C.

[0036] Before the reaction starts, the catalyst needs to be pre-sulfurized. The sulfurizing agent is the first side stream straight-run diesel added with 1.5 v% DMDS, and the sulfurization operating conditions are: sulfurization pressure 6.4 MPa, liquid hourly space velocity 1.5 h -1 , hydrogen-oil volume ratio 400:1. Wet the catalyst in the reactor completely at 140 °C, then increase the temperature to 320 °C at a heating rate of 1 °C / min, and keep it at a constant temperature for 10 h to complete the sulfurization. The reaction operating conditions are as follows: reaction pressure 6.4 MPa, reaction temperature 360 °C, liquid hourly space velocity 1.5 h -1 , hydrogen-oil volume ratio 400:1. After the initial activity is stabilized for 24 h, analyze the product properties. The properties and relative desulfurization activities of the catalysts are listed in Table 1.

[0037] Table 1 Properties and Desulfurization Activities of Catalysts in 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, Features: It includes the following: (1) calcining the alkali metal poisoning hydrogenation catalyst in an inert atmosphere; (2) impregnating the catalyst obtained in step (1) with an organic acid solution, and then drying; (3) The catalyst obtained in step (2) is rinsed with a buffer solution, and then dried and calcined to obtain a final regenerated hydrogenation catalyst.

2. The method according to claim 1, Features: In step (1), based on the mass of the alkali metal deposited deactivated catalyst after the removal of sulfur and carbon, the alkali metal content in the alkali metal poisoned hydrogenation catalyst is 0.2wt%-8.0wt%, preferably 0.3wt%-5.0wt%, more preferably 0.5wt%-3.0wt%, and even more preferably 1wt%-2.0wt%; the alkali metal includes one or more of lithium, sodium and potassium.

3. The method according to claim 1, Features: 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 an argon atmosphere, a helium atmosphere and a neon atmosphere.

4. The method according to claim 1, Features: The calcination temperature in step (1) is 400-800°C, preferably 500-700°C, and the calcination time is 1-3h.

5. The method according to claim 1, Features: The molar ratio of the organic acid contained in the organic acid solution in step (2) to the Group VIB metal and the Group VIII metal (calculated as metal elements) in the alkali metal poisoning hydrogenation catalyst is 0.03 to 0.6, preferably 0.05 to 0.

5.

6. The method according to claim 1, Features: The organic acid solution in step (2) contains a solute organic acid and a solvent, wherein the organic acid is an organic acid having 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; and 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.

7. The method according to claim 1, Features: The impregnation in step (2) is saturated impregnation or supersaturated impregnation.

8. The method according to claim 1, Features: The drying treatment temperature in step (2) is 60-140°C and the time is 2-8 hours.

9. The method according to claim 1, Features: The buffer solution in step (3) is an aqueous solution containing an ammonium salt, wherein the concentration of ammonium ions is 0.003-0.04 mol / 100 g; the ammonium salt is one or more of ammonium carbonate, ammonium bicarbonate, triammonium phosphate, diammonium phosphate, monoammonium phosphate, ammonium acetate and ammonium formate.

10. The method according to claim 1, Features: The buffer solution in step (3) is slightly acidic / neutral, with a pH value of 6.0-7.

0.

11. The method according to claim 1, Features: The specific operation process of the washing described 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 lower than 0.1 wt%.

12. According to the method described in claim 1, it is characterized in that: the drying temperature in step (3) is 90 to 150 °C, and the drying time is 2 to 8 h.

13. According to the method described in claim 1, it is characterized in that: the calcination in step (3) is carried out in an oxygen-containing atmosphere, and the oxygen content of the oxygen-containing atmosphere is 15 v% to 100 v%, preferably an air atmosphere.

14. According to the method described in claim 1, it is characterized in that: the calcination temperature in step (3) is 380 to 530 °C, and the time is 2 to 6 h.

15. A regenerated hydrogenation catalyst obtained by the method according to any one of claims 1-14.

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