Method for performance improvement of hydrofining catalyst

Abstract

The application belongs to the technical field of hydrogenation catalysts, and particularly relates to a performance improvement method of a hydrogenation refining catalyst. The performance improvement method of the hydrogenation refining catalyst controls the temperature of a reactor filled with the hydrogenation refining catalyst at 320-370 DEG C, uses aviation kerosene to flush the hydrogenation refining catalyst, and then uses normal industrial oil as a solvent to carry dimethyl disulfide to supplement sulfur to the hydrogenation refining catalyst, so as to improve the performance of the hydrogenation refining catalyst. The performance improvement method of the hydrogenation refining catalyst does not need to be regenerated outside the reactor, controls the pretreatment temperature of the catalyst, flushes the catalyst with aviation kerosene, and adds dimethyl disulfide in the reactor of the catalyst device for closed-loop circulation, so that the performance of the hydrogenation refining catalyst is improved, the influence of the change of the performance of the catalyst on the quality of industrial white oil is avoided, and the industrial white oil has good yellowing resistance.

Description

Technical Field

[0001] This invention belongs to the field of hydrogenation catalyst technology, and specifically relates to a method for improving the performance of a hydrogenation refining catalyst. Background Technology

[0002] Lubricating oil hydrotreating refers to the removal of elements such as sulfur, nitrogen, and oxygen from oil through a hydrogenation reaction, thereby generating hydrogen sulfide gas. The solubility of hydrogen sulfide in the hydrotreated oil varies under different pressures. A portion of the hydrogen sulfide dissolves in the treated oil within the hydrotreating unit. Long-term operation of this equipment can easily lead to reduced or even deactivated catalyst activity in the hydrotreating unit, increasing production costs.

[0003] Currently, the industry generally improves catalyst performance through external regeneration of the catalyst. For example, patent CN114130418A discloses a method for regenerating a hydrogenation catalyst. This method involves mixing deactivated hydrogenation catalysts A1 and A2, immersing the mixture in a solvent, and ultrasonically treating it to obtain catalyst B and a mixture containing black powder. Catalyst B is recovered, and the mixture containing black powder is filtered to obtain powder C. Catalyst B is ground into powder, sieved, and then catalyst powder D is obtained. Catalyst powder D is shaped, dried, and calcined to obtain a regenerated support. Powder C is dissolved in liquid paraffin, impregnated onto the regenerated support, cooled, carbonized, and then subjected to hydrothermal treatment to obtain the regenerated hydrogenation catalyst. This method does not require additional replenishment of active metal components, the regenerated catalyst exhibits good desulfurization performance, and it can reduce the amount of sulfiding agent used and shorten the sulfidation time.

[0004] Patent CN103480435A discloses a method for external regeneration of a hydrogenation catalyst. First, the hydrogenation catalyst with appropriately sized particles is separated by a first separation screen. Then, a two-stage continuous coking process is completed by a rotary kiln and a regeneration mesh belt kiln. The dust from the first separation screen is absorbed by a first dust collector, while the flue gas generated in the rotary kiln and the regeneration mesh belt kiln is discharged into the atmosphere after the harmful gases are absorbed by a desulfurization device. This equipment realizes two-stage coking and has the advantages of simple structure, reasonable design, good regeneration effect, and no pollution.

[0005] However, in actual production, after a period of use, even without a significant decrease in activity, the hydrorefining catalyst already affects the quality of the hydrotreated oil, especially industrial white oil. This leads to poor yellowing resistance in the industrial white oil, reducing product quality. If the above problems are solved by external regeneration of the hydrorefining catalyst, frequent catalyst replacement is required, which greatly increases production costs, and frequent start-ups and shutdowns also affect production efficiency. Therefore, it is necessary to study a method to improve the performance of the hydrorefining catalyst, thereby improving product quality without replacing the catalyst. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for improving the performance of hydrorefining catalysts without the need for external regeneration. By controlling the catalyst pretreatment temperature, washing the catalyst with jet fuel, and adding dimethyl disulfide into the reactor of the catalyst device in a closed loop, the performance of the hydrorefining catalyst is improved, avoiding the impact of catalyst performance changes on the quality of industrial white oil products, and giving industrial white oil good resistance to yellowing.

[0007] The method for improving the performance of the hydrorefining catalyst of the present invention is as follows: the temperature of the reactor filled with the hydrorefining catalyst is controlled at 320-370℃, the hydrorefining catalyst is rinsed with jet fuel, and then sulfur is replenished to the hydrorefining catalyst by carrying dimethyl disulfide with ordinary first-line oil as a solvent, thereby improving the performance of the hydrorefining catalyst.

[0008] Preferably, the temperature is controlled at 320-350℃.

[0009] Based on the research on the actual operation of hydrorefining catalysts, increasing the temperature of the hydrorefining catalyst can enhance the catalyst's activity and achieve the effect of removing S, N, and aromatics from the feedstock.

[0010] In this invention, during flushing, the volume of jet fuel is 20-40% of the reactor volume, and an external circulation pump is used to circulate the jet fuel to flush the hydrorefining catalyst.

[0011] In this invention, the rinsing time is 6-24 hours, preferably 12 hours.

[0012] According to the operating cycle of hydrorefining catalysts, during high-temperature production, impurities and coke easily adhere to the surface of the hydrorefining catalyst, reducing the acidic centers and resulting in substandard product quality. This invention uses jet fuel as a flushing medium to wash away the coke, exposing the acidic centers and improving the catalyst's activity. If the flushing time is too short, the coke adhering to the catalyst surface cannot be effectively removed; if the flushing time is too long, production efficiency is affected. Experiments show that a flushing time between 6 and 24 hours can effectively remove most of the coke.

[0013] In this invention, the mass of dimethyl disulfide during sulfur replenishment is 10-20% of the amount of hydrorefining catalyst loaded.

[0014] In this invention, the volume ratio of first-grade oil to dimethyl disulfide is (5-30):1 during sulfur replenishment.

[0015] In this invention, during sulfur replenishment, the total volume of the primary oil and dimethyl disulfide is 20-40% of the reactor volume. An external circulation pump is used to circulate the primary oil carrying dimethyl disulfide to replenish the sulfur in the hydrorefining catalyst.

[0016] In this invention, the sulfur replenishment time is 6-24 hours, preferably 12 hours.

[0017] Hydrorefining catalysts are inherently sulfurized catalysts. During high-temperature production, low hydrogen sulfide concentrations can lead to sulfur loss and reduced activity in the hydrorefining catalyst. This invention employs a method of adding dimethyl disulfide to the catalyst using crude oil as a medium to replenish sulfur, which can significantly increase the sulfur content of the catalyst and enhance its activity.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) The method for improving the performance of the hydrogenation refining catalyst of the present invention does not require external regeneration. By controlling the catalyst pretreatment temperature, washing the catalyst with jet fuel, and adding dimethyl disulfide in a closed-loop circulation to the catalyst device reactor, the catalyst's own activity and attached sulfur content are greatly improved, the acidity center of the catalyst is increased, the quality of subsequent products can be improved, the yellowing resistance of the products can be improved, and the treated catalyst can initially achieve the activity performance of a new catalyst.

[0020] (2) By improving the performance of the hydrorefining catalyst, this invention shortens the maintenance and regeneration cycle, solves the problem of product yellowing, ensures the long-term operation of the production system, and improves economic efficiency. Detailed Implementation

[0021] The present invention will be further described below with reference to the embodiments. Unless otherwise specified, the raw materials used in the embodiments are all commercially available conventional raw materials; unless otherwise specified, the process methods used in the embodiments are all conventional methods in the art. The hydrorefining catalyst used in the embodiments is RL-2. When the resistance of the white oil to yellowing deteriorates, the operation is stopped, and the performance of the hydrorefining catalyst at this time is improved.

[0022] Example 1

[0023] A method for improving the performance of a hydrorefining catalyst is as follows:

[0024] The temperature of the reactor containing the hydrorefining catalyst was controlled at 330℃. The hydrorefining catalyst was flushed with jet fuel, with the volume of jet fuel being 30% of the reactor volume. An external circulation pump was used to circulate the jet fuel and flush the hydrorefining catalyst for 12 hours. Then, dimethyl disulfide was carried by ordinary primary oil as a solvent to replenish sulfur in the hydrorefining catalyst. The mass of dimethyl disulfide was 15% of the hydrorefining catalyst loading, and the volume ratio of ordinary primary oil to dimethyl disulfide was 20:1. The total volume of ordinary primary oil and dimethyl disulfide was 30% of the reactor volume. An external circulation pump was used to circulate the ordinary primary oil carrying dimethyl disulfide for 12 hours to complete the performance improvement of the hydrorefining catalyst.

[0025] Example 2

[0026] A method for improving the performance of a hydrorefining catalyst is as follows:

[0027] The temperature of the reactor containing the hydrorefining catalyst was controlled at 320℃. The hydrorefining catalyst was flushed with jet fuel, with the volume of jet fuel being 20% ​​of the reactor volume. An external circulation pump was used to circulate the jet fuel and flush the hydrorefining catalyst for 6 hours. Then, dimethyl disulfide was carried by ordinary crude oil as a solvent to replenish sulfur in the hydrorefining catalyst. The mass of dimethyl disulfide was 10% of the hydrorefining catalyst loading, and the volume ratio of ordinary crude oil to dimethyl disulfide was 5:1. The total volume of ordinary crude oil and dimethyl disulfide was 20% of the reactor volume. An external circulation pump was used to circulate the ordinary crude oil carrying dimethyl disulfide for 6 hours to complete the performance improvement of the hydrorefining catalyst.

[0028] Example 3

[0029] A method for improving the performance of a hydrorefining catalyst is as follows:

[0030] The temperature of the reactor containing the hydrorefining catalyst was controlled at 350℃. The hydrorefining catalyst was flushed with jet fuel, with the jet fuel volume accounting for 25% of the reactor volume. An external circulation pump was used to circulate the jet fuel and flush the hydrorefining catalyst for 24 hours. Then, dimethyl disulfide was carried by ordinary primary oil as a solvent to replenish sulfur in the hydrorefining catalyst. The mass of dimethyl disulfide was 20% of the hydrorefining catalyst loading, and the volume ratio of ordinary primary oil to dimethyl disulfide was 30:1. The total volume of ordinary primary oil and dimethyl disulfide was 25% of the reactor volume. An external circulation pump was used to circulate the ordinary primary oil carrying dimethyl disulfide for 24 hours to complete the performance improvement of the hydrorefining catalyst.

[0031] Example 4

[0032] A method for improving the performance of a hydrorefining catalyst is as follows:

[0033] The temperature of the reactor containing the hydrorefining catalyst was controlled at 370℃. The hydrorefining catalyst was flushed with jet fuel, with the jet fuel volume accounting for 40% of the reactor volume. An external circulation pump was used to circulate the jet fuel and flush the hydrorefining catalyst for 18 hours. Then, dimethyl disulfide was carried by ordinary crude oil as a solvent to replenish sulfur in the hydrorefining catalyst. The mass of dimethyl disulfide was 12% of the hydrorefining catalyst loading, and the volume ratio of ordinary crude oil to dimethyl disulfide was 10:1. The total volume of ordinary crude oil and dimethyl disulfide was 40% of the reactor volume. An external circulation pump was used to circulate the ordinary crude oil carrying dimethyl disulfide for 18 hours to complete the performance improvement of the hydrorefining catalyst.

[0034] Comparative Example 1

[0035] Hydrogenation refining catalyst before performance improvement.

[0036] Comparative Example 2

[0037] Catalyst RL-2 Freshener.

[0038] Comparative Example 3

[0039] The only difference between this comparative example and Example 1 is that the temperature of the reactor containing the hydrorefining catalyst is controlled at 250°C.

[0040] Comparative Example 4

[0041] The only difference between this comparative example and Example 1 is that jet fuel flushing was not performed.

[0042] Comparative Example 5

[0043] The only difference between this comparative example and Example 1 is that dimethyl disulfide supplementation was not performed.

[0044] The content of the hydrorefining catalysts in Examples 1-4 and Comparative Examples 1-4, as well as before performance improvement, was analyzed, and their effect on the yellowing resistance of the white oil product was studied. The results are shown in Table 1.

[0045] Table 1

[0046]

[0047]

[0048] As can be seen from Table 1, the theoretical sulfur content of the fresh catalyst is 9.08%, while the actual value is 6.40%. Before the performance improvement, the sulfur content of the hydrorefining catalyst was only about 5%, the sulfidation degree of the catalyst was less than 50%, and the carbon deposition was as high as 12% or more (affected by the unclean hot hydrogen carrying oil during shutdown). After treatment by the method of the present invention, the performance of the catalyst can be basically restored.

Claims

1. A method for improving the performance of a hydrorefining catalyst, characterized in that: The temperature of the reactor containing the hydrorefining catalyst is controlled at 320-350℃. The hydrorefining catalyst is rinsed with jet fuel and then sulfur is replenished to the hydrorefining catalyst by carrying dimethyl disulfide with ordinary first-line oil as a solvent, thereby improving the performance of the hydrorefining catalyst. During rinsing, the rinsing cycle lasts for 6-24 hours.

2. The method for improving the performance of the hydrorefining catalyst according to claim 1, characterized in that: During flushing, the volume of jet fuel is 20-40% of the reactor volume.

3. The method for improving the performance of the hydrorefining catalyst according to claim 2, characterized in that: During flushing, an external circulation pump is used to circulate the jet fuel and flush the hydrorefining catalyst.

4. The method for improving the performance of the hydrorefining catalyst according to claim 1, characterized in that: When adding sulfur, the mass of dimethyl disulfide should be 10-20% of the amount of hydrorefining catalyst loaded.

5. The method for improving the performance of the hydrorefining catalyst according to claim 1, characterized in that: When adding sulfur, the volume ratio of first-line oil to dimethyl disulfide is usually (5-30):

1.

6. The method for improving the performance of the hydrorefining catalyst according to claim 1, characterized in that: When adding sulfur, the total volume of primary oil and dimethyl disulfide is usually 20-40% of the reactor volume.

7. The method for improving the performance of the hydrorefining catalyst according to claim 6, characterized in that: During sulfur replenishment, an external circulation pump is used to circulate the first-stage oil carrying dimethyl disulfide to replenish the sulfur in the hydrorefining catalyst.

8. The method for improving the performance of the hydrorefining catalyst according to claim 7, characterized in that: During sulfur replenishment, the cyclic sulfur replenishment time is 6-24 hours.

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