A method for starting a fixed-bed heavy oil hydrogenation process

Abstract

The present invention discloses a method for starting a fixed-bed heavy oil hydrogenation process. The method comprises: (1) preparing an oxidized hydrogenation protective agent, a hydrogenation demetallization catalyst, a hydrogenation desulfurization catalyst and a hydrogenation denitrogenation catalyst respectively; (2) preparing an oil-soluble impregnation liquid, wherein the oil-soluble impregnation liquid comprises an organic molybdenum salt, an organic nickel salt, a dispersant and an aromatic-rich solvent, wherein the molybdenum mass concentration is 1% to 6%, and the mass ratio of molybdenum to nickel is 1:1 to 10:1; (3) using the oil-soluble impregnation liquid of step (2) to impregnate the hydrogenation protective agent, the hydrogenation demetallization catalyst, the hydrogenation desulfurization catalyst and the hydrogenation denitrogenation catalyst respectively; (4) loading the catalyst obtained in step (3) into a fixed-bed hydrogenation device; (5) performing temperature-raising sulfurization in the presence of hydrogen, and then gradually switching to heavy oil raw materials for normal production. The method can simplify the start-up steps, shorten the start-up time, reduce the addition of additional sulfides during the start-up process, and achieve a good sulfurization effect.

Description

Technical Field

[0001] The invention relates to a fixed bed hydrogenation process start-up method, and is particularly suitable for a fixed bed heavy oil hydrogenation process start-up method. Background Art

[0002] The efficient use of heavy oil is an important means of clean use of global oil refining. There are three main types of heavy oil hydrogenation technology: fixed bed, fluidized bed and slurry bed. Among them, the fixed bed hydrogenation process technology is relatively mature, easy to operate, and the device investment is relatively low. It is more common in various refineries.

[0003] The complexity of residual oil raw materials, the diversity of reactions and the non-renewable nature of catalysts determine that the operation cycle of fixed-bed residual oil hydrotreating units is relatively short, usually only one to two years, and the agent changes and start-ups are relatively frequent. The operation cycle of residual oil hydrotreating units is short, and the length of time taken for intermediate shutdowns, agent changes and restarts seriously affects the company's crude oil configuration and the operation of downstream catalytic cracking units, and directly affects the company's economic benefits. The conventional shutdown time of residual oil hydrotreating units is about 10 days, and the process time for starting to switch to residual oil is also relatively long. It usually takes about 5 days to switch to residual oil. Among them, the fixed-bed heavy oil hydrogenation process technology mainly uses the method of ex-situ sulfurization for startup, which consumes a large amount of sulfurized oil and requires 2 to 3 days of sulfurization.

[0004] CN201210453946.4 discloses a method for dry presulfurization of hydrogenation catalysts for application in a residual oil hydrogenation switchable reactor system. The method utilizes H2S-rich residual oil hydrogenation unit high-pressure separator gas to presulfurize the catalyst updated online in the residual oil hydrogenation switchable reactor system, and has the advantages of short sulfurization time, low sulfurization cost, and simple operation.

[0005] CN00110706.2 discloses a method for sulfurizing a hydroprocessing catalyst. The method uses a dry sulfurization method followed by a wet sulfurization method to sulfurize the hydroprocessing catalyst. Compared with the traditional sulfurization method, the sulfurization method can greatly save sulfurization time and sulfurized oil, thereby reducing the sulfurization cost.

[0006] CN201610916418.6 discloses a hydrodesulfurization catalyst and a preparation method thereof and a preparation method of a sulfurized hydrodesulfurization catalyst. When the hydrodesulfurization catalyst prepared by the method is used, the oxidized catalyst is directly converted into a sulfurized catalyst by a programmed temperature rise sulfurization method without going through a drying stage.

[0007] CN102041049B discloses a method for starting a sulfided hydrogenation catalyst. The catalyst prepared by the method has two types of active phases and has high catalyst activity, but the heat treatment process of the method still requires the introduction of hydrogen sulfide.

[0008] Although the above methods have good vulcanization effects, they all require the use of additional sulfides for vulcanization. Summary of the invention

[0009] In order to overcome the shortcomings of the prior art, the present invention provides a fixed-bed heavy oil hydrogenation process start-up method, which is particularly suitable for the fixed-bed residual oil hydrogenation process start-up. The method can simplify the start-up steps, shorten the start-up time, reduce the addition of additional sulfides during the start-up process, and achieve a good sulfiding effect.

[0010] The fixed bed heavy oil hydrogenation process start-up method provided by the present invention comprises:

[0011] (1) preparing an oxidized hydrogenation protective agent, a hydrodemetallization catalyst, a hydrodesulfurization catalyst and a hydrodenitrogenation catalyst respectively,

[0012] (2) preparing an oil-soluble impregnation solution, wherein the oil-soluble impregnation solution comprises an organic molybdenum salt, an organic nickel salt, a dispersant and an aromatic-rich solvent, wherein the mass concentration of molybdenum is 1% to 6%, and the mass ratio of molybdenum to nickel is 1:1 to 10:1;

[0013] (3) using the oil-soluble impregnation liquid of step (2) to respectively impregnate the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst,

[0014] (4) loading the catalyst obtained in step (3) into a fixed bed hydrogenation device,

[0015] (5) Performing temperature-raising vulcanization in the presence of hydrogen, including introducing diesel as the start-up oil at 180-230°C for the first vulcanization, switching to wax oil as the start-up oil at 230-280°C for the second vulcanization, and then gradually switching to heavy oil feedstock for normal production.

[0016] In the method of the present invention, in step (1), the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst can be catalysts with corresponding functions commonly used in the art, such as CEN, FZC, ZTN, and ZTS series residue oil hydrotreating catalysts produced by the Catalyst Branch of Sinopec. The grading method of the above catalysts in the present invention can adopt a conventional grading method, that is, the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst are loaded in sequence according to the liquid phase flow direction.

[0017] In the method of the present invention, the amounts of the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst described in step (1) are prepared according to actual needs. Preferably, the filling volume ratio of the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst is 5-15:25-45:15-35:15-35.

[0018] In the method of the present invention, in step (2), the oil-soluble impregnation liquid comprises an organic molybdenum salt, an organic nickel salt, a dispersant and an aromatic-rich solvent, wherein the mass concentration of molybdenum is 1% to 6%, and the mass ratio of molybdenum to nickel is 1:1 to 10:1. The organic molybdenum salt is at least one of molybdenum cyclohexaneate, dialkyl dithiophosphate oxymolybdenum, nitrogen-containing dialkyl dithiophosphate oxymolybdenum and dialkyl dithiocarbamate molybdenum; the organic nickel salt is at least one of nickel cyclohexaneate, nickel oleate, 2-ethylhexanoate nickel and nickel stearate; the dispersant is at least one of methyl acetate, ethyl acetate, butyl acetate and ethyl benzoate; the aromatic-rich solvent is at least one of diesel, deasphalted oil, wax oil and the like, the sulfur mass content of the aromatic-rich solvent is 1% to 5%, and the aromatic mass content is 30% to 50%. The dispersant accounts for 0.5% to 3.0% of the total volume of the oily impregnation liquid, and the aromatic-rich solvent accounts for 85% to 95% of the total volume of the oily impregnation liquid.

[0019] In the method of the present invention, in step (3), the oil-soluble impregnation liquid of step (2) is used to impregnate the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst respectively, so that the mass content of molybdenum loaded on the hydrogenation protective agent by the oil-soluble impregnation liquid is 0.30% to 1.50%, the mass content of molybdenum loaded on the hydrodemetallization catalyst by the oil-soluble impregnation liquid is 0.20% to 1.25%, the mass content of molybdenum loaded on the hydrodesulfurization catalyst by the oil-soluble impregnation liquid is 0.10% to 1.0%, and the mass content of molybdenum loaded on the hydrodenitrogenation catalyst by the oil-soluble impregnation liquid is 0.05% to 0.75%. The mass content of molybdenum loaded on the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst by the oil-soluble impregnation liquid decreases in sequence, and the difference between adjacent two agents is at least 0.05 percentage points, preferably at least 0.08 percentage points.

[0020] In the method of the present invention, the impregnation described in step (3) adopts an unsaturated impregnation method, the amount of the oil-soluble impregnation liquid used is independently 5% to 60% of the saturated liquid absorption amount of the corresponding catalyst, the impregnation time is 0.5 to 2.0 hours, and the impregnation temperature is 30 to 70° C. The mass content of molybdenum loaded by the oil-soluble impregnation liquid in the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst can be reduced in sequence by controlling the amount of the impregnation liquid used in the unsaturated impregnation, or by controlling the concentration of the impregnation liquid.

[0021] In the method of the present invention, during the sulfurization process of step (5), the hydrogen pressure is 14-17 MPa, the hydrogen-to-oil volume ratio is 500-800, and the liquid hourly volume space velocity is 0.18-0.30 h -1 .

[0022] In the method of the present invention, the specific process of step (5) is as follows: heating and vulcanizing in the presence of hydrogen, heating to the first vulcanizing stage at a heating rate of 5-40°C / h, maintaining the temperature for 3-10h, then introducing the start-up oil diesel in the first vulcanizing stage, the first vulcanizing temperature is 180-230°C, the hydrogen sulfide content in the circulating hydrogen is controlled to be 0-0.2vol%, preferably 0.05vol%-0.2vol%, then heating to the second vulcanizing stage at a heating rate of 8-15°C, switching the start-up oil to wax oil in the second vulcanizing stage, the starting temperature of the second vulcanizing stage is 230-280°C, the second vulcanizing stage The first stage includes a first constant temperature vulcanization and a second constant temperature vulcanization. The first constant temperature vulcanization temperature is 270-290°C, the constant temperature time is 3-10h, the temperature is increased from the first vulcanization stage to the second vulcanization stage, and the hydrogen sulfide content in the circulating hydrogen is controlled to be 0.2vol%-1.0vol% in the first constant temperature vulcanization stage. After the first constant temperature vulcanization, the temperature is increased to the second constant temperature vulcanization at a rate of 8-15°C. The second constant temperature vulcanization temperature is 300-320°C, the constant temperature time is 3-10h, the temperature is increased from the first constant temperature vulcanization to the second constant temperature vulcanization, and the hydrogen sulfide content in the circulating hydrogen is controlled to be 1.0vol%-2.0vol%.

[0023] In the method of the present invention, the process of gradually switching to heavy oil raw materials for normal production after the second vulcanization is as follows: the wax oil feed is reduced to 70wt% to 80wt%, and 30wt% to 20wt% of heavy oil raw materials are supplemented at the same time; after the switching is completed, the reactor is operated at a constant temperature for 3 to 5h, and then the reactor bed temperature is increased to 340 to 360°C at a heating rate of 1 to 2°C / h. During the heating process, the proportion of residual oil is gradually increased to 55wt% to 65wt%, and then the operating conditions and the processing volume of raw oil are adjusted according to normal production.

[0024] In the method of the present invention, the diesel may be at least one of straight-run diesel, catalytic diesel and coking diesel, and the sulfur content of the diesel is 1.5% to 4.5%.

[0025] In the method of the present invention, the wax oil can be at least one of straight-run wax oil and coker wax oil. The sulfur content of the wax oil is 1.5% to 4.5%.

[0026] In the method of the present invention, no additional vulcanizing agent needs to be added.

[0027] Compared with the prior art, the method of the present invention has the following advantages:

[0028] 1. The method of the present invention first uses an oil-soluble impregnation liquid to pretreat a conventional heavy oil hydrogenation series catalyst, so that at the initial stage of catalyst start-up, the oil-soluble impregnation liquid loaded on each catalyst is contacted with the start-up oil to carry out a desulfurization reaction to quickly provide H2S gas, which is beneficial to the rapid vulcanization of the catalyst system. At the same time, by controlling the amount of metal loaded in the oil-soluble impregnation liquid impregnated with each catalyst, on the one hand, a large amount of adsorption and reaction heat generated during the reaction process can be better controlled, and the temperature rise of the reactor bed can be easily controlled. On the other hand, it is ensured that sufficient hydrogen sulfide is provided for the vulcanization of each catalyst, so that each catalyst is fully vulcanized and a good vulcanization effect is achieved. In addition, during the vulcanization process, the oil-soluble metal is gradually dissolved in the start-up oil, thereby not affecting the performance of the catalyst after vulcanization.

[0029] 2. The vulcanization process of the present invention does not require the introduction of additional vulcanizing agents. The sulfur contained in the start-up oil itself can meet the vulcanization requirements, thereby reducing the start-up cost, avoiding the risk of accidents during the start-up process, and being more environmentally friendly and reliable. DETAILED DESCRIPTION

[0030] The scheme and effects of the present invention are further described below in conjunction with embodiments, but are not limited to the following embodiments.

[0031] The content of metal components in the catalyst of the present invention is analyzed by spectrophotometry.

[0032] The start-up oils of the embodiments of the present invention and the comparative examples are catalytic diesel and straight-run wax oil, and the evaluation experiment is based on Middle East residual oil as raw material. The raw material analysis results are shown in Table 2. The experiment was carried out on a residual oil hydrogenation evaluation device with four reactors, and the catalyst loading amount of each reactor was 100 mL. The four types of catalysts used are a series of heavy oil hydrogenation catalysts produced by Sinopec Catalyst Branch, and the catalyst properties are shown in Table 1.

[0033] Table 1 Physicochemical properties of catalysts

[0034]

[0035] Table 2 Properties of start-up oil and residual oil raw materials

[0036] Analyze Project diesel fuel Wax oil Residue <![CDATA[Density (20 °C) / g·cm -3 > 0.865 0.901 0.932 Sulfur, wt% 0.78 2.8 2.73 Carbon residue, wt% - - 11.5 Nickel + Vanadium, μg / g - 1.0 70.29

[0037] Implementation 1

[0038] The volume ratio of the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst (see Table 1 for details) is 10:40:20:30, and the total volume of the catalyst is 400mL. Take 100g of dialkyl dithiophosphoric acid oxygen molybdenum, 33g of nickel naphthenate, 10g of cyclohexyl acetate, 1000mL of diesel (sulfur mass content is 1.8%, aromatic mass content is 38.5%), and prepare an oil-soluble active metal solution. The hydrogenation protective agent is impregnated with the above-mentioned oil-soluble active metal solution according to a 50% liquid absorption rate, the hydrodemetallization is impregnated with the above-mentioned oil-soluble active metal solution according to a 30% liquid absorption rate, the hydrodesulfurization catalyst is impregnated with the above-mentioned oil-soluble active metal solution according to a 20% liquid absorption rate, and the hydrodenitrogenation catalyst is impregnated with the above-mentioned oil-soluble active metal solution according to a 10% liquid absorption rate. The impregnation time is 30 minutes, the impregnation temperature is 60°C, and the amount of molybdenum loaded on the catalyst by the oil-soluble impregnation liquid is shown in Table 3. After impregnation, the four reactors were loaded with hydrogenation protective agent, hydrodemetallization catalyst, hydrodesulfurization catalyst and hydrodenitrogenation catalyst in the order of liquid phase flow. The sulfurization process was started according to Table 5. The hydrogen pressure was 15 MPa, the hydrogen-to-oil volume ratio was 700, and the liquid hourly volume space velocity was 0.2 h -1 After the sulfurization is completed, the wax oil feed is reduced to 75wt%, and 25wt% of residual oil is supplemented at the same time; after the switch is completed, the constant temperature is operated for 4h, and then the reactor bed is heated to 350℃ at a heating rate of 1.5℃ / h. During the heating process, the proportion of residual oil is gradually increased to 60%, and then the operating conditions and crude oil processing volume are adjusted according to normal production. The evaluation results are shown in Table 7.

[0039] Example 2

[0040] The difference from Example 1 is that 80 g of molybdenum naphthenate, 20 g of nickel naphthenate, 8 g of butyl acetate, and 1000 mL of wax oil (sulfur content of 2.5% and aromatic content of 37.3%) are used to prepare an oil-soluble impregnation solution. The amount of molybdenum loaded on the catalyst by the oil-soluble impregnation solution is shown in Table 3. The evaluation results are shown in Table 7.

[0041] Example 3

[0042] Different from Example 1, 90 g of dialkyl dithiocarbamate molybdenum, 25 g of nickel oleate, 9 g of butyl acetate, and 1000 mL of deasphalted oil (sulfur content of 3.1% by mass, aromatic content of 40.1% by mass) were used to prepare an oil-soluble impregnation solution. The amount of molybdenum loaded on the catalyst by the oil-soluble impregnation solution is shown in Table 3. The evaluation results are shown in Table 7.

[0043] Example 4

[0044] The difference from Example 3 is that 130 g of dialkyl dithiocarbamate molybdenum, 37 g of nickel oleate, 20 g of butyl acetate, and 1000 mL of deasphalted oil (sulfur content of 3.1% by mass and aromatic content of 40.1% by mass) are used to prepare an oil-soluble impregnation solution. The amount of molybdenum loaded on the catalyst by the oil-soluble impregnation solution is shown in Table 3. The sulfurization process is shown in Table 6, and the evaluation results are shown in Table 7.

[0045] Example 5

[0046] The difference from Example 1 is that 100 g of dialkyl dithiophosphoryl molybdenum, 33 g of nickel cyclohexane, 10 g of cyclohexyl acetate, and 750 mL of diesel (sulfur content of 1.8% and aromatic content of 38.5%) are used to prepare an oil-soluble active metal solution. The amount of molybdenum loaded on the catalyst by the oil-soluble impregnation solution is shown in Table 3. The evaluation results are shown in Table 7.

[0047] Comparative Example 1

[0048] The difference from Example 1 is that each catalyst is not treated with an oil-soluble impregnation solution, but the catalyst is directly loaded into the reactor by a traditional method, and the traditional vulcanization method is used for vulcanization. The vulcanizing agent added to the start-up oil is DMDS (dimethyl disulfide), and the amount of the vulcanizing agent added is 10g. The specific vulcanization process is shown in Table 4, and the evaluation results are shown in Table 7. The evaluation conditions are the same as those in Example 1.

[0049] Table 3 Molybdenum amount loaded by each catalyst through oil-soluble impregnation solution

[0050]

[0051] Table 4 Conventional vulcanization process and conditions of Comparative Example 1

[0052]

[0053] Table 5 Vulcanization process and conditions of Examples 1-3 and 5 of the present invention

[0054]

[0055] Table 6 Vulcanization process and conditions of Example 4 of the present invention

[0056]

[0057] Table 7 Curing time and evaluation results of each example

[0058]

[0059]

[0060] It can be seen from the comparison results in Table 7 that the method of the present invention has a short start-up time, does not require a vulcanizing agent, has a fast heating process, and can achieve a good vulcanization effect.

Claims

1. A method for starting a fixed-bed heavy oil hydrogenation process, comprising: (1) Prepare oxidized hydrogenation protective agent, hydrodemetallization catalyst, hydrodesulfurization catalyst and hydrodenitrogenation catalyst respectively; (2) preparing an oil-soluble impregnation solution, wherein the oil-soluble impregnation solution comprises an organic molybdenum salt, an organic nickel salt, a dispersant and an aromatic solvent, wherein the mass concentration of molybdenum is 1% to 6%, and the mass ratio of molybdenum to nickel is 1:1 to 10:1; (3) using the oil-soluble impregnation liquid of step (2) to impregnate the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst respectively, (4) loading the catalyst obtained in step (3) into a fixed bed hydrogenation device, (5) Performing temperature-raising vulcanization in the presence of hydrogen, including introducing diesel as the start-up oil for the first vulcanization at 180-230°C, switching to wax oil as the start-up oil for the second vulcanization at 230-280°C, and then gradually switching to heavy oil feedstock for normal production; In the oil-soluble impregnation liquid, the organic molybdenum salt is at least one of molybdenum cyclopentaneate, dialkyl dithiophosphate oxymolybdenum, nitrogen-containing dialkyl dithiophosphate oxymolybdenum and dialkyl dithiocarbamate molybdenum; the organic nickel salt is at least one of nickel cyclopentaneate, nickel oleate, nickel 2-ethylhexanoate and nickel stearate; the dispersant is at least one of methyl acetate, ethyl acetate, butyl acetate and ethyl benzoate; the aromatic-rich solvent is at least one of diesel, deasphalted oil and wax oil, the sulfur content of the aromatic-rich solvent is 1% to 5%, and the aromatic content is 30% to 50%; In step (3), the oil-soluble impregnation liquid of step (2) is used to impregnate the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst respectively, so that the mass content of molybdenum loaded on the hydrogenation protective agent by the oil-soluble impregnation liquid is 0.30% to 1.50%, the mass content of molybdenum loaded on the hydrodemetallization catalyst by the oil-soluble impregnation liquid is 0.20% to 1.25%, the mass content of molybdenum loaded on the hydrodesulfurization catalyst by the oil-soluble impregnation liquid is 0.10% to 1.0%, and the mass content of molybdenum loaded on the hydrodenitrogenation catalyst by the oil-soluble impregnation liquid is 0.05% to 0.75%; the mass content of molybdenum loaded on the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst by the oil-soluble impregnation liquid decreases in sequence; In step (5), the sulfur content in the diesel is 1.5% to 4.5% by mass, and / or the sulfur content in the wax oil is 1.5% to 4.5% by mass.

2. The method according to claim 1, characterized in that The filling volume ratio of the hydrogenation protective agent, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst is 5-15:25-45:15-35:15-35.

3. The method according to claim 1, characterized in that The dispersant accounts for 0.5% to 3.0% of the total volume of the oily impregnation liquid, and the aromatic-rich solvent accounts for 85% to 95% of the total volume of the oily impregnation liquid.

4. The method according to claim 1, characterized in that: The mass contents of molybdenum loaded by the oil-soluble impregnation liquid in the hydrogenation protectant, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst decrease in sequence, and the difference between two adjacent agents is at least 0.05 percentage points.

5. The method according to claim 4, characterized in that The mass contents of molybdenum loaded by the oil-soluble impregnation liquid in the hydrogenation protectant, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrogenation catalyst decrease in sequence, and the difference between two adjacent agents is at least 0.08 percentage points.

6. The method according to claim 1 or 4, characterized in that: The impregnation in step (3) adopts an unsaturated impregnation method, the amount of the oil-soluble impregnation liquid used is independently 5% to 60% of the saturated liquid absorption amount of the corresponding catalyst, the impregnation time is 0.5 to 2.0 hours, and the impregnation temperature is 30 to 70°C.

7. The method according to claim 1, characterized in that During the sulfurization process in step (5), the hydrogen pressure is 14-17 MPa, the hydrogen-to-oil volume ratio is 500-800, and the liquid hourly volume space velocity is 0.18-0.30 h -1 .

8. The method according to claim 1, characterized in that The specific process of step (5) is as follows: temperature rises and vulcanization is performed in the presence of hydrogen, and the temperature rises to the first vulcanization stage at a temperature rise rate of 5-40°C / h, and the temperature is kept constant for 3-10h, and then the start-up oil diesel is introduced into the first vulcanization stage, the first vulcanization temperature is 180-230°C, and the hydrogen sulfide content in the circulating hydrogen is controlled to be 0-0.2vol% in the first vulcanization stage, and then the temperature rises to the second vulcanization stage at a temperature rise rate of 8-15°C, and the start-up oil is switched to wax oil in the second vulcanization stage. The starting temperature of the second vulcanization stage is 230-280°C, and the second vulcanization stage includes a first constant temperature vulcanization and a second constant temperature vulcanization. Sulfurization, the first constant temperature vulcanization temperature is 270~290℃, the constant temperature time is 3~10h, the temperature is increased from the first vulcanization stage to the second vulcanization stage and the hydrogen sulfide content in the circulating hydrogen is controlled to be 0.2vol%~1.0vol%. After the first constant temperature vulcanization, the temperature is increased to the second constant temperature vulcanization at a rate of 8~15℃. The second constant temperature vulcanization temperature is 300~320℃, the constant temperature time is 3~10h, the temperature is increased from the first constant temperature vulcanization to the second constant temperature vulcanization and the hydrogen sulfide content in the circulating hydrogen is controlled to be 1.0vol%~2.0vol%.

9. The method according to claim 8, characterized in that In the first sulfidation stage, the hydrogen sulfide content in the circulating hydrogen is controlled to be 0.05 vol%~0.2 vol%.

10. The method according to claim 1, characterized in that The process of gradually switching to heavy oil feedstock for normal production after the second vulcanization is as follows: the wax oil feed is reduced to 70wt%~80wt%, and 30wt%~20wt% of heavy oil feedstock is supplemented at the same time; after the switch is completed, the reactor is operated at a constant temperature for 3~5h, and then the reactor bed temperature is increased to 340~360℃ at a heating rate of 1~2℃ / h. During the heating process, the proportion of residual oil is gradually increased to 55wt%~65wt%, and then the operating conditions and crude oil processing volume are adjusted according to normal production.

11. The method according to claim 1, characterized in that: In step (5), the diesel is at least one of straight-run diesel, catalytic diesel and coker diesel; and / or the wax oil is at least one of straight-run wax oil and coker wax oil.

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