A method for hydroprocessing of wax oil

Abstract

The present application provides a kind of wax oil hydroprocessing method.This method includes: raw oil is mixed with hydrogen and flows through catalyst zone to carry out hydrofining reaction;Wherein, along the material flow direction, the total acid amount of catalyst in catalyst zone first increases and then decreases, and the maximum value of total acid amount is located in the middle of catalyst zone, weak acid amount first increases and then decreases, and the maximum value of weak acid amount is located in the middle of catalyst zone, the mass content of active metal increases in turn, and the reaction temperature of front part of catalyst zone is lower than the middle reaction temperature, the reaction temperature of rear part is not higher than the middle reaction temperature, and the catalyst in front part of catalyst zone does not contain molecular sieve, the catalyst in middle and rear part contains molecular sieve, the molecular sieve content of catalyst in rear part is less than the molecular sieve content of catalyst in middle part.This method can effectively realize the deep removal of sulfur and nitrogen in high-sulfur and high-nitrogen wax oil.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of petroleum chemical industry, and particularly relates to a wax oil hydroprocessing method. BACKGROUND

[0002] With the deterioration and heavyization of crude oil, the contents of sulfur, nitrogen, metals and residual carbon in the crude oil increase. The wax oil hydroprocessing process is an important means for the cleanization of heavy oil. The main purpose of the wax oil hydroprocessing process is to remove a large amount of impurities such as sulfur, nitrogen, metals and asphaltene in the heavy oil feedstock, and to provide a raw material for a hydrocracking or catalytic cracking device. The main reactions of the wax oil hydroprocessing process include hydrodemetallization, hydrodesulfurization, hydrodenitrogenation, aromatic hydrocarbon saturation and hydrocracking of hydrocarbons. The core technology of the wax oil hydroprocessing process is the catalyst, and the performance of the catalyst affects the ability to remove sulfur, nitrogen, residual carbon and metals in the raw material.

[0003] The desulfurization and denitrogenation ability of the existing wax oil hydroprocessing process is not strong, resulting in high sulfur and nitrogen content in the product obtained when the high-sulfur and high-nitrogen wax oil is subjected to hydroprocessing. How to effectively achieve deep removal of sulfur and nitrogen in high-sulfur and high-nitrogen wax oil is a technical problem to be solved in the current wax oil hydroprocessing process. SUMMARY

[0004] The present application aims to provide a wax oil hydroprocessing method capable of effectively achieving deep removal of sulfur and nitrogen in high-sulfur and high-nitrogen wax oil.

[0005] In order to achieve the above-mentioned purpose, the present application provides a wax oil hydroprocessing method, wherein the method comprises:

[0006] The raw oil is mixed with hydrogen and then flows through the catalyst zone for hydrofining reaction;

[0007] Among them, along the material flow direction (i.e. the contact order of the raw oil), the total acid amount of the catalyst in the catalyst zone first increases and then decreases, and the maximum total acid amount is located in the middle of the catalyst zone, the weak acid amount first increases and then decreases, and the maximum weak acid amount is located in the middle of the catalyst zone, the mass content of active metal increases in turn, and the reaction temperature of the front part of the catalyst zone is lower than that of the middle part, the reaction temperature of the rear part is not higher than that of the middle part, the catalyst in the front part of the catalyst zone does not contain molecular sieve, the catalyst in the middle and rear parts contains molecular sieve, and the content of molecular sieve in the catalyst in the rear part is less than that in the catalyst in the middle part;

[0008] Among them, the demarcation line between the middle part of the catalyst zone and the front part of the catalyst zone is located in the 1 / 6 volume-1 / 3 volume region in the catalyst zone along the material flow direction, and the demarcation line between the middle part of the catalyst zone and the rear part of the catalyst zone is located in the 5 / 9 volume-7 / 9 volume region in the catalyst zone along the material flow direction.

[0009] According to the preferred embodiment of the first aspect, in the process of performing the hydrofining reaction, the raw oil and hydrogen are mixed and then flow through the guard agent zone before flowing through the catalyst zone (i.e., the raw oil and hydrogen are mixed and then flow through the guard agent zone and the catalyst zone in sequence to perform the hydrofining reaction); along the material flow direction (i.e., the contact order of the raw oil), the pore volume of the guard agent in the guard agent zone decreases in sequence and the specific surface area increases in sequence, and the temperature difference between the guard agent zone and the front part of the catalyst zone is not more than 10℃, and the temperature of the guard agent zone is not higher than the reaction temperature of the front part of the catalyst zone.

[0010] Further, the guard agent in the guard agent zone is selected from a guard agent with a pore volume of 0.3-0.9mL / g and a specific surface area of 50-200m 2 / g.

[0011] Further, the guard agent in the guard agent zone is selected from a guard agent containing 0-10wt% of active metal and 90-100wt% of carrier, based on 100% of the mass of the guard agent; further, the active metal in the guard agent includes at least one of Co, Mo, Ni and W; further, the carrier in the guard agent includes at least one of alumina, amorphous silica-alumina (ASA), silicon dioxide and Al2O3-SiO2.

[0012] Further, the guard agent zone includes two or more guard agent layers; the guard agents in the same guard agent layer are the same (including the same pore volume and the same specific surface area); for example, the guard agent zone is composed of two guard agent layers, which are a first guard agent layer and a second guard agent layer in sequence along the material flow direction (i.e., the contact order of the raw oil), the pore volume of the guard agent in the first guard agent layer is smaller than that of the guard agent in the second guard agent layer, and the specific surface area of the guard agent in the first guard agent layer is greater than that of the guard agent in the second guard agent layer.

[0013] Further, the temperature of the guard agent zone is the same as the reaction temperature of the front part of the catalyst zone.

[0014] Further, the guard agent zone includes two or more guard agents.

[0015] Further, based on 100% of the sum of the volume of the guard agent in the guard agent zone and the volume of the catalyst in the catalyst zone, the volume of the guard agent in the guard agent zone is 2-10%, and the volume of the catalyst in the catalyst zone is 90-98%.

[0016] According to the preferred embodiment of the first aspect, the catalyst zone includes three or more catalyst layers; the catalysts in the same catalyst layer are the same (including the same total acid amount, the same weak acid amount, the same mass content of active metal, and the same molecular sieve content) and the reaction temperature of the same catalyst layer is the same.

[0017] For example, the catalyst zone is composed of three catalyst layers, in the order of front catalyst layer, middle catalyst layer and rear catalyst layer along the material flow direction (i.e. the order of contacting with the raw oil), the middle catalyst layer is located in the middle of the catalyst zone, the total acid amount of the catalyst in the front catalyst layer is less than that in the middle catalyst layer, the total acid amount of the catalyst in the middle catalyst layer is greater than that in the rear catalyst layer, the weak acid amount of the catalyst in the front catalyst layer is less than that in the middle catalyst layer, the weak acid amount of the catalyst in the middle catalyst layer is greater than that in the rear catalyst layer, the mass content of active metal of the catalyst in the front catalyst layer is less than that in the middle catalyst layer, the mass content of active metal of the catalyst in the middle catalyst layer is less than that in the rear catalyst layer, the reaction temperature of the front catalyst layer is lower than that of the middle catalyst layer, the reaction temperature of the rear catalyst layer is not higher than that of the middle catalyst layer, the catalyst in the front catalyst layer does not contain molecular sieve, the catalyst in the middle catalyst layer and the rear catalyst layer contains molecular sieve, the content of molecular sieve of the catalyst in the rear catalyst layer is less than that in the middle catalyst layer.

[0018] According to the preferred embodiment of the first aspect, the catalyst in the catalyst zone is selected from catalysts with a total acid amount of 0.2-20 μmol / g and a weak acid amount of 0.1-15 μmol / g.

[0019] According to the preferred embodiment of the first aspect, the catalyst in the catalyst zone is selected from catalysts with a pore volume of 0.2-0.6 mL / g.

[0020] According to the preferred embodiment of the first aspect, the catalyst in the catalyst zone is composed of active metal, carrier and acidic adjuvant.

[0021] Further, the carrier of the catalyst is amorphous porous material or a mixture of amorphous porous material and molecular sieve; wherein the amorphous porous material preferably includes at least one of alumina, amorphous silica-alumina (ASA), titanium dioxide, zirconium dioxide, silicon dioxide, Al2O3-SiO2, Al2O3-TiO2 composite oxide, Al2O3-ZrO2 composite oxide, ZrO2-TiO2 composite oxide and TiO2-SiO2 composite oxide; and the molecular sieve preferably includes at least one of Y molecular sieve, ZSM-5, ZSM-22, ZSM-23, ZSM-35, Beta and ZSM-48.

[0022] Further, the active metal of the catalyst includes at least one of Co, Mo, Ni and W.

[0023] Further, the acid promoter of the catalyst comprises at least one of phosphoric acid, boric acid, hydrofluoric acid, nitric acid, citric acid, tartaric acid and malic acid;

[0024] Further, the mass content of the active metal of the catalyst is 10%-40%, the mass content of the acid promoter is 0.5%-3%, the mass content of the molecular sieve is 0-10%, and the balance is the amorphous porous material, based on 100% of the mass of the catalyst.

[0025] According to the preferred embodiment of the first aspect, the reaction temperature of the catalyst zone is 300-400℃.

[0026] According to the preferred embodiment of the first aspect, the volume ratio of hydrogen to raw oil is 100-1000:1.

[0027] According to the preferred embodiment of the first aspect, the reaction pressure of the hydrofining reaction is 6-15 MPa.

[0028] According to the preferred embodiment of the first aspect, the total liquid hourly space velocity of the hydrofining reaction is 0.5-2.0 h -1 .

[0029] According to the preferred embodiment of the first aspect, the raw oil is selected from at least one of coking wax oil (CGO), vacuum wax oil (VGO), coking diesel and wax oil.

[0030] According to the preferred embodiment of the first aspect, the sulfur content of the raw oil is 0.3-2%, and the nitrogen content is 0.1-1%, based on 100% of the mass of the raw oil.

[0031] In the wax oil hydroprocessing method provided by the application, the raw oil is contacted with the catalyst under a hydrogen atmosphere to perform a hydrofining reaction (including hydrodesulfurization, hydrodenitrogenation, hydrodemetallization and de-carbon residue). The wax oil hydroprocessing method provided by the application improves the catalytic efficiency by grading the metal content, carrier composition, acid amount and acid distribution, and reaction temperature of the catalyst, on the one hand, so that sulfur, nitrogen, metal and carbon residue in the raw oil are deeply removed, and excellent desulfurization, denitrification, de-carbon residue and demetallization effects are achieved, on the other hand, the cracking activity of the catalyst is controlled, so that the yield of light products is low and the liquid yield is high. DETAILED DESCRIPTION

[0032] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0033] In the description of the present application, the terms such as "upper", "lower", "front", "middle" and "rear" are only used for the purpose of description, for example, distinguishing parts, so as to make the technical solutions clearer / explained, and cannot be understood as indicating or implying the number of the indicated technical features or the order with substantial meaning.

[0034] In the present application, the amount and strength of the acid of the catalyst are determined by using the ammonia temperature programmed desorption (NH3-TPD) method. The strength of the acid of the catalyst is divided into weak acid, medium-strong acid and strong acid. In the NH3-TPD desorption graph, the amount of ammonia desorbed between 100℃ and 230℃ corresponds to the amount of weak acid, the amount of ammonia desorbed between 230℃ and 370℃ corresponds to the amount of medium-strong acid, and the amount of ammonia desorbed above 370℃ corresponds to the amount of strong acid. The total amount of the acid of the catalyst is the sum of the amounts of the weak acid, the medium-strong acid and the strong acid. The specific operation method includes: after the catalyst sample is purged with helium at 500℃ for 1 hour and then cooled to 60℃, ammonia saturated vapor is introduced, and pulse adsorption is performed five times to reach equilibrium; then, the temperature is raised to 100℃ and purged for 2 hours, and then temperature programmed desorption of ammonia is performed at a temperature rising rate of 10℃ / min, and the temperature is raised to 650℃; the desorbed ammonia is absorbed by hydrochloric acid solution, and then the excess hydrochloric acid is titrated by sodium hydroxide solution, and the amount of hydrochloric acid consumed by the absorption of ammonia is defined as the amount of the weak acid, the medium-strong acid, the strong acid and the total acid of the catalyst, respectively.

[0035] Embodiment 1

[0036] The present embodiment provides a wax oil hydroprocessing method, wherein the method comprises:

[0037] The mixture of the raw oil (the parameters of the raw oil are shown in Table 1) and hydrogen in the hydroprocessing reactor flows through the guard bed zone and the catalyst zone in sequence to perform hydrofining reaction.

[0038] Among them, along the material flow direction (i.e. the contact order of the raw oil), the upper guard bed layer, the lower guard bed layer, the front catalyst layer, the middle catalyst layer and the rear catalyst layer are sequentially filled in the hydroprocessing reactor, the upper guard bed layer and the lower guard bed layer form the guard bed zone, and the front catalyst layer, the middle catalyst layer and the rear catalyst layer form the catalyst zone.

[0039] The protection agent in the same protection agent layer is of the same type, the pore volume of the protection agent in the upper protection agent layer is greater than the pore volume of the protection agent in the second protection agent layer, and the specific surface area of the protection agent in the upper protection agent layer is less than the specific surface area of the protection agent in the lower protection agent layer. The protection agent in the protection agent zone is selected from a protection agent with a pore volume of 0.3-0.9 mL / g and a specific surface area of 50-200 m 2 / g, which is composed of a carrier and an active metal and has a mass content of the active metal of 0-10% (based on 100% of the mass of the protection agent).

[0040] The catalysts in the same catalyst layer are the same in kind and the reaction temperature of the same catalyst layer is the same; the middle catalyst layer is located in the middle of the catalyst zone; the total acid amount of the catalyst of the front catalyst layer is less than that of the catalyst of the middle catalyst layer, the total acid amount of the catalyst of the middle catalyst layer is greater than that of the catalyst of the rear catalyst layer, the weak acid amount of the catalyst of the front catalyst layer is less than that of the catalyst of the middle catalyst layer, the weak acid amount of the catalyst of the middle catalyst layer is greater than that of the catalyst of the rear catalyst layer, the mass content of the active metal of the catalyst of the front catalyst layer is less than that of the catalyst of the middle catalyst layer, the mass content of the active metal of the catalyst of the middle catalyst layer is less than that of the catalyst of the rear catalyst layer, the reaction temperature of the front catalyst layer is lower than that of the middle catalyst layer, the reaction temperature of the rear catalyst layer is not higher than that of the middle catalyst layer, the catalyst of the front catalyst layer does not contain molecular sieve, the catalysts of the middle catalyst layer and the rear catalyst layer contain molecular sieve, and the content of the molecular sieve of the catalyst of the rear catalyst layer is less than that of the catalyst of the middle catalyst layer. The catalysts in the catalyst zone are selected from catalysts with a total acid amount of 0.2-20 μmol / g, a weak acid amount of 0.1-15 μmol / g, and a pore volume of 0.2-0.6 mL / g; the catalysts in the catalyst zone are composed of active metal, carrier and acidic additive, the carrier of the catalyst is amorphous porous material or a mixture of amorphous porous material and molecular sieve, the amorphous porous material includes at least one of alumina, amorphous silica-alumina (ASA), titanium dioxide, zirconium dioxide, silicon dioxide, Al2O3-SiO2, Al2O3-TiO2 composite oxide, Al2O3-ZrO2 composite oxide, ZrO2-TiO2 composite oxide and TiO2-SiO2 composite oxide, the molecular sieve includes at least one of Y molecular sieve, ZSM-5, ZSM-22, ZSM-23, ZSM-35, Beta and ZSM-48, the active metal of the catalyst includes at least one of Co, Mo, Ni and W, the acidic additive of the catalyst contains at least one of phosphoric acid, boric acid, hydrofluoric acid, nitric acid, citric acid, tartaric acid and malic acid, the mass content of the active metal of the catalyst is 10%-40% based on 100% of the mass of the catalyst, the mass content of the acidic additive is 0.5%-3%, the mass content of the molecular sieve is 0-10%, and the balance is amorphous porous material.

[0041] The volume of the protective agent in the protective agent zone accounts for 2-10% based on 100% of the sum of the volume of the protective agent in the protective agent zone and the volume of the catalyst in the catalyst zone, and the volume of the catalyst in the catalyst zone accounts for 90-98%.

[0042] The kind and filling amount of the protective agent filled in each protective agent layer, and the kind and filling amount of the catalyst filled in each catalyst layer are shown in Table 2.

[0043] Wherein, the temperature of the upper protective agent layer and the lower protective agent layer is 350℃, the reaction temperature of the front catalyst layer is 360℃, the reaction temperature of the middle catalyst layer is 380℃, and the reaction temperature of the rear catalyst layer is 370℃. The reaction pressure of the hydrofining reaction is 15 MPa, the total liquid hourly space velocity is 1.2 h -1 , and the hydrogen to oil volume ratio is 800:1.

[0044] The hydroprocessing results are shown in Table 4 (including the density, sulfur content, nitrogen content, carbon residue content, metal (mainly Fe, Ni, V) content, light naphtha yield, and total liquid yield of the liquid product).

[0045] Example 2

[0046] This example provides a wax oil hydroprocessing method, wherein the only difference between this method and the method provided in Example 1 is that the types and filling amounts of the protective agents filled in the protective agent layers and the types and filling amounts of the catalysts filled in the catalyst layers are not completely the same. In this example, the types and filling amounts of the protective agents filled in the protective agent layers and the types and filling amounts of the catalysts filled in the catalyst layers are shown in Table 2.

[0047] The hydroprocessing results are shown in Table 4 (including the density, sulfur content, nitrogen content, carbon residue content, metal (mainly Fe, Ni, V) content, light naphtha yield, and total liquid yield of the liquid product).

[0048] Example 3

[0049] This example provides a wax oil hydroprocessing method, wherein the only difference between this method and the method provided in Example 1 is that the types and filling amounts of the protective agents filled in the protective agent layers and the types and filling amounts of the catalysts filled in the catalyst layers are not completely the same. In this example, the types and filling amounts of the protective agents filled in the protective agent layers and the types and filling amounts of the catalysts filled in the catalyst layers are shown in Table 2.

[0050] The hydroprocessing results are shown in Table 4 (including the density, sulfur content, nitrogen content, carbon residue content, metal (mainly Fe, Ni, V) content, light naphtha yield, and total liquid yield of the liquid product).

[0051] Comparative Example 1

[0052] This comparative example provides a wax oil hydroprocessing method, wherein the only difference between this method and the method provided in Example 1 is that:

[0053] The protective agent filled in the upper protective agent layer is the same as the protective agent filled in the lower protective agent layer, the total acid amount of the catalyst filled in the front catalyst layer, the catalyst filled in the middle catalyst layer and the catalyst filled in the rear catalyst layer is the same, and none of the catalysts contains molecular sieve. The type and filling amount of the protective agent filled in each protective agent layer and the type and filling amount of the catalyst filled in each catalyst layer in the present comparative example are shown in Table 3.

[0054] The temperature of the upper protective agent layer and the lower protective agent layer is 380 ℃, the reaction temperature of the front catalyst layer, the reaction temperature of the middle catalyst layer and the reaction temperature of the rear catalyst layer are 380 ℃. The reaction pressure of the hydrofining reaction is 15 MPa, the total liquid hourly space velocity is 1.2 h -1 , and the hydrogen to oil volume ratio is 800:1.

[0055] The hydroprocessing results are shown in Table 4 (including the density, sulfur content, nitrogen content, carbon residue content, metal (mainly Fe, Ni and V) content, light naphtha yield and total liquid yield of the liquid product).

[0056] Comparative Example 2

[0057] The present comparative example provides a wax oil hydroprocessing method, wherein the method is different from the method provided in Example 1 in that:

[0058] The protective agent filled in the upper protective agent layer is the same as the protective agent filled in the lower protective agent layer, the total acid amount of the catalyst filled in the front catalyst layer, the catalyst filled in the middle catalyst layer and the catalyst filled in the rear catalyst layer increases in turn, and none of the catalysts contains molecular sieve. The type and filling amount of the protective agent filled in each protective agent layer and the type and filling amount of the catalyst filled in each catalyst layer in the present comparative example are shown in Table 3.

[0059] The temperature of the upper protective agent layer and the lower protective agent layer is 380 ℃, the reaction temperature of the front catalyst layer, the reaction temperature of the middle catalyst layer and the reaction temperature of the rear catalyst layer are 380 ℃. The reaction pressure of the hydrofining reaction is 15 MPa, the total liquid hourly space velocity is 1.2 h -1 , and the hydrogen to oil volume ratio is 800:1.

[0060] The hydroprocessing results are shown in Table 4 (including the density, sulfur content, nitrogen content, carbon residue content, metal (mainly Fe, Ni and V) content, light naphtha yield and total liquid yield of the liquid product).

[0061] Comparative Example 3

[0062] The present comparative example provides a wax oil hydroprocessing method, wherein the method is different from the method provided in Example 1 in that:

[0063] The protective agent filled in the upper protective agent layer is the same as the protective agent filled in the lower protective agent layer, the total acid amount of the catalyst filled in the front catalyst layer, the catalyst filled in the middle catalyst layer and the catalyst filled in the rear catalyst layer decreases in turn and none of them contains molecular sieve. The type and filling amount of the protective agent filled in each protective agent layer and the type and filling amount of the catalyst filled in each catalyst layer in this comparative example are shown in Table 3.

[0064] The temperature of the upper protective agent layer and the lower protective agent layer is 380℃, the reaction temperature of the front catalyst layer, the reaction temperature of the middle catalyst layer and the reaction temperature of the rear catalyst layer are all 380℃. The reaction pressure of the hydrofining reaction is 15 MPa, the total liquid hourly space velocity is 1.2 h -1 , and the hydrogen to oil volume ratio is 800:1.

[0065] The hydroprocessing results are shown in Table 4 (including the density, sulfur content, nitrogen content, carbon residue content, metal (mainly Fe, Ni and V) content, light naphtha yield and total liquid yield of the liquid product).

[0066] Comparative Example 4

[0067] This comparative example provides a method for hydroprocessing of wax oil, wherein the only difference between this method and the method provided in Example 2 is that:

[0068] The temperature of the upper protective agent layer and the lower protective agent layer is 390℃, the reaction temperature of the front catalyst layer is 390℃, the reaction temperature of the middle catalyst layer is 380℃ and the reaction temperature of the rear catalyst layer is 370℃.

[0069] The hydroprocessing results are shown in Table 4 (including the density, sulfur content, nitrogen content, carbon residue content, metal (mainly Fe, Ni and V) content, light naphtha yield and total liquid yield of the liquid product).

[0070] Table 1 Properties of raw oil

[0071]

[0072] Table 2 Properties and grading of catalysts and protective agents

[0073]

[0074]

[0075] Table 3 Properties and grading of catalysts and protective agents

[0076]

[0077]

[0078]

[0079] Table 4 Hydroprocessing results

[0080]

[0081] From Table 4, it can be seen that, compared with Comparative Examples 1 to 4, Examples 1 to 3 improve the desulfurization, denitrification, decarburization and demetallization of the wax oil by adjusting the pore volume (tending to decrease in the direction of material flow) and specific surface area (tending to increase in the direction of material flow) of the protective agent, the reactor bed temperature (the reaction temperature of the front catalyst layer is lower than that of the middle catalyst layer, and the temperature of the rear catalyst layer is not higher than that of the middle catalyst layer), the total acid amount of the catalyst layer (tending to increase first and then decrease in the direction of material flow), the weak acid amount of the catalyst layer (tending to increase first and then decrease in the direction of material flow), the active metal content in the catalyst layer (tending to increase in the direction of material flow), and the molecular sieve content in the catalyst bed (no molecular sieve is contained in the front catalyst layer, the middle and rear catalyst layers contain molecular sieve, and the molecular sieve content in the rear catalyst layer is less than that in the middle catalyst layer), so that more light naphtha products can be produced, the liquid yield is improved, and the proportion of gas products is reduced.

[0082] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that they can still modify the technical solutions described in the above examples, or make equivalent replacement for part or all of the technical features; and such modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A wax oil hydroprocessing process wherein, The method comprises: The raw oil and hydrogen are mixed and then flow through the catalyst zone for hydrofining reaction; In the catalyst zone, the total acid amount of the catalyst increases first and then decreases along the material flow direction, the maximum total acid amount is located in the middle of the catalyst zone, the weak acid amount increases first and then decreases, the maximum weak acid amount is located in the middle of the catalyst zone, the mass content of the active metal increases in turn, the reaction temperature in the front part of the catalyst zone is lower than that in the middle part, the reaction temperature in the rear part is not higher than that in the middle part, the catalyst in the front part of the catalyst zone does not contain molecular sieve, the catalyst in the middle and rear parts contains molecular sieve, the content of the molecular sieve in the catalyst in the rear part is less than that in the catalyst in the middle part; The dividing line between the middle part of the catalyst zone and the front part of the catalyst zone is located in the 1 / 6 volume-1 / 3 volume region in the catalyst zone along the material flow direction, and the dividing line between the middle part of the catalyst zone and the rear part of the catalyst zone is located in the 5 / 9 volume-7 / 9 volume region in the catalyst zone along the material flow direction.

2. The method of claim 1, wherein, In the hydrofining reaction process, the raw oil and hydrogen are mixed and then flow through the catalyst zone first through the guard catalyst zone; along the material flow direction, the pore volume of the guard catalyst in the guard catalyst zone decreases in turn, the specific surface area increases in turn, the temperature difference between the guard catalyst zone and the front part of the catalyst zone is not more than 10℃, and the temperature of the guard catalyst zone is not higher than that of the front part of the catalyst zone.

3. The method of claim 2, wherein, The protective agent of the protective agent zone is selected from protective agents having a pore volume of 0.3-0.9 mL / g and a specific surface area of 50-200 m 2 / g.

4. The method of claim 2, wherein, The guard catalyst in the guard catalyst zone contains 0-10wt% active metal and 90-100wt% carrier based on 100% mass of the guard catalyst.

5. The method of claim 4, wherein, The active metal in the guard catalyst includes at least one of Co, Mo, Ni and W.

6. The method of claim 4, wherein, The carrier in the guard catalyst includes at least one of alumina, amorphous silica-alumina, silicon dioxide and Al2O3-SiO2.

7. The method of claim 2, wherein, The guard catalyst zone includes two or more guard catalyst layers; the guard catalyst in the same guard catalyst layer is of the same type.

8. The method of claim 2, wherein, The volume of the guard catalyst in the guard catalyst zone is 2-10% based on the sum of the volume of the guard catalyst in the guard catalyst zone and the volume of the catalyst in the catalyst zone being 100%.

9. The method of claim 1, wherein, The catalyst zone includes three or more catalyst layers; the catalyst in the same catalyst layer is of the same type and has the same reaction temperature.

10. The method of claim 9, wherein, The catalyst zone is composed of three catalyst layers, in sequence along the material flow direction, a front catalyst layer, a middle catalyst layer, and a rear catalyst layer, the middle catalyst layer is located in the middle of the catalyst zone, the total acid amount of the catalyst in the front catalyst layer is less than that in the middle catalyst layer, the total acid amount of the catalyst in the middle catalyst layer is greater than that in the rear catalyst layer, the weak acid amount of the catalyst in the front catalyst layer is less than that in the middle catalyst layer, the weak acid amount of the catalyst in the middle catalyst layer is greater than that in the rear catalyst layer, the mass content of active metal of the catalyst in the front catalyst layer is less than that in the middle catalyst layer, the mass content of active metal of the catalyst in the middle catalyst layer is less than that in the rear catalyst layer, the reaction temperature of the front catalyst layer is lower than that of the middle catalyst layer, the reaction temperature of the rear catalyst layer is not higher than that of the middle catalyst layer, the catalyst in the front catalyst layer does not contain molecular sieve, the catalyst in the middle catalyst layer and the rear catalyst layer contains molecular sieve, and the content of molecular sieve in the catalyst in the rear catalyst layer is less than that in the catalyst in the middle catalyst layer.

11. The method of claim 1, wherein, The catalyst in the catalyst zone is selected from a catalyst with a total acid amount of 0.2-20 μmol / g and a weak acid amount of 0.1-15 μmol / g.

12. The method of claim 1, wherein, The catalyst in the catalyst zone is selected from a catalyst with a pore volume of 0.2-0.6 mL / g.

13. The method of claim 1, wherein, The catalyst in the catalyst zone is composed of active metal, carrier, and acidic additive; The carrier of the catalyst is an amorphous porous material or a mixture of an amorphous porous material and a molecular sieve. The active metal of the catalyst includes at least one of Co, Mo, Ni, and W. The acidic additive of the catalyst includes at least one of phosphoric acid, boric acid, hydrofluoric acid, nitric acid, citric acid, tartaric acid, and malic acid.

14. The method of claim 13, wherein, The amorphous porous material includes at least one of alumina, amorphous silica-alumina, titanium dioxide, zirconium dioxide, silicon dioxide, Al2O3-SiO2, Al2O3-TiO2 composite oxide, Al2O3-ZrO2 composite oxide, ZrO2-TiO2 composite oxide, and TiO2-SiO2 composite oxide; and / or The molecular sieve includes at least one of Y molecular sieve, ZSM-5, ZSM-22, ZSM-23, ZSM-35, Beta, and ZSM-48.

15. The method of claim 10, wherein, The mass content of active metal of the catalyst is 10%-40%, the mass content of acidic additive is 0.5%-3%, the mass content of molecular sieve is 0-10%, and the balance is the amorphous porous material, based on 100% of the mass of the catalyst.

16. The method of claim 1, wherein, The reaction temperature of the catalyst zone is 300-400℃; and / or The volume ratio of hydrogen to raw oil is 100-1000:1; and / or The reaction pressure of the hydrofining reaction is 6-15 MPa; and / or The total liquid hourly space velocity of the hydrofinishing reaction is 0.5-2.0 h -1 ; and / or The raw oil is selected from at least one of coking wax oil, vacuum wax oil, coking diesel, and wax oil; and / or The sulfur content of the raw oil is 0.3-2% and the nitrogen content is 0.1-1% based on 100% of the mass of the raw oil. The sulfur content of the raw oil is 0.3-2% and the nitrogen content is 0.1-1% based on 100% of the mass of the raw oil.

Images