Wax oil hydrotreating method

Abstract

The invention provides a wax oil hydrotreating method. The method comprises the following steps: mixing raw material oil with hydrogen, and carrying out hydrofining reaction by flowing through a catalyst zone; wherein in the material flowing direction, the total acid amount of a catalyst in the catalyst area is firstly increased and then decreased, the maximum value of the total acid amount is located in the middle of the catalyst area, the weak acid amount is firstly increased and then decreased, the maximum value of the weak acid amount is located in the middle of the catalyst area, and the mass content of the active metal is sequentially increased; the front reaction temperature of the catalyst area is lower than the middle reaction temperature, the rear reaction temperature is not higher than the middle reaction temperature, the catalyst in the front of the catalyst area does not contain molecular sieves, the catalysts in the middle and the rear of the catalyst area contain molecular sieves, and the molecular sieve content of the catalyst in the rear is smaller than that of the catalyst in the middle. The method can effectively realize deep removal of sulfur and nitrogen in high-sulfur and high-nitrogen wax oil.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry, and in particular relates to a wax oil hydrogenation treatment method. Background Art

[0002] As crude oil deteriorates and becomes heavier, the content of sulfur, nitrogen, metals and residual carbon in crude oil increases. Wax oil hydrotreating process is an important means to clean heavy oil products. The main purpose of the wax oil hydrotreating process is to remove a large amount of impurities contained in heavy crude oil, such as sulfur, nitrogen, metals and asphaltene, and provide raw materials for hydrocracking or catalytic cracking units. The main reactions of the wax oil hydrotreating process include hydrodemetallization, hydrodesulfurization, hydrodenitrogenation, aromatic saturation and hydrocarbon hydrocracking. The core technology of the wax oil hydrotreating process is the catalyst, and the performance of the catalyst affects the ability to remove sulfur, nitrogen, residual carbon and metals from the raw material.

[0003] The desulfurization and denitrification capabilities of existing wax oil hydroprocessing processes are not strong, resulting in high sulfur and nitrogen content in the products obtained when used for hydroprocessing high-sulfur and high-nitrogen wax oils. How to effectively achieve deep removal of sulfur and nitrogen from high-sulfur and high-nitrogen wax oils is a technical problem that needs to be solved in the current wax oil hydroprocessing process. Summary of the invention

[0004] The object of the present invention is to provide a wax oil hydroprocessing method which can effectively achieve deep removal of sulfur and nitrogen from high-sulfur and high-nitrogen wax oil.

[0005] In order to achieve the above object, the present invention provides a wax oil hydroprocessing method, wherein the method comprises:

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

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

[0008] Among them, the dividing line between the middle of the catalyst zone and the front of the catalyst zone is located in the 1 / 6 volume to 1 / 3 volume area along the material flow direction in the catalyst zone, and the dividing line between the middle of the catalyst zone and the back of the catalyst zone is located in the 5 / 9 volume to 7 / 9 volume area along the material flow direction in the catalyst zone.

[0009] According to a preferred embodiment of the first aspect, during the hydrofining reaction, the feedstock oil flows through the protective agent zone before flowing through the catalyst zone after being mixed with hydrogen (i.e., the feedstock oil flows through the protective agent zone and the catalyst zone in sequence for hydrofining reaction after being mixed with hydrogen); along the material flow direction (i.e., the contact sequence with the feedstock oil), the pore volume of the protective agent in the protective agent zone decreases in sequence, and the specific surface area increases in sequence, and the temperature difference between the protective agent zone and the front reaction temperature of the catalyst zone is not greater than 10°C, and the temperature of the protective agent zone is not higher than the front reaction temperature of the catalyst zone;

[0010] Furthermore, the protective agent in the protective agent zone has a pore volume of 0.3-0.9 mL / g and a specific surface area of ​​50-200 m 2 / g of protective agent.

[0011] Furthermore, the protective agent in the protective agent zone is selected to contain 0-10wt% of active metal and 90-100wt% of carrier based on the mass of the protective agent as 100%; further, the active metal in the protective agent includes at least one of Co, Mo, Ni, and W; further, the carrier in the protective agent includes at least one of alumina, amorphous silica alumina (ASA), silica, and Al2O3-SiO2.

[0012] Further, the protective agent zone includes more than two protective agent layers; the protective agents in the same protective agent layer are of the same type (including the same pore volume and the same specific surface area); for example, the protective agent zone is composed of two protective agent layers, which are the first protective agent layer and the second protective agent layer in the material flow direction (i.e., the contact sequence with the crude oil), the pore volume of the protective agent in the first protective agent layer is smaller than the pore volume of the protective agent in the second protective agent layer, and the specific surface area of ​​the protective agent in the first protective agent layer is larger than the specific surface area of ​​the protective agent in the second protective agent layer;

[0013] Further, the temperature of the protective agent zone is the same as the reaction temperature at the front of the catalyst zone;

[0014] Further, the protective agent zone includes two or more protective agents;

[0015] Furthermore, taking the sum of the volume of the protective agent in the protective agent zone and the volume of the catalyst in the catalyst zone as 100%, the volume of the protective agent in the protective agent zone is 2-10%, and the volume of the catalyst in the catalyst zone is 90-98%.

[0016] According to a preferred embodiment of the first aspect, the catalyst zone includes three or more catalyst layers; the catalyst types 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 metals, 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, which are the front catalyst layer, the middle catalyst layer, and the rear catalyst layer along the material flow direction (i.e., the order of contact with the crude 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 the total acid amount of the catalyst in the middle catalyst layer, and the total acid amount of the catalyst in the middle catalyst layer is greater than the total acid amount of the catalyst in the rear catalyst layer, the weak acid amount of the catalyst in the front catalyst layer is less than the weak acid amount of the catalyst in the middle catalyst layer, and the weak acid amount of the catalyst in the middle catalyst layer is greater than the weak acid amount of the catalyst in the rear catalyst layer, the mass content of the active metal in the catalyst in the front catalyst layer is less than the mass content of the active metal in the catalyst in the middle catalyst layer, and the mass content of the active metal in the catalyst in the middle catalyst layer is less than the mass content of the catalyst in the rear catalyst layer, the reaction temperature of the front catalyst layer is lower than the reaction temperature of the middle catalyst layer, and the reaction temperature of the rear catalyst layer is not higher than the reaction temperature of the middle catalyst layer, the catalyst in the front catalyst layer does not contain molecular sieves, the catalysts in the middle catalyst layer and the rear catalyst layer contain molecular sieves, and the molecular sieve content of the catalyst in the rear catalyst layer is less than the molecular sieve content of the catalyst in the middle catalyst layer.

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

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

[0020] According to a preferred embodiment of the first aspect, the catalyst in the catalyst zone is composed of an active metal, a carrier and an acidic promoter;

[0021] Further, the carrier of the catalyst is an amorphous porous material or a mixture of an amorphous porous material and a 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; wherein 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 acidic auxiliary agent of the catalyst comprises at least one of phosphoric acid, boric acid, hydrofluoric acid, nitric acid, citric acid, tartaric acid and malic acid;

[0024] Furthermore, based on 100% of the mass of the catalyst, the mass content of the active metal of the catalyst is 10%-40%, the mass content of the acidic additive is 0.5%-3%, the mass content of the molecular sieve is 0-10%, and the remainder is amorphous porous material.

[0025] According to a preferred embodiment of the first aspect, the reaction temperature in the catalyst zone is 300-400°C

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

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

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

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

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

[0031] In the wax oil hydroprocessing method provided by the present invention, the raw oil is contacted with a catalyst in a hydrogen atmosphere to carry out a hydrorefining reaction (including hydrodesulfurization, hydrodenitrogenation, hydrodemetallization and carbon removal). The wax oil hydroprocessing method provided by the present invention improves the catalytic efficiency by grading the metal content, carrier composition, acid amount and acid distribution, and reaction temperature in the catalyst, so that sulfur, nitrogen, metal and carbon in the raw oil are deeply removed, and excellent desulfurization, denitrification, carbon removal and demetallization effects are obtained. 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 purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0033] In the description of the present invention, terms such as "upper part", "lower part", "front part", "middle part" and "rear part" are used only for descriptive purposes, such as distinguishing between various parts to more clearly illustrate / explain the technical solution, and cannot be understood as indicating or implying the number of indicated technical features or the order with substantial significance.

[0034] In the present invention, the ammonia temperature-programmed desorption (NH3-TPD) method is used to determine the acid amount and acid strength of the catalyst. The acid strength of the catalyst is divided into weak acid, medium-strong acid and strong acid. On the NH3-TPD desorption chart, the amount of ammonia desorbed between 100°C and 230°C corresponds to the amount of weak acid, the amount of ammonia desorbed between 230°C and 370°C corresponds to the amount of medium-strong acid, and the amount of ammonia desorbed above 370°C corresponds to the amount of strong acid. The total acid amount of the catalyst is the sum of the amounts of weak acid, medium-strong acid and strong acid. The specific operation method includes: purging the catalyst sample with helium at 500°C for 1 hour and then cooling it to 60°C, introducing saturated ammonia vapor, and pulse adsorption five times to reach equilibrium; heating to 100°C and purging for 2 hours, and then program heating at a heating rate of 10°C / min to desorb ammonia and raise the temperature to 650°C; the desorbed ammonia is absorbed by hydrochloric acid solution, and then the excess hydrochloric acid is titrated with sodium hydroxide solution, and the amount of hydrochloric acid consumed to absorb ammonia is used to define the amount of weak acid, medium-strong acid, strong acid, and total acid of the catalyst, respectively.

[0035] Example 1

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

[0037] In the hydroprocessing reactor, a mixture of raw oil (raw oil parameters refer to Table 1) and hydrogen flows through the protective agent zone and the catalyst zone in sequence to perform a hydrorefining reaction.

[0038] Among them, along the material flow direction (i.e. the order of contact with the crude oil), the upper protective agent layer, the lower protective agent layer, the front catalyst layer, the middle catalyst layer, and the rear catalyst layer are filled in the hydroprocessing reactor in sequence, the upper protective agent layer and the lower protective agent layer constitute the protective agent zone, and the front catalyst layer, the middle catalyst layer, and the rear catalyst layer constitute the catalyst zone.

[0039] The protective agents in the same protective agent layer are of the same type, the pore volume of the protective agent in the upper protective agent layer is greater than the pore volume of the protective agent in the second protective agent layer, and the specific surface area of ​​the protective agent in the upper protective agent layer is smaller than the specific surface area of ​​the protective agent in the lower protective agent layer. The protective agent in the protective agent zone is selected to have a pore volume of 0.3-0.9mL / g and a specific surface area of ​​50-200m 2 / g, a protective agent consisting of a carrier and an active metal, wherein the mass content of the active metal is 0-10% (based on the mass of the protective agent being 100%).

[0040] The types of catalysts in the same catalyst layer are the same and the reaction temperatures of the same catalyst layer are the same; 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 the total acid amount of the catalyst in the middle catalyst layer, and the total acid amount of the catalyst in the middle catalyst layer is greater than the total acid amount of the catalyst in the rear catalyst layer; the weak acid amount of the catalyst in the front catalyst layer is less than the weak acid amount of the catalyst in the middle catalyst layer, and the weak acid amount of the catalyst in the middle catalyst layer is greater than the weak acid amount of the catalyst in the rear catalyst layer; the mass content of the active metal in the catalyst in the front catalyst layer is less than the mass content of the active metal in the catalyst in the middle catalyst layer, and the mass content of the active metal in the catalyst in the middle catalyst layer is less than the mass content of the catalyst in the rear catalyst layer; the reaction temperature of the front catalyst layer is lower than the reaction temperature of the middle catalyst layer, and the reaction temperature of the rear catalyst layer is not higher than the reaction temperature of the middle catalyst layer; the catalyst in the front catalyst layer does not contain molecular sieves, the catalysts in the middle catalyst layer and the rear catalyst layer contain molecular sieves, and the molecular sieve content of the catalyst in the rear catalyst layer is less than the molecular sieve content of the catalyst in the middle catalyst layer. The catalyst in the catalyst zone is selected from catalysts with a total acid content of 0.2-20 μmol / g, a weak acid content of 0.1-15 μmol / g, and a pore volume of 0.2-0.6 mL / g; the catalyst in the catalyst zone is composed of an active metal, a carrier and an acidic additive, the carrier of the catalyst is an amorphous porous material or a mixture of an amorphous porous material and a molecular sieve, and the amorphous porous material includes alumina, amorphous silica aluminum (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 oxides, 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, and 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. Based on the mass of the catalyst as 100%, the mass content of the active metal of the catalyst is 10%-40%, the mass content of the acidic additive is 0.5%-3%, the mass content of the molecular sieve is 0-10%, and the remainder is amorphous porous material.

[0041] Taking the sum of the volume of the protective agent in the protective agent zone and the volume of the catalyst in the catalyst zone as 100%, the volume of the protective agent in the protective agent zone is 2-10%, and the volume of the catalyst in the catalyst zone is 90-98%.

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

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

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

[0045] Example 2

[0046] The present embodiment provides a wax oil hydrogenation treatment method, wherein the method differs from the method provided in Example 1 only in that 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 are not exactly the same. For 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 embodiment, please refer to Table 2 for details.

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

[0048] Example 3

[0049] The present embodiment provides a wax oil hydrogenation treatment method, wherein the method differs from the method provided in Example 1 only in that 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 are not exactly the same. For 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 embodiment, please refer to Table 2 for details.

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

[0051] Comparative Example 1

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

[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, and 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 does not contain molecular sieves. 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 specifically referred to Table 3.

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

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

[0056] Comparative Example 2

[0057] This comparative example provides a wax oil hydroprocessing method, wherein the difference between this method and the method provided in Example 1 is:

[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, and 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 sequence and does not contain molecular sieves. 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 specifically referred to Table 3.

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

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

[0061] Comparative Example 3

[0062] This comparative example provides a wax oil hydroprocessing method, wherein the difference between this method and the method provided in Example 1 is:

[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, and 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 sequence and does not contain molecular sieves. 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 specifically referred to Table 3.

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

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

[0066] Comparative Example 4

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

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

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

[0070] Table 1 Raw oil properties

[0071]

[0072] Table 2 Catalyst and protective agent properties and graded loading

[0073]

[0074]

[0075] Table 3 Catalyst and protective agent properties and grading filling

[0076]

[0077]

[0078]

[0079] Table 4 Hydrotreatment results

[0080]

[0081] As can be seen from Table 4, relative to Comparative Examples 1 to 4, Examples 1 to 3 achieve the desulfurization, denitrification, carbon removal and demetallization capabilities of wax oil by adjusting the pore volume (the material flow direction shows a decreasing trend) and specific surface area (increasing trend along the material flow direction) of the protective agent, the reactor bed temperature (the reaction temperature of the front catalyst layer is lower than the reaction temperature of the middle catalyst layer, and the temperature of the rear catalyst layer is not higher than the reaction temperature of the middle catalyst layer), and the total acid amount of the catalyst layer (increasing first and then decreasing along the material flow direction); the weak acid amount of the catalyst layer (increasing first and then decreasing along the material flow direction), the active metal content in the catalyst layer (increasing along the material flow direction), and the molecular sieve content of the catalyst bed (the front catalyst layer does not contain molecular sieves, the middle and rear catalyst layers contain molecular sieves, and the molecular sieve content in the rear catalyst layer is less than the molecular sieve content in the middle catalyst sublayer). More light naphtha products can be produced, while taking into account the improvement of liquid yield and the reduction of the generation ratio of gas products.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wax oil hydrotreating method, wherein: The method includes: The feedstock oil is mixed with hydrogen and flows through the catalyst zone for a hydrofining reaction; Among them, along the material flow direction, the total acid amount of the catalyst in the catalyst zone increases first and then decreases, and the maximum total acid amount is located in the middle of the catalyst zone, the weak acid amount increases first and then decreases, and the maximum weak acid amount is located in the middle of the catalyst zone, the mass content of active metals increases successively, and the reaction temperature in the front of the catalyst zone is lower than the reaction temperature in the middle, the reaction temperature in the rear is not higher than the reaction temperature in the middle, and the catalyst in the front of the catalyst zone does not contain molecular sieves, the catalysts in the middle and rear contain molecular sieves, and the molecular sieve content of the catalyst in the rear is less than the molecular sieve content of the catalyst in the middle; Among them, the dividing line between the middle of the catalyst zone and the front of the catalyst zone is located in the 1 / 6 volume to 1 / 3 volume area along the material flow direction in the catalyst zone, and the dividing line between the middle of the catalyst zone and the back of the catalyst zone is located in the 5 / 9 volume to 7 / 9 volume area along the material flow direction in the catalyst zone.

2. The method according to claim 1, wherein: During the hydrotreating reaction, the crude oil and hydrogen are mixed and flow through the protective agent zone before flowing through the catalyst zone; along the flow direction of the material, the pore volume of the protective agent in the protective agent zone decreases successively, and the specific surface area increases successively, and the temperature difference between the protective agent zone and the front reaction temperature of the catalyst zone is not greater than 10°C, and the temperature of the protective agent zone is not higher than the front reaction temperature of the catalyst zone.

3. The method according to claim 2, wherein: The protective agent in the protective agent zone has a pore volume of 0.3-0.9 mL / g and a specific surface area of ​​50-200 m 2 / g of protective agent.

4. The method according to claim 2, wherein: The protective agent in the protective agent zone is selected to contain 0-10wt% of active metal and 90-100wt% of carrier based on 100% of the mass of the protective agent; Preferably, the active metal in the protective agent includes at least one of Co, Mo, Ni, and W; Preferably, the carrier in the protective agent includes at least one of alumina, amorphous silica-alumina, silicon dioxide, and Al2O3-SiO2.

5. The method according to claim 2, wherein: The protective agent area includes more than two protective agent layers; the protective agents in the same protective agent layer are of the same type.

6. The method according to claim 2, wherein: Taking the sum of the volume of the protective agent in the protective agent zone and the volume of the catalyst in the catalyst zone as 100%, the volume of the protective agent in the protective agent zone is 2-10%, and the volume of the catalyst in the catalyst zone is 90-98%.

7. The method according to claim 1, wherein: The catalyst zone includes more than three catalyst layers; the catalysts in the same catalyst layer are of the same type and the reaction temperature of the same catalyst layer is the same; Preferably, the catalyst zone is composed of three catalyst layers, which are the front catalyst layer, the middle catalyst layer, and the rear catalyst layer in order along the material flow direction. 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 the total acid amount of the catalyst in the middle catalyst layer, and the total acid amount of the catalyst in the middle catalyst layer is greater than the total acid amount of the catalyst in the rear catalyst layer, the weak acid amount of the catalyst in the front catalyst layer is less than the weak acid amount of the catalyst in the middle catalyst layer, and the weak acid amount of the catalyst in the middle catalyst layer is greater than the weak acid amount of the catalyst in the rear catalyst layer, the mass content of the active metal in the catalyst in the front catalyst layer is less than the mass content of the active metal in the catalyst in the middle catalyst layer, and the mass content of the active metal in the catalyst in the middle catalyst layer is less than the mass content of the catalyst in the rear catalyst layer, the reaction temperature of the front catalyst layer is lower than the reaction temperature of the middle catalyst layer, and the reaction temperature of the rear catalyst layer is not higher than the reaction temperature of the middle catalyst layer, the catalyst in the front catalyst layer does not contain molecular sieves, the catalysts in the middle catalyst layer and the rear catalyst layer contain molecular sieves, and the molecular sieve content of the catalyst in the rear catalyst layer is less than the molecular sieve content of the catalyst in the middle catalyst layer.

8. The method according to claim 1, wherein: The catalyst in the catalyst zone has a total acid content of 0.2-20 μmol / g and a weak acid content of 0.1-15 μmol / g.

9. The method according to claim 1, wherein: The catalyst in the catalyst zone has a pore volume of 0.2-0.6 mL / g.

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

11. The method according to claim 10, wherein: The amorphous porous material comprises at least one of aluminum oxide, amorphous silicon aluminum, 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 preferably includes at least one of Y molecular sieve, ZSM-5, ZSM-22, ZSM-23, ZSM-35, Beta and ZSM-48.

12. The method according to claim 10, wherein: Taking the mass of the catalyst as 100%, the mass content of the active metal of the catalyst is 10%-40%, the mass content of the acidic auxiliary agent is 0.5%-3%, the mass content of the molecular sieve is 0-10%, and the remainder is amorphous porous material.

13. The method according to claim 1, wherein: The reaction temperature in the catalyst zone is 300-400°C; and / or The volume ratio of hydrogen to crude oil is 100-1000:1; and / or The reaction pressure of the hydrotreating reaction is 6-15 MPa; and / or The total liquid hourly volumetric space velocity of the hydrofining reaction is 0.5-2.0h -1 ; and / or The feedstock oil is selected from at least one of coker gas oil, vacuum gas oil, coker diesel and wax lower oil; and / or Taking the mass of the raw oil as 100%, the sulfur content of the raw oil is 0.3-2% and the nitrogen content is 0.1-1%.

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