CN110938469B

CN110938469B - One-stage series hydrocracking method

Info

Publication number: CN110938469B
Application number: CN201811114273.3A
Authority: CN
Inventors: 崔哲; 吴子明; 王仲义; 孙士可; 彭冲; 曹正凯; 范思强
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2018-09-25
Filing date: 2018-09-25
Publication date: 2021-10-08
Anticipated expiration: 2038-09-25
Also published as: CN110938469A

Abstract

The invention discloses a one-stage series hydrocracking method, which comprises the following steps: (1) mixing the wax oil raw material with hydrogen, and firstly, feeding the mixture into a hydrofining reactor to perform desulfurization, denitrification and aromatic saturation reaction; (2) enabling the effluent in the step (1) to enter a hydrocracking reactor, wherein the hydrocracking reactor comprises 1 st to nth catalyst bed layers along the material direction, wherein n is more than or equal to 3, and each catalyst bed layer is filled with hydrocracking catalysts with different contents of modified Y molecular sieves; (3) and (3) carrying out gas-liquid separation and liquid-phase fractionation on the effluent of the hydrocracking reactor to obtain naphtha, aviation kerosene and diesel oil products. The method takes wax oil as a raw material, and increases the yield of heavy naphtha with high aromatic hydrocarbon potential and improves the quality of aviation kerosene and diesel oil products by setting a reasonable catalyst grading mode and regulating the composition and structure of a catalyst in a grading bed layer.

Description

One-stage series hydrocracking method

Technical Field

The invention relates to a hydrocracking method, in particular to a hydrocracking method for producing high-quality clean fuel by using vacuum wax oil as a raw material.

Background

The hydrocracking technology has the characteristics of strong raw material adaptability, large flexibility of production operation and product scheme, good product quality and the like, can directly convert various heavy inferior feeds into high-quality jet fuel, diesel oil, lubricating oil base stock which are urgently needed by the market and ethylene raw materials prepared by cracking chemical naphtha and tail oil steam, becomes one of the most important heavy oil deep processing technologies in modern oil refining and petrochemical industries, and is increasingly widely applied at home and abroad.

CN200610008413.X discloses a combined hydrocracking method, which comprises the steps of firstly carrying out hydrotreating on poor quality catalytic cracking diesel, mixing a cracking product with VGO and other raw materials, entering a second hydrocracking reaction zone, and then separating various light products and hydrogenated tail oil.

CN200510068180.8 discloses a hydrocracking method for producing chemical raw materials to the maximum, in which heated raw oil and hydrogen enter a first reaction zone to be sequentially contacted with a hydrofining catalyst and a hydrocracking catalyst, the reaction material flow is subjected to oil-gas separation, the obtained hydrogen-rich gas is compressed and recycled, the liquid is fractionated to obtain light naphtha, heavy naphtha, diesel fraction and tail oil fraction, wherein the diesel fraction is pressurized and then mixed with recycle hydrogen and then contacted with the hydrocracking catalyst, and the reaction material flow of the step and the reaction material flow of the previous step are mixed and enter a separation and fractionation system.

CN201110284518.9 discloses a hydrocracking method for selectively increasing yield of aviation kerosene, which comprises the steps of mixing raw oil with hydrogen, sequentially carrying out hydrofining reaction and hydrocracking reaction, cooling and separating reaction effluent, returning obtained heavy diesel oil fraction to a raw material tank for continuous reaction, wherein the fraction has lower content of aromatic hydrocarbon and cycloparaffin, and is suitable fraction for selectively increasing yield of aviation kerosene fraction. Although the method can achieve the effect of increasing the yield of the aviation kerosene, only a small part of the circulating oil undergoes cracking reaction, and the effect of increasing the yield of chemical raw materials is not obvious.

CN200610008420.X discloses a hydrocracking method for producing chemical raw material, which mixes poor quality catalytic cracking diesel oil and heavy hydrocracking raw material in proportion, then carries out hydrotreating and hydrocracking, controls the operation condition to make the yield of heavy naphtha reach about 40wt%, and simultaneously protects the yield of tail oil to be about 20 wt%.

CN200610008416.3 discloses a parallel hydrocracking method, which comprises the steps of hydrocracking heavy distillate oil and poor quality catalytic cracking diesel oil respectively, mixing the obtained cracking products, then carrying out gas-liquid separation, and fractionating the obtained liquid phase to obtain light naphtha, heavy naphtha, aviation kerosene, diesel oil and tail oil.

CN200610008417.8 discloses a hydrocracking method for middle distillate oil circulation, which comprises the steps of mixing poor-quality catalytic cracking diesel and heavy hydrocracking raw materials, firstly carrying out hydrocracking, and carrying out two-stage hydrocracking on the obtained middle distillate oil to obtain high aromatic heavy naphtha and tail oil with low BMCI value.

CN201210440422.1 discloses a hydrogenation method combining hydrocracking and hydrogenation dearomatization, which carries out hydrofining on poor-quality catalytic cracking diesel and hydrogen in a gas-liquid countercurrent mode; carrying out hydrogenation dearomatization reaction on refined oil in the presence of a noble metal catalyst; carrying out hydrocracking pretreatment reaction on the wax oil and hydrogen, and carrying out hydrocracking reaction after mixing the hydrocracking pretreatment effluent and the hydrodearomatization effluent; separating and fractionating the hydrocracking effluent to obtain different fraction products; the cracking tail oil is circulated to the hydrogenation dearomatization reactor, and the method can solve the problem of limited catalytic diesel oil treatment capacity, greatly improve the light oil yield and improve the product quality, but has high equipment investment and complex device operation.

CN201310540392.6 discloses a low energy consumption hydrocracking method for producing high quality jet feedstock. Mixing raw oil with hydrogen, performing heat exchange twice, and sequentially passing through a hydrofining reaction zone and a hydrocracking reaction zone; the hydrocracking reaction zone comprises at least two hydrocracking catalysts, wherein the upstream is filled with a catalyst I, and the downstream is filled with a catalyst II; wherein the catalyst I contains 15-50 wt% of modified Y molecular sieve, the catalyst II contains 3-30 wt% of modified Y molecular sieve, and the content of the modified Y molecular sieve in the catalyst I is 10-25 percent higher than that of the catalyst II. The method organically combines a high-temperature high-pressure countercurrent heat transfer technology with a hydrocracking catalyst grading technology, comprehensively utilizes hydrocracking reaction heat, not only fully exerts the characteristics of two different types of hydrocracking catalysts, improves the quality of a target product while maintaining the selectivity of the catalysts, but also reduces the engineering investment and the operation energy consumption.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a one-stage series hydrocracking method, which takes vacuum wax oil as a raw material, increases the yield of heavy naphtha with high aromatic hydrocarbon potential, improves the quality of aviation kerosene and diesel oil products and improves the property of tail oil by reasonably combining hydrocracking catalysts with different functions.

The one-stage series hydrocracking method comprises the following steps:

(1) mixing the wax oil raw material with hydrogen, and firstly, feeding the mixture into a hydrofining reactor to perform desulfurization, denitrification and aromatic saturation reaction; the hydrofining reactor at least comprises two hydrofining catalyst beds, wherein the upper part of each hydrofining catalyst bed is filled with a hydrofining catalyst A, the lower part of each hydrofining catalyst bed is filled with a hydrofining catalyst B, the hydrofining catalyst A is a non-roasted hydrofining catalyst and is loaded with an organic compound while being loaded with active metal, and the hydrofining catalyst B is a roasted catalyst;

(2) enabling the effluent in the step (1) to enter a hydrocracking reactor, wherein the hydrocracking reactor comprises 1 st to nth catalyst bed layers along the material direction, n is more than or equal to 3, preferably n is 3 or 4, and each catalyst bed layer is filled with a hydrocracking catalyst containing a modified Y molecular sieve;

wherein the percentage content C of the modified Y molecular sieve in the hydrocracking catalyst of each bed layer₁~C_n(based on the total amount of catalyst) has the following relationship: c₁/C₂＜1，C_n-1/C_n> 1, wherein C₁≥C₂~C_nMinimum value of (1), C_n≤C₁~C_n-1Minimum value of (1);

average pore diameter D of hydrocracking catalyst of each bed layer₁~D_nHas the following relationship: d₁/D₂＞1，D_n-1/ D_n< 1 wherein D₁≤D₂~D_nMaximum value of (1), D_n≥D₁~D_n-1Maximum value of (1);

percentage active metal content M of hydrocracking catalyst of each bed layer₁~M_n(to catalyzeTotal amount of agent as reference) has the following relationship: m₁/M₂＞1，M_n-1/ M_n< 1, wherein M₁≥M₂~M_nMinimum value of (1), M_n≥M₁~M_nMaximum value of (1);

wherein the percentage content of the modified Y molecular sieve in the hydrocracking catalyst of each bed layer and the percentage content of active metal have the following relationship: c is more than or equal to 0.5₁/M₁~C_n/M_nAny ratio is less than or equal to 3;

(3) and separating the effluent of the hydrocracking reactor into a gas phase and a liquid phase, recycling the gas phase, and introducing the liquid phase into a fractionating tower for fractionating to obtain naphtha, aviation kerosene, diesel oil and tail oil.

In the process according to the invention, the packing volume V of the catalyst in the beds in the direction of flow₁~V_nHas the following relationship: v is more than 0.1₂/V₁＜5，1＜V_n-1/V_n< 10, wherein V_n-1＞V₁~V_nMinimum value of (1).

In the method of the present invention, the vacuum wax oil raw material is generally Vacuum Gas Oil (VGO), and may also include one or more of straight run wax oil (AGO), coker wax oil (CGO), catalytic cracking Heavy Cycle Oil (HCO), deasphalted oil (DAO), coal synthetic oil or coal tar. The method is particularly suitable for the initial boiling point of the raw oil which is generally 220-450 ℃, and preferably 330-390 ℃; the final distillation point is generally 500-650 ℃, preferably 550-600 ℃, and the nitrogen content is not lower than 1500 mu g/g. The density of the raw oil is not less than 0.9g/cm³， C₇Insoluble substances are not more than 300 mug/g, and the sum of the contents of Fe, Ca, Ni and V is not more than 10.0 mug/g.

In the method, the hydrocracking catalyst can be in the shape of a strip or a ball, if a strip catalyst is selected, the granularity of the catalyst is 3-15 mm, if a ball catalyst is selected, the granularity of the catalyst is 1-8 mm, the granularity of the catalyst is P, and the granularity of the catalyst is P₁~P_nHas the following relationship: p₁/P₂＞1，P_n-1/ P_n< 1 wherein P₁≤P₂~P_nThe maximum value of (a) is,P_n≥P₁~P_n-1maximum value of (1);

in the method, the granularity of the hydrofining catalyst A is higher than that of the hydrofining catalyst B, and the granularity of the hydrofining catalyst A is 1.3-3 times that of the hydrofining catalyst B. The hydrofining catalysts A and B can be in the shape of a strip or a ball, for example, a strip catalyst is selected, the granularity of the catalyst A is 5-10 mm, for example, a ball catalyst is selected, and the granularity of the catalyst A is 3-6 mm. The aperture of the hydrofining catalyst A is 4-15 nm, preferably 6-12 nm, and the aperture of the hydrofining catalyst B is 1.2-4 times of that of the hydrofining catalyst A.

The active component in the catalyst is one or more of W, Mo, Ni and Co, the active component is in an oxidation state, and the content of the active component is generally 15-45% by weight of oxide. The oxidation state catalyst is selected to be subjected to conventional vulcanization treatment before use, so that the hydrogenation active component is converted into a vulcanization state. The catalyst A is subjected to high-temperature roasting after the carrier is formed, roasting is carried out for 0.5-20 hours at the temperature of 300-750 ℃, and then an active metal component and an organic auxiliary agent are impregnated, wherein the organic compound comprises but is not limited to at least one of sulfoxide, the hydrorefining catalyst is obtained without roasting after drying, the drying temperature is 70-290 ℃, and the drying time is 0.5-20 hours; the commercially available catalysts comprise FF-46 and FF-56 which are developed by the research and development institute of petrochemical engineering (FRIPP), and can also be prepared by the method of CN101491766A and the like; the catalyst A can not be dried at high temperature in the start-up process, and the temperature of a catalyst bed layer can not be higher than 160 ℃ before start-up oil is introduced. The catalyst B is roasted at high temperature after the carrier is molded, the catalyst B is roasted at the temperature of 300-750 ℃ for 0.5-20 hours, then an active metal component and an organic auxiliary agent are impregnated, and the hydrogenation refining catalyst is obtained by roasting, wherein the roasting temperature is 300-750 ℃, the roasting time is 0.5-20 hours, the commercially available catalysts comprise hydrogenation catalysts such as 3926, 3936, CH-20, FF-14, FF-18, FF-24, FF-26, FF-36, FH-98, FH-UDS, FZC-41 and the like developed by the research and development institute of petrochemical industry (FRIPP), hydrogenation catalysts such as HR-416, HR-448 and the like of IFP company, hydrogenation catalysts such as ICR174, ICR178, ICR 179 and the like of CLG company, hydrogenation catalysts such as HC-P, HC-K UF-210/220, TK-525, TK-555, TK-557 and the like of Topsor company, KF-752, KF-840, KF-848, KF-901, KF-907 and the like hydrogenation catalysts available from AKZO corporation.

In the method, the filling volume of the hydrofining catalyst A in the first hydrofining catalyst bed layer accounts for 1-80 v%, preferably 10-50 v%, of the first hydrofining catalyst bed layer; the hydrofining catalyst B filled in the second hydrofining catalyst bed layer is 5-60% higher than the hydrofining catalyst B filled in the first hydrofining catalyst bed layer, and the preferred range is 10-50%.

In the process of the present invention, the reaction conditions in the hydrofining reactor are generally: the reaction pressure is 5.0-35.0 MPa, preferably 6.0-19.0 MPa; the average reaction temperature is 200-480 ℃, and preferably 270-450 ℃; the volume space velocity is 0.1-15.0 h^-1Preferably 0.2 to 3.0 hours^-1(ii) a The volume ratio of hydrogen to oil is 100: 1-2500: 1, preferably 400: 1-2000: 1. the inlet temperature of each bed layer of the hydrofining reactor is T_nIs represented by, and n is ≧ 2, wherein T_n≥T_n-1，T_n-T_n-1≤20℃。

In the prior art, more than ten theoretical models have been proposed in turn for the structure of the active phase of hydroprocessing catalysts, of which the Co-Mo-S model proposed by Tops Brother et al is the one that has the most extensive influence at present. The Co-Mo-S active phase is divided into single-layer (also called type I Co-Mo-S) and multi-layer (also called type II Co-Mo-S). The type I Co-Mo-S is connected with a carrier through a Mo-O-Al bond, is a low-sulfur coordinated Co-Mo-S active phase, and Mo and Al have strong interaction, thereby influencing MoS₂The edge, corner Co electronic states, result in low intrinsic (intrinsic) activity per active center. The type II Co-Mo-S has lower interaction with the carrier, so the type II Co-Mo-S is easier to completely vulcanize and is in a stacked MoS₂The structure, a highly sulfur coordinated Co-Mo-S active phase, is usually stacked (laminated) together from larger sheets, not attached to a support, and the intrinsic activity of each active center of the type II active phase is high. Pure Al₂O₃By Mo-O-Al connection, MoS₂The single-layer dispersion is good, the single-layer dispersion is an I-type active phase, and the P, B, Si auxiliary agent is added, so that Mo-O-Al connection can be weakened, and a mixed active phase of the I type and the II type can be generated. Wherein, the II type active phase catalyst has better hydrogenation activityParticularly, the effects of hydrodenitrogenation and aromatic hydrocarbon saturation are better at a lower flat reaction temperature; however, the catalyst is not calcined at high temperature in the preparation process, so that the high-temperature stability of the catalyst is poor, and therefore, when heavy and poor-quality raw materials are processed, a high reaction temperature is required, and the catalytic activity of the catalyst in a high-temperature reaction zone of a reactor cannot be effectively exerted. The invention fills II type active phase hydrogenation catalyst on the upper part (namely low temperature reaction zone) of each catalyst bed layer in the refining reactor, and fills common I type active phase hydrogenation catalyst on the lower part (namely high temperature reaction zone), thereby fully playing the characteristic of good low temperature activity of the II type active phase hydrogenation catalyst, improving the hydrogenation saturation effect, generating larger reaction heat, promoting the activity of the common I type active phase hydrogenation catalyst, better improving the aromatic hydrocarbon saturation and denitrification depth of the hydrogenation refining reaction, and improving the product quality.

In the method of the invention, the hydrocracking operation conditions comprise: the reaction pressure is 5.0-35.0 MPa, preferably 6.0-19.0 MPa; the average reaction temperature is 200-480 ℃, preferably 270-450 ℃; the volume space velocity is 0.1-15.0 h^-1Preferably 0.2 to 3.0 hours^-1(ii) a The volume ratio of hydrogen to oil is 100: 1-2500: 1, preferably 400: 1-2000: 1.

in the method, the hydrocracking catalyst comprises an active metal component and a carrier, wherein the active metal component is selected from one or more of group VIII and/or group VIB metals, the group VIII metal is Co and/or Ni generally, the group VIB metal is Mo and/or W generally, and the carrier is amorphous silicon-aluminum and/or aluminum oxide. Hydrocracking catalysts generally comprise a cracking component, a hydrogenation component and a binder. Such as any suitable hydrocracking catalyst including those known in the art. The cracking component typically comprises amorphous silica-alumina and/or molecular sieves, typically molecular sieves such as Y-type or USY-type molecular sieves. The binder is typically alumina or silica. The hydrogenation component is a metal, a metal oxide or a metal sulfide of a metal in a VI group, a VII group or a VIII group, and more preferably one or more of iron, chromium, molybdenum, tungsten, cobalt, nickel or sulfides or oxides thereof. The hydrogenation component content is usually 5 to 40wt% based on the weight of the catalyst. Specifically, the existing hydrocracking catalyst may be selected, or a specific hydrocracking catalyst may be prepared as required. Commercial hydrocracking catalysts are mainly: HC-12, HC-14, HC-24, HC-39, etc. by UOP, 3905, 3955, FC-12, FC-16, FC-24, FC-32, 3971, 3976, FC-26, FC-28, etc. by FRIPP, and ICR126, ICR210, etc. by CHEVRON. The commercial hydrogenation modification catalyst can be FC-14 catalyst developed by the Fushun petrochemical research institute (FRIPP), SDD-800 catalyst developed by the American Shell company, and the like.

In the method of the invention, three catalyst beds are arranged in the hydrocracking reactor as an example: the hydrocracking catalyst containing the modified Y molecular sieve in the first catalyst bed layer has the following properties: content C of modified Y molecular sieve₁5wt% to 30wt%, preferably 15wt% to 25wt%, average pore diameter D of the catalyst₁5-20nm, preferably 9-13 nm, and the active metal content M in the catalyst₁10wt% to 40wt%, preferably 20wt% to 30 wt%; if a catalyst in the form of a strip is used, the particle size P of the catalyst₁5-12 mm, preferably 6-10 mm, if a spherical catalyst is selected, the particle size P of the catalyst₁2-7 mm, preferably 3-5 mm; wherein 0.6 is less than or equal to C₁/M₁≤1。

In the second catalyst bed, the average pore diameter D of the catalyst₂Ratio D₁The content of the modified Y molecular sieve is 0.5-5 nm, preferably 1-2 nm₂Ratio C₁10-30 wt% higher, and the active metal content M in the catalyst₂Ratio M₁5-10 wt% lower; if a catalyst in the form of a strip is used, the particle size P of the catalyst₂2-8 mm, preferably 3-6 mm, if a spherical catalyst is selected, the particle size P of the catalyst₂1-5 mm, preferably 2-4 mm; wherein 1.5 is less than or equal to C₂/M₂≤2。

In the third catalyst bed, the average pore diameter D of the catalyst₃Ratio D₂The height is 1-7 nm, preferably 2-4 nm, and the content of the modified Y molecular sieve is C₃Ratio C₂20-40 wt% lower, active metal content M₃Ratio M₂10-20 wt%, if a bar catalyst is selected, the particle size P of the catalyst₃6-15 mm, preferably 8-12 mm, if spherical catalysis is selectedParticle size P of catalyst₁3-8 mm, preferably 4-6 mm; wherein 0.4 is less than or equal to C₃/M₃≤0.8。

The filling volumes of the three catalyst bed layers are respectively V₁、V₂And V₃Wherein 0.5<V₁/ V₂<2，1<V₂/ V₃<5。

In the prior art, a hydrocracking device mainly produces high aromatic hydrocarbon potential heavy naphtha, a 3# jet fuel blending component, a high-quality diesel oil blending component and a cracking raw material, in the hydrocracking process, macromolecule polycyclic aromatic hydrocarbon has high polarity and is more easily adsorbed on the surface of a catalyst to generate a cracking reaction to generate monocyclic aromatic hydrocarbon, the monocyclic aromatic hydrocarbon is more difficult to generate aromatic hydrocarbon saturation and ring-opening reaction, the unconverted monocyclic aromatic hydrocarbon is enriched in aviation kerosene and diesel oil fractions to influence the combustibility of aviation kerosene and diesel oil products, and particularly when the raw material property is poor and the operation condition is harsh, the influence on the combustibility of aviation kerosene and diesel oil products is more obvious. The hydrocracking catalyst with larger aperture and moderate cracking activity is filled in the upper bed layer of the hydrocracking reactor, the polycyclic aromatic hydrocarbon in the raw material is firstly subjected to hydrogenation saturation and ring-opening reaction to be converted into monocyclic aromatic hydrocarbon with side chains, because the monocyclic aromatic hydrocarbon is difficult to convert, the average aperture of the catalyst is reduced, the reaction that macromolecular polycyclic aromatic hydrocarbon enters into a catalyst pore passage and preferentially reacts can be reduced, the influence of competitive adsorption on the cracking reaction of the monocyclic aromatic hydrocarbon can be reduced, the retention time of reactants in the catalyst can be increased, the content of a molecular sieve of the small-aperture catalyst is increased, the side chain of the monocyclic aromatic hydrocarbon which is difficult to convert can be subjected to the cracking reaction of naphtha to generate monocyclic aromatic hydrocarbon and paraffin, thus the aromatic hydrocarbon in the aviation kerosene and diesel oil component can be effectively converted into heavy petroleum naphtha component, and the paraffin hydrocarbon can be retained in the aviation kerosene and diesel oil component, the catalyst with larger aperture, strong hydrogenation activity and weak cracking activity is filled at the bottom of the reactor, so that unsaturated aromatic hydrocarbon in the raw material can be fully saturated, the occurrence of secondary cracking reaction is reduced, and the yield of low value-added products such as liquefied gas, dry gas and the like is reduced, thus increasing the yield of heavy naphtha with high aromatic hydrocarbon potential, improving the quality of aviation kerosene and diesel oil products, improving the BMCI value of tail oil, reducing the yield of light hydrocarbon and effectively improving the economic benefit of the device.

Detailed Description

The technical features of the process of the present invention are further described by way of examples, which are not intended to limit the invention. In the examples and comparative examples,% is the mass percentage unless otherwise specified. Wherein the hydrofining catalyst is a commercially available FF-56 catalyst (catalyst A), a FF-36 catalyst (catalyst B), a hydrocracking catalyst I, a hydrocracking catalyst II, a hydrocracking catalyst III and a hydrocracking catalyst IV, and the properties are shown in Table 1. The properties of the feed oil 1 are shown in Table 2, and the properties of the feed oil 2 are shown in Table 3.

Table 1 main physicochemical properties of the catalyst.

TABLE 2 Primary Properties of stock oil 1

TABLE 3 Primary Properties of stock oil 2

Example 1

Raw oil 1 is used as a raw material, 2 catalyst bed layers are arranged in a hydrofining reactor, 3 catalyst bed layers are arranged in a hydrocracking reactor, a catalyst I, a catalyst II and a catalyst III are sequentially filled along the material flow direction, and the filling volume ratio of the catalysts is 1:1: 1. Specific hydrogenation conditions, product distribution and properties are shown in tables 4 and 5.

Example 2

In the same manner as in example 1, 2 catalyst beds were installed in the hydrorefining reactor, and 3 catalyst beds were installed in the hydrocracking reactor, except that the catalyst loading volume ratio was 2: 1: 1. specific hydrogenation conditions, product distribution and properties are shown in tables 4 and 5.

Example 3

In the same manner as in example 1, 2 catalyst beds were installed in the hydrorefining reactor, and 3 catalyst beds were installed in the hydrocracking reactor, except that the catalyst loading volume ratio was 1: 2: 1. specific hydrogenation conditions, product distribution and properties are shown in tables 4 and 5.

Example 4

Raw oil 1 is used as a raw material, 2 catalyst beds are arranged in a hydrofining reactor, wherein a hydrocracking reactor is provided with 4 catalyst beds, a catalyst I, a catalyst II and a catalyst III are sequentially filled along a material flow direction, and the filling volume ratio of the catalysts is 1:1: 2: 1. specific hydrogenation conditions, product distribution and properties are shown in tables 4 and 5.

Example 5

Raw oil 1 is used as a raw material, 1 catalyst bed layer is arranged in a hydrofining reactor, a hydrofining catalyst A is filled in the catalyst bed layer, 3 catalyst bed layers are arranged in a hydrocracking reactor, a catalyst I, a catalyst IV and a catalyst III are sequentially filled in the material flow direction, and the filling volume ratio of the catalysts is 1:1: 1. Specific hydrogenation conditions, product distribution and properties are shown in tables 4 and 5.

Example 6

The same procedure as in example 5 was repeated, except that the hydrofinishing reactor was charged with the catalyst B.

Comparative example 1

Raw oil 1 is used as a raw material, and a hydrofining reactor is filled with a catalyst A, wherein the hydrocracking reactor is provided with 1 catalyst bed layer and is filled with a catalyst I.

Comparative example 2

Raw oil 1 is used as a raw material, a hydrofining reactor is filled with a catalyst B, a hydrocracking reactor is provided with 2 catalyst beds, a catalyst I and a catalyst II are sequentially filled along a material flow direction, and the filling volume ratio of the catalysts is 1: 1.

comparative example 3

The method comprises the following steps of taking raw oil 1 as a raw material, filling a first bed layer of a hydrofining reactor with a catalyst A, filling a second bed layer of the hydrofining reactor with a catalyst B, arranging 2 catalyst bed layers in a hydrocracking reactor, and sequentially filling a catalyst II and a catalyst III along a material flow direction, wherein the filling volume ratio of the catalyst is 1: 1.

table 4 main process conditions and product distribution.

Table 4 (next) main process conditions and product distribution.

Table 5 product key properties.

Table 5 (next) main product properties.

Example 7

Raw oil 2 is used as a raw material, 2 catalyst bed layers are arranged in a hydrofining reactor, 3 catalyst bed layers are arranged in a hydrocracking reactor, a catalyst I, a catalyst II and a catalyst III are sequentially filled in a material flow direction, and the filling volume ratio of the catalysts is 1: 2: 1. the process conditions, product distribution and properties are shown in tables 6 and 7.

Example 8

Comparative example 4

Raw oil 2 is used as a raw material, a hydrocracking reactor is provided with 2 catalyst beds, a catalyst I and a catalyst II are sequentially filled along the material flow direction, and the filling volume ratio of the catalysts is 1: 1. the process conditions, product distribution and properties are shown in tables 6 and 7.

TABLE 6 Main Process conditions and product distribution

TABLE 7 Main Properties of the product

As can be seen from the examples and comparative examples, the wax oil raw material can produce high-quality catalytic reforming raw material, 3# jet fuel blending component and high-quality diesel oil blending component by the technology, and tail oil can be used as steam to be cracked to ethylene raw material, so that the investment cost of the device is low, and the operation is simple.

Claims

1. A hydrocracking process characterized by comprising: (1) mixing the wax oil raw material and hydrogen, and allowing the mixture to enter a hydrofining reactor for desulfurization, denitrification and aromatic saturation reaction; the hydrofining reactor at least comprises two hydrofining catalyst beds, wherein the upper part of each hydrofining catalyst bed is filled with a hydrofining catalyst A, the lower part of each hydrofining catalyst bed is filled with a hydrofining catalyst B, the hydrofining catalyst A is a non-roasted hydrofining catalyst and is loaded with an organic compound while being loaded with active metal, and the hydrofining catalyst B is a roasted catalyst;

(2) the effluent of the step (1) enters a hydrocracking reactor to carry out hydrocracking reaction;

the hydrocracking reactor comprises n beds along the material direction, wherein n is more than or equal to 3, and each catalyst bed is filled with a hydrocracking catalyst containing a modified Y molecular sieve;

wherein: percentage content C of modified Y molecular sieve in hydrocracking catalyst of each bed layer₁~C_nBased on the total amount of the catalystHas the following relationship; c₁/C₂＜1，C_n-1/C_n> 1, wherein C₁≥C₂~C_nMinimum value of (1), C_n≤C₁~C_n-1Minimum value of (1);

average pore diameter D of hydrocracking catalyst of each bed layer₁~D_nHas the following relationship: d₁/D₂＞1，D_n-1/D_n< 1 wherein D₁≤D₂~D_nMaximum value of (1), D_n≥D₁~D_n-1Maximum value of (1);

percentage active metal content M of hydrocracking catalyst of each bed layer₁~M_nThe catalyst has the following relation based on the total amount of the catalyst: m₁/M₂＞1，M_n-1/M_n< 1, wherein M₁≥M₂~M_nMinimum value of (1), M_n≥M₁~M_n-1Maximum value of (1);

(3) the effluent of the hydrocracking reactor is separated into a gas phase and a liquid phase, and the liquid phase is fractionated to obtain naphtha, aviation kerosene, diesel oil and tail oil.

2. The method of claim 1, wherein: n is any natural number of 3-10.

3. The method of claim 1, wherein: the granularity of the hydrofining catalyst A is 1.3-3 times that of the hydrofining catalyst B; the aperture of the hydrofining catalyst B is 1.2-4 times of that of the hydrofining catalyst A.

4. The method of claim 1, wherein: and (2) roasting the hydrofining catalyst A at high temperature after the carrier is molded, roasting at the temperature of 300-750 ℃ for 0.5-20 hours, impregnating with an active metal component and an organic assistant, wherein the organic compound comprises but is not limited to at least one of sulfoxide, drying, and obtaining the hydrofining catalyst without roasting, wherein the drying temperature is 70-290 ℃, and the drying time is 0.5-20 hours.

5. The method of claim 1, wherein: and (2) roasting the hydrofining catalyst B at high temperature after the carrier is formed for 0.5-20 hours at the temperature of 300-750 ℃, then impregnating the active metal component and the organic auxiliary agent, and roasting to obtain the hydrofining catalyst, wherein the roasting temperature is 300-750 ℃, and the roasting time is 0.5-20 hours.

6. The method of claim 1, wherein: the filling volume of the hydrofining catalyst A in the first hydrofining catalyst bed layer accounts for 1-80 v% of that of the first hydrofining catalyst bed layer; and the hydrofining catalyst B filled in the second hydrofining catalyst bed layer is 5-60% higher than the hydrofining catalyst B filled in the first hydrofining catalyst bed layer.

7. The method of claim 1, wherein: in the step (2), the filling volume V of the catalyst in each bed layer along the material flow direction₁~V_nHas the following relationship: v is more than 0.1₂/V₁＜5，1＜V_n-1/V_n< 10, wherein V_n-1＞V₁~V_n-2And V_nMinimum value of (1).

8. The method of claim 1, wherein: in the step (2), C is more than or equal to 0.5₁/M₁~C_n/M_nAny ratio is less than or equal to 3.

9. The method of claim 1, wherein: the granularity of the hydrocracking catalyst is 3-15 mm, and the granularity P of each bed layer catalyst₁~P_nHas the following relationship: p₁/P₂＞1，P_n-1/ P_n< 1 wherein P₁≤P₂~P_nMaximum value of (1), P_n≥P₁~P_n-1Maximum value of (2).

10. The method of claim 1, wherein: the wax oil raw material comprises one or more of vacuum gas oil, straight-run wax oil, coker wax oil, catalytic cracking heavy cycle oil, deasphalted oil, coal synthetic oil or coal tar.

11. The method of claim 1, wherein: the reaction conditions in the hydrofining reactor are as follows: the reaction pressure is 5.0-35.0 MPa, the average reaction temperature is 200-480 ℃, and the volume space velocity is 0.1-15.0 h^-1The volume ratio of hydrogen to oil is 100: 1-2500: 1.

12. the method of claim 1, wherein: the inlet temperature of each bed layer of the hydrofining reactor is T_nIs represented by, and n is ≧ 2, wherein T_n≥T_n-1，T_n-T_n-1≤20℃。

13. The method of claim 1, wherein: hydrocracking operating conditions: the reaction pressure is 5.0-35.0 MPa, the average reaction temperature is 200-480 ℃, and the volume space velocity is 0.1-15.0 h^-1The volume ratio of hydrogen to oil is 100: 1-2500: 1.

14. the method of claim 1, wherein: the hydrocracking reactor is provided with three catalyst beds along the material direction: the hydrocracking catalyst containing the modified Y molecular sieve in the first catalyst bed layer has the following properties: content C of modified Y molecular sieve₁5-30 wt%, average pore diameter D of catalyst₁5-20nm, active metal content M in the catalyst₁10wt% -40 wt%; particle size P of the catalyst₁5-12 mm; wherein 0.6 is less than or equal to C₁/M₁Less than or equal to 1; in the second catalyst bed, the average pore diameter D of the catalyst₂Ratio D₁Low by 0.5-5 nm, modified Y molecular sieve content C₂Ratio C₁10-30 wt% higher, and the active metal content M in the catalyst₂Ratio M₁5-10 wt% lower; wherein 1.5 is less than or equal to C₂/M₂Less than or equal to 2; in the third catalyst bed, the average pore diameter D of the catalyst₃Ratio D₂1 to 7nm in height, modifiedY molecular sieve content C₃Ratio C₂20-40 wt% lower, active metal content M₃Ratio M₂10-20 wt% higher; wherein 0.4 is less than or equal to C₃/M₃≤0.8。

15. The method of claim 14, wherein: the filling volumes of the three catalyst bed layers are respectively V₁、V₂And V₃Wherein 0.5<V₁/ V₂<2，1<V₂/ V₃<5。