CN109988623B

CN109988623B - Flexible reverse hydrocracking process

Info

Publication number: CN109988623B
Application number: CN201711469564.XA
Authority: CN
Inventors: 刘涛; 李宝忠; 崔哲; 赵玉琢; 黄新露; 王阔
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: 2017-12-29
Filing date: 2017-12-29
Publication date: 2021-06-04
Anticipated expiration: 2037-12-29
Also published as: CN109988623A

Abstract

The invention discloses a flexible reverse hydrocracking process. Mixing wax oil raw oil with a hydrocracking generated material, then carrying out hydrogenation pretreatment, separating and fractionating a hydrogenation pretreatment generated material flow to obtain gas, distillate oil and tail oil, carrying out hydrocracking pretreatment on the obtained tail oil, and passing through a first hydrocracking catalyst bed layer in a hydrocracking reactor to obtain a material which is divided into two strands; a part of material enters a separator for separation, and the obtained liquid phase material flow is pumped out of a hydrocracking reactor and enters a hydroisomerization cracking reactor for isomerization cracking reaction; the other material continuously flows downwards through a second hydrocracking catalyst bed layer; and (3) carrying out gas-liquid separation and fractionation on the hydroisomerization cracking reaction material to obtain hydroisomerization cracking naphtha, aviation kerosene, diesel oil and tail oil products. The invention provides a hydrocracking process for simultaneously producing more than two different specifications of light naphtha, heavy naphtha, aviation kerosene, diesel oil and tail oil products on a set of hydrogenation process equipment.

Description

Flexible reverse hydrocracking process

Technical Field

The invention belongs to the field of petroleum refining, and particularly relates to a reverse hydrocracking process for flexibly producing high-quality light naphtha, heavy naphtha, aviation kerosene, diesel oil and tail oil products with different properties.

Background

The hydrogenation technology is an important processing means for the lightening of heavy oil and the upgrading of the quality of light oil. The hydrocracking technology has the advantages of strong raw oil adaptability, good product flexibility, high liquid product yield, high product quality and the like, and is developed quickly. The existing hydrocracking technology can be divided into three types according to the processing flow: a one-stage series hydrocracking process flow, a single-stage hydrocracking process flow and a two-stage hydrocracking process flow. The operation can be divided into three types according to whether the tail oil is circulated or not: a single-pass once-through process flow, a partial circulation process flow and a full circulation process flow. The reverse hydrocracking technology is developed aiming at the problems that light fractions in raw materials are more, or impurities (such as oxygen, metal and the like) are more. The hydrocracking technology uses two types of catalysts, namely a hydrocracking pretreatment catalyst and a hydrocracking catalyst, wherein the hydrocracking catalyst can be divided into different types of catalysts according to different cracking components, and the main cracking components comprise amorphous silica-alumina, a Y-type molecular sieve, a beta-type molecular sieve, an SAPO-series molecular sieve, a ZSM-5 molecular sieve and the like. When different types of hydrocracking components are used, the composition and the property of the obtained light oil are greatly different, and the composition and the property of tail oil are also greatly different.

CN101333459A discloses a hydro-conversion method using a reverse hydrocracking process flow, which is suitable for processing wide-cut raw oil; CN105733674A discloses a reverse hydrocracking method, which mainly extracts a part of gas phase produced in the hydrocracking process out of a reactor, thereby reducing the further cracking of small molecular materials; CN103055922B discloses a preparation method of a bulk phase hydrocracking catalyst, and CN105018139B, CN 001293228A, CN001508225A and CN104611020B all disclose a method for grading two different Y-type molecular sieves in a hydrocracking method of low energy consumption high yield high quality chemical raw materials. The technology can produce high-quality products by using a hydrocracking method containing a Y-type molecular sieve hydrocracking catalyst by using wax oil as raw oil, wherein the tail oil has high alkane content and low BMCI value and is a raw material for preparing ethylene by high-quality steam cracking, but the product of each fraction obtained by hydrocracking has only one specification.

CN105582992A discloses a hydroisomerization catalyst, a preparation method and application thereof, and a hydrocracking tail oil hydroisomerization method, which can produce high-quality products by using a hydrocracking method containing an isomerization type molecular sieve hydrocracking catalyst and taking wax oil as raw oil, wherein the tail oil has high isomerization content, low condensation point and high viscosity index and is a raw material of high-quality lubricating oil base oil, but the product of each fraction obtained by hydrocracking only has one specification.

CN103394368B discloses a light oil type hydrocracking catalyst containing a composite molecular sieve, a preparation method and an application thereof, CN103551186B discloses a medium oil type hydrocracking catalyst containing a composite molecular sieve, a preparation method and an application thereof, and US4837396A discloses a preparation of a composite molecular sieve catalyst. The technology can produce various high-quality hydrocracking products by using a hydrocracking method of a hydrocracking catalyst containing a Y-type molecular sieve and an isomeric molecular sieve composite molecular sieve by using wax oil as raw oil, but the product of each fraction has only one specification.

CN001169919C discloses a method for increasing the yield of high-quality diesel oil by distillate oil. The technology can produce various high-quality hydrocracking products by using wax oil as raw oil and simultaneously using a hydrocracking method containing two catalysts, namely a Y-type molecular sieve catalyst and an isomeric molecular sieve hydrocracking catalyst, but the product of each fraction has only one specification.

In conclusion, compared with the existing hydrocracking technology using two different types of molecular sieve catalysts and the hydrocracking technology using the Y-type molecular sieve hydrocracking catalyst, the obtained heavy naphtha product has low sulfur content, relatively high aromatic hydrocarbon potential, relatively high smoke point of aviation kerosene products, low sulfur content of diesel oil products, high cetane number, but relatively high condensation point, low aromatic hydrocarbon content of tail oil products, relatively low density, relatively low BMCI value, but very high condensation point which is usually more than 30 ℃; by using a hydrocracking technology of an isomeric molecular sieve hydrocracking catalyst, the obtained heavy naphtha product has low sulfur content, slightly low aromatic hydrocarbon potential, low sulfur content and low condensation point of a diesel product, but has relatively slightly low cetane number and relatively high tail oil density, but has high content of isomeric hydrocarbon and very low condensation point which is usually less than 0 ℃; the hydrocracking technology using the Y-heterogeneous compound molecular sieve-containing catalyst or the hydrocracking technology using the Y-heterogeneous compound molecular sieve-containing hydrocracking catalyst and the heterogeneous molecular sieve-containing hydrocracking catalyst in a grading manner, and the property of the obtained tail oil is between that of the Y-heterogeneous compound molecular sieve-containing hydrocracking catalyst and that of the heterogeneous molecular sieve-containing hydrocracking catalyst. The hydrocracking process technology has the advantages that the hydrocracking tail oil products produced at the same conversion rate are greatly different, wherein the tail oil using the Y-type molecular sieve catalyst is a high-quality raw material for preparing ethylene through steam cracking, the tail oil using the heterogeneous molecular sieve catalyst is a raw material capable of directly producing high-quality lubricating oil base oil or serving as the high-quality lubricating oil base oil, and the tail oil obtained by using the Y-heterogeneous compound molecular sieve-containing catalyst or grading the Y-type molecular sieve-containing hydrocracking catalyst and the heterogeneous molecular sieve-containing hydrocracking catalyst can be used as a raw material for preparing ethylene through steam cracking or serving as a raw material for the high-quality lubricating oil base oil. Therefore, when the above hydrocracking processes are used alone, different types of hydrocracking catalysts can be selected according to requirements, or two molecular sieve composite catalysts are used, or two hydrocracking catalysts are selected for use in a graded manner, or a reverse hydrocracking process technology is used, but products in the same fraction range of the processes can only produce products of one specification, namely, the operation flexibility is relatively poor.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a flexible reverse hydrocracking process, namely, a part of liquid-phase reaction material flow is extracted from a gas-liquid separator arranged in the middle of a hydrocracking reactor using a Y-shaped hydrocracking catalyst, and the wax oil raw oil is subjected to hydrocracking by the Y-shaped hydrocracking catalyst and hydrogenation and isomerization by an isomerization type hydrocracking catalyst to be combined with reverse hydrocracking to flexibly produce high-quality lubricating oil base oil raw materials, naphtha products with various specifications and high-quality motor fuel products.

The flexible reverse hydrocracking process of the invention comprises the following steps:

a. the method comprises the following steps that (1) wax oil raw oil and a hydrocracking generated material flow enter a hydrogenation pretreatment reactor under a hydrogenation pretreatment condition and pass through a hydrogenation pretreatment catalyst bed layer to obtain a hydrogenation pretreatment material flow;

b. separating and fractionating the hydrogenation pretreatment material flow obtained in the step a to obtain hydrocracking high-pressure hydrogen-rich gas, a hydrocracking gas product, a hydrocracking naphtha product, a hydrocracking aviation kerosene product, a hydrocracking diesel oil product and hydrocracking tail oil (circulating oil);

c. b, mixing the hydrocracking tail oil (circulating oil) obtained in the step b with circulating hydrogen, allowing the mixture to enter a hydrocracking pretreatment reactor under a hydrocracking pretreatment condition and pass through a hydrocracking pretreatment catalyst bed layer to obtain a hydrocracking pretreatment material flow, allowing the hydrocracking treatment material flow to pass through a first hydrocracking catalyst bed layer containing a Y-type molecular sieve catalyst in the hydrocracking reactor under the hydrocracking condition to obtain a first hydrocracking material flow, dividing the part of the reaction material flow into two parts, wherein one part of the reaction material flow is a liquid material flow obtained by separation through a gas-liquid separator, and pumping out the part of the hydrocracking catalyst bed layer;

d. c, continuously passing the rest part of the first hydrocracking material flow in the step c through a second hydrocracking catalyst bed layer containing a Y-type molecular sieve catalyst in the hydrocracking reactor under the hydrocracking condition to obtain a hydrocracking material flow, mixing the hydrocracking material flow with the raw oil, and feeding the mixture into a hydrogenation pretreatment reactor;

e. and c, mixing the first hydrocracking liquid material flow extracted from the reactor in the step c with circulating hydrogen, passing through a hydroisomerization cracking catalyst bed layer containing an isomerization type molecular sieve catalyst in a hydroisomerization cracking reactor under a hydroisomerization cracking condition, and separating and fractionating the hydroisomerization cracking material flow to obtain a hydroisomerization cracking high-pressure hydrogen-rich gas, a hydroisomerization cracking gas product, a hydroisomerization cracking naphtha product, a hydroisomerization cracking aviation kerosene product, a hydroisomerization cracking diesel product and a hydroisomerization cracking tail oil product.

The hydrocracking process according to the present invention may further comprise step f: and (e) mixing the hydrocracking high-pressure hydrogen-rich gas obtained in the step (b) with the hydroisomerization cracking high-pressure hydrogen-rich gas obtained in the step (e) for recycling.

S, N, O and other impurities in the wax oil raw oil are removed to a certain degree when passing through a hydrogenation pretreatment catalyst, aromatic hydrocarbon is hydrogenated and saturated to a certain degree, hydrocracking tail oil (circulating oil) obtained after the hydrogenation pretreatment product stream is separated and fractionated is actually mixed oil obtained after the hydrocracking tail oil is subjected to hydrogenation pretreatment again and the wax oil raw oil is subjected to hydrogenation pretreatment, the stream is subjected to hydrocracking pretreatment to obtain a hydrocracking pretreatment product stream, the ring-opening reaction of the cyclic hydrocarbon is partially generated when the hydrocracking pretreatment product stream continuously passes through a hydrocracking catalyst bed layer containing a Y-type molecular sieve catalyst, the aromatic hydrocarbon is further hydrogenated and saturated, the large molecule is cracked into small molecules, and the hydrocracking of a part of the hydrocracking product stream is continuously carried out Diesel products and tail oils; and (3) after a part of the extracted first hydrocracking material flow passes through a hydroisomerization cracking catalyst containing an isomerization type molecular sieve catalyst, continuing isomerization hydrocracking, wherein the isomerization hydrocracking product with high isomerization hydrocarbon content can be obtained due to the characteristics of isomerization and cracking of the isomerization type molecular sieve, and particularly the obtained diesel oil product has low condensation point, the tail oil product has low condensation point and high viscosity index.

Compared with the prior art, the flexible reverse hydrocracking process has the advantages that:

1. in the invention, the hydrocracking reactor comprises at least two hydrocracking catalyst beds. A part of cracked liquid materials are extracted by a gas-liquid separator arranged in the middle of a hydrocracking reactor bed layer, so that the hydrocracking material stock can be effectively distributed, and the obtained materials are subjected to different hydrocracking processes, so that target products with different specifications can be flexibly produced, and particularly, low-condensation-point tail oil products are added. At the same time, it is technically easy to extract the reactant stream in the middle of the reactor bed. In the prior art, although a plurality of light products can be obtained by adjusting the conversion rate and the distillation range of the products, only one type of light naphtha products, heavy naphtha products, aviation kerosene products and diesel oil products can be generally obtained in the same distillation range of a set of hydrocracking unit, and particularly only one type of tail oil products can be obtained because only one hydrocracking reactor outlet is arranged; if different specifications of hydrocracking products are required, more than two sets of hydrocracking units are required. Therefore, the invention provides a hydrocracking process for simultaneously producing more than two same-fraction ranges, but different specifications of tail oil products, more than two different specifications of aviation kerosene products, more than two different specifications of diesel oil products and a plurality of different specifications of naphtha products on one hydrocracking process device for the first time.

2. According to the invention, the gas-liquid separator is arranged in the middle of the catalyst bed layer of the hydrocracking reactor, the first hydrocracking liquid material flow of the wax oil raw material after hydrogenation pretreatment and hydrocracking is extracted out of the reactor and sent into the separately arranged hydrocracking reactor for the hydrocracking reaction, and the condensation point of the hydrocracked material is further reduced, so that the method disclosed by the invention can be used for flexibly producing naphtha products, aviation kerosene products, diesel oil products and tail oil products with different aromatic hydrocarbon contents and different isomeric hydrocarbon contents.

3. In the invention, heavy naphtha obtained by hydrocracking a product obtained by fractionating the material flows of the two reactors by using a catalyst containing a Y-type molecular sieve has relatively high aromatic hydrocarbon potential, a aviation kerosene product has relatively high smoke point, and a diesel oil product has relatively high cetane number; the naphtha obtained by partial hydrocracking of the catalyst containing the Y-type molecular sieve and the hydroisomerization of the catalyst containing the heterogeneous molecular sieve has high content of isomeric hydrocarbon, low freezing point of aviation kerosene products, low condensation point of diesel oil products, high content of isomeric hydrocarbon of tail oil products, large viscosity index and low condensation point; can respectively meet the requirements of producing naphtha, aviation kerosene products, diesel oil products and tail oil products with different specifications.

4. In the invention, the wax oil raw oil is pretreated by hydrogenation and then has a gas-liquid separation process, and H generated in the hydrogenation process₂S and NH₃Will be removed from the system, although unreacted sulfur and nitrogen will continue to react during hydrotreating to produce H₂S and NH₃But H in the system₂S partial pressure and NH₃The partial pressure is effectively reduced, so the severity of the hydrocracking reaction and the hydroisomerization cracking reaction is reduced, the operation conditions of the hydrocracking reactor and the hydroisomerization cracking reactor are optimized, the product quality is improved, or the operation period is prolonged.

5. In the invention, the liquid obtained in the middle of the hydrocracking catalyst bed layer of the hydrocracking reactor has very high temperature and pressure, and can directly enter a newly arranged hydrocracking reactor for reaction, thereby fully utilizing the heat carried by the part of cracking materials and realizing the coupling operation of the hydrocracking reactor and the hydrocracking reactor.

Drawings

Fig. 1 is a schematic flow chart of the principle of the present invention.

Wherein: 1-raw oil, 2-hydrogenation pretreatment reactor, 3-hydrocracking pretreatment reactor, 4-hydrocracking reactor, 5-hydroisomerization cracking raw material flow, 6-hydrocracking flow, 7-hydroisomerization cracking reactor, 8-hydrocracking high-pressure separator, 9-hydroisomerization cracking high-pressure separator, 10-hydrocracking fractionating tower, 11-hydroisomerization cracking fractionating tower, 12-hydrocracking light naphtha product, 13-hydrocracking heavy naphtha product, 14-hydrocracking aviation kerosene product, 15-hydrocracking diesel oil product, 16-hydrocracking tail oil, 17-hydroisomerization cracking light naphtha product, 18-hydroisomerization cracking heavy naphtha product, 19-hydrocracking aviation kerosene product, 20-hydroisomerization cracking diesel oil product, 21-hydroisomerization cracking tail oil product, 22-hydrocracking high-pressure separator hydrogen-rich gas, 23-hydroisomerization cracking high-pressure separator hydrogen-rich gas, 24-make-up hydrogen, 25-gas-liquid separator and 26-hydroisomerization cracking circulating hydrogen.

Detailed Description

The initial boiling point of the wax oil raw material in the step a is 100-400 ℃, and the final boiling point is 405-650 ℃. The wax oil raw material oil can be one of straight-run wax oil, coking wax oil, deasphalted oil, catalytic cycle oil and the like obtained by petroleum processing, one of coal tar, coal direct liquefaction oil, coal indirect liquefaction oil, synthetic oil, shale oil and the like obtained from coal, and can also be mixed oil of a plurality of the coal tar, the coal direct liquefaction oil, the coal indirect liquefaction oil, the synthetic oil and the shale oil.

The hydrogenation pretreatment catalyst in the step a and the hydrocracking pretreatment catalyst in the step c are both conventional wax oil hydrogenation pretreatment catalysts. Generally, metals in a VIB group and/or a VIII group are used as active components, alumina or silicon-containing alumina is used as a carrier, the metals in the VIB group are generally Mo and/or W, and the metals in the VIII group are generally Co and/or Ni. Based on the weight of the catalyst, the content of the VIB group metal is 10 to 35 weight percent calculated by oxide, the content of the VIII group metal is 3 to 15 weight percent calculated by oxide, and the catalyst comprisesThe properties were as follows: the specific surface area is 100 to 650m²The pore volume is 0.15 to 0.6 mL/g. The main catalysts comprise hydrogenation pretreatment catalysts such as 3936, 3996, FF-16, FF-26, FF-36, FF-46 and FF-56 series developed by the petrochemical research institute, and can also be similar catalysts with functions developed by domestic and foreign catalyst companies, such as HC-K, HC-P of UOP company, TK-555 and TK-565 of Topsoe company, KF-847 and KF-848 of Akzo company, and the like. The hydrotreating catalyst in step a and the hydrocracking catalyst in step c may be the same or different. The operation condition of the hydrogenation pretreatment can adopt the conventional operation condition, generally the reaction pressure is 3.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.2h^-1～6.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

The separation described in step b generally comprises separating two parts, a hydrocracking high-pressure separator and a low-pressure separator. Wherein the high-pressure separator separates to obtain the hydrocracking high-pressure hydrogen-rich gas and liquid, and the liquid separated by the high-pressure separator enters the low-pressure separator. The low pressure separator separates the high pressure liquid product to yield a hydrocarbon-rich gas and a low pressure liquid product. The hydrocarbon-rich gas is separated to obtain the required hydrocracking gas product.

The fractionation described in step b is carried out in a hydrocracking fractionator system. And fractionating the low-pressure liquid product in a fractionating tower to obtain a hydrocracking light naphtha product, a hydrocracking heavy naphtha product, a hydrocracking aviation kerosene product, a hydrocracking diesel oil product and hydrocracking tail oil (circulating oil).

The hydrocracking pretreatment operation conditions in the step c can adopt conventional operation conditions, generally the reaction pressure is 3.0-19.0 MPa, the reaction temperature is 300-450 ℃, and the liquid hourly volume space velocity is 0.2h^-1～6.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

The hydrocracking catalyst in the step c is a conventional wax oil hydrocracking catalyst. Generally, metals in a VIB group and/or a VIII group are used as active components, the metals in the VIB group are generally Mo and/or W, and the metals in the VIII group are generally Co and/or Ni. The catalyst support comprises aluminaAnd/or siliceous alumina, and Y-type molecular sieves. Based on the weight of the catalyst, the content of the VIB group metal is 10-35 wt% calculated by oxide, the content of the VIII group metal is 3-15 wt% calculated by oxide, and the content of the molecular sieve is 5-80 wt%. The main catalysts are 3824, 3825, 3976, FC-12, FC-24, FC-26, FC-32, FC-50 catalysts and the like developed by the petrochemical research institute, HC-12, HC-14, HC-24, HC-39 and the like of UOP company. For hydrocracking catalysts, certain hydrogenation activity and certain cracking activity are required, so that hydrogenation saturation of olefins and aromatics in hydrotreating generated oil and fractions generated in a hydrocracking process is ensured, and ring-opening reaction of saturated aromatics is also required. The hydrocracking operating conditions may be conventional and are generally: the reaction pressure is 3.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.2h^-1～6.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

And in the step c, the gas-liquid separator is a device arranged between the hydrocracking reactor beds or at the inlet of the catalyst bed. The gas-liquid separator at least comprises a reactant stream inlet, a liquid phase conduit, a gas phase conduit and the like, wherein the liquid phase conduit extracts a separated liquid phase out of the hydrocracking reactor, and the gas phase conduit introduces a separated gas phase into a lower hydrocracking catalyst bed layer.

And c, allowing a part of hydrocracking reactant flow in the step c to enter a gas-liquid separator through an inlet of the gas-liquid separator, wherein the extracted part of liquid phase material flow accounts for 5-95 wt% of the raw oil, and preferably 10-80 wt%.

The hydrocracking conditions in step d may be conventional conditions, and are generally: the reaction pressure is 3.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.2h^-1～6.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

And e, the hydroisomerization cracking catalyst is a conventional wax oil hydroisomerization cracking catalyst. Generally, metals in a VIB group and/or a VIII group are used as active components, the metals in the VIB group are generally Mo and/or W, and the metals in the VIII group are generally Co and/or Ni. The catalyst is supportedThe body is one or more of alumina, silicon-containing alumina and molecular sieve, preferably molecular sieve, and the molecular sieve can be beta type molecular sieve, Sapo type molecular sieve, etc. Based on the weight of the catalyst, the content of the VIB group metal is 10-35 wt% calculated by oxide, the content of the VIII group metal is 3-15 wt% calculated by oxide, and the content of the molecular sieve is 5-80 wt%. The main catalysts comprise FC-14, FC-20 and the like developed by the petrochemical research institute. For hydrocracking catalysts, certain hydrogenation activity and certain cracking activity are required, and both the hydrogenation saturation of olefins and aromatics in reaction materials and the isomerization of straight-chain paraffins are required. The hydroisomerization cracking may be carried out under conventional operating conditions, which are generally: the reaction pressure is 3.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.2h^-1～6.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

The separation described in step e is carried out in a hydroisomerization cracking high pressure separator and a low pressure separator. Wherein, the hydroisomerization cracking high-pressure separator separates to obtain the hydroisomerization cracking high-pressure hydrogen-rich gas and liquid, and the liquid separated by the high-pressure separator enters the low-pressure separator. The low pressure separator separates the high pressure liquid product to yield a hydrocarbon-rich gas and a low pressure liquid product. The hydrocarbon-rich gas is separated to obtain the required hydroisomerized cracked gas product.

The fractionation described in step e is carried out in a hydroisomerization cracking fractionator system. And fractionating the low-pressure liquid product in a fractionating tower to obtain a hydroisomerized cracked light naphtha product, a hydroisomerized cracked heavy naphtha product, a hydroisomerized cracked aviation kerosene product, a hydroisomerized cracked diesel oil product and a hydroisomerized cracked tail oil product.

The hydrocracking gas product and the hydroisomerization cracking gas product in the steps b and e can be used as products independently or can be mixed into a mixed gas product.

The hydrocracked light naphtha product and the hydroisomerized cracked light naphtha product in the step b and the step e can be used as products independently or can be mixed into a mixed light naphtha product.

The hydrocracked heavy naphtha product and the hydroisomerized cracked heavy naphtha product in the step b and the step e can be used as the products independently or can be mixed into a mixed heavy naphtha product.

The hydrocracking aviation kerosene product and the hydroisomerization cracking aviation kerosene product in the step b and the step e can be independently used as products, and can also be mixed into a mixed aviation kerosene product.

The hydrocracking diesel oil product and the hydroisomerization diesel oil product in the step b and the step e can be used as products independently or can be mixed into a mixed diesel oil product.

The hydrocracked tail oil (cycle oil) in step b may also be used alone as a product.

And e, independently using the hydroisomerized cracked tail oil in the step e as a product.

And e, mixing the high-pressure hydrogen-rich gas in the step e, and then directly using the mixed gas as recycle hydrogen, or recycling the mixed gas after hydrogen sulfide is removed by a recycle hydrogen desulfurization system.

With reference to fig. 1, the method of the present invention is as follows: raw oil 1 and a hydrocracking product stream 6 are mixed and enter a hydrogenation pretreatment reactor 2, the hydrogenation pretreatment product stream passing through a hydrogenation pretreatment catalyst bed enters a hydrocracking high-pressure separator 8 for gas-liquid separation, the separated liquid enters a fractionating tower 10 for fractionation to obtain a hydrocracking light naphtha product 12, a hydrocracking heavy naphtha product 13, a hydrocracking aviation kerosene product 14, a hydrocracking diesel product 15 and a hydrocracking tail oil 16, the hydrocracking tail oil 16 and hydrogen are mixed and enter a hydrocracking pretreatment reactor 3, the product stream passing through the cracking pretreatment catalyst bed enters a hydrocracking reactor 4, a part of the reaction stream passing through the first hydrocracking catalyst bed enters a gas-liquid separator 25 for gas-liquid separation, the liquid phase is extracted to serve as a hydrocracking raw material stream 5, and the stream after the hydrocracking raw material stream 5 is extracted continues to enter a subsequent hydrocracking catalyst bed, the obtained hydrocracking product stream 6 enters a hydrogenation pretreatment reactor 2, the hydroisomerization cracking raw material stream 5 and recycle hydrogen 26 are mixed and then enter a hydroisomerization cracking reactor 7, the product stream passing through a hydroisomerization cracking catalyst bed enters a hydroisomerization cracking high-pressure separator 9 for gas-liquid separation, the separated liquid enters a fractionating tower 11 for fractionation to obtain a hydroisomerization cracked light naphtha product 17, a hydroisomerization cracked heavy naphtha product 18, a hydroisomerization cracked aviation kerosene product 19, a hydroisomerization cracked diesel product 20 and a hydroisomerization cracked tail oil product 21, the hydrocracking light naphtha product 12 and the hydroisomerization cracked light naphtha product 17 can be independently used as products or can be mixed to obtain a mixed light naphtha product, the hydrocracking heavy naphtha product 13 and the hydroisomerization cracked heavy naphtha product 18 can be independently used as products, or mixed to obtain a mixed heavy naphtha product, the hydrocracking aviation kerosene product 14 and the hydroisomerization cracking aviation kerosene product 19 can be independently used as products or mixed to obtain a mixed aviation kerosene product, the hydrocracking diesel oil product 15 and the hydroisomerization cracking diesel oil product 20 can be independently used as products or mixed to obtain a mixed diesel oil product, and the gas 22 obtained by separating the hydrocracking high-pressure separator 8 and the gas 23 obtained by separating the hydroisomerization cracking high-pressure separator 9 are mixed and then are pressurized by a recycle hydrogen compressor and then are mixed with make-up hydrogen 24 to be used as recycle hydrogen.

The embodiments and effects of the present invention are described below by way of examples.

Examples 1 to 3

The protective agents FZC-100, FZC-105 and FZC106 are hydrogenation protective agents developed and produced by the smooth petrochemical research institute of the China petrochemical industry, Inc.; the catalyst FF-56 is a hydrotreating catalyst developed and produced by the smooth petrochemical research institute of China petrochemical company Limited; the catalyst FC-32 is a hydro-upgrading catalyst developed and produced by China petrochemical company Limited, compliant petrochemical research institute, and contains a Y-type molecular sieve; the catalyst FC-20 is a hydroisomerization cracking catalyst which is developed and produced by the smooth petrochemical research institute of China petrochemical company Limited and contains a beta-type molecular sieve.

TABLE 1 essential Properties of wax oil base stocks

TABLE 2 Process conditions

Table 2 Process conditions

TABLE 3 test results

It can be seen from the examples that the flexible reverse hydrocracking process of the present invention can achieve the purpose of producing hydrocracking products of different properties by withdrawing a part of the reactant stream from the hydrocracking reactor and using the hydrocracking catalyst and the hydroisomerization cracking catalyst, and the production mode is flexible.

Claims

1. A flexible reverse order hydrocracking process comprising the steps of:

b. separating and fractionating the hydrogenation pretreatment material flow obtained in the step a to obtain hydrocracking high-pressure hydrogen-rich gas, a hydrocracking gas product, a hydrocracking naphtha product, a hydrocracking aviation kerosene product, a hydrocracking diesel oil product and hydrocracking tail oil;

c. b, mixing the hydrocracking tail oil obtained in the step b with circulating hydrogen, allowing the mixture to enter a hydrocracking pretreatment reactor under a hydrocracking pretreatment condition and pass through a hydrocracking pretreatment catalyst bed layer to obtain a hydrocracking pretreatment material flow, allowing the hydrocracking treatment material flow to pass through a first hydrocracking catalyst bed layer containing a Y-type molecular sieve catalyst in the hydrocracking reactor under the hydrocracking condition to obtain a first hydrocracking material flow, dividing the part of the reaction material flow into two parts, separating one part of the reaction material flow through a gas-liquid separator, and pumping the obtained liquid material flow out of the hydrocracking reactor;

d. c, continuously passing the rest part of the first hydrocracking material flow through a second hydrocracking catalyst bed layer containing a Y-shaped molecular sieve catalyst in the hydrocracking reactor under the hydrocracking condition to obtain a hydrocracking material flow, mixing the hydrocracking material flow with the wax oil raw oil, and feeding the mixture into a hydrogenation pretreatment reactor;

2. The hydrocracking process of claim 1, further comprising step f: and (e) mixing the hydrocracking high-pressure hydrogen-rich gas obtained in the step (b) with the hydroisomerization cracking high-pressure hydrogen-rich gas obtained in the step (e) for recycling.

3. The hydrocracking process according to claim 1, wherein the initial boiling point of the wax oil raw material in step a is 100-400 ℃ and the final boiling point is 405-650 ℃.

4. The hydrocracking process according to claim 3, wherein said wax oil feedstock is at least one selected from the group consisting of virgin wax oil, coker wax oil, deasphalted oil, catalytic cycle oil, coal tar, coal direct liquefaction oil, coal indirect liquefaction oil, synthetic oil and shale oil.

5. As claimed in claim 1, plusThe hydrocracking process is characterized in that the hydrogenation pretreatment catalyst in the step a and the hydrocracking pretreatment catalyst in the step c take VIB group and/or VIII group metals as active components, and alumina or silicon-containing alumina as a carrier; based on the weight of the catalyst, the content of the VIB group metal is 10-35 wt% calculated by oxide, and the content of the VIII group metal is 3-15 wt% calculated by oxide; the properties are as follows: the specific surface area is 100 to 650m²The pore volume is 0.15 to 0.6 mL/g.

6. The hydrocracking process according to claim 1, wherein the hydrotreating pretreatment conditions in step a are: the reaction pressure is 3.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.2h^-1～6.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

7. The hydrocracking process according to claim 1, wherein the hydrocracking pretreatment conditions in step c are: the reaction pressure is 3.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.2h^-1～6.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

8. The hydrocracking process according to claim 1, wherein the hydrocracking catalyst of step c comprises a group VIB and/or group VIII metal as an active component, and the catalyst carrier comprises alumina and/or siliceous alumina and a Y-type molecular sieve.

9. The hydrocracking process of claim 8, wherein the group VIB metal content is 10wt% to 35wt% in terms of oxide, the group VIII metal content is 3wt% to 15wt% in terms of oxide, and the Y-type molecular sieve content is 5wt% to 80wt% based on the weight of the catalyst.

10. The hydrocracking process according to claim 1, wherein the hydrocracking conditions in step c and step d are: the reaction pressure is 3.0-19.0 MPa, and the reaction temperature isThe temperature is 300-450 ℃, and the liquid hourly volume space velocity is 0.2h^-1～6.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

11. The hydrocracking process according to claim 1, wherein the liquid stream withdrawn in step c is 5 to 95 wt% based on the feed oil.

12. The hydrocracking process according to claim 1, wherein the hydrocracking conditions in step d are: the reaction pressure is 3.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.2h^-1～6.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

13. The hydrocracking process according to claim 1, wherein the hydroisomerization catalyst of step e comprises a group VIB and/or group VIII metal as an active component, a catalyst carrier comprises alumina and/or siliceous alumina, and a molecular sieve, and the molecular sieve is a beta-type molecular sieve or a SAPO-type molecular sieve.

14. The hydrocracking process of claim 13, wherein the group VIB metal content is 10wt% to 35wt% as oxide, the group VIII metal content is 3wt% to 15wt% as oxide and the molecular sieve content is 5wt% to 80wt% based on the weight of the catalyst.

15. The hydrocracking process according to claim 1, wherein said hydroisomerization cracking conditions are: the reaction pressure is 3.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.2h^-1～6.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

16. The hydrocracking process according to claim 11, wherein the liquid stream withdrawn in step c is 10 to 80wt% based on the feed oil.