CN109988636B

CN109988636B - Flexible single stage hydrocracking process

Info

Publication number: CN109988636B
Application number: CN201711468903.2A
Authority: CN
Inventors: 刘涛; 孙洪江; 李宝忠; 王阔; 孙士可; 周勇
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: 2021-07-09
Anticipated expiration: 2037-12-29
Also published as: CN109988636A

Abstract

The invention discloses a flexible single-stage hydrocracking process. Mixing a wax oil raw material with hydrogen, then feeding the mixture into a single-section hydrocracking reactor, and dividing the material passing through an upper single-section hydrocracking catalyst bed into two parts; separating a strand of material by a gas-liquid separator in the middle of a bed layer to obtain liquid, pumping out the liquid from a hydrocracking reactor, and introducing the liquid and hydrogen into a hydroisomerization cracking reactor to perform an isomerization cracking reaction; the other material is a gas-liquid mixture flow, and the mixture flow continuously flows downwards through a single-section hydrocracking catalyst bed layer at the lower part; and respectively carrying out gas-liquid separation and fractionation on the single-stage hydrocracking reaction material and the hydroisomerization cracking reaction material to obtain naphtha, aviation kerosene, diesel oil and tail oil products with different specifications. The invention provides a single-stage hydrocracking process for simultaneously producing more than two distillate oil products with different specifications on a set of hydrogenation device, which can fully utilize the heat carried by part of cracked materials to realize the coupling operation of a single-stage hydrocracking reactor and a hydroisomerization cracking reactor.

Description

Flexible single stage hydrocracking process

Technical Field

The invention belongs to the field of petroleum refining, and particularly relates to a single-stage hydrocracking process for flexibly producing high-quality 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 catalyst used in the single-stage hydrocracking technology is mainly a type of single-stage hydrocracking catalyst, the using amount of the catalyst usually accounts for more than 80% of the volume of the total catalyst, the cracking component of the catalyst is mainly amorphous silica-alumina, and a small amount of Y-type molecular sieve, beta-type molecular sieve, SAPO series molecular sieve, ZSM-5 molecular sieve and the like can also be contained. 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.

CN100569921C discloses a single-stage hydrocracking method, which is a single-stage hydrocracking process using a hydrogenation pretreatment catalyst prepared by a bulk phase method; CN001075550C discloses a single-stage hydrocracking method, which is a single-stage hydrocracking process using a single-stage hydrocracking catalyst containing a Y-type molecular sieve; CN001415707A discloses a method for increasing the yield of high-quality diesel oil by distillate oil, which fills a hydrocracking catalyst with isomerization performance at the rear part of the original hydrocracking catalyst to achieve the purpose of reducing the condensation point of a hydrocracking product, but the products of each fraction obtained by hydrocracking only have one specification.

CN001566283A, CN001766051A, CN101402048A and the like all disclose a medium oil type hydrocracking catalyst and a preparation method thereof, and a single-stage hydrocracking catalyst taking amorphous silicon-aluminum and a small amount of Y-type molecular sieve as acid centers is prepared; CN001712498A discloses a hydrogenation catalyst for maximum diesel production and its preparation method, the catalyst uses amorphous silica-alumina and modified beta molecular sieve as main cracking center, but the hydrocracking technology using these hydrocracking catalysts can obtain only one specification of each fraction product.

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 US6670295 and US4837396A disclose 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 material oil, but the product of each fraction has only one specification and is basically used in a section of series hydrocracking or hydro-upgrading process.

In conclusion, compared with the existing hydrocracking technology using several different types of cracking center catalysts, the single-stage hydrocracking technology using an amorphous silicon-aluminum single-stage hydrocracking catalyst or an amorphous silicon-aluminum-Y type molecular sieve single-stage hydrocracking catalyst has the advantages that the freezing point of the obtained aviation kerosene product is relatively high, the smoke point is relatively low, the cetane number of the diesel oil product is high, but the condensation point is relatively high, and the condensation point of the tail oil product is very high and is usually more than 30 ℃; by using the single-stage hydrocracking technology of the heterogeneous molecular sieve hydrocracking catalyst, the obtained aviation kerosene has relatively high smoke point, the diesel oil product has low sulfur content and low condensation point, the tail oil has relatively high density, but the content of the heterogeneous hydrocarbon is high, the condensation point is very low and is usually less than 0 ℃. The hydrocracking tail oil products produced by the single-stage hydrocracking process technology have larger difference under the same conversion rate, wherein the tail oil using the Y-type molecular sieve catalyst is a high-quality catalytic cracking raw material and a raw material for preparing ethylene by steam cracking, and the tail oil using the heterogeneous molecular sieve catalyst is a raw material which can be used for directly producing high-quality lubricating oil base oil or used as the high-quality lubricating oil base oil. Therefore, when the above hydrocracking processes are used alone, different types of single-stage 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 grading manner, but the processes can only produce tail oil products with one property, namely, the operation flexibility is relatively poor.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a flexible single-stage hydrocracking process, namely, part of reaction material flow is extracted from the middle part of a single-stage hydrocracking reactor using a single-stage hydrocracking catalyst, and the wax oil raw oil is subjected to hydrocracking by the single-stage hydrocracking catalyst and the hydrogenation and isomerization of the isomerization type hydrocracking catalyst to flexibly produce various high-quality hydrocracking tail oil products, naphtha products with various specifications and high-quality motor fuel products with various specifications.

The method for the flexible single-stage hydrocracking process comprises the following steps:

a. the method comprises the following steps that firstly, wax oil raw oil passes through a single-stage hydrocracking catalyst bed layer on the upper portion of a single-stage hydrocracking reactor under the single-stage hydrocracking condition to obtain a first single-stage hydrocracking material flow, the first single-stage hydrocracking material flow is divided into two parts, one part of the first single-stage hydrocracking material flow passes through a gas-liquid separator, and a liquid material flow obtained through separation is pumped out of the single-stage hydrocracking reactor;

b. b, continuously enabling the rest part of the first single-stage hydrocracking material flow in the step a to pass through a single-stage hydrocracking catalyst bed layer at the lower part of the single-stage hydrocracking reactor under a hydrocracking condition, and separating and fractionating the single-stage hydrocracking material flow to obtain single-stage hydrocracking high-pressure hydrogen-rich gas, a single-stage hydrocracking gas product, a single-stage hydrocracking naphtha product, a single-stage hydrocracking aviation kerosene product, a single-stage hydrocracking diesel oil product and a single-stage hydrocracking tail oil product;

c. and b, mixing the first hydrocracking liquid material flow extracted from the reactor in the step a with circulating hydrogen, and then passing the mixture through a single-stage hydrocracking catalyst bed layer containing an isomeric molecular sieve catalyst in a single-stage hydrocracking reactor under a single-stage hydroisomerization cracking condition, wherein the single-stage hydrocracking material flow is separated and fractionated to obtain a single-stage hydroisomerization cracking high-pressure hydrogen-rich gas, a single-stage hydroisomerization cracking gas product, a single-stage hydroisomerization cracked naphtha product, a single-stage hydroisomerization cracking aviation kerosene product, a single-stage hydroisomerization cracking diesel oil product and a single-stage hydroisomerization cracking tail oil product.

The hydrocracking process according to the present invention may further comprise a step d: and c, mixing the single-stage hydrocracking high-pressure hydrogen-rich gas obtained in the step b with the single-stage hydrocracking high-pressure hydrogen-rich gas obtained in the step c for recycling.

S, N, O and other impurities in the wax oil raw oil are effectively removed when passing through a single-stage hydrocracking catalyst, aromatic hydrocarbon is hydrogenated and saturated to a certain extent, cyclic hydrocarbon is subjected to partial ring opening reaction, macromolecules are cracked into micromolecules, and a part of single-stage hydrocracking material flow is continuously subjected to single-stage hydrocracking to obtain aviation kerosene products, diesel oil products and tail oil products with high normal hydrocarbon content and low aromatic hydrocarbon content; and (3) continuously carrying out isomeric hydrocracking on a part of the extracted first single-stage hydrocracking liquid material flow after passing through a hydroisomerization cracking catalyst containing an isomeric molecular sieve catalyst, wherein the isomeric molecular sieve has the characteristics of isomerization and cracking, so that an isomeric cracked product with high isomeric hydrocarbon content can be obtained, and particularly, a diesel product has a low condensation point, a tail oil product has a low condensation point, and the viscosity index is high.

Compared with the prior art, the flexible single-stage hydrocracking process has the advantages that:

1. in the invention, the single-stage hydrocracking reactor comprises at least two single-stage hydrocracking catalyst beds. The effective distribution of single-stage hydrocracking material strands can be realized by extracting a part of cracking liquid materials through a gas-liquid separator arranged in the middle of a single-stage hydrocracking reactor bed layer, and the obtained materials are subjected to different hydrocracking processes, so that target products with different specifications, particularly tail oil products, can be flexibly produced. 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 single-stage hydrocracking reactor outlet is arranged, so that only one type of light naphtha products, heavy naphtha products, aviation kerosene products, diesel oil products and tail oil products can be generally obtained in the same distillation range of a set of single-stage hydrocracking devices; if different specifications of hydrocracking products are required, more than two sets of single-stage hydrocracking units are required. Therefore, the invention provides a single-stage 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 a single-stage 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 single-stage hydrocracking liquid phase material flow of the wax oil raw material subjected to single-stage hydrocracking is extracted out of the reactor and sent into the independently arranged hydrocracking reactor for the hydrocracking reaction, and the condensation point of the hydrocracked material is further reduced, so that naphtha products, aviation kerosene products, diesel oil products and tail oil products with different aromatic hydrocarbon contents and different isomeric hydrocarbon contents can be flexibly produced by the method.

3. In the invention, heavy naphtha obtained by hydrocracking a product obtained by fractionating the material flows of two reactors by a hydrocracking catalyst containing a single-stage hydrocracking catalyst or a hydrocracking catalyst containing a small amount of Y-type molecular sieve has relatively high aromatic hydrocarbon potential, a aviation kerosene product has relatively high smoke point, a diesel oil product has relatively high cetane number, a tail oil product has high paraffin content and a BMCI value is relatively low; the naphtha obtained by partial hydrocracking containing a single-stage hydrocracking catalyst and the hydroisomerization cracking containing an isomeric molecular sieve catalyst has high content of isomeric hydrocarbon, a aviation kerosene product has low freezing point, a diesel oil product has low freezing point, and a tail oil product has high content of isomeric hydrocarbon, large viscosity index and low freezing 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, impurities such as S, N in the raw oil are converted into H after hydrogenation pretreatment and partial hydrocracking₂S and NH₃Most of H is separated by a gas-liquid separator₂S and NH₃Present in the gas phase, and H in the liquid phase₂S and NH₃The content of the catalyst is less, so that the inhibiting effect on the molecular sieve of the hydroisomerization cracking catalyst is reduced, the reaction activity of the hydroisomerization cracking catalyst is improved, namely the reaction temperature required when the same reaction effect is achieved is reduced, the liquid obtained in the middle of a hydrocracking catalyst bed layer of a single-stage hydrocracking reactor has very high temperature and pressure, the temperature of the liquid after the liquid is mixed with circulating hydrogen is slightly reduced, but the liquid can still directly enter the newly-arranged hydroisomerization cracking reactor for reaction and achieve the reaction effect, and therefore the heat carried by the part of cracking materials is fully utilized, and the coupling operation of the hydroisomerization cracking reactor and the single-stage hydrocracking reactor is realized.

Drawings

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

Wherein: 1-raw oil, 2-hydrocracking reactor, 3-hydrocracking material flow, 4-hydroisomerization cracking material flow, 5-hydroisomerization cracking reactor, 6-hydrocracking high-pressure separator hydrogen-rich gas, 7-hydroisomerization cracking high-pressure separator hydrogen-rich gas, 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 product, 17-hydroisomerization cracking light naphtha product, 18-hydrocracking heavy naphtha product, 19-hydroisomerization cracking aviation kerosene product, 20-hydroisomerization cracking diesel oil product, 21-hydroisomerization cracking tail oil product, 22-make-up hydrogen, 23-gas-liquid separator, 24-hydroisomerization cracking recycle hydrogen and 25-hydrocracking recycle 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 405-600 ℃. 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 single-stage hydrocracking catalyst in the step a is a conventional wax oil single-stage 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 carrier of the catalyst is one or more of alumina, silicon-containing alumina and a molecular sieve, and the carrier can also contain the molecular sieve, and the molecular sieve can be a Y-type molecular sieve. 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 0-40 wt%. The main catalysts are ZHC-01, ZHC-02, which are developed by the research institute of petrochemical engineering,ZHC-03, ZHC-04, FC-28, FC-34 catalysts, etc., TK-925, TK-951, etc. developed by Haldor Topsoe, KF-1023 and KF-1023, etc. developed by Albemarle. 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.

The inlet of the single-stage hydrocracking reactor in the step a can be filled with a conventional hydrogenation protective agent, the upper part of a single-stage hydrocracking catalyst bed layer can be filled with a small amount of hydrogenation pretreatment catalysts, and the hydrogenation pretreatment catalysts are 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 10-35 wt% calculated by oxide, the content of the VIII group metal is 3-15 wt% calculated by oxide, and the properties are 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 filling volume of the hydrogenation pretreatment catalyst accounts for no more than 20% of the total catalyst volume in the single-stage hydrocracking reactor. The hydrogenation pretreatment operation condition 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.

In the step a, the gas-liquid separator is a device arranged between single-section hydrocracking reactor beds or at the inlet of a catalyst bed. The gas-liquid separator at least comprises a reaction material flow inlet, a liquid phase conduit, a gas phase conduit and the like, wherein the liquid phase conduit pumps the separated liquid phase out of the single-stage hydrocracking reactor, and the gas phase conduit introduces the separated gas phase into the lower single-stage hydrocracking catalyst bed layer.

And b, allowing a part of the single-stage hydrocracking reactant flow in the step a 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 in terms of liquid phase, and preferably 10-80 wt%.

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 a hydrocracking tail oil product.

The single-stage hydroisomerization cracking catalyst in the step c 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 carrier of the catalyst 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 2-40 wt%. The main catalyst is FC-14 developed by petrochemical research institute. For hydrocracking catalysts, a certain hydrogenation activity is requiredAnd certain cracking activity, namely ensuring the hydrogenation saturation of olefin and aromatic hydrocarbon in reaction materials and requiring the isomerization reaction of straight-chain alkane. 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 c 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 c 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 c 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 c 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 c 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 c can be used as products independently or can 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 c can be used as products independently or can be mixed into a mixed diesel oil product.

And (c) taking the hydrocracking tail oil in the step b as a product.

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

And d, mixing the high-pressure hydrogen-rich gas in the step d, 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 is firstly mixed with single-stage hydrocracking recycle hydrogen 25 and enters a single-stage hydrocracking reactor 2, a reaction material flow passing through a first single-stage hydrocracking catalyst bed layer is pumped out a hydroisomerization liquid raw material flow 4 through a gas-liquid separator 23, the material flow after the hydroisomerization cracking raw material flow 4 is pumped out continues to enter a subsequent single-stage hydrocracking catalyst bed layer, a single-stage hydrocracking generated material flow 3 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 oil product 15 and a hydrocracking tail oil product 16, the hydroisomerization cracking raw material flow 4 and the single-stage hydrocracking recycle hydrogen 24 are mixed and then enter a hydrocracking reactor 5, and the generated material flow passing through the hydrocracking catalyst bed layer enters a hydrocracking high-pressure separator 9 for gas-liquid separation Separating, fractionating the separated liquid in a fractionating tower 11 to obtain a hydroisomerized cracked light naphtha product 17, a hydroisomerized cracked heavy naphtha product 18, a hydroisomerized cracked aviation kerosene product 19, a hydroisomerized cracked diesel oil product 20 and a hydroisomerized cracked tail oil product 21, wherein the hydroisomerized cracked light naphtha product 12 and the hydroisomerized cracked light naphtha product 17 can be used as products independently or mixed to obtain a mixed light naphtha product, the hydroisomerized cracked heavy naphtha product 13 and the hydroisomerized cracked heavy naphtha product 18 can be used as products independently or mixed to obtain a mixed heavy naphtha product, the hydroisomerized cracked aviation kerosene product 14 and the hydroisomerized cracked aviation kerosene product 19 can be used as products independently or mixed to obtain a mixed aviation kerosene product, and the hydroisomerized cracked diesel oil product 15 and the hydroisomerized cracked diesel oil product 20 can be used as products independently, or mixed to obtain a mixed diesel product, and the gas 6 obtained by separating the hydrocracking high-pressure separator 8 and the gas 7 obtained by separating the hydroisomerization high-pressure separator 9 are mixed and then are pressurized by a recycle hydrogen compressor and then are mixed with make-up hydrogen 22 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-28 is a single-stage hydrocracking catalyst developed and produced by the smooth petrochemical research institute of China petrochemical company Limited, and contains a Y-type molecular sieve; the catalyst ZHC-02 is a single-stage hydrocracking catalyst which is developed and produced by China petrochemical company Limited, compliant petrochemical research institute and does not contain a molecular sieve; the catalyst FC-14 is a single-stage hydroisomerization cracking catalyst 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 3 test results

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

Claims

1. A flexible single stage hydrocracking process comprising the steps of:

b. b, continuously enabling the rest part of the first single-stage hydrocracking material flow in the step a to pass through a single-stage hydrocracking catalyst bed layer at the lower part of a hydrocracking reactor under a hydrocracking condition, and separating and fractionating the single-stage hydrocracking material flow to obtain a single-stage hydrocracking high-pressure hydrogen-rich gas, a single-stage hydrocracking gas product, a single-stage hydrocracking naphtha product, a single-stage hydrocracking aviation kerosene product, a single-stage hydrocracking diesel product and a single-stage hydrocracking tail oil product;

c. and a, allowing the first single-stage hydrocracking material flow extracted from the reactor in the step a to pass through a single-stage hydrocracking catalyst bed layer containing heterogeneous molecular sieve catalysts of a single-stage hydrocracking reactor under a single-stage hydroisomerization cracking condition, and separating and fractionating the single-stage hydrocracking material flow to obtain a single-stage hydroisomerization cracking high-pressure hydrogen-rich gas, a single-stage hydroisomerization cracked gas product, a single-stage hydroisomerization cracked naphtha product, a single-stage hydroisomerization cracked aviation kerosene product, a single-stage hydroisomerization cracked diesel oil product and a single-stage hydroisomerization cracked tail oil product.

2. The hydrocracking process of claim 1, further comprising step d: and c, mixing the single-stage hydrocracking high-pressure hydrogen-rich gas obtained in the step b with the single-stage hydrocracking high-pressure hydrogen-rich gas obtained in the step c for recycling.

3. The hydrocracking process according to claim 1, wherein the wax oil feedstock has an initial boiling point of 100 to 400 ℃ and an end point of 405 to 600 ℃.

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. The hydrocracking process of claim 1, wherein the single-stage hydrocracking catalyst comprises a group VIB and/or group VIII metal as an active component, the catalyst carrier comprises one or more of alumina, siliceous alumina and a molecular sieve, and the molecular sieve is a Y-type molecular sieve.

6. The hydrocracking process of claim 5, 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 0wt% to 40wt% based on the weight of the catalyst.

7. The hydrocracking process of claim 1, wherein said single stage hydrocracking 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.

8. The hydrocracking process according to claim 1, wherein the inlet of the single-stage hydrocracking reactor in step a is filled with a hydrogenation protecting agent, and a hydrogenation pretreatment catalyst is filled above the single-stage hydrocracking catalyst bed.

9. Hydrocracking chemical according to claim 8The hydrogenation pretreatment catalyst is characterized in that VIB group and/or VIII group metal is used as an active component, and alumina or silicon-containing alumina is used 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.

10. The hydrocracking process of claim 8, wherein the hydrotreating pretreatment catalyst loading volume as a volume percentage of the total catalyst volume in the single-stage hydrocracking reactor is not more than 20%.

11. The hydrocracking process according to claim 8, wherein said hydrotreating pretreatment is carried out under the operating conditions: 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.

12. The hydrocracking process according to claim 1, wherein the part of the liquid phase stream withdrawn in step a accounts for 5 to 95 wt% of the raw oil in terms of liquid phase.

13. The hydrocracking process according to claim 1, wherein the single-stage hydrocracking catalyst comprises metals of group VIB and/or group VIII as active components, a catalyst carrier comprises alumina/siliceous alumina and a molecular sieve, and the molecular sieve is a beta type molecular sieve or a Sapo type molecular sieve; 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 2-40 wt%.

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

15. The hydrocracking process according to claim 12, wherein the part of the liquid phase stream withdrawn in step a accounts for 10 to 80 wt% of the raw oil in terms of liquid phase.