CN109988625B

CN109988625B - Hydrofining and hydrocracking combined process

Info

Publication number: CN109988625B
Application number: CN201711470870.5A
Authority: CN
Inventors: 刘涛; 李宝忠; 曾榕辉; 张学辉; 吴锐; 关明华
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: CN109988625A

Abstract

The invention discloses a hydrofining and hydrocracking combined process. The wax oil raw material enters a hydrogenation pretreatment reactor, and the material passing through the upper hydrogenation pretreatment catalyst bed layer is divided into two parts; one material enters a gas-liquid separator arranged in the middle of a bed layer, and the gas-phase material is pumped out of the hydrogenation pretreatment reactor and is mixed with LCO for hydrogenation refining reaction; the other material is a mixture of liquid phase in the reactor, the residual material flow after extraction and newly-supplemented hydrogen, and continuously flows downwards through a hydrogenation pretreatment catalyst bed layer at the lower part, and the hydrogenation pretreatment material flow enters the hydrocracking reactor; carrying out gas-liquid separation and fractionation on the obtained hydrocracking reaction material to obtain hydrocracking products such as naphtha, aviation kerosene, diesel oil and tail oil; and carrying out gas-liquid separation and fractionation on the hydrorefining reaction material flow to obtain naphtha and hydrogenated LCO. The invention provides a hydrogenation combined process for simultaneously producing a hydrocracking light product and hydrogenation LCO on a set of hydrogenation process devices for the first time.

Description

Hydrofining and hydrocracking combined process

Technical Field

The invention belongs to the field of petroleum refining, and particularly relates to a hydrofining and hydrocracking combined process for generating a high-quality catalytic cracking raw material and a high-quality hydrocracking product.

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. One-stage series hydrocracking technology uses two types of catalysts, namely a hydrocracking pretreatment catalyst and a hydrocracking catalyst, which are respectively filled in a hydrocracking pretreatment reactor and a hydrocracking reactor, and the catalysts in each reactor are usually filled in layers. The catalytic cracking is one of the important means for the heavy oil conversion, but with the deterioration and the heavy conversion of the catalytic cracking processing raw material, the operation conditions are more and more strict, the light product yield and the product property are poor, and the catalytic cracking raw material hydrotreating technology can not only remove the content of sulfur, nitrogen, metal and other impurities, but also improve the cracking performance of the feeding material, reduce the FCC operation severity, improve the product distribution, improve the selectivity of the target product, reduce the yield of dry gas and coke, improve the economy of an FCC device, reduce the sulfur content of the target product, reduce the SOx and NOx content in the regeneration flue gas and the like. The catalytic cracking Light Cycle Oil (LCO) contains a certain content of sulfur and nitrogen, both of which exist in the form of organic compounds, and has high aromatic hydrocarbon content, especially the content of aromatic hydrocarbons with more than two rings, and the LCO is generally directly circulated back to a catalytic cracking device for continuous conversion, or enters a hydrotreating device for hydrogenation and then enters the catalytic cracking device, or enters other devices for processing or directly serves as a product.

CN101003746A, CN001955260A, CN001955257A, CN103059960A and CN001955263A all disclose a hydrocracking process or a combined process for combined processing of wax oil and catalytic cracking diesel oil. The technology can produce high-quality products, especially high-quality heavy naphtha, as a raw material for catalytic reforming by a hydrocracking method or a combined method by using wax oil and LCO as raw materials, but does not generate a catalytic cracking raw material and does not return to a catalytic cracking unit for conversion again.

CN106701175A, CN102465035A and CN001896192A disclose a process technology for blending LCO in a hydrotreating process, which mainly aims to produce high-quality catalytic cracking raw materials or realize clean production of a catalytic cracking device by a coupling technology for circulating LCO between a hydrotreating device and the catalytic cracking device, but because wax oil, slag oil and the like are directly hydrogenated after being mixed with the LCO, the hydrogenation depth of the LCO cannot be effectively controlled, and high-quality hydrocracking products cannot be produced.

In summary, compared with the existing LCO hydrogenation technology and hydrocracking technology, the LCO is usually blended directly into the catalytic cracking raw material pretreatment device for hydrogenation and then returned to the catalytic cracking device, or the LCO is blended into the hydrocracking raw material oil, and the hydrocracking raw material oil is subjected to hydrogenation pretreatment and then enters the hydrocracking device to produce the hydrocracking naphtha product.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a combined process of hydrofining and hydrocracking, namely, a part of reaction gas phase material flow is extracted from the middle part of a hydrogenation pretreatment reactor using a hydrocracking device, and the wax oil raw oil and the LCO raw oil are subjected to combined hydrogenation pretreatment-hydrocracking and hydrofining process to produce high-quality hydrocracking products and high-quality catalytic cracking raw materials.

The invention relates to a hydrofining and hydrocracking combined process, which comprises the following steps:

a. the method comprises the following steps that firstly, wax oil raw oil passes through a first hydrogenation pretreatment catalyst bed layer of a hydrogenation pretreatment reactor under a hydrogenation pretreatment condition to obtain a first hydrogenation pretreatment material flow, the part of the reaction material flow is divided into two parts, one part of the reaction material flow is separated through a gas-liquid separator, and the obtained gas phase material flow is pumped out of the hydrogenation pretreatment reactor;

b. mixing the rest part of the first hydrogenation pretreatment material flow obtained in the step a with the supplemented hydrogen, continuously passing through a second hydrogenation pretreatment catalyst bed layer of a hydrogenation pretreatment reactor under the hydrogenation pretreatment condition, continuously passing the hydrogenation pretreatment material flow through a hydrocracking catalyst bed layer of a hydrocracking reactor under the hydrocracking condition, and separating and fractionating the hydrocracking product flow 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 a hydrocracking tail oil product;

c. and b, mixing the first hydrogenation pretreatment gas phase material flow extracted from the reactor in the step a with LCO, passing through a hydrogenation refining catalyst bed layer of a hydrogenation refining reactor under the hydrogenation treatment condition, and separating and fractionating the hydrogenation refining material flow to obtain hydrogenation treatment high-pressure hydrogen-rich gas, hydrogenation refining naphtha and hydrogenation refining diesel.

The combined hydrofinishing and hydrocracking process according to the present invention may further comprise a step d: and c, mixing the hydrocracking high-pressure hydrogen-rich gas obtained in the step b and the hydrofining 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 partially removed when passing through the first hydrogenation pretreatment catalyst bed layer, aromatic hydrocarbons are subjected to hydrogenation saturation to a certain extent, part of hydrogenation pretreatment gas-phase materials are extracted, and new hydrogen is supplemented to obtain material flows which continuously pass through the hydrogenation pretreatment catalyst bed layer and the hydrocracking catalyst bed layer to obtain high-quality hydrocracking products, such as hydrocracking light naphtha, hydrocracking heavy naphtha, hydrocracking aviation kerosene, hydrocracking diesel oil, hydrocracking tail oil and the like, and because part of ammonia produced by hydrodenitrogenation is extracted, the inhibition of ammonia on the cracking activity center of the hydrocracking catalyst is reduced, which is equivalent to improving the activity of the hydrocracking catalyst or reducing the scale of hydrocracking operation; the research shows that: the aromatic hydrogenation saturation depth of LCO has great influence on the quality of catalytic cracking gasoline products, particularly monocyclic aromatic hydrocarbon in the gasoline is a high-octane component, the octane value of the catalytic cracking gasoline can be increased by increasing the content of the monocyclic aromatic hydrocarbon in the hydrogenated LCO, and the extracted hydrogenation pretreatment gas phase material flow contains hydrogen sulfide and ammonia with certain concentration, the inhibiting effect is equivalent to reducing the activity of the hydrogenation catalyst, and the hydrogenation depth of LCO can be just controlled by adjusting the volume space velocity and the reaction temperature, namely, the bicyclic aromatic hydrocarbon and polycyclic aromatic hydrocarbon in LCO are hydrogenated to monocyclic aromatic hydrocarbon on the premise of meeting the sulfur content, but the naphthenic hydrocarbon is not excessively generated by the deep hydrogenation, or the hydrogenation depth is not enough to generate the bicyclic aromatic hydrocarbon, so that the content of the aromatic hydrocarbon in the catalytic cracking gasoline can be improved when the product after the hydrogenation treatment enters the catalytic cracking device again, and the octane number of the catalytic cracking gasoline is improved.

Compared with the prior art, the hydrofining and hydrocracking combined process has the advantages that:

1. in the invention, the hydrogenation pretreatment reactor comprises at least two hydrogenation pretreatment catalyst beds. The method comprises the steps of extracting a part of hydrogenation pretreatment gas-phase materials through a gas-liquid separator arranged in the middle of a hydrogenation pretreatment reactor bed layer, realizing effective distribution of hydrogenation pretreatment material strands, and then enabling the obtained materials to pass through a hydrogenation combination process, thereby producing target products with different specifications. In the prior art, however, hydrofinishing and hydrocracking technologies are generally only capable of producing one desired product of a hydrogenation process according to the present technology.

2. According to the method, a gas-liquid separator is arranged in the middle of a catalyst bed layer of a hydrogenation pretreatment reactor, a first hydrogenation pretreatment gas phase material flow of a wax oil raw material subjected to hydrogenation pretreatment is extracted out of the hydrogenation pretreatment reactor, and is mixed with LCO and sent into a separately arranged hydrogenation refining reactor for hydrogenation reaction, the extracted gas phase material flow contains hydrogen sulfide and ammonia, so that the hydrogenation desulfurization reaction of the LCO is not facilitated, but the hydrogenation depth of the LCO is controlled by adjusting reaction conditions such as volume space velocity, reaction temperature and the like, namely the hydrogenation saturation depth of two-ring aromatic hydrocarbons and polycyclic aromatic hydrocarbons in the LCO is controlled, the two-ring aromatic hydrocarbons and the polycyclic aromatic hydrocarbons are hydrogenated to single-ring aromatic hydrocarbons as much as possible, and thus the reaction difficulty is reduced or the aromatic hydrocarbon content in catalytic cracking gasoline is increased when the hydrogenated LCO is subjected to catalytic cracking again, and the octane number of the gasoline is increased; for the hydrocracking part, the gas phase part containing ammonia produced by the hydrodenitrogenation reaction of the first hydrogenation pretreatment catalyst bed catalyst is extracted, so that the inhibition of the ammonia partial pressure on the cracking active center of the subsequent hydrocracking catalyst is correspondingly reduced, which is equivalent to the improvement of the activity of the hydrocracking catalyst or the reduction of the severity of the hydrocracking operation.

3. In the invention, the extracted gas-phase material flow obtained in the middle of the hydrogenation pretreatment catalyst bed layer of the hydrogenation pretreatment reactor has very high temperature and pressure, and can directly enter a newly arranged hydrofining reactor for reaction after being mixed with the LCO after heat exchange, thereby fully utilizing the heat carried by the pretreated gas-phase material and realizing the coupling operation of the hydrogenation pretreatment reactor and the hydrofining reactor.

4. In the invention, the operating pressure of the hydrocracking reaction system and the hydrorefining reaction system is the same, so that the high-pressure hydrogen-rich gas in the two systems can use a set of hydrogen desulfurization system and a set of hydrogen circulation system, the requirement of the hydrorefining reaction can be met by mixing the heat of the extracted gas phase and the LCO after heat exchange by using the hydrogenation pretreatment, and the heat source requirement of the combined process can be met by only using one heating furnace, thereby saving the equipment investment and the operating cost.

Drawings

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

Wherein: 1-wax oil raw oil, 2-hydrogenation pretreatment reactor, 3-hydrogenation pretreatment gas phase material flow, 4-LCO raw oil, 5-hydrocracking reactor, 6-hydrocracking material flow, 7-hydrofining reactor, 8-hydrocracking high-pressure separator, 9-hydrofining high-pressure separator, 10-hydrocracking fractionating tower, 11-hydrotreating 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-hydrofining gas product, 18-hydrofining naphtha, 19-hydrofining diesel oil, 20-hydrocracking high-pressure separator hydrogen-rich gas, 21-hydrofining high-pressure separator hydrogen-rich gas, 22-make-up hydrogen, 23-gas-liquid separator.

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 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 steps a and b is a conventional wax oil hydrogenation pretreatment catalyst. Generally, metals in VIB group and/or VIII group are used as active components, alumina or silicon-containing alumina is used as a carrier, metals in VIB group are generally Mo and/or W, metals in VIII group are generally usedIs 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, 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. 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 hydrogenation pretreatment condition can adopt the conventional operation condition in the field, 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 c, the volume proportion of the part of the extracted material flow in the step a to the total amount of hydrogen at the inlet of the hydrogenation pretreatment reactor is 5-95 v% in terms of gas phase, and preferably 10-80 v%.

The hydrocracking catalyst in the step b 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 carrier of the catalyst contains one or more of alumina, silicon-containing alumina and molecular sieve, preferably contains molecular sieve, and the molecular sieve can be Y-type molecular sieve, beta-type molecular sieve, Sapo-type molecular sieve and the like. 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 commercial catalysts are 3824, 3825, 3976, FC-12, FC-14, FC-20, FC-24, FC-26, FC-32, FC-50 catalysts 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. Hydrogenation ofThe cracking 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 separation described in step b typically comprises a hydrocracking high pressure separator and a low pressure separator separating the two parts. 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.

And c, the LCO raw material is light cycle oil of a catalytic cracking unit, the initial boiling point of the LCO raw material is 100-200 ℃, and the final boiling point of the LCO raw material is 320-400 ℃. The LCO raw oil can also be mixed with one or more of diesel fractions with high aromatic hydrocarbon content, such as coking diesel, ethylene cracking tar, coal tar and the like.

And c, all the hydrofining catalysts in the step c are conventional diesel hydrofining 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 refining catalysts such as 3936, FF-14, FF-16, FF-24, FF-26, FF-36, FF-56, FHUDS-5, FHUDS-7 and the like which are researched and developed by the petrochemical research institute, and can also be similar-function catalysts developed by catalyst companies at home and abroad, such as HC-K, HC-P of UOP company, TK-555 and TK-565 of Topsoe companyAnd KF-847, KF-848 by Akzo, and the like. The operation condition can adopt the conventional operation condition, generally the reaction pressure is 3.0MPa to 19.0MPa, the reaction temperature is 260 ℃ to 450 ℃, the preferred temperature is 280 ℃ to 410 ℃, and the liquid hourly 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 hydroprocessing high pressure separator and a low pressure separator. The high-pressure hydrogen-rich gas and the liquid are separated by the high-pressure hydrotreating separator, 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 hydrofined gas product.

The fractionation described in step c is carried out in a hydrofinishing fractionator system. And fractionating the low-pressure liquid product in a fractionating tower to obtain a hydrofined naphtha product and hydrofined diesel oil.

The hydrocracking gas product and the hydrofining 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 hydrofined naphtha in the step b and the step c can be used as products independently or can be mixed into a mixed naphtha product.

The hydrocracked heavy naphtha product as described in step b may be used alone as product.

The hydrocracked aviation kerosene product described in step b may be used alone as a product.

The hydrocracked diesel product as described in step b may be used alone as a product.

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

And d, using the hydrofined diesel oil in the step c as raw oil of a catalytic cracking unit.

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.

In the invention, the hydrofining reactor preferably contains two hydrofining catalyst beds, namely a first hydrofining catalyst bed and a second hydrofining catalyst bed (which are divided according to the contact sequence with the reaction materials). And simultaneously, a process of distilling and cutting the LCO raw material is added, preferably, the LCO raw material oil is divided into two parts according to a light fraction and a heavy fraction, wherein the cutting temperature point is 245-300 ℃, namely the fraction range of the light fraction is from the initial distillation point to the division point, and the fraction range of the heavy fraction is from the division point to the final distillation point. The obtained heavy fraction is firstly mixed with a gas-phase material flow extracted from a hydrogenation pretreatment reactor and enters a first hydrogenation refining catalyst bed layer in a hydrogenation refining reactor, then a hydrogenation refining reaction material is continuously mixed with a light fraction and enters a second hydrogenation refining catalyst bed layer, or the gas-phase material flow extracted from the hydrogenation pretreatment reactor is firstly mixed with the heavy fraction and enters a first hydrogenation refining reactor, and the hydrogenation refining reaction material flow is continuously mixed with the light fraction and enters a subsequent hydrogenation refining reactor. The heavy fraction mainly contains polycyclic aromatic hydrocarbon and can achieve the purpose of controlling the hydrogenation depth of the aromatic hydrocarbon through more hydrogenation refining catalyst reactions, and the light fraction contains less bicyclic aromatic hydrocarbon and can achieve the purpose of controlling the hydrogenation depth of the aromatic hydrocarbon with the heavy fraction at the same time, namely, the hydrogenated and refined bicyclic aromatic hydrocarbon and polycyclic aromatic hydrocarbon meet the sulfur content and are properly hydrogenated to monocyclic aromatic hydrocarbon at the same time, the hydrogenated and refined bicyclic aromatic hydrocarbon and polycyclic aromatic hydrocarbon can meet the catalytic cracking gasoline meeting the sulfur content requirement after further catalytic cracking, and the octane number of the gasoline can be improved.

In the invention, the first hydrogenation pretreatment catalyst bed layer and the second hydrogenation pretreatment catalyst bed layer are arranged in one hydrogenation pretreatment reactor or are respectively arranged in more than two hydrogenation pretreatment reactors. The first mode is preferably employed in the present invention.

Similarly, the first hydrofining catalyst bed layer and the second hydrofining catalyst bed layer are arranged in one hydrofining reactor, or are respectively arranged in more than two hydrofining reactors. The first mode is preferably employed in the present invention.

With reference to fig. 1, the method of the present invention is as follows: the method comprises the steps of mixing wax oil raw oil 1 with recycle hydrogen, feeding the mixture into a hydrogenation pretreatment reactor 2, feeding part of reactant flow passing through a first hydrogenation pretreatment catalyst bed into a gas-liquid separator 23, pumping out a hydrogenation pretreatment gas phase flow 3, mixing the flow pumped out the hydrogenation pretreatment gas phase flow 3 with supplementary hydrogen, feeding the mixture into a hydrocracking reactor 5, feeding a hydrocracking product flow 6 into a hydrocracking high-pressure separator 8 for gas-liquid separation, feeding the separated liquid into 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, mixing the pumped out hydrogenation pretreatment gas phase flow 3 with LCO raw oil, feeding the mixture into a hydrofining reactor 7, and feeding the product flow passing through the hydrofining catalyst bed into a hydrofining high-pressure separator 9 for gas-liquid separation, the separated liquid enters a fractionating tower 11 to be fractionated to obtain a hydrofined gas product 17, hydrofined naphtha 18, hydrofined diesel oil 19, gas 20 separated by a hydrocracking high-pressure separator 8 and gas 21 separated by a hydrofining high-pressure separator 9, and the mixture is pressurized by a recycle hydrogen compressor and then 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 4

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 hydrocracking catalyst developed and produced by China petrochemical company Limited, compliant petrochemical research institute, and contains a Y-type molecular sieve; the catalyst FHUDS-5 is a hydrofining catalyst developed and produced by the smoothing petrochemical research institute of China petrochemical industry Limited company.

TABLE 1 essential Properties of wax oil base stocks

TABLE 2 Process conditions

Table 2 Process conditions

In example 4, the LCO light and heavy cuts were cut at 280 ℃.

TABLE 3 test results

It can be seen from the examples that, by adopting the combined process of hydrofining and hydrocracking of the present invention, a part of the gas phase reactant stream is extracted from the hydrogenation pretreatment reactor, the gas phase reactant stream is extracted to be mixed with LCO for hydrofining to produce high quality catalytic cracking raw material, and the remaining hydrogenation pretreatment stream is continuously subjected to hydrogenation pretreatment and hydrocracking catalyst to produce high quality hydrocracking products, so that the production mode is flexible.

Claims

1. A combined hydrorefining and hydrocracking process comprising the steps of:

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

3. The combined process of claim 1, wherein the wax oil feedstock has an initial boiling point of 100 to 400 ℃ and an end point of 405 to 650 ℃.

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

5. The process of claim 1, wherein said LCO has an initial boiling point of 100 to 200 ℃ and an end point of 320 to 400 ℃.

6. The process of claim 1, wherein said LCO is further blended with at least one of coker gas oil, ethylene pyrolysis tar, and coal tar.

7. The combined process of claim 1, wherein saidThe hydrogenation pretreatment catalyst takes VIB group and/or VIII group metal as an active component and takes 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.

8. The combined process according to claim 1, characterized in that the conditions of the hydrotreating pretreatment 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.

9. The combined process according to claim 1, wherein the gas phase stream withdrawn in step a is 5 to 95% by volume of the total amount of hydrogen at the inlet of the hydrogenation pretreatment reactor.

10. The combined process of claim 1, wherein the 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, a beta-type molecular sieve or a SAPO-type molecular sieve.

11. The process of claim 10 wherein the catalyst comprises from 10wt% to 35wt% of a group VIB metal, as an oxide, from 3wt% to 15wt% of a group VIII metal, as an oxide, and from 5wt% to 80wt% of a molecular sieve, based on the weight of the catalyst.

12. The combined process of claim 1, wherein the 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.

13. The combined process of claim 1 wherein the hydrofinishing catalyst comprises a group VIB and/or group VIII metal as an active component and alumina or silica-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.

14. The combined process of claim 1, wherein the hydrotreating 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.

15. The combined process of claim 1, wherein the hydrofinishing reactor contains two hydrofinishing catalyst beds, a first hydrofinishing catalyst bed and a second hydrofinishing catalyst bed.

16. The combined process of claim 15, wherein the process further comprises: cutting an LCO raw material into a light fraction and a heavy fraction, wherein the cutting temperature is 245-300 ℃; and the heavy fraction and the first hydrogenation pretreatment gas-phase material flow pumped out by the hydrogenation pretreatment reactor are mixed and then pass through a first hydrogenation refining catalyst bed layer in the hydrogenation refining reactor, and the first hydrogenation refining reaction material and the light fraction are mixed and pass through a second hydrogenation refining catalyst bed layer.

17. The combined process of claim 1, wherein the first and second beds of hydroprocessing catalyst are disposed in one hydroprocessing reactor or in more than two hydroprocessing reactors, respectively.

18. The combined process according to claim 15 or 16, wherein the first and second beds of hydrofinishing catalyst are provided in one hydrofinishing reactor or in more than two hydrofinishing reactors respectively.

19. The combined process according to claim 1, wherein the gas phase stream withdrawn in step a is 10 to 80% by volume of the total amount of hydrogen at the inlet of the hydrogenation pretreatment reactor.