CN109988624B

CN109988624B - Residual oil hydrotreating and hydrofining combined process

Info

Publication number: CN109988624B
Application number: CN201711470755.8A
Authority: CN
Inventors: 刘涛; 韩照明; 李宝忠; 袁胜华; 耿新国; 方向晨
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: CN109988624A

Abstract

The invention discloses a combined process of residual oil hydrotreating and hydrofining. Mixing a residual oil raw material with hydrogen, then feeding the mixture into a hydrotreating reaction zone, and dividing the material passing through an upstream protective agent and a hydrotreating catalyst bed into two parts; one material enters a gas-liquid separator arranged in the middle of a bed layer, is separated to obtain a gas-phase material, is pumped out of a hydrotreating reaction zone, is mixed with LCO, and enters a hydrofining reactor for hydrogenation reaction; the other material continuously passes through a downstream hydrogenation catalyst bed layer, and the hydrotreating reaction material and the hydrofining reaction material are subjected to gas-liquid separation and fractionation to obtain naphtha, diesel oil, hydrogenation heavy fraction and the like. The present invention provides a hydrogenation combination process for flexibly processing different raw oil on a set of hydrogenation device to produce high-quality catalytic cracking raw material.

Description

Residual oil hydrotreating and hydrofining combined process

Technical Field

The invention belongs to the field of petroleum refining, and particularly relates to a combined residual oil hydrotreating and hydrofining process for flexibly producing a high-quality catalytic cracking raw material by using residual oil and LCO as raw oil.

Background

Fluid Catalytic Cracking (FCC) is one of the important means for the conversion of heavy oil into light oil, but with the deterioration and the heavy conversion of the catalytic cracking processing raw material, the operation conditions are more and more strict, the yield of light products and the product properties are poor, and the hydrotreating technology of the catalytic cracking raw material can not only remove the contents of sulfur, nitrogen, metal and other impurities, but also improve the cracking performance of the feeding material, reduce the operation severity of FCC, improve the product distribution, improve the selectivity of target products, reduce the yield of dry gas and coke, improve the economy of an FCC device, reduce the sulfur content of the target products, 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.

CN106701189A, CN106701190A, CN106701191A and CN102732314A disclose a process technology for blending LCO and/or heavy cycle oil in a residual oil hydrotreating process, which mainly aims to produce high-quality catalytic cracking raw materials, or a combined processing technology for circulating LCO between a residual oil hydrotreating device and a catalytic cracking device, so as to realize clean production of the catalytic cracking device.

In summary, compared with the existing LCO hydrogenation technology and residual oil hydrogenation technology, LCO is usually directly blended into a residual oil hydrogenation device for hydrogenation, and hydrogenated residual oil and hydrogenated LCO obtained after mixed hydrogenation are jointly used as raw materials of a catalytic cracking device, namely, LCO is hydrogenated and then returned to the catalytic cracking device.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a combined process of hydrotreatment and hydrorefining of residual oil. Extracting partial reaction gas phase material flow from a gas-liquid separator arranged in the middle of a hydrotreating reaction zone, and producing high-quality catalytic cracking raw materials from the residual oil raw oil and the LCO raw oil by a combined process of hydrotreating and hydrofining.

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

a. the method comprises the following steps that firstly, residual oil raw oil passes through an upstream protective agent and a graded hydrotreating catalyst bed layer of a hydrotreating reaction zone under a hydrotreating condition to obtain a first hydrotreating material flow, the part of the material flow is divided into two parts, one part of the material flow is separated through a gas-liquid separator, and the obtained gas phase material flow is pumped out of the hydrotreating reaction zone;

b. mixing the rest part of the hydrotreating material flow and the supplementary hydrogen in the step a, continuously passing through a downstream grading hydrotreating catalyst bed layer of a hydrotreating reaction zone under a hydrotreating condition to obtain a material flow generated in the hydrotreating reaction zone, and separating and fractionating (or stripping) the material flow to obtain a hydrotreating gas product, a hydrotreating naphtha product, hydrotreating diesel oil and a hydrotreating heavy fraction;

c. and b, mixing the gas phase material flow extracted from the hydrotreating reaction zone and LCO, passing through a hydrofining catalyst bed of a hydrofining reactor under the hydrofining condition to obtain a hydrofining reaction zone generated material flow, and separating and fractionating (or stripping) the obtained hydrofining reaction zone generated material flow to obtain a hydrofining gas product, a hydrofining naphtha product and hydrofining diesel.

According to the combined process of residual oil hydrotreating and hydrofining, the generated material flow of the hydrotreating reaction zone obtained in the step b and the generated material flow of the hydrofining reaction zone obtained in the step c are mixed and then are separated and fractionated (or stripped), so that a hydrogenated gas product, a hydrogenated naphtha product and hydrogenated diesel oil are obtained. That is, the separation and fractionation described in step b and step c share a single separation and fractionation system. And c, recycling the high-pressure hydrogen-rich gas obtained in the step b and the step c.

The requirements of product quality, environmental protection, process condition operation and the like all limit the properties of raw oil of a catalytic cracking unit, particularly the sulfur content, and the distribution and the properties of catalytic cracking products are greatly different due to different raw oil compositions; the research shows that: the influence of the aromatic hydrogenation saturation depth of LCO on the quality of catalytic cracking gasoline products is larger, 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 hydrotreating 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 combined process of residual oil hydrotreating and hydrofining has the advantages that:

1. in the present invention, the hydrotreating reaction zone includes at least two graded hydrotreating catalyst beds. The method comprises the steps of extracting a part of hydrotreating gas-phase materials by a gas-liquid separator arranged in the middle of a bed layer of a hydrotreating reaction zone, realizing effective distribution of hydrotreating material strands, and then subjecting the obtained materials to a hydrogenation combination process, thereby producing target products with different specifications. In the prior art, hydrofining and hydrotreating technologies generally produce only one desired product of a hydrogenation process according to the present technology.

2. The method comprises the steps of arranging a gas-liquid separator in the middle of a catalyst bed layer of a hydrotreating reaction zone, extracting a hydrogenation pretreatment gas phase material flow of a residual oil raw material subjected to hydrotreating out of the hydrotreating reaction zone, mixing the hydrogenation pretreatment gas phase material flow with LCO, and sending the mixture and the LCO into a hydrofining reactor which is independently arranged for hydrogenation reaction, wherein the extracted gas phase material flow contains hydrogen sulfide and ammonia, so that the hydrodesulfurization reaction of the LCO is not facilitated, but the hydrogenation depth of the LCO can be 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 polycyclic aromatic hydrocarbons are hydrogenated to monocyclic aromatic hydrocarbons as much as possible, the cracking 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; for the hydrotreating part, because the extracted gas phase part contains hydrogen sulfide and ammonia produced by hydrodesulfurization and hydrodenitrogenation reactions of the hydrotreating catalyst bed catalyst, the mixing of the residual material flow after the gas phase extraction and the make-up hydrogen is equivalent to the reduction of the hydrogen sulfide partial pressure and the ammonia partial pressure in the range of the lower hydrotreating catalyst bed, namely the inhibition of the activity center of the subsequent hydrotreating catalyst is reduced, or the activity of the hydrotreating catalyst is improved, and the severity of the hydrotreating operation is reduced.

3. In the invention, the extracted gas-phase material flow obtained in the middle of the hydrotreating catalyst bed in the hydrotreating reaction zone 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 part of the hydrotreating gas-phase material and realizing the coupling operation of the hydrotreating reactor and the hydrofining reactor.

4. In the invention, the operation pressure of the hydrotreating reaction system and the hydrofining 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, and if the two systems share a set of separation and fractionation (or stripping) system, the equipment investment and the operation cost can be greatly saved.

Drawings

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

Fig. 2 is another schematic flow chart of the present invention.

Wherein: 1-residue raw oil, 2-hydrotreating reactor, 3-hydrotreating extracted gas phase material flow, 4-LCO raw oil, 5-hydrotreating reactor circulating hydrogen, 6-hydrotreating reactor generated material flow, 7-hydrofining reactor, 8-hydrofining reactor generated material flow, 9-hydrofining high-pressure separator, 10-hydrofining fractionating tower, 11-hydrofining gas, 12-hydrofining naphtha, 13-hydrofining diesel oil, 14-hydrofining high-pressure separator hydrogen-rich gas, 15-make-up hydrogen, 16-hydrotreating high-pressure separator, 17-hydrotreating fractionating tower, 18-hydrotreating naphtha, 19-hydrotreating diesel oil, 20-hydrotreating heavy fraction oil and 21-hydrotreating high-pressure separator hydrogen-rich gas, 22-mixed high-pressure separator, 23-mixed fractionating tower, 24-mixed hydrogenated naphtha, 25-mixed hydrogenated diesel oil, 26-hydrotreated heavy distillate oil, 27-mixed high-pressure separator hydrogen-rich gas and 28-gas-liquid separator.

Detailed Description

The initial boiling point of the residual oil raw material in the step a is 200-450 ℃, and the final boiling point is 550-750 ℃. The residual oil raw oil can be one of atmospheric residual oil, vacuum residual oil, coking heavy oil, deasphalted oil, recycle oil and the like obtained by petroleum processing, one of coal tar, direct coal liquefaction oil, indirect coal liquefaction oil, synthetic residual oil, shale oil and the like obtained from coal, and can also be mixed oil of a plurality of the coal tar, the direct coal liquefaction oil, the indirect coal liquefaction oil, the synthetic residual oil and the shale oil.

The protective agent and the hydrotreating catalyst in the steps a and b are conventional residual oil hydrogenation series catalysts, and mainly comprise a hydrogenation protective agent, a hydrodemetallization agent, a hydrodesulfurization catalyst, a hydrodecarbonization catalyst and the like. The hydrogenation catalyst contains one or more of Co, Mo, W and Ni as hydrogenation active component in 5-70 wt% calculated in oxide, and the carrier of the hydrogenation catalyst is alumina, amorphous silica-alumina, silica, titania, etc. and may contain other assistant, such as P, Si, B, Ti, Zr, etc. The catalyst may be used commercially or may be prepared by methods known in the art. The hydrogenation active component is a catalyst in an oxidation state, and is subjected to conventional vulcanization treatment before use, so that the hydrogenation active component is converted into a vulcanization state. The commercial hydrogenation catalysts mainly include hydrogenation catalyst steps such as FZC-1 series protective agents, FZC-2 series demetallization catalysts, FZC-3 series desulfurization catalysts, FZC-4 series carbon residue removal catalysts and the like developed by the Fushun petrochemical research institute (FRIPP), hydrogenation catalysts such as HMC945 and HMC841 of IFP company, RF series catalysts and R series catalysts developed by UOP company, KFR series participation of AKZO company, HT series catalysts developed by Axen company and TK series catalysts developed by Haldor Topsoe company. Based on the flow direction of the mixture of raw oil and hydrogen, the catalyst is loaded in a grading mode according to the principle that the particle size is gradually reduced and the activity of the catalyst is gradually increased.

The operation conditions of the step a can adopt conventional operation conditions, generally the reaction pressure is 5.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.05h^-1～5.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

In the step a, one reactor or a plurality of reactors, such as 2 to 8 reactors, may be arranged in the first hydrotreating reaction zone.

The position of the catalyst corresponding to the part of the reaction material flow extracted in the step a is any position between the hydrodemetallization catalyst and the hydrodecarbonization catalyst bed layer, namely the position where the hydrodemetallization catalyst is connected with the hydrodemetallization catalyst, the position inside the hydrodecarbonization catalyst bed layer, and the position where the hydrodecarbonization catalyst is connected with the hydrodecarbonization catalyst bed layer.

The volume percentage of the gas phase material flow extracted in the step a to the hydrogen amount at the inlet of the hydrotreating reaction zone is 5-90 wt%, and preferably 10-50 wt%.

The operation conditions of the step b can adopt the conventional operation conditions, generally the reaction pressure is 5.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.05h^-1～5.0h^-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 high-pressure separator and a low-pressure separator, for hydroprocessing. Wherein the high-pressure separator separates to obtain the hydrogen-rich gas and liquid under high pressure, 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 hydrotreating gas product.

The fractionation (or stripping) described in step b is carried out in a hydrotreating fractionator (or stripper) system. And fractionating the low-pressure liquid product in a fractionating tower to obtain a hydrotreated naphtha product, hydrotreated diesel oil and hydrotreated heavy fraction.

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.

Step c placeThe hydrofining catalyst is a conventional hydrofining catalyst. 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 3936, FF-14, FF-16, FF-24, FF-26, FF-36, FF-56, FHUDS-5, FHUDS-7 and other hydrofining catalysts 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. 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 and the hydrofining are carried out in the high-pressure separator and the low-pressure separator in the step c. Wherein the hydrofining high-pressure separator is used for separating to obtain hydrofining 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 hydrofined gas product.

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

The hydrotreated gas product and the hydrofinished gas product in the steps b and c can be used as products independently or can be mixed into a mixed gas product.

The hydrotreated naphtha product and the hydrotreated naphtha product described in step b and step c may be used as separate products or may be mixed to form a mixed naphtha product.

The hydrotreated diesel oil in the step b can be independently used as a product, and can also be mixed with the hydrofined diesel oil in the step c to be used as raw oil of a catalytic cracking unit.

And d, using the hydrotreated heavy fraction in the step b as raw oil of a catalytic cracking unit.

The separation described in steps b and c can also be carried out in a mixed high-pressure separator and a mixed low-pressure separator, i.e. the product streams of both reactors are mixed into one and the same high-pressure separator and one and the same low-pressure separator. The mixed high-pressure separator separates to obtain mixed high-pressure hydrogen-rich gas and mixed liquid, and the mixed liquid separated by the mixed high-pressure separator enters the mixed low-pressure separator. The mixed low pressure separator separates the high pressure liquid product to produce a mixed hydrocarbon-rich gas and a mixed low pressure liquid product. The mixed hydrocarbon-rich gas is separated to obtain the required mixed gas product. The mixed high-pressure hydrogen-rich gas can be directly used as recycle hydrogen, and can also be recycled after hydrogen sulfide is removed by a recycle hydrogen desulfurization system.

The fractionation (or stripping) described in steps b and c is carried out in a mixed fractionation (or mixed stripping) column system. And fractionating the mixed low-pressure liquid product in a mixed fractionating tower to obtain a mixed hydrogenated naphtha product, mixed hydrogenated diesel oil and hydrogenated heavy distillate oil.

In the invention, the hydrofining process in the hydrofining reactor comprises two reaction stages which are sequentially carried out, wherein the first reaction stage is carried out in a catalyst bed layer A containing a hydrofining catalyst, and the second reaction stage is carried out in a catalyst bed layer B containing a hydrofining catalyst. Preferably, the method also comprises a process of cutting the LCO raw oil into a light fraction and a heavy fraction, wherein the cutting temperature is 245-300 ℃. And c, mixing the heavy fraction with the first hydrotreating gas-phase material flow extracted in the step a, and allowing the mixture to pass through a catalyst bed layer A, and mixing the hydrofined material flow obtained by the catalyst bed layer A with the LCO light fraction, and allowing the mixture to pass through a catalyst bed layer B.

Further, a second reaction stage in the hydrofining reactorReaction temperature y of₂Below the reaction temperature y of the first reaction stage₁Preferably y₂Ratio y₁The lower temperature is 5-20 ℃.

The LCO heavy fraction obtained by cutting the LCO raw oil is mainly polycyclic aromatic hydrocarbon and can achieve the purpose of controlling the hydrogenation depth of the aromatic hydrocarbon through more hydrofining catalyst reactions, and the bicyclic aromatic hydrocarbon in the LCO light fraction can achieve the purpose of controlling the hydrogenation depth of the aromatic hydrocarbon simultaneously with the LCO heavy fraction through less hydrofining catalyst reactions, namely the hydrofined LCO meets the requirement of sulfur content, meanwhile, the bicyclic aromatic hydrocarbon and the polycyclic aromatic hydrocarbon are properly hydrogenated to monocyclic aromatic hydrocarbon, and the catalytic cracking gasoline can meet the requirement of the sulfur content after further catalytic cracking, and the octane number of the gasoline can be improved. In addition, the catalyst bed layer B in the hydrofining reactor is operated at the temperature lower than that of the catalyst bed layer A, and the hydrogenation saturation conversion of the bicyclic aromatic hydrocarbon into the monocyclic aromatic hydrocarbon is facilitated.

In the invention, the catalyst bed layer A and the catalyst bed layer B can be arranged in one hydrofining reactor, and can also be respectively arranged in more than two hydrofining reactors. The first mode is preferably employed in the present invention.

In the present invention, in the hydrotreating reaction zone, the "upstream" and "downstream" are divided according to the order of contact of the reaction materials, and the catalyst bed layer which is first contacted with the reaction materials is the "upstream" and the catalyst bed layer which is then contacted with the reaction materials is located at the "downstream".

With reference to fig. 1, the method of the present invention is as follows: mixing residual oil raw oil 1 with recycle hydrogen 5, feeding the mixture into a hydrotreating reactor 2, extracting a hydrotreating extraction material flow 3 from a reaction material flow passing through a first hydrotreating catalyst bed, mixing the material flow after the extraction of the material flow 3 with make-up hydrogen, continuing to feed the mixture into a hydrotreating catalyst bed at the lower part, mixing the extracted hydrotreating extraction material flow 3 with LCO raw oil 4, feeding the mixture into a hydrofining reactor 7, feeding a resultant flow 8 passing through the hydrofining catalyst bed into a hydrofining high-pressure separator 9 for gas-liquid separation, feeding the separated liquid into a hydrofining fractionating tower 10 for fractionating to obtain a hydrofining gas 11, a hydrofining naphtha 12 and a hydrofining diesel 13, feeding the hydrotreating reactor resultant flow 6 into a hydrotreating high-pressure separator 16 for gas-liquid separation, and feeding the separated liquid into a hydrotreating fractionating tower 17 for fractionating to obtain a hydrotreating naphtha 18, The hydrogen-rich gas 14 obtained by separating the hydrotreated diesel oil 19, the hydrotreated heavy fraction 20 and the hydrofining high-pressure separator 9 is mixed with the hydrogen-rich gas 21 obtained by separating the hydrotreating high-pressure separator 16, then the mixture is pressurized by a recycle hydrogen compressor and then is further mixed with make-up hydrogen 15 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 hydrotreating experimental study is carried out by using a FZC series catalyst system which is a combination of a protective agent, a demetallization catalyst, a desulfurization catalyst and a carbon residue removal catalyst developed and produced by FRIPP; hydrofining experimental research is carried out on the hydrofining catalyst FHUDS-5 developed and produced by FRIPP.

TABLE 1 essential Properties of resid feed oils

	Residual oil 1	Residual oil 2	LCO
				Density, g/cm³	0.925	0.948	0.932
Fraction specificationWeiqi deg.C	320～650	450～750	156~370
				Sulfur content, wt.%	3.5	3.0	1.3
Nitrogen content, wt%	0.27	0.21	0.09
				Carbon residue in wt%	12.0	10.1	—
Ni + V content, microgram/g	105	88	—
				Aromatic content, wt.%	—	—	91.2

TABLE 2 Process conditions

Table 2 Process conditions

TABLE 3 test results

Wherein the cutting temperature of the LCO light fraction and the heavy fraction is 270 ℃.

It can be seen from the examples that, by adopting the combined process of residue hydrotreating and hydrofining of the present invention, a high quality catalytic cracking feedstock is provided by extracting a portion of the gas phase reactant stream from the hydrotreating reactor, extracting the gas phase reactant stream to mix with LCO for hydrofining to produce a high quality catalytic cracking feedstock, and continuing to hydrotreat the remaining hydrotreated stream after the gas phase reactant stream is extracted to produce high quality naphtha, hydrogenated diesel oil and hydrogenated heavy distillate, with a flexible production mode.

Claims

1. A combined process of hydrotreatment and hydrofining of residual oil comprises the following steps:

b. mixing the rest part of the hydrotreating material flow and the supplementary hydrogen in the step a, continuously passing through a downstream grading hydrotreating catalyst bed layer of a hydrotreating reaction zone under a hydrotreating condition to obtain a material flow generated in the hydrotreating reaction zone, and separating and fractionating the material flow to obtain a hydrotreating gas product, a hydrotreating naphtha product, hydrotreating diesel oil and a hydrotreating heavy fraction;

c. providing a hydrofinishing reactor, said hydrofinishing reactor comprising two reaction sections: a catalyst bed layer A containing a hydrofining catalyst and a catalyst bed layer B containing a hydrofining catalyst; cutting LCO raw oil into light fraction and heavy fraction, wherein the cutting temperature is 245-300 ℃; b, mixing the obtained LCO heavy fraction with the gas phase material flow obtained in the step a, and then passing through a catalyst bed layer A; mixing the hydrofining material flow obtained by the catalyst bed layer A with LCO light fraction, and then passing through the catalyst bed layer B; and separating and fractionating the obtained hydrorefining reactor product flow to obtain a hydrorefining gas product, a hydrorefining naphtha product and hydrorefining diesel.

2. The combined process according to claim 1, wherein the crude oil of residual oil has an initial boiling point of 200-450 ℃ and an end boiling point of 550-750 ℃.

3. The combined process of claim 2, wherein the resid feed oil is selected from the group consisting of at least one of atmospheric resid, vacuum resid, coker heavy oil, deasphalted oil, recycle oil, coal tar, coal direct liquefaction oil, coal indirect liquefaction oil, synthetic resid, and shale oil.

4. The combination process of claim 1, wherein in the protective agent and the hydrotreating catalyst in the steps a and b, the hydrogenation active component is one or more of Co, Mo, W and Ni, and the weight content of the hydrogenation active component calculated by oxide is 5-70%; the catalyst carrier contains at least one of alumina, amorphous silicon-aluminum, silica and titania.

5. The combination of claim 4 wherein said protectant hydrotreating catalyst comprises a promoter selected from at least one of P, Si, B, Ti, and Zr.

6. The combined process of claim 1, wherein the hydrotreating conditions in step a are: the reaction pressure is 5.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.05h^-1～5.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

7. The combined process according to claim 1, wherein the withdrawn gas phase stream in step a is 5 to 90wt% based on the volume of hydrogen at the inlet of the hydroprocessing reaction zone.

8. The combined process of claim 7, wherein the hydrotreating conditions in step b are: the reaction pressure is 5.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.05h^-1～5.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

9. The combined process of claim 1, wherein the catalyst location to which the portion of the first hydrotreated gas phase stream is withdrawn in step a is anywhere between the hydrodemetallization catalyst and the hydrodecarbonization catalyst bed.

10. The combined process of claim 1, wherein the hydrotreating conditions in step b are: the reaction pressure is 5.0MPa to 19.0MPa, the reaction temperature is 300 ℃ to 450 ℃, and the liquid hourly volume space velocity is 0.05h^-1～5.0h^-1The volume ratio of the hydrogen to the oil is 100: 1-2000: 1.

11. 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 ℃.

12. 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.

13. The combined process of claim 1, wherein the hydrofinishing conditions in step c are: the reaction pressure is 3.0MPa to 19.0MPa, the reaction temperature is 260 ℃ 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.

14. The combined process of claim 1, wherein the reaction temperature y of the catalyst bed B₂Lower than the reaction temperature y of the catalyst bed A_1。

15. The process of claim 14, wherein y is₂Ratio y₁The lower temperature is 5-20 ℃.

16. The combined process according to claim 7, wherein the withdrawn gas phase stream in step a is in the range of 10 to 50wt% based on the volume of hydrogen at the inlet of the hydroprocessing reaction zone.