Combined hydrogenation process and system for maximum production of reforming raw materials

Abstract

The present invention discloses a combined hydrogenation process and system for maximizing the production of reforming raw materials, the process comprising: (1) fractionating the hydrogenated diesel obtained by reacting a high aromatic diesel raw material with hydrogen into a light hydrogenated diesel fraction and a heavy hydrogenated diesel fraction; (2) reacting a wax oil raw material with hydrogen to obtain hydrogenated wax oil; (3) the heavy hydrogenated diesel fraction and the hydrogenated wax oil enter a first hydrocracking reaction zone for reaction, and the reaction products are fractionated to obtain gas, naphtha and heavy fractions; (4) the heavy fraction enters a second hydrocracking reaction zone for reaction, and the reaction products are separated to obtain light cycle oil and heavy cycle oil, wherein the light cycle oil is mixed with the liquid phase material separated from the reaction products of the first hydrocracking reaction zone for treatment; the heavy cycle oil is returned to the hydrocracking pretreatment reactor for treatment. A system for implementing the above combined hydrogenation process is also provided. The present invention combines a two-stage hydrocracking process with a diesel refining process to retain the aromatics in high-aromatic diesel in the heavy naphtha product, while solving the inherent problems of a single two-stage hydrocracking process and a high-aromatic diesel hydrogenation process, providing favorable technical support for improving the efficiency of enterprises.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry, and particularly relates to a two-stage hydrocracking and high-aromatic inferior diesel hydrogenation combined processing process with the main purpose of producing reforming raw materials. Background Art

[0002] In recent years, the apparent consumption of diesel in the domestic refined oil consumption structure has begun to decrease year by year, and reducing the diesel-to-gasoline ratio is the consensus of major refining companies. In particular, high-aromatic low-quality diesel has become the most difficult fraction for refining companies to use with high added value. Currently, common treatment methods include hydroconversion of high-aromatic low-quality diesel, hydrocracking or hydromodification as one of the mixed raw materials, but all of them will generate some diesel products with poor product quality.

[0003] At the same time, as the market demand for chemical raw materials such as benzene, toluene, and xylene rises against the trend, catalytic reforming units have become the most economically valuable units for major refining companies, and the two-stage hydrocracking process is an effective means to convert wax oil into high-quality catalytic reforming raw materials. For this reason, relevant research institutions and refining and chemical production companies are vigorously developing refining and chemical technologies that produce more chemical raw materials and reduce the diesel-gasoline ratio. In the conventional wax oil two-stage hydrocracking process, the first-stage hydrocracking reaction product is extracted through a fractionation tower to extract light products such as heavy naphtha and light naphtha, and then the fraction with a distillation range greater than heavy naphtha enters the second hydrocracking reactor for reaction. The second-stage hydrocracking reaction product is circulated to the fractionation tower to extract light products such as heavy naphtha and light naphtha, and the fraction with a distillation range greater than heavy naphtha continues to enter the second-stage hydrocracking reactor, thereby achieving the maximum production of heavy naphtha products. The selectivity of heavy naphtha in the conventional wax oil two-stage hydrocracking process has a limit, and the yield of heavy naphtha is limited to less than 70%. It is difficult to solve the above problems simply by iteratively upgrading the performance of hydrocracking catalysts.

[0004] CN109777509A discloses a two-stage hydrocracking process method, which is characterized in that the hydrocracking pretreatment product enters a flash tank, and the gas phase material obtained by flash evaporation enters a hydrocracking reactor through different feed ports, thereby improving product distribution.

[0005] CN1952067A discloses a two-stage hydrocracking method. The first hydrocracking reactor of the patent adopts a single-stage two-dose idea to load two catalysts, with the upper part loaded with refined catalyst and the lower part loaded with hydrocracking catalyst. The method of the present invention not only maintains the advantages of the single-stage two-dose hydrocracking technology, such as high yield of middle distillate oil, low chemical hydrogen consumption and low total catalyst cost, but also has the characteristics of the single-stage series hydrocracking technology, such as strong adaptability to raw oil, long catalyst operation cycle and good quality of hydrocracking products. However, the device realizes the maximum production of middle distillate oil, which does not conform to the current trend of refining enterprises to reduce the diesel-gasoline ratio.

[0006] CN109777514A discloses a method for catalytic diesel hydrogenation conversion to aromatics, wherein two hydrofining reactors with different process conditions are arranged in series, and unconverted diesel is circulated to the second hydrofining reactor. The second hydrofining reaction temperature is 30-120°C higher than the first hydrofining reaction temperature, and the volume space velocity is 0.2-1.5h lower than that of the first hydrofining reaction zone. -1 The heavy naphtha fraction produced is used in conjunction with an aromatics extraction unit to produce BTX. However, this patent also inevitably produces a large amount of diesel products as a by-product, and an additional hydrotreating reactor is required, resulting in high equipment investment. Summary of the invention

[0007] The existing two-stage hydrocracking process for the maximum production of catalytic reforming raw materials has a technical bottleneck that it is difficult to break through the 70% mark of heavy naphtha selectivity by relying solely on catalyst upgrades. The applicant found in the research process that the main reasons are: (1) increasing the conversion rate will lead to an increase in light naphtha and gas products, reducing the selectivity of the target product and the yield of liquid products; (2) when processing high aromatic content raw materials, the polycyclic aromatic hydrocarbons in the circulating oil obtained from the second-stage hydrocracking reaction zone will accumulate as the operation cycle is extended, resulting in a decrease in the second-stage hydrocracking conversion rate; (3) the second-stage hydrocracking catalyst cannot maintain the hydrogen sulfide content in the atmosphere required for the stable operation of the hydrocracking catalyst due to the extremely low sulfur content of the first-stage unconverted oil it processes, resulting in a further decrease in the activity of the hydrocracking catalyst. At the same time, the applicant found in the research process that the hydrocracking reaction has a dynamic inhibition and guidance phenomenon in the cracking reaction area, that is, in the hydrocracking process of the full-fraction reactants, the introduction of substances with a distillation range of A to B°C will promote the substances with a distillation range of A to B°C to preferentially react with light components (<A°C), while inhibiting the reaction of substances with a distillation range of >B°C. It is based on this principle that the applicant improves the selectivity of the target product by optimizing the hydrocracking reaction pathway.

[0008] In view of the deficiencies in the prior art, the main purpose of the present invention is to provide a combined hydrogenation process and system for the maximum production of reforming raw materials. The combined hydrogenation process can completely convert inferior high-aromatic diesel into heavy naphtha and light naphtha with high aromatic potential content. At the same time, the light hydrogenated diesel and heavy hydrogenated diesel obtained after diesel hydrogenation enter the two-stage hydrocracking reaction zone and the one-stage hydrocracking reaction zone respectively, on the one hand, optimizing the selectivity of the hydrocracking reaction, and on the other hand, supplementing sulfur to the two-stage hydrocracking catalyst to achieve long-term stable maximum production of reforming raw materials. The two-stage hydrocracking process is combined with the diesel refining process to retain the aromatics in the high-aromatic diesel in the heavy naphtha product, while solving the inherent problems of the single two-stage hydrocracking process and the high-aromatic diesel hydrogenation process, providing favorable technical support for the physical efficiency improvement of enterprises.

[0009] In order to achieve the above-mentioned object of the invention, the present invention first provides a combined hydrogenation process for producing reforming raw materials in maximum quantity, comprising the following steps:

[0010] (1) High aromatic diesel feedstock and hydrogen enter the diesel hydrogenation reaction zone and react under the action of a diesel hydrogenation catalyst to obtain hydrogenated diesel. The hydrogenated diesel is fractionated to obtain a light hydrogenated diesel fraction and a heavy hydrogenated diesel fraction.

[0011] (2) The wax oil feedstock and hydrogen enter the hydrocracking pretreatment reaction zone and react under the action of the hydrogenation pretreatment catalyst to obtain hydrogenated wax oil;

[0012] (3) the heavy hydrogenated diesel fraction obtained in step (1) and the hydrogenated wax oil obtained in step (2) are fed together into a first hydrocracking reaction zone to react under the action of hydrogen and a hydrocracking catalyst, and the reaction products are separated into gas and liquid to obtain gas phase material and liquid phase material, and the liquid phase material is fractionated to obtain gas, naphtha and heavy fraction;

[0013] (4) The heavy fraction obtained in step (3) enters the second-stage hydrocracking reaction zone, where it reacts under the action of hydrogen and a hydrocracking catalyst. The reaction products are separated to obtain light cycle oil and heavy cycle oil. The light cycle oil is mixed with the liquid phase material separated from the reaction products in the first-stage hydrocracking reaction zone and treated together; the heavy cycle oil is returned to the hydrocracking pretreatment reactor for treatment.

[0014] Furthermore, in the above-mentioned combined hydrogenation process for producing the reforming raw material in the largest amount, the distillation range of the high aromatic diesel feedstock is generally 200°C to 450°C, and the aromatic content is 30% to 95%, preferably 50% to 90%; there is no special restriction on the sulfur and nitrogen content. Under normal circumstances, the sulfur content is not more than 2.0wt% and the nitrogen content is not more than 2500ppm. More specifically, the high aromatic diesel feedstock can be selected from one or a mixture of catalytic diesel, coking diesel, heavy aromatic oil, etc.

[0015] Furthermore, in the combined hydrogenation process for maximizing the production of reforming feedstock, the hydrogenated diesel is fractionated to obtain a light hydrogenated diesel fraction and a heavy hydrogenated diesel fraction, and the splitting temperature of the light hydrogenated diesel fraction and the heavy hydrogenated diesel fraction is 180-400°C, preferably 280-360°C.

[0016] Further, in the combined hydrogenation process for the maximum production of reforming raw materials, the diesel hydrogenation reaction zone includes at least one hydrogenation reactor, and at least one hydrogenation refining catalyst is loaded in the hydrogenation reactor. Generally, the hydrogenation refining catalyst includes a hydrogenation active metal component and a carrier. The hydrogenation active metal component can be one or more of the metal elements of Group VI, Group VII or Group VIII, and can be specifically selected from two or more metals of Co, Mo, Ni, and W as the hydrogenation active metal component. The carrier can generally be an inorganic refractory oxide such as alumina and silicon oxide. The hydrogenation refining catalyst can be selected from commercial products or prepared according to the common sense in the field as needed. Specifically, commercial diesel hydrogenation refining catalysts such as FHUDS-3, FHUDS-6, FHUDS-7, and FHUDS-8 developed by Fushun Petrochemical Research Institute (FRIPP) of Sinopec can be selected.

[0017] Furthermore, in the combined hydrogenation process for producing the reforming feedstock in the maximum amount, the reaction conditions in the diesel hydrogenation reaction zone are generally as follows: the reaction pressure is 2.0 to 19.0 MPa, preferably 5.0 to 10.0 MPa, the reaction temperature is 280 to 420°C, preferably 310 to 380°C, and the volume space velocity is 0.1 to 15.0 h -1 , preferably 0.2 to 2.5 hours -1 , the volume ratio of hydrogen to oil is 100~2500.

[0018] Furthermore, in the above-mentioned combined hydrogenation process for producing the maximum amount of reforming raw materials, the wax oil raw material can be one or more of atmospheric wax oil, vacuum wax oil, deep-drawn wax oil and boiling bed wax oil. The distillation range of the wax oil raw material is generally 300°C to 600°C, and there are no special requirements for its sulfur and nitrogen content and composition.

[0019] Furthermore, in the combined hydrogenation process for the maximum production of reforming raw materials, at least one hydrogenation reactor is provided in the hydrocracking pretreatment reaction zone, and the hydrogenation reactor contains at least one hydrocracking pretreatment catalyst, preferably 2 to 4 hydrocracking pretreatment catalysts. Generally, the hydrocracking pretreatment catalyst includes a carrier and a hydrogenation metal component supported on the carrier, and the hydrogenation metal component can be at least one selected from the metal elements of Group VI, Group VII or Group VIII, preferably two or more metals of Co, Mo, Ni, and W as active components. Specifically, commercial hydrocracking pretreatment catalysts such as FF-33, FF-46, FF-66, and FTX developed by Fushun Petrochemical Research Institute of Sinopec can be selected, and can also be prepared according to the common sense in the art as needed.

[0020] Furthermore, in the combined hydrogenation process for the maximum production of reforming feedstock, the reaction conditions of the hydrocracking pretreatment reaction zone are generally as follows: reaction pressure of 5.0 to 21.0 MPa, preferably 10.0 to 18.0 MPa, reaction temperature of 280 to 430°C, preferably 330 to 410°C, volume space velocity of 0.6 to 15.0 h -1 , preferably 0.2~1.8h -1 , the volume ratio of hydrogen to oil is 800~1800.

[0021] Further, in the combined hydrogenation process for the maximum production of reforming raw materials, at least one hydrocracking reactor is set in the first hydrocracking reaction zone, and at least one hydrocracking catalyst is contained in the hydrocracking reactor. The hydrocracking catalyst includes a hydrogenation component and a carrier. The hydrogenation component can generally be one or more of group VI, group VII or group VIII metal elements, preferably two or more of Co, Mo, Ni, and W; the carrier includes at least one of Y molecular sieve, β molecular sieve, modified Y molecular sieve, modified β molecular sieve, alumina, and amorphous silicon aluminum. In general, the content of the hydrogenation component calculated as oxide is 15% to 45% based on the weight of the catalyst. The content of β molecular sieve in the catalyst is 2% to 35%, preferably 5% to 15%. Specifically, commercial hydrocracking catalysts such as FC-60 and FC-28 developed by Fushun Petrochemical Research Institute (FRIPP) of Sinopec can be selected, and can also be prepared according to common sense in the field as needed.

[0022] Furthermore, in the above-mentioned combined hydrogenation process for producing the reforming raw material in the maximum amount, the gaseous material obtained by gas-liquid separation of the reaction product of the first hydrocracking reaction zone is purified and compressed by a circulating hydrogen compressor to obtain circulating hydrogen, which can enter the diesel hydrogenation reaction zone, the hydrocracking pretreatment reaction zone, the first hydrocracking reaction zone, and the second hydrocracking reaction zone for use. Generally, the purification treatment includes removing hydrogen sulfide from the gaseous material, and the specific purification treatment process can adopt any one of the existing processes for removing hydrogen sulfide.

[0023] Furthermore, in the combined hydrogenation process for producing the reforming feedstock in the maximum amount, the reaction conditions of the first hydrocracking reaction zone are generally as follows: reaction pressure 5.0-19.0 MPa, preferably 12.0-18.0 MPa, average reaction temperature 300-450°C, preferably 350-420°C, volume space velocity 0.2-3.0 h -1 , preferably 0.6 to 1.5h -1 , the volume ratio of hydrogen to oil is 600~2000.

[0024] Further, in the above-mentioned combined hydrogenation process for the maximum production of reforming raw materials, at least one hydrocracking reactor is set in the second-stage hydrocracking reaction zone, and at least one hydrocracking catalyst is contained in the hydrocracking reactor. The hydrocracking catalyst includes a hydrogenation component and a carrier. The hydrogenation component can generally be one or more of group VI, group VII or group VIII metal elements, preferably two or more of Co, Mo, Ni, and W; the carrier includes at least one of β molecular sieve, modified β molecular sieve, alumina, and amorphous silicon aluminum. In general, based on the weight of the catalyst, the content of the hydrogenation component calculated as oxide is 18% to 40%. The content of β molecular sieve in the catalyst is 5% to 55%, preferably 8% to 18%. Specifically, commercial hydrocracking catalysts such as FC-86 and FC-32 developed by Fushun Petrochemical Research Institute (FRIPP) of Sinopec can be selected, and can also be prepared according to common sense in the field as needed.

[0025] Furthermore, in the combined hydrogenation process for maximizing the production of reforming feedstock, the splitting temperature of the light cycle oil and the heavy cycle oil in step (4) is 80 to 300°C, preferably 100 to 180°C.

[0026] Furthermore, in the combined hydrogenation process for producing the reforming feedstock in the maximum amount, the heavy fraction in step (4) enters the reactor through the feed port in the middle and lower part of the reactor shell in the hydrocracking pretreatment reaction zone, and the reactor volume below the feed port accounts for 10% to 80% of the total reactor volume, preferably 25% to 50%. Taking downflow feeding as an example, according to the flow direction of the liquid phase material, the wax oil feedstock enters the reactor through the feed port at the top of the reactor, and the heavy fraction enters the reactor through the feed port in the middle and lower part of the reactor shell.

[0027] Furthermore, in the combined hydrogenation process for producing the reforming feedstock in the maximum amount, the reaction conditions of the second-stage hydrocracking reaction zone are generally as follows: reaction pressure 6.0-22.0 MPa, preferably 10-20.0 MPa, average reaction temperature 200-410°C, preferably 340-380°C, volume space velocity 0.2-8.0 h -1 , preferably 0.5~2.0h -1 , the volume ratio of hydrogen to oil is 600~1600.

[0028] A second aspect of the present invention provides a combined hydrogenation system for maximizing the production of reforming feedstock, the processing system comprising:

[0029] A diesel hydrogenation reaction zone, which is used to receive high aromatic diesel feedstock and hydrogen, and obtain hydrogenated diesel after reaction;

[0030] A fractionation unit A, which is used to receive the hydrogenated diesel from the diesel hydrogenation reaction zone and obtain light hydrogenated diesel and heavy hydrogenated diesel after separation;

[0031] A hydrocracking pretreatment reaction zone, which is used to receive wax oil feedstock and hydrogen, and obtain hydrogenated wax oil after the reaction is completed;

[0032] A first hydrocracking reaction zone, which is used to receive hydrogen, hydrogenated wax oil from the hydrocracking pretreatment reaction zone, and heavy hydrogenated diesel from the fractionation unit A to obtain a reaction product;

[0033] The gas-liquid separation unit is used to receive the reaction products from the first hydrocracking reaction zone and obtain gas phase materials and liquid phase materials after separation.

[0034] A fractionation unit B, which is used to receive the liquid phase material from the gas-liquid separation unit and obtain gas, naphtha and heavy fractions after separation;

[0035] The second-stage hydrocracking reaction zone is used to receive hydrogen, light hydrogenated diesel from fractionation unit A, and heavy fraction from fractionation unit B to obtain a reaction product;

[0036] The fractionation unit C is used to receive the reaction products from the second-stage hydrocracking reaction zone, and obtain light cycle oil and heavy cycle oil after separation, wherein the light cycle oil is connected to the feed port of the fractionation unit B via a pipeline, and the heavy cycle oil is connected to the hydrocracking pretreatment reaction zone via a pipeline, preferably entering the reactor through the feed port in the middle and lower part of the reactor shell in the hydrocracking pretreatment reaction zone, and the reactor volume below the feed port accounts for 10% to 80% of the total reactor volume, preferably 25 to 50%. Taking downflow feeding as an example, according to the flow direction of the liquid phase material, the wax oil raw material enters the reactor through the feed port at the top of the reactor, and the heavy fraction enters the reactor through the feed port in the middle and lower part of the reactor shell.

[0037] Furthermore, in the above-mentioned combined hydrogenation system for producing the reforming feedstock in maximum quantity, at least one hydrogenation reactor is provided in the diesel hydrogenation reaction zone.

[0038] Furthermore, in the above-mentioned combined hydrogenation system for producing the reforming feedstock in maximum quantity, at least one hydrogenation reactor is provided in the hydrocracking pretreatment reaction zone.

[0039] Furthermore, in the combined hydrogenation system for producing the reforming feedstock in the maximum amount, the fractionation unit A, the fractionation unit B, and the fractionation unit C may be a fractionation tower or other equipment having different separation functions according to the distillation range.

[0040] Furthermore, in the above-mentioned combined hydrogenation system for producing the reforming raw material in the largest amount, the gas-liquid separation unit generally includes a hot high-pressure separator, a hot low-pressure separator, a cold high-pressure separator and a cold low-pressure separator according to actual conditions. The connection method between the separators and between the separators and the distillation tower can adopt the existing connection method in the field, and technical personnel in this field can freely choose according to actual needs.

[0041] Furthermore, in the above-mentioned combined hydrogenation system for producing the reforming feedstock in maximum quantity, at least one hydrocracking reactor is provided in the first-stage hydrocracking reaction zone.

[0042] Furthermore, in the combined hydrogenation system for producing the reforming feedstock in the maximum amount, at least one hydrocracking reactor is provided in the second-stage hydrocracking reaction zone.

[0043] Furthermore, the above-mentioned combined hydrogenation system for producing reforming raw materials in maximum quantity also includes a purification unit, which is used to receive the gaseous material from the gas-liquid separation unit and obtain purified hydrogen after treatment. The purified hydrogen can enter the diesel hydrogenation reaction zone, the hydrocracking pretreatment reaction zone, the first-stage hydrocracking reaction zone, and the second-stage hydrocracking reaction zone after being compressed by the circulating hydrogen compressor. Generally, the purification unit is used to remove hydrogen sulfide from the gaseous material. The specific purification unit can adopt any one of the existing processes for removing hydrogen sulfide.

[0044] Compared with the prior art, the combined hydrogenation process and system for producing the maximum amount of reforming raw materials provided by the present invention has the following advantages:

[0045] (1) The present invention introduces the light diesel fraction and the heavy diesel fraction separated after hydrogenation of the high aromatic diesel feedstock into the second-stage hydrocracking reaction zone and the first-stage hydrocracking reaction zone respectively, and utilizes the dynamic inhibition and guiding phenomenon of the hydrocracking reaction to greatly increase the concentration of the heavy diesel fraction in the first-stage hydrocracking reaction zone, inhibit the conversion of the tail oil fraction to the heavy diesel fraction, and promote the efficient conversion of the heavy diesel fraction to naphtha and light diesel fraction; in the conventional second-stage hydrocracking reactor, the heavy diesel fraction has a large polarity and is preferentially adsorbed on the catalyst to be converted into a light diesel component, reducing the reaction rate of light diesel to heavy naphtha, and the generated light diesel fraction does not enter the product distillation range, so it will circulate into the second-stage hydrocracking zone, which is prone to over-cracking, resulting in an increase in light naphtha and gas products, and then resulting in a decrease in the yield of heavy naphtha and liquefied products. In the process of the present invention, the concentration of the light diesel fraction in the second-stage hydrocracking reaction zone is greatly increased, inhibiting the conversion of the heavy diesel fraction to the light diesel fraction and promoting the efficient conversion of the light diesel fraction to naphtha. The reaction difficulty of light diesel fraction requires significantly lower catalyst activity, allowing the unit to achieve efficient conversion at a lower reaction temperature.

[0046] (2) The sulfur content in the feedstock of the second hydrocracking reaction zone is extremely low. As the reaction proceeds, the catalyst exhibits a "sulfur loss" problem. Therefore, the "sulfur loss" problem will cause the catalyst activity to gradually decrease during the second-stage hydrocracking reaction, resulting in a decrease in conversion rate. The present invention introduces the light diesel refined product oil after refining high-aromatic low-quality diesel into the second hydrocracking reaction zone. The sulfur content of the light diesel refined product oil is approximately between 50 and 200 ppm, which not only plays a role in sulfur supplementation for the second-stage hydrocracking catalyst but also does not affect the product properties of the second-stage hydrocracking.

[0047] (3) The present invention realizes high-aromatic low-quality high-economic hydrogenation conversion by setting a reasonable reaction path. First, the reaction temperature of the diesel hydrogenation reaction zone is lowered to provide more favorable thermodynamic conditions for reactions such as aromatic saturation of high-aromatic low-quality diesel. At the same time, the unconverted oil from the second-stage hydrocracking is introduced into the hydrogenation pretreatment reactor, avoiding the accumulation of aromatics in the circulating oil of the conventional second-stage hydrocracking process, which leads to the deterioration of the selectivity of the second-stage hydrocracking. Secondly, the high-aromatic low-quality diesel feedstock is completely converted into high-value-added products such as light naphtha and heavy naphtha, truly realizing the reduction of the diesel-to-gasoline ratio to zero.

[0048] (4) The aromatics in the high-aromatic low-quality diesel feedstock are efficiently retained in the heavy naphtha fraction, so that the aromatic potential content of the heavy naphtha product is significantly increased compared with the aromatic potential content of the heavy naphtha product produced by the conventional two-stage hydrocracking process. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a schematic diagram of the combined hydrogenation process and system for producing the reforming raw material in the maximum amount according to the present invention.

[0050] The main drawings are described as follows:

[0051] Figure 1 In: 1-high aromatic diesel feedstock; 2-diesel hydrogenation reaction zone; 3-hydrogenated diesel; 4-wax oil feedstock; 5-hydrocracking pretreatment reactor zone; 6-hydrogenated wax oil; 7-gas-liquid separator; 8-gas phase material; 9-circulating hydrogen; 10-new hydrogen; 11-liquid phase material; 12-first stage hydrocracking reaction zone; 13-reaction product of first stage hydrocracking reaction zone; 14-fractionator B; 15-gas; 16-naphtha; 17-heavy fraction; 18-second stage hydrocracking reaction zone; 19-reaction product of second stage hydrocracking reaction zone; 20-fractionator C; 21-light cycle oil; 22-heavy cycle oil; 23-fractionator A; 24-light hydrogenated diesel; 25-heavy hydrogenated diesel.

[0052] Figure 2 It is a schematic diagram of the combined process flow of existing conventional wax oil hydrocracking and diesel hydrorefining. DETAILED DESCRIPTION

[0053] The technical scheme and technical effects of the present invention are further described below in conjunction with the accompanying drawings and specific implementation methods.

[0054] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0055] In this document, for the convenience of description, spatial relative terms such as "below", "below", "down", "above", "above", "upper", etc. may be used to describe the relationship between one element or feature and another element or feature in the accompanying drawings. It should be understood that the spatial relative terms are intended to include different directions of objects in use or operation in addition to the directions drawn in the drawings. For example, if the object in the figure is turned over, the elements described as being "below" or "below" other elements or features will be oriented "above" the elements or features. Therefore, the exemplary term "below" can include both below and above directions. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatial relative terms used in this document should be interpreted accordingly.

[0056] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable.

[0057]

[0043] All numerical values ​​for parameters (eg, amounts or conditions) herein are to be understood as being modified in all instances by the term "about", whether or not "about" actually appears before the numerical value.

[0058] The properties of the raw oil used in the examples of the present invention and the comparative examples are shown in Table 1.

[0059] Table 1 Raw oil properties

[0060]

[0061] like Figure 1As shown, the combined hydrogenation process for producing reforming raw materials in the largest amount according to the present invention is as follows: a high aromatic diesel feedstock 1 and new hydrogen 10 enter a diesel hydrogenation reaction zone 2 for reaction, and after the reaction, hydrogenated diesel 3 is obtained. The hydrogenated diesel 3 enters a fractionating tower A for separation to obtain light hydrogenated diesel 24 and heavy hydrogenated diesel 25; a wax oil feedstock 4 and new hydrogen 10 enter a hydrocracking pretreatment reaction zone 5 from a top feed port, and after the reaction, hydrogenated wax oil 6 is obtained. The hydrogenated wax oil 6, the heavy hydrogenated diesel 25 and the new hydrogen 10 enter a first hydrocracking reaction zone 12 for reaction, and a reaction effluent 13 obtained after the reaction enters a gas-liquid separator 7 for separation to obtain a gas phase material 8 and a liquid phase material 11. The gas phase material 8 is treated and compressed by a circulating hydrogen compressor to obtain circulating hydrogen 9. The circulating hydrogen 9 can be further circulated back to the diesel hydrogenation reaction zone, the hydrocracking pretreatment reaction zone, the first hydrocracking reaction zone, The two-stage hydrocracking reaction zone is used, and the liquid phase material 11 enters the fractionation tower B14 for separation to obtain gas 15, naphtha 16 (naphtha can be further separated into light naphtha and heavy naphtha as needed, which is not specifically drawn in the figure) and heavy fraction 17, wherein the heavy fraction 17 and the light hydrogenated diesel 24 enter the two-stage hydrocracking reaction zone together, and the reaction product 19 obtained after the reaction enters the fractionation tower C20 for separation to obtain light cycle oil 21 and heavy cycle oil 22, wherein the light cycle oil 21 is mixed with the liquid phase material 11 obtained by separating the reaction product of the first hydrocracking reaction zone for treatment; the heavy cycle oil 22 returns to the hydrocracking pretreatment reaction zone for treatment, preferably entering the reactor through the feed port in the lower middle part of the reactor shell in the hydrocracking pretreatment reaction zone, and the reactor volume below the feed port accounts for 10% to 80% of the total reactor volume, preferably 25 to 50%.

[0062] like Figure 2 As shown, the combined process of wax oil hydrocracking and diesel hydrofining in the conventional process is as follows: wax oil feedstock 1 and new hydrogen 15 enter the hydrocracking pretreatment reaction zone 2, the pretreatment reaction product 3 obtained after the reaction enters the first hydrocracking reaction zone 4, and reacts in the presence of new hydrogen 15. After the reaction is completed, the reaction product 16 obtained enters the wax oil gas-liquid separator 5 for separation to obtain gas phase material 13 and liquid phase material 6. The gas phase material 13 is treated and compressed by the circulating hydrogen compressor 14 to obtain circulating hydrogen. The circulating hydrogen can be further recycled to the hydrocracking pretreatment reaction zone 2, the first hydrocracking reaction zone 4, and the second hydrocracking reaction zone 11 for use. The liquid phase material 6 enters the wax oil fractionation tower 7, and after separation, the first gas 8, the first naphtha 9 (including light naphtha and heavy naphtha), and the unconverted oil 10 are obtained. The unconverted oil 10 enters the second hydrocracking reaction zone 11 for reaction, and the second stage hydrocracking product 12 obtained after the reaction enters the wax oil fractionation tower 7 for treatment.

[0063] The diesel feedstock 27 and the new hydrogen 15 enter the diesel hydrotreating refining reactor 17 for reaction, and the reaction product 18 obtained by the reaction enters the diesel gas-liquid separator 19 for separation to obtain a gas phase stream 25 and a liquid phase stream 20, wherein the gas phase stream 25 is treated and compressed by the circulating hydrogen compressor 26 to obtain circulating hydrogen, and the circulating hydrogen can be further recycled back to the diesel hydrotreating refining reactor for use; the liquid phase stream 20 enters the diesel distillation tower 21 for separation to obtain a second gas product 22, a second naphtha 23 and refined diesel 24.

[0064] Example 1

[0065] use Figure 1 The combined hydrogenation process flow for the maximum production of reforming raw materials is shown in Table 1. The properties of the processed high aromatic diesel and wax oil raw materials are shown in Table 1. The diesel hydrogenation reactor is filled with FHUDS-6 and FF-12 diesel hydrorefining catalysts in the direction of liquid material flow, and the mass ratio of FHUDS-6 and FF-12 diesel hydrorefining catalysts is 90:10; the hydrocracking pretreatment reactor is filled with FF-24 and FF-56 pretreatment catalysts in the direction of liquid material flow, and the mass ratio of FF-24 and FF-56 pretreatment catalysts is 10:90; and the reactor volume below the lower feed port in the pretreatment reactor accounts for 50% of the total reactor volume, the first stage hydrocracking reactor is filled with FC-28 hydrocracking catalyst, and the second stage hydrocracking reactor is filled with FC-86 hydrocracking catalyst. The split temperature of light hydrocracking diesel and heavy hydrocracking diesel is 360℃, and the split temperature of light cycle oil and heavy cycle oil is 180℃. The reaction conditions of the diesel hydrogenation reaction zone are: reaction pressure 5.0 MPa, reaction temperature 380°C, volume space velocity 0.5 h -1 , the hydrogen-to-oil volume ratio is 1200; the reaction conditions of the hydrocracking pretreatment reaction zone are: reaction pressure is 10.0 MPa, reaction temperature is 390℃, volume space velocity is 1.8h -1 , the hydrogen-oil volume ratio is 1600; the reaction conditions of the first hydrocracking reaction zone are: reaction pressure 18.0MPa, average reaction temperature 400℃, volume space velocity 1.0h -1 , the hydrogen-oil volume ratio is 1500; the reaction conditions of the second-stage hydrocracking reaction zone are: reaction pressure 18.0MPa, average reaction temperature 340℃, volume space velocity 2.0h -1 , the hydrogen to oil volume ratio is 1200, and the reaction results are shown in Table 2.

[0066] Example 2

[0067] use Figure 1The combined hydrogenation process flow for the maximum production of reforming raw materials is shown in Table 1. The properties of the processed high-aromatic diesel and wax oil raw materials are shown in Table 1. The diesel hydrogenation reactor is loaded with FHUDS-8 diesel hydrorefining catalyst, the hydrocracking pretreatment reactor is loaded with FF-66 pretreatment catalyst, and the reactor volume below the lower feed inlet in the pretreatment reactor accounts for 35% of the total reactor volume. The first-stage hydrocracking reaction zone is loaded with FC-14 hydrocracking catalyst, and the second-stage hydrocracking reactor is loaded with FC-76 hydrocracking catalyst. The splitting temperature of light hydrocracking diesel and heavy hydrocracking diesel is 280°C, and the splitting temperature of light cycle oil and heavy cycle oil is 100°C. The reaction conditions of the diesel hydrogenation reaction zone: reaction pressure is 10.0 MPa, reaction temperature is 320°C, volume space velocity is 2.5h -1 , the hydrogen-to-oil volume ratio is 1800; the reaction conditions of the hydrocracking pretreatment reaction zone are: reaction pressure is 16.0 MPa, reaction temperature is 330℃, volume space velocity is 0.7h -1 , the hydrogen-oil volume ratio is 800; the reaction conditions of the first hydrocracking reaction zone are: reaction pressure 16.0MPa, average reaction temperature 350℃, volume space velocity 1.2h -1 , the hydrogen-oil volume ratio is 1000; the reaction conditions of the second-stage hydrocracking reaction zone are: reaction pressure 16.0MPa, average reaction temperature 380℃, volume space velocity 1.0h -1 , the hydrogen to oil volume ratio is 1600, and the reaction results are shown in Table 2.

[0068] Example 3

[0069] use Figure 1The combined hydrogenation process flow for the maximum production of reforming raw materials is shown in Table 1. The properties of the processed high aromatic diesel and wax oil raw materials are shown in Table 1. The diesel hydrogenation reactor is loaded with FHUDS-3 diesel hydrorefining catalyst, and the hydrocracking pretreatment reactor is sequentially loaded with FF-66 and FTX pretreatment catalysts according to the flow direction of the liquid phase material. The mass ratio of FF-66 and FTX pretreatment catalysts is 75:25; and the reactor volume below the lower feed port in the hydrocracking pretreatment reactor accounts for 25% of the total reactor volume. The first-stage hydrocracking reactor is filled with a self-made hydrocracking catalyst with a pore volume of 0.36 mL / g, and the composition of Ni metal oxide and Co metal oxide loadings are 3.5wt% and 19.5wt% respectively (the total metal loading is 23.0wt%), and the β molecular sieve content is 9wt%. The second-stage hydrocracking reactor is filled with a self-made hydrocracking catalyst with a pore volume of 0.28 mL / g. The Ni metal oxide and W metal oxide loadings are 2.5 wt% and 18.0 wt% respectively (the total metal loading is 20.5 wt%), and the Y molecular sieve content is 9 wt%. The split temperature of light hydrogenated diesel and heavy hydrogenated diesel is 300 ° C, and the split temperature of light cycle oil and heavy cycle oil is 125 ° C. The reaction conditions of the diesel hydrogenation reaction zone are: reaction pressure of 7.0 MPa, reaction temperature of 360 ° C, volume space velocity of 1.2 h -1 , the hydrogen-oil volume ratio is 1600; the reaction conditions of the hydrocracking pretreatment reaction zone are: reaction pressure is 15.0MPa, reaction temperature is 400℃, volume space velocity is 1.7h -1 , the hydrogen-oil volume ratio is 1500; the reaction conditions of the first hydrocracking reaction zone are: reaction pressure 15.5MPa, average reaction temperature 380℃, volume space velocity 0.8h -1 , the hydrogen-oil volume ratio is 2000; the reaction conditions of the second-stage hydrocracking reaction zone are: reaction pressure 15.5MPa, average reaction temperature 355℃, volume space velocity 1.8h -1 , the hydrogen to oil volume ratio is 1300, and the reaction results are shown in Table 2.

[0070] Example 4

[0071] use Figure 1The combined hydrogenation process flow for the maximum production of reforming raw materials is shown in the figure, in which the heavy cycle oil and the wax oil raw material enter the pretreatment reactor from the top feed port of the hydrocracking pretreatment reactor, and the properties of the processed high aromatic diesel and wax oil raw materials are shown in Table 1. The diesel hydrogenation reactor is loaded with FHUDS-3 diesel hydrorefining catalyst, and the hydrocracking pretreatment reactor is sequentially loaded with FF-66 and FTX pretreatment catalysts according to the flow direction of the liquid phase material, and the mass ratio of FF-66 and FTX pretreatment catalysts is 75:25; the first-stage hydrocracking reactor is filled with a self-made hydrocracking catalyst, with a pore volume of 0.36mL / g, and the composition of Ni metal oxide and Co metal oxide loadings are 3.5wt% and 19.5wt% respectively (the total metal loading is 23.0wt%), and the β molecular sieve content is 9wt%. The second-stage hydrocracking reactor is filled with a self-made hydrocracking catalyst with a pore volume of 0.28 mL / g. The Ni metal oxide and W metal oxide loadings are 2.5 wt% and 18.0 wt% respectively (the total metal loading is 20.5 wt%), and the Y molecular sieve content is 9 wt%. The split temperature of light hydrogenated diesel and heavy hydrogenated diesel is 300 ° C, and the split temperature of light cycle oil and heavy cycle oil is 125 ° C. The reaction conditions of the diesel hydrogenation reaction zone are: reaction pressure of 7.0 MPa, reaction temperature of 360 ° C, volume space velocity of 1.2 h -1 , the hydrogen-to-oil volume ratio is 1600; the reaction conditions of the hydrocracking pretreatment reaction zone are: reaction pressure is 15.0 MPa, reaction temperature is 400℃, volume space velocity is 1.7h -1 , the hydrogen-oil volume ratio is 1500; the reaction conditions of the first hydrocracking reaction zone are: reaction pressure 15.5MPa, average reaction temperature 380℃, volume space velocity 0.8h -1 , the hydrogen-oil volume ratio is 2000; the reaction conditions of the second-stage hydrocracking reaction zone are: reaction pressure 15.5MPa, average reaction temperature 355℃, volume space velocity 1.8h -1 , the hydrogen to oil volume ratio is 1300, and the reaction results are shown in Table 3.

[0072] Comparative Example 1

[0073] use Figure 2The process flow and the properties of the processed high-aromatic low-quality diesel and wax oil raw materials are shown in Table 1. The diesel hydrogenation reactor is filled with FHUDS-6 and FF-12 diesel hydrogenation refining catalysts in the direction of liquid material flow, and the mass ratio of FHUDS-6 and FF-12 diesel hydrogenation refining catalysts is 90:10; the hydrocracking pretreatment reactor is filled with FF-24 and FF-56 pretreatment catalysts in the direction of liquid material flow, and the mass ratio of FF-24 and FF-56 pretreatment catalysts is 10:90; the first-stage hydrocracking reactor is filled with FC-28 hydrocracking catalyst, and the second-stage hydrocracking reactor is filled with FC-86 hydrocracking catalyst. The reaction conditions of the diesel hydrogenation reaction zone are: reaction pressure of 5.0 MPa, reaction temperature of 380 ° C, volume space velocity of 0.5h -1 , the hydrogen-oil volume ratio is 1200; the reaction conditions of the hydrocracking pretreatment reaction zone are: reaction pressure is 10.0MPa, reaction temperature is 390℃, volume space velocity is 1.8h -1 , the hydrogen-oil volume ratio is 1600; the reaction conditions of the first hydrocracking reaction zone are: reaction pressure 18.0MPa, average reaction temperature 400℃, volume space velocity 1.0h -1 , the hydrogen-oil volume ratio is 1500; the reaction conditions of the second-stage hydrocracking reaction zone are: reaction pressure 18.0MPa, average reaction temperature 340℃, volume space velocity 2.0h -1 , the hydrogen to oil volume ratio is 1200, and the reaction results are shown in Table 3.

[0074] Comparative Example 2

[0075] use Figure 2 The process flow and the properties of the processed high-aromatic low-quality diesel and wax oil raw materials are shown in Table 1. The diesel hydrofining reactor is loaded with FHUDS-8 diesel hydrofining catalyst, the hydrocracking pretreatment reactor is loaded with FF-66 pretreatment catalyst, the first-stage hydrocracking reactor is loaded with FC-14 hydrocracking catalyst, and the second-stage hydrocracking reactor is loaded with FC-76 hydrocracking catalyst. The reaction conditions of the diesel hydrogenation reaction zone are: reaction pressure of 10.0 MPa, reaction temperature of 320℃, volume space velocity of 2.5h -1 , the hydrogen-to-oil volume ratio is 1800; the reaction conditions of the hydrocracking pretreatment reaction zone are: reaction pressure is 16.0 MPa, reaction temperature is 330℃, volume space velocity is 0.7h -1 , the hydrogen-oil volume ratio is 800; the reaction conditions of the first hydrocracking reaction zone are: reaction pressure 16.0MPa, average reaction temperature 350℃, volume space velocity 1.2h -1 , the hydrogen-oil volume ratio is 1000; the reaction conditions of the second hydrocracking reaction zone are: reaction pressure 16.0MPa, average reaction temperature 380℃, volume space velocity 1.0h-1 , the hydrogen to oil volume ratio is 1600, and the reaction results are shown in Table 3.

[0076] Comparative Example 3

[0077] use Figure 2 The process flow and the properties of the processed high-aromatic low-quality diesel and wax oil raw materials are shown in Table 1. The diesel hydrofining reactor is loaded with FHUDS-3 diesel hydrofining catalyst, and the hydrocracking pretreatment reactor is graded according to the flow direction of the liquid phase material. The mass ratio of FF-66 and FTX pretreatment catalyst is 75:25; the first-stage hydrocracking reactor is filled with a homemade hydrocracking catalyst with a pore volume of 0.36mL / g, and the composition of Ni metal oxide and Co metal oxide loadings are 3.5wt% and 19.5wt% respectively (the total metal loading is 23.0wt%), and the β molecular sieve content is 9wt%. The second-stage hydrocracking reactor is filled with a homemade hydrocracking catalyst with a pore volume of 0.28mL / g, and the composition of Ni metal oxide and W metal oxide loadings are 2.5wt% and 18.0wt% respectively (the total metal loading is 20.5wt%), and the Y molecular sieve content is 9wt%. The reaction conditions of the diesel hydrogenation reaction zone are: reaction pressure 7.0 MPa, reaction temperature 360°C, volume space velocity 1.2 h -1 , the hydrogen-to-oil volume ratio is 1600; the reaction conditions of the hydrocracking pretreatment reaction zone are: reaction pressure is 15.0 MPa, reaction temperature is 400℃, volume space velocity is 1.7h -1 , the hydrogen-oil volume ratio is 1500; the reaction conditions of the first hydrocracking reaction zone are: reaction pressure 15.5MPa, average reaction temperature 380℃, volume space velocity 0.8h -1 , the hydrogen-oil volume ratio is 2000; the reaction conditions of the second-stage hydrocracking reaction zone are: reaction pressure 15.5MPa, average reaction temperature 355℃, volume space velocity 1.8h -1 , the hydrogen to oil volume ratio is 1300, and the reaction results are shown in Table 3.

[0078] Table 2 Reaction results of the examples

[0079]

[0080] Table 3 Comparative Example Reaction Results

[0081]

[0082] In the comparative example, the light naphtha yield, heavy naphtha yield and diesel yield are calculated based on the total of the products and raw materials of the two sets of equipment.

[0083] The experimental results of the above embodiments and comparative examples show that the yield of heavy naphtha is significantly increased under the process flow of the two-stage cracking and high aromatic low-quality diesel hydrogenation combined treatment of the maximum production of reforming feed of the present invention, and the activity of the hydrocracking catalyst is stable as the operation cycle is extended. The diesel-to-gasoline ratio is reduced to zero and the aromatic potential content of heavy naphtha is also significantly improved, which brings significant economic benefits to the refinery.

Claims

1. A combined hydrogenation process for producing a maximum amount of reforming feedstock, comprising the following steps: (1) High aromatic diesel feedstock and hydrogen enter the diesel hydrogenation reaction zone and react under the action of a diesel hydrogenation catalyst to obtain hydrogenated diesel. The hydrogenated diesel is fractionated to obtain a light hydrogenated diesel fraction and a heavy hydrogenated diesel fraction. The splitting temperature of the light hydrogenated diesel fraction and the heavy hydrogenated diesel fraction is 180 to 400°C. The aromatic content of the high aromatic diesel feedstock is 30 wt% to 95 wt%. (2) The wax oil feedstock and hydrogen enter the hydrocracking pretreatment reaction zone and react under the action of the hydrogenation pretreatment catalyst to obtain hydrogenated wax oil; (3) the heavy hydrogenated diesel fraction obtained in step (1) and the hydrogenated wax oil obtained in step (2) are fed together into a first hydrocracking reaction zone to react under the action of hydrogen and a hydrocracking catalyst, and the reaction products are separated into gas and liquid to obtain gas phase material and liquid phase material, and the liquid phase material is fractionated to obtain gas, naphtha and heavy fraction; (4) The heavy fraction obtained in step (3) and the light hydrotreated diesel fraction obtained in step (1) enter the second-stage hydrocracking reaction zone, react under the action of hydrogen and a hydrocracking catalyst, and separate the reaction products to obtain light cycle oil and heavy cycle oil, wherein the light cycle oil is mixed with the liquid phase material separated from the reaction products in the first-stage hydrocracking reaction zone and treated together; the heavy cycle oil returns to the hydrocracking pretreatment reaction zone for treatment.

2. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The distillation range of high aromatic diesel feedstock is 200℃~450℃.

3. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The distillation range of high aromatic diesel feedstock is 200℃~450℃.

4. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The aromatic content of high aromatic diesel feedstock is 50wt% to 90wt%.

5. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The high aromatic diesel feedstock is selected from catalytic diesel and coking diesel or a mixture of several of them.

6. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The splitting temperature of the light hydrogenated diesel fraction and the heavy hydrogenated diesel fraction is 280-360°C.

7. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The reaction conditions of the diesel hydrogenation reaction zone are as follows: reaction pressure is 2.0-19.0 MPa, reaction temperature is 280-420°C, volume space velocity is 0.1-15.0h -1 , the volume ratio of hydrogen to oil is 100~2500.

8. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The reaction conditions of the diesel hydrogenation reaction zone are as follows: reaction pressure is 5.0-10.0 MPa, reaction temperature is 310-380°C, volume space velocity is 0.2-2.5 h -1 , the volume ratio of hydrogen to oil is 100~2500.

9. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The wax oil raw material is one or more of atmospheric wax oil, vacuum wax oil and fluidized bed wax oil.

10. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The wax oil raw material is deep drawn wax oil.

11. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The reaction conditions of the hydrocracking pretreatment reaction zone are: reaction pressure of 5.0-21.0 MPa, reaction temperature of 280-430°C, volume space velocity of 0.6-15.0 h -1 , the volume ratio of hydrogen to oil is 800~1800.

12. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The reaction conditions of the hydrocracking pretreatment reaction zone are: reaction pressure of 10.0-18.0 MPa, reaction temperature of 330-410°C, volume space velocity of 0.2-1.8 h -1 , the volume ratio of hydrogen to oil is 800~1800.

13. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The reaction conditions of the first hydrocracking reaction zone are: reaction pressure of 5.0-19.0 MPa, average reaction temperature of 300-450°C, volume space velocity of 0.2-3.0 h -1 , the volume ratio of hydrogen to oil is 600~2000.

14. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The reaction conditions of the first hydrocracking reaction zone are: reaction pressure of 12.0-18.0 MPa, average reaction temperature of 350-420°C, volume space velocity of 0.6-1.5 h -1 , the volume ratio of hydrogen to oil is 600~2000.

15. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: In step (4), the separation temperature of the light cycle oil and the heavy cycle oil is 80 to 300°C.

16. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: In step (4), the splitting temperature of the light cycle oil and the heavy cycle oil is 100 to 180°C.

17. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: In step (4), the heavy cycle oil enters the reactor through the feed inlet in the lower middle part of the reactor shell in the hydrocracking pretreatment reaction zone, and the volume of the reactor below the feed inlet accounts for 10% to 80% of the total volume of the reactor.

18. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: In step (4), the heavy cycle oil enters the reactor through the feed inlet in the lower middle part of the reactor shell in the hydrocracking pretreatment reaction zone, and the volume of the reactor below the feed inlet accounts for 25-50% of the total volume of the reactor.

19. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The reaction conditions of the second-stage hydrocracking reaction zone are: reaction pressure of 6.0-22.0 MPa, average reaction temperature of 200-410°C, volume space velocity of 0.2-8.0 h -1 , the volume ratio of hydrogen to oil is 600~1600.

20. The combined hydrogenation process for maximizing the production of reforming feedstock according to claim 1, characterized in that: The reaction conditions of the second-stage hydrocracking reaction zone are: reaction pressure of 10-20.0 MPa, average reaction temperature of 340-380°C, volume space velocity of 0.5-2.0 h -1 , the volume ratio of hydrogen to oil is 600~1600.

21. A combined hydrogenation system for maximizing the production of reforming feedstock, the combined hydrogenation system comprising: A diesel hydrogenation reaction zone, which is used to receive high aromatic diesel feedstock and hydrogen, and obtain hydrogenated diesel after reaction; A fractionation unit A, which is used to receive the hydrogenated diesel from the diesel hydrogenation reaction zone and obtain light hydrogenated diesel and heavy hydrogenated diesel after separation; A hydrocracking pretreatment reaction zone, which is used to receive wax oil feedstock and hydrogen, and obtain hydrogenated wax oil after the reaction is completed; A first hydrocracking reaction zone, which is used to receive hydrogen, hydrogenated wax oil from the hydrocracking pretreatment reaction zone, and heavy hydrogenated diesel from the fractionation unit A to obtain a reaction product; A gas-liquid separation unit, which is used to receive the reaction product from the first hydrocracking reaction zone and obtain gas phase material and liquid phase material after separation; A fractionation unit B, which is used to receive the liquid phase material from the gas-liquid separation unit and obtain gas, naphtha and heavy fractions after separation; The second-stage hydrocracking reaction zone is used to receive hydrogen, light hydrogenated diesel from fractionation unit A, and heavy fraction from fractionation unit B to obtain a reaction product; The fractionation unit C is used to receive the reaction products from the second-stage hydrocracking reaction zone, and obtain light cycle oil and heavy cycle oil after separation, wherein the light cycle oil is connected to the feed port of the fractionation unit B through a pipeline, and the heavy cycle oil is connected to the hydrocracking pretreatment reaction zone through a pipeline.

22. The combined hydrogenation system for maximizing the production of reforming feedstock according to claim 21, characterized in that: The heavy cycle oil enters the reactor through a pipeline through a feed port in the lower middle part of the reactor shell in the hydrocracking pretreatment reaction zone, and the reactor volume below the feed port accounts for 10% to 80% of the total reactor volume.

23. The combined hydrogenation system for maximizing the production of reforming feedstock according to claim 21, characterized in that: The heavy cycle oil enters the reactor through a pipeline through a feed port in the lower middle part of the reactor shell in the hydrocracking pretreatment reaction zone, and the reactor volume below the feed port accounts for 25-50% of the total reactor volume.

24. The combined hydrogenation system for maximizing the production of reforming feedstock according to claim 21, characterized in that: It also includes a purification unit, which is used to receive the gaseous material from the gas-liquid separation unit and obtain purified hydrogen after processing. The purified hydrogen is compressed by a circulating hydrogen compressor and then enters the diesel hydrogenation reaction zone, the hydrocracking pretreatment reaction zone, the first hydrocracking reaction zone, and the second hydrocracking reaction zone for use.

Images