A hydrocracking method for producing high-yield reforming materials

Abstract

The present invention relates to the technical field of heavy and low-quality wax oil processing, and discloses a hydrocracking method for producing high-yield reforming materials. The method comprises: introducing heavy and low-quality wax oil into a hydrorefining reaction zone I filled with a hydrorefining catalyst I to perform a first reaction to obtain a reaction effluent I; sequentially subjecting the reaction effluent I to gas-liquid separation and gas impurity removal to obtain a mixture I1; introducing the mixture I1 into a hydrorefining reaction zone II filled with a hydrorefining catalyst II to perform a second reaction to obtain a reaction effluent II; introducing the reaction effluent II into a hydrocracking reaction zone to perform a third reaction to obtain a reaction effluent III; separating the reaction effluent III to obtain a light naphtha fraction, a heavy naphtha fraction, and a tail oil fraction; and recycling the tail oil fraction to perform a second reaction. The method provided by the present invention can convert heavy and low-quality wax oil feedstock into heavy naphtha in maximum quantity.

Description

Technical Field

[0001] The present invention relates to the technical field of heavy and inferior wax oil processing, and in particular to a hydrocracking method for producing high-yield reforming materials. Background Art

[0002] In recent years, domestic apparent consumption of aromatics has been growing annually. To meet this demand, refinery hydrocracking units have been gradually increasing their processing depth to produce more heavy naphtha, which can be used as reforming feed. At the same time, as crude oil production has grown annually, the supply of high-quality and conventional crude oil has been decreasing and prices have been rising. Meanwhile, the supply of heavy and low-quality crude oil has been increasing annually, and prices have been relatively low. While heavy and low-quality crude oil is difficult to process, developing hydrocracking technology that can directly convert this inexpensive and abundant heavy and low-quality crude into a high-value reforming feed with strong market demand offers the potential for significant economic returns.

[0003] To meet the demand for deep conversion of heavy and inferior crude oil, delayed coking technology for lightening heavy oil, as well as slurry bed, ebullating bed, and suspension bed heavy oil hydrocracking technologies have been further developed in recent years. However, heavy oil delayed coking, slurry bed, ebullating bed, and suspension bed heavy oil hydrocracking technologies will produce a considerable proportion of wax oil fractions or heavy distillate oils during the process of lightening residual oil or heavy oil. Compared with the wax oil raw materials obtained by conventional crude oil fractionation, the heavy and inferior wax oil fractions or wide-fraction heavy and inferior wax oils obtained by lightening heavy and inferior crude oil have the characteristics of high density, high dry point, high sulfur content, high nitrogen content, and high carbon residue value. The density at 20°C is about 0.94g / cm 3 -0.99g / cm 3 The distillation dry point is about 600℃-720℃, the aromatic content is about 60%-85%, the sulfur content is about 1.5%-3.5%, the nitrogen content is about 1800μg / g-5000μg / g, the residual carbon value is about 1.5%-5.0%, etc. It is difficult to realize the conversion of heavy and inferior wax oil raw materials into light products and high-value products under the existing hydrocracking technology.

[0004] CN104611051A and CN103102957A disclose a two-stage hydrocracking method for high-drying-point heavy distillate oil. This method uses a two-stage denitrogenation method to process heavy straight-run wax oil raw materials with low nitrogen content but complex nitrogen-containing compound structures to produce conventional hydrocracking products.

[0005] CN104611053A discloses a high-drying-point raw material hydrocracking process, which adopts a two-stage denitrification method and arranges a gas-liquid countercurrent contact reaction zone and a gas-liquid separation zone in one stage to realize the processing of heavy and inferior deep-drawn wax oil raw materials with a final distillation point of about 580°C-620°C to produce chemical raw materials and conventional clean fuel oil.

[0006] CN1940030A discloses a two-stage hydrocracking method for producing more diesel from high-nitrogen heavy crude oil. The method realizes the conversion of high-nitrogen heavy low-quality raw materials into high-quality diesel products by partitioning the feed and setting a hot flash tank between the first refining stage and the second refining stage.

[0007] CN103059944A discloses a hydrocracking process for processing inferior raw materials. The method adopts a two-stage hydrocracking process equipped with two fractionation units to convert inferior raw oil with a nitrogen content greater than 2000 μg / g and a final distillation point of approximately 450°C-620°C into chemical raw materials and conventional clean fuel oil.

[0008] CN103443251A discloses a hydrocracking method with feed bottom logistics treatment, which realizes the conversion of heavy and inferior raw materials by adopting a combined process of adsorption denitrogenation and removal of polynuclear aromatics and hydrocracking.

[0009] CN104560169A discloses a hydrocracking method for producing heavy naphtha from a high-nitrogen feedstock. The method realizes the conversion of the high-nitrogen feedstock into a heavy naphtha product by setting a second tail oil fraction conversion reaction zone.

[0010] CN104611010A and CN104611016A disclose a two-stage hydrocracking method for high-drying-point raw materials. This method realizes the conversion of heavy and low-quality raw materials with a final distillation point of 580°C-620°C into conventional clean oil products and chemical raw materials by setting up a gas-liquid separation method in the second-stage refining reaction zone equipped with a bulk catalyst.

[0011] CN104611022A discloses a two-stage hydrocracking method for inferior heavy distillate oil. The method achieves the conversion of heavy and inferior raw materials with a nitrogen content of 2000μg / g-15000μg / g and a final distillation point of 470°C-550°C into conventional clean fuels and chemical fuels by loading refined catalysts with different average pore sizes in two-stage hydrorefining reaction zones.

[0012] CN1508232A discloses a full-cycle hydrocracking process, which achieves the conversion of heavy crude oil with a distillation range of 200°C-600°C by adopting a hydrocracking method of first cracking and then refining, and using two or more high-nitrogen-resistant hydrocracking catalysts in the cracking reaction zone.

[0013] However, there are two main problems in the above existing hydrocracking technology:

[0014] On the one hand, the raw materials processed by existing hydrocracking technology are not of low quality and are difficult to match the processing needs of low-quality raw materials; on the other hand, existing hydrocracking products mainly focus on processing conventional raw materials to produce clean fuel oil (diesel and jet fuel) and some chemical raw materials. There is little research on the development of reforming material hydrocracking technology for direct maximum production of heavy and low-quality wax oil.

[0015] To this end, the development of hydrocracking technology for the maximum production of heavy naphtha from heavy and inferior wax oil raw materials is of great significance for refining and chemical companies to achieve high-value conversion of heavy and inferior crude oil. Summary of the Invention

[0016] The purpose of the present invention is to solve the problems of difficulty in converting heavy and inferior wax oil raw materials and relatively single product routes in the prior art, and to provide a method for producing heavy naphtha in maximum quantity from heavy and inferior wax oil.

[0017] To achieve the above-mentioned object, the present invention provides a hydrocracking method for producing a high-yield reformate. The method is carried out in a device comprising a hydrofining reaction zone and a hydrocracking reaction zone, wherein the hydrofining reaction zone comprises a hydrofining reaction zone I and a hydrofining reaction zone II. The method comprises:

[0018] (1) introducing the heavy low-quality wax oil into the hydrotreating reaction zone I filled with a hydrotreating catalyst I to perform a first reaction to obtain a reaction effluent I; and sequentially performing gas-liquid separation and gas impurity removal on the reaction effluent I to obtain a mixture I1;

[0019] (2) introducing the mixture I1 into the hydrotreating reaction zone II filled with a hydrotreating catalyst II to perform a second reaction to obtain a reaction effluent II;

[0020] (3) introducing the reaction effluent II into the hydrocracking reaction zone filled with a hydrocracking catalyst to perform a third reaction to obtain a reaction effluent III;

[0021] (4) separating the reaction effluent III to obtain a light naphtha fraction, a heavy naphtha fraction, and a tail oil fraction; and recycling the tail oil fraction to step (2) for the second reaction;

[0022] The heavy low-quality wax oil has a 95% distillation temperature of 580° C. to 700° C. according to ASTM D-1160, a nitrogen content of 1800 μg / g to 3500 μg / g, and a sum of two-ring or higher cycloalkanes and two-ring or higher aromatics of 50 wt % to 80 wt %.

[0023] The mixture I1 contains the liquid phase material obtained after the gas-liquid separation and the hydrogen obtained after the gas impurity removal;

[0024] The hydrorefining catalyst I contains a carrier I and an active metal component I supported on the carrier I, and the hydrorefining catalyst II contains a carrier II and an active metal component II supported on the carrier II, and the weight ratio of the content of the active metal component I calculated as oxide to the content of the active metal component II calculated as oxide is 1.30-1.45:1;

[0025] The conditions of the first reaction are controlled so that the desulfurization rate of the heavy low-quality wax oil is 85%-92%, and the total aromatic saturation rate in the reaction effluent I is 10%-25%.

[0026] The present invention introduces heavy low-quality wax oil into a hydrorefining reaction zone I and a hydrorefining reaction zone II in sequence to carry out a two-stage hydrorefining reaction, simultaneously controls the weight ratio of the metal active components contained in the hydrorefining catalyst I and the hydrorefining catalyst II, coordinates the process conditions of the hydrorefining reaction, and circulates all the obtained tail oil to the hydrorefining reaction zone II for the hydrorefining reaction, thereby being able to convert the heavy low-quality wax oil feedstock into heavy naphtha in a maximum amount. DETAILED DESCRIPTION

[0027] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0028] In the present invention, the content of two-ring or higher cycloalkanes in the heavy low-quality wax oil = the mass of two-ring or higher cycloalkanes in the heavy low-quality wax oil / the total mass of hydrocarbon groups in the heavy low-quality wax oil × 100%.

[0029] In the present invention, the content of two-ring or higher aromatic hydrocarbons in the heavy low-quality wax oil = the mass of two-ring or higher aromatic hydrocarbons in the heavy low-quality wax oil / the total mass of hydrocarbon groups in the heavy low-quality wax oil × 100%.

[0030] In the present invention, the hydrocarbon family includes alkanes, cycloalkanes and aromatic hydrocarbons, and the alkanes include straight-chain alkanes and branched-chain alkanes.

[0031] In the present invention, the desulfurization rate of heavy low-quality wax oil = (sulfur mass content in heavy low-quality wax oil - sulfur mass content in reaction effluent I) / sulfur mass content in heavy low-quality wax oil × 100%.

[0032] In the present invention, the total aromatic saturation rate in the reaction effluent I = (total aromatic mass content in the heavy inferior wax oil - total aromatic mass content in the reaction effluent I) / total aromatic mass content in the heavy inferior wax oil × 100%.

[0033] In the present invention, the total aromatic saturation rate in the reaction effluent II = (total aromatic mass content in the heavy inferior wax oil - total aromatic mass content in the reaction effluent II) / total aromatic mass content in the heavy inferior wax oil × 100%.

[0034] In the present invention, the yield of the tail oil fraction = the mass of the separated tail oil fraction / the mass of the heavy inferior wax oil × 100%.

[0035] In the present invention, the 95% distillation temperature refers to the temperature corresponding to the moment when 95 wt% of the substances in the heavy inferior wax oil evaporate.

[0036] In the present invention, the pore size test is carried out with reference to the catalyst pore size distribution calculation method (nitrogen desorption isotherm calculation method) in SH / T 0572-1993, and the pore volume is tested with reference to the zeolite specific surface area and micropore volume determination method in NB / SH / T 0571-2021 catalyst.

[0037] In the present invention, the mesopore area and specific surface area are tested with reference to NB / SH / T 0571-2021 Method for Determining Specific Surface Area and Micropore Volume of Zeolite in Catalysts and GB / T 5816-1995 Method for Determining Surface Area of Catalysts and Adsorbents.

[0038] As described above, the present invention provides a hydrocracking method for producing high-yield reformate. The method is carried out in an apparatus comprising a hydrofining reaction zone and a hydrocracking reaction zone, wherein the hydrofining reaction zone comprises a hydrofining reaction zone I and a hydrofining reaction zone II. The method comprises:

[0039] (1) introducing the heavy low-quality wax oil into the hydrotreating reaction zone I filled with a hydrotreating catalyst I to perform a first reaction to obtain a reaction effluent I; and sequentially performing gas-liquid separation and gas impurity removal on the reaction effluent I to obtain a mixture I1;

[0040] (2) introducing the mixture I1 into the hydrotreating reaction zone II filled with a hydrotreating catalyst II to perform a second reaction to obtain a reaction effluent II;

[0041] (3) introducing the reaction effluent II into the hydrocracking reaction zone filled with a hydrocracking catalyst to perform a third reaction to obtain a reaction effluent III;

[0042] (4) separating the reaction effluent III to obtain a light naphtha fraction, a heavy naphtha fraction, and a tail oil fraction; and recycling the tail oil fraction back to step (2) to perform the second reaction;

[0043] The heavy low-quality wax oil has a 95% distillation temperature of 580° C. to 700° C. according to ASTM D-1160, a nitrogen content of 1800 μg / g to 3500 μg / g, and a sum of two-ring or higher cycloalkanes and two-ring or higher aromatics of 50 wt % to 80 wt %.

[0044] The mixture I1 contains the liquid phase material obtained after the gas-liquid separation and the hydrogen obtained after the gas impurity removal;

[0045] The hydrorefining catalyst I contains a carrier I and an active metal component I supported on the carrier I, and the hydrorefining catalyst II contains a carrier II and an active metal component II supported on the carrier II, and the weight ratio of the content of the active metal component I calculated as oxide to the content of the active metal component II calculated as oxide is 1.30-1.45:1;

[0046] The conditions of the first reaction are controlled so that the desulfurization rate of the heavy low-quality wax oil is 85%-92%, and the total aromatic saturation rate in the reaction effluent I is 10%-25%.

[0047] During the research process, the inventors of the present invention discovered that by adopting different hydrotreating catalysts with metal active component content ratios within the above-mentioned range, on the one hand, the metal cost of the catalyst can be reduced, and on the other hand, by reducing the number of active centers of the catalyst, the aromatic hydrocarbon saturation rate in the hydrotreating reaction zone II can be controlled to reduce the reaction hydrogen consumption. In addition, retaining a certain proportion of the number of metal active centers is also beneficial to achieving the saturated conversion of trace condensed ring aromatics in the circulating oil and reducing the catalyst deactivation rate.

[0048] At the same time, the inventors of the present invention also discovered during the research process that, after carrying out the desulfurization reaction and light aromatic saturation in the hydrorefining reaction zone I, on the one hand, the competitive adsorption reaction of the aromatic molecules on the metal active center of the hydrorefining catalyst by hydrogen sulfide, ammonia, etc. in the reaction system can be removed, so that the ring-opening cracking of the second-stage aromatic saturation and cracking reaction unit can be carried out more efficiently; in addition, by retaining a certain content of sulfur-containing compounds, a certain concentration of hydrogen sulfide can be provided for the sulfurized active centers of the catalysts in the hydrorefining reaction zone II and the hydrocracking reaction zone, thereby ensuring the stability of the active centers of the catalyst.

[0049] Preferably, the conditions of the second reaction are controlled so that the total aromatic saturation fraction in the reaction effluent II is 55%-70%. The inventors of the present invention have discovered that this preferred condition allows for highly selective conversion of the heavy, low-quality wax oil feedstock into a reformate while simultaneously avoiding excessive conversion of aromatics in the reformate to cycloalkanes, thereby achieving both product selectivity and reduced chemical hydrogen consumption.

[0050] Preferably, the conditions of the third reaction are controlled so that the yield of the tail oil fraction is 40%-60%. The inventors of the present invention have discovered that by controlling the yield of the tail oil fraction, that is, the amount of tail oil recycled to the hydrotreating reaction zone II, the severity of the cracking reaction can be reduced, the generation of by-product liquefied gas and gas can be reduced, and the selectivity of the product heavy naphtha can be improved. At the same time, the temperature rise distribution of the reaction bed can be optimized, which is conducive to more stable operation of the device.

[0051] Preferably, in step (3), the hydrocracking catalyst comprises a carrier III and an active metal component III supported on the carrier III; and the weight ratio of the active metal component II (calculated as oxide) to the active metal component III (calculated as oxide) is 1.30-1.55:1. The inventors of the present invention have discovered that this preferred embodiment can achieve lower hydrogen consumption while producing heavy naphtha in large quantities.

[0052] Preferably, in step (4), the initial boiling point of the tail oil fraction is 165°C-175°C.

[0053] Preferably, in step (1) and step (2), the loading volume ratio of the hydrotreating catalyst I to the hydrotreating catalyst II is 1:0.2-1.5.

[0054] According to a preferred embodiment, in step (1), in the hydrorefining catalyst I, the carrier I is alumina or silica-alumina, and the active metal component I contains at least one metal element selected from Group VIII non-precious metal elements and Group VIB non-precious metal elements; and the content of the active metal component I calculated as oxide is 40 wt% to 60 wt% based on the total weight of the hydrorefining catalyst I.

[0055] Further preferably, in step (1), in the hydrotreating catalyst I, the Group VIII non-noble metal element is selected from at least one of nickel and cobalt, and the Group VIB non-noble metal element is a combination of molybdenum and tungsten.

[0056] Particularly preferably, in step (1), based on the total weight of the hydrotreating catalyst I, the content of the non-noble metal elements of Group VIII calculated as oxides is 1 wt%-15 wt%, and the content of the non-noble metal elements of Group VIB calculated as oxides is 5 wt%-45 wt%.

[0057] Preferably, in step (1), in the hydrorefining catalyst I, in the carrier I, the ratio of the total volume of pores with a pore diameter greater than or equal to 10 nm to the total pore volume is 0.6-0.8:1. The total pore volume is the total pore volume of the carrier I.

[0058] Preferably, in step (1), in the hydrorefining catalyst I, in the carrier I, the ratio of the mesopore area to the total specific surface area is 0.3-0.7:1. The mesopore area is also the surface area. The total specific surface area is the total specific surface area of the carrier I.

[0059] Preferably, in step (2), in the hydrorefining catalyst II, the carrier II is alumina or silica-alumina, and the active metal component II contains at least one metal element selected from Group VIII non-precious metal elements and Group VIB non-precious metal elements; and the content of the active metal component II calculated as oxide is 25wt%-35wt% based on the total weight of the hydrorefining catalyst II.

[0060] Further preferably, in step (2), in the hydrotreating catalyst II, the Group VIII non-noble metal element is selected from at least one of nickel and cobalt, and the Group VIB non-noble metal element is selected from at least one of molybdenum and tungsten.

[0061] Furthermore, based on the total weight of the hydrorefining catalyst II, the content of the Group VIII non-noble metal elements is 1 wt%-6 wt%, and the content of the Group VIB non-noble metal elements in terms of oxides is 5 wt%-30 wt%.

[0062] Preferably, in step (3), in the hydrocracking catalyst, the carrier III contains a heat-resistant inorganic oxide and an acidic component, the heat-resistant inorganic oxide is selected from at least one of silicon oxide and aluminum oxide, and the acidic component contains a Y-type molecular sieve; the active metal component III is selected from at least two metal elements of Group VIB metal elements and Group VIII metal elements; and based on the total weight of the hydrocracking catalyst, the content of the Group VIB metal element calculated as oxide is 15wt%-27wt%, and / or the content of the Group VIII metal element calculated as oxide is 2wt%-8wt%.

[0063] More preferably, the content of the acidic component is 40 wt% to 75 wt% based on the total weight of the carrier III. The inventors of the present invention have found that under this preferred embodiment, heavy low-quality wax oil feedstock can be converted into heavy naphtha with high aromatic potential with high selectivity at low hydrogen consumption.

[0064] Preferably, in step (1), the hydrorefining reaction zone I is filled with a hydrogenation protection catalyst and a hydrodemetallization catalyst.

[0065] Preferably, in step (1), the hydrogenation protected catalyst contains a carrier IV and / or an active metal component IV supported on the carrier IV, the carrier IV is selected from at least one of aluminum oxide, silicon oxide and titanium oxide, and the active metal component IV contains at least one metal element selected from Group VIII non-precious metal elements and Group VIB metal elements; and the content of the active metal component IV in terms of oxide is 0.1 wt% to 15 wt% based on the total weight of the hydrogenation protected catalyst.

[0066] Preferably, the linear average particle size of the hydrogenation protection catalyst is 0.5 mm to 50.0 mm, and the bulk density is 0.3 g / cm 3 -1.2g / cm 3 , with a specific surface area of 50m 2 / g-300m 2 / g.

[0067] Preferably, in step (1), the hydrodemetallization catalyst contains a carrier V and an active metal component V supported on the carrier V, the carrier V is selected from at least one of aluminum oxide, silicon oxide and titanium oxide, and the active metal component V contains at least one metal element selected from Group VIII non-noble metal elements and Group VIB metal elements; and the content of the active metal component V calculated as oxide is 3 wt% to 30 wt% based on the total weight of the hydrodemetallization catalyst.

[0068] Preferably, the linear average particle size of the hydrodemetallization catalyst is 0.2 mm to 6.0 mm, and the bulk density is 0.3 g / cm 3 -0.8g / cm 3 , with a specific surface area of 100m 2 / g-250m 2 / g.

[0069] According to a preferred embodiment, in step (1) and step (2), the conditions of the first reaction and the second reaction independently include: a hydrogen partial pressure of 10.0 MPa-20.0 MPa, a reaction temperature of 280°C-400°C, a liquid hourly space velocity of 0.5 h -1 -6h -1 , the hydrogen-to-oil volume ratio is 300-2000.

[0070] According to another preferred embodiment, in step (3), the conditions of the third reaction include: hydrogen partial pressure of 6.0MPa-20.0MPa, reaction temperature of 290℃-420℃, liquid hourly space velocity of 0.3h -1 -5h -1 , the hydrogen-to-oil volume ratio is 300-2000.

[0071] Preferably, the heavy low-quality wax oil is selected from at least one of straight-run wax oil and secondary processed oil.

[0072] Further preferably, the straight-run wax oil is selected from at least one of second-line wax oil, third-line wax oil, fourth-line wax oil and fifth-line wax oil; the secondary processing oil is selected from at least one of slurry bed wax oil, boiling bed wax oil and deasphalted oil.

[0073] The present invention will be described in detail below through examples.

[0074] In the following examples, unless otherwise specified, all raw materials used were commercially available.

[0075] In the following examples, the preparation method of purified CAT1 is as follows:

[0076] Weigh 1000g of pseudo-boehmite (purchased from Sinopec Catalyst Changling Branch, with a dry basis of 0.73 and a specific surface area of 300m 2 / g, pore volume of 0.97 mL / g), extruded into clover-shaped strips with a circumscribed circle diameter of 1.6 mm, dried at 110 ° C for 8 h, ventilated with air, heated to 600 ° C at a rate of 3 ° C / min, and calcined for 3 h to prepare alumina support I1;

[0077] 200 g of carrier I1 was placed in a polytetrafluoroethylene-lined self-pressurized sealed autoclave, 100 g of deionized water was added and sealed, and the autoclave was subjected to a constant temperature hydrothermal treatment at 90°C for 12 h, followed by filtration. The obtained solid was dried at 120°C for 4 h to obtain carrier I2;

[0078] At room temperature (25±2°C), 200g of carrier I2 was placed in 242mL of an aqueous solution containing 68.5g of ammonium metatungstate, 13.7g of ammonium paramolybdate, 20.1g of basic nickel carbonate and 3.2g of boric acid, and the mixture was immersed for 1h and filtered. The obtained solid was dried at 120°C for 6h and then calcined at 400°C for 3h to obtain carrier I3; carrier I3 was placed in 242mL of an aqueous solution containing 23.14g of citric acid and immersed for 1h and filtered. The obtained solid was dried at 120°C for 3h to obtain refined CAT1.

[0079] In the following example,

[0080] The yield of C1-C4 gas is defined as: the mass of separated C1-C4 gas / the mass of heavy low-quality wax oil × 100%;

[0081] The yield of light naphtha fraction is defined as: the mass of the separated light naphtha fraction (<65°C) / the mass of the heavy low-quality wax oil × 100%;

[0082] The yield of the heavy naphtha fraction is defined as: the mass of the separated heavy naphtha fraction (initial boiling point is 65° C., final boiling point is 165° C.-175° C.) / the mass of the heavy inferior wax oil×100%.

[0083] raw material:

[0084] Hydrorefining catalyst:

[0085] Refined CAT1: Carrier I is alumina, and as oxides, the content of molybdenum is 5.6wt%, the content of tungsten is 32wt%, and the content of nickel is 6.3wt%. The ratio of the total volume of pores with a pore diameter greater than or equal to 10nm in carrier I to the total pore volume is 0.693:1. The surface area of carrier I is 71.68m 2 / g, and the ratio of the total specific surface area is 0.3106:1;

[0086] Refined CAT2-1: Brand RN-410B, carrier II is alumina, calculated as oxide, the molybdenum content is 26.5wt%, and the nickel content is 4.2wt%;

[0087] Refined CAT2-2: Brand RN-32V, carrier II is alumina, calculated as oxide, the tungsten content is 23.0wt%, the molybdenum content is 2.3wt%, and the nickel content is 2.4wt%;

[0088] Hydrogenation protection catalyst:

[0089] Protective CAT3: Brand is RG-200, carrier IV is alumina, does not contain active metal components, linear average particle size is 16mm, specific surface area is 100m 2 / g, bulk density is 0.65g / cm 3 ;

[0090] Protective CAT4: Brand is RG-201, carrier IV is alumina, calculated as oxide, the molybdenum content is 1.2wt%, the nickel content is 0.3wt%, the linear average particle size is 10mm, and the specific surface area is 95m 2 / g, bulk density is 0.56g / cm 3 ;

[0091] Protection CAT5: Brand is RG-30A, carrier IV is alumina, calculated as oxide, the molybdenum content is 2.5wt%, the nickel content is 0.5wt%, the linear average particle size is 6.0mm, and the specific surface area is 90m 2 / g, bulk density is 0.48g / cm 3 ;

[0092] Protective CAT6: Brand is RG-30B, carrier IV is alumina, calculated as oxide, the molybdenum content is 5.5wt%, the nickel content is 1.0wt%, the linear average particle size is 3.0mm, and the specific surface area is 90.0m 2 / g, bulk density is 0.50g / cm 3 ;

[0093] Hydrodemetallization catalyst:

[0094] Demetallized CAT7: The brand is RAM-100, the carrier V is alumina, the content of molybdenum is 7.5wt%, the content of nickel is 1.3wt%, the linear average particle size is 1.8mm, and the specific surface area is 160m 2 / g, bulk density is 0.45g / cm 3 ;

[0095] Hydrocracking catalyst:

[0096] Cracking CAT8: RHC-210F, molybdenum content of 15.5 wt%, nickel content of 4.5 wt%, and the balance of carrier III, calculated as oxides; acidic component (Y-type molecular sieve) content of 45 wt%, based on the total weight of carrier III, with the balance being alumina;

[0097] Cracking CAT9: RHC-133, with a tungsten content of 24.5 wt% and a nickel content of 6.5 wt% as oxides, with the balance being carrier III; based on the total weight of carrier III, the acidic component (Y-type molecular sieve) content is 10 wt%, with the balance being alumina;

[0098] Cracking CAT10: The brand is RHC-210. Calculated as oxides, the tungsten content is 27.0wt%, the nickel content is 2.7wt%, and the balance is carrier III; based on the total weight of carrier III, the content of the acidic component (Y-type molecular sieve) is 65wt%, and the balance is alumina.

[0099] In the following examples, the properties of the heavy low-quality wax oil used are shown in Table 1.

[0100] Table 1

[0101]

[0102] Example 1

[0103] (1) introducing the heavy low-quality wax oil into the hydrotreating reaction zone I filled with a hydrotreating catalyst I to perform a first reaction to obtain a reaction effluent I; and sequentially performing gas-liquid separation and gas impurity removal on the reaction effluent I to obtain a mixture I1;

[0104] (2) introducing the mixture I1 into the hydrotreating reaction zone II filled with a hydrotreating catalyst II to perform a second reaction to obtain a reaction effluent II;

[0105] (3) introducing the reaction effluent II into the hydrocracking reaction zone filled with a hydrocracking catalyst to perform a third reaction to obtain a reaction effluent III;

[0106] (4) separating the reaction effluent III to obtain a light naphtha fraction, a heavy naphtha fraction, and a tail oil fraction; and recycling the tail oil fraction to step (2) for the second reaction;

[0107] The mixture I1 contains the liquid phase material obtained after the gas-liquid separation and the hydrogen obtained after the gas impurity removal;

[0108] The specific process parameters are shown in Table 2, and the yield and property parameters of the product are shown in Table 3.

[0109] Example 2

[0110] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0111] The reaction temperature of the second reaction is 370°C;

[0112] The remaining process parameters are the same as those in Example 1.

[0113] The nitrogen mass fraction in the reaction effluent II in this example is 12 μg·g -1 , the total aromatic saturation rate is 65.24%;

[0114] The yield of tail oil fraction is 50.0%;

[0115] The tail oil fraction discarded >175℃ is 0.44%.

[0116] The yield and property parameters of the product are shown in Table 3.

[0117] Example 3

[0118] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0119] The reaction temperature of the second reaction is 370°C;

[0120] The reaction temperature of the third reaction was 383°C.

[0121] The remaining process parameters are the same as those in Example 1.

[0122] The nitrogen mass fraction in the reaction effluent II in this example is 12 μg·g -1, the total aromatic saturation rate is 65.24%;

[0123] The yield of tail oil fraction is 60.0%;

[0124] The tail oil fraction with a temperature of >175℃ is 0.45%.

[0125] The yield and property parameters of the product are shown in Table 3.

[0126] Example 4

[0127] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0128] The reaction temperature of the third reaction is 398°C;

[0129] In the hydrocracking reaction zone, an equal volume of cracking CAT8 is replaced by cracking CAT9.

[0130] The remaining process parameters are the same as those in Example 1.

[0131] In this embodiment, the tail oil fraction yield is 40.0%;

[0132] The tail oil fraction with a temperature of >175℃ is 1.00%.

[0133] The yield and property parameters of the product are shown in Table 3.

[0134] Example 5

[0135] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0136] The reaction temperature of the third reaction was 372°C;

[0137] In the hydrocracking reaction zone, the same volume of cracking CAT8 was replaced by cracking CAT10.

[0138] The remaining process parameters are the same as those in Example 1.

[0139] In this embodiment, the tail oil fraction yield is 40.0%;

[0140] The tail oil fraction at >175℃ is 0.42%.

[0141] The yield and property parameters of the product are shown in Table 3.

[0142] Example 6

[0143] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0144] The reaction temperature of the second reaction is 380°C;

[0145] The reaction temperature of the third reaction is 378°C;

[0146] The remaining process parameters are the same as those in Example 1.

[0147] The nitrogen mass fraction in the reaction effluent II in this example is 5 μg·g -1 , the total aromatic saturation rate is 83.20%;

[0148] The yield of tail oil fraction is 40.0%;

[0149] The tail oil fraction with a temperature of >175℃ is 0.40%.

[0150] The yield and property parameters of the product are shown in Table 3.

[0151] Example 7

[0152] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0153] The reaction temperature of the third reaction is 386°C;

[0154] The remaining process parameters are the same as those in Example 1.

[0155] In this embodiment, the tail oil fraction yield is 20.0%;

[0156] The tail oil fraction with a temperature of >175℃ is 0.40%.

[0157] The yield and property parameters of the product are shown in Table 3.

[0158] Comparative Example 1

[0159] (1) introducing the heavy low-quality wax oil into the hydrotreating reaction zone I filled with a hydrotreating catalyst I to perform a first reaction to obtain a reaction effluent I;

[0160] (2) introducing the reaction effluent I into the hydrotreating reaction zone II filled with a hydrotreating catalyst II to perform a second reaction to obtain a reaction effluent II;

[0161] (3) introducing the reaction effluent II into the hydrocracking reaction zone filled with a hydrocracking catalyst to perform a third reaction to obtain a reaction effluent III;

[0162] (4) separating the reaction effluent III to obtain a light naphtha fraction, a heavy naphtha fraction, and a tail oil fraction; and recycling the tail oil fraction to step (2) for the second reaction;

[0163] The specific process parameters are shown in Table 2, and the yield and property parameters of the product are shown in Table 3.

[0164] Comparative Example 2

[0165] This comparative example was carried out in the same manner as in Example 1, except that:

[0166] The reaction temperature of the first reaction was 383°C;

[0167] The remaining process parameters are the same as those in Example 1.

[0168] In this comparative example, the total aromatic saturation rate in the reaction effluent I was 24.0%, and the desulfurization rate was 94.0%;

[0169] The nitrogen mass fraction in the reaction effluent II is 13 μg·g -1 , the total aromatic saturation rate is 58.10%;

[0170] The yield of tail oil fraction is 40.0%;

[0171] The tail oil fraction discarded >175℃ is 0.41%.

[0172] The yield and property parameters of the product are shown in Table 3.

[0173] Comparative Example 3

[0174] This comparative example was carried out in the same manner as in Example 1, except that:

[0175] The reaction temperature of the second reaction was 357°C;

[0176] In the hydrofining reaction zone II, an equal volume of refined CAT2-1 was replaced with refined CAT2-2;

[0177] The reaction temperature of the third reaction is 384°C;

[0178] The remaining process parameters are the same as those in Example 1.

[0179] The nitrogen mass fraction in the reaction effluent II in this comparative example is 17 μg·g -1 , the total aromatic saturation rate is 53.00%;

[0180] The yield of tail oil fraction is 50.0%;

[0181] The tail oil fraction with a temperature of >175℃ is 2.00%.

[0182] The yield and property parameters of the product are shown in Table 3.

[0183] Comparative Example 4

[0184] This comparative example was carried out in the same manner as in Example 1, except that:

[0185] The reaction temperature of the first reaction is 360°C;

[0186] The reaction temperature of the second reaction is 380°C;

[0187] The reaction temperature of the third reaction was 382°C;

[0188] The remaining process parameters are the same as those in Example 1.

[0189] In this comparative example, the total aromatic saturation rate in the reaction effluent I was 13.0%, and the desulfurization rate was 76.0%. The nitrogen mass fraction in the reaction effluent II was 17 μg·g -1 , the total aromatic saturation rate is 53.20%; the tail oil fraction yield is 45.0%;

[0190] The tail oil fraction with a temperature of >175℃ is 1.00%.

[0191] The yield and property parameters of the product are shown in Table 3.

[0192] Table 2

[0193]

[0194]

[0195] Note: 1. Protection CAT3+Protection CAT4+Protection CAT5+Protection CAT6+Demetallization CAT7+Refined CAT1 means that according to the direction of liquid material flow, Protection CAT3, Protection CAT4, Protection CAT5, Protection CAT6, Demetallization CAT7 and Refined CAT1 are loaded in sequence;

[0196] 2. The column of "Packing Volume Ratio" refers to the loading volume ratio of hydrotreating catalyst I to hydrotreating catalyst II.

[0197] Table 3

[0198]

[0199] From the data in Table 2 and Table 3, we can see that:

[0200] In Examples 1 to 3, the desulfurization rate of the heavy low-quality wax oil is controlled to 85%-92%, and the total aromatic saturation rate in the reaction effluent I is controlled to 10%-25%; and the weight ratio of the active metal components in the hydrorefining catalyst I to the hydrorefining catalyst II, calculated as oxides, is controlled to be 1.30-1.45:1; heavy naphtha with a yield of more than 70% and an aromatic potential content of more than 47 wt% can be obtained, which can be used as a high-quality reforming material;

[0201] In Example 4, a hydrocracking catalyst containing a Y-type molecular sieve content not in the range of 40 wt% to 75 wt% was used in the hydrocracking reaction zone. Accordingly, the cracking activity of the catalyst was significantly reduced. To achieve a conversion depth similar to that of Example 1, the hydrocracking reaction temperature needed to be increased to 398°C, which would shorten the operating cycle of the device.

[0202] In Example 5, when the weight ratio of the active metal component content in the hydrorefining catalyst II to the active metal component content in the hydrocracking catalyst is not within the range of 1.30-1.55:1, although the operation can be carried out at a lower temperature, the secondary cracking and supersaturation ratio of the reaction product will increase accordingly, resulting in an increase in the yield of by-product gas and light naphtha, and a decrease in the yield and aromatic potential content of the target product heavy naphtha.

[0203] In Example 6, the total aromatic saturation rate in the reaction effluent II was increased to 83.2%. On the one hand, this resulted in a mismatch in the operating temperatures of the hydrotreating reaction zone I and the hydrotreating reaction zone II. On the other hand, excessive aromatic saturation led to excessive ring-opening cracking, poor reaction product selectivity, increased hydrogen consumption, and reduced aromatic potential of the product heavy naphtha.

[0204] In Example 7, the tail oil fraction yield was controlled at 20.0%, which reduced the amount of tail oil recycled to the hydrofining reaction zone II and increased the severity of the cracking reaction, resulting in poor product selectivity.

[0205] In Comparative Example 1, the reaction effluent I in the hydrotreating reaction zone I and the hydrotreating reaction zone II directly enters the hydrocracking reaction zone without gas-liquid separation. Without gas-liquid separation and gas impurity removal, the total aromatic saturation rate of the reaction effluent II is still relatively low, only 49.22%, under the harsh hydrotreating reaction conditions, due to the influence of the reaction atmosphere and competitive adsorption. This will increase the difficulty of the hydrocracking reaction conversion. -1 Under the condition of hydrocracking reaction temperature of 410℃, 10% of tail oil needs to be discarded to reach reaction equilibrium; it can be seen that if the method provided by the present invention is not adopted, it is difficult to achieve a large proportion of conversion of heavy low-quality wax oil raw materials into heavy naphtha products;

[0206] In Comparative Example 2, the tail oil is recycled back to the hydrorefining reaction zone I, which increases the liquid hourly space velocity of the hydrorefining reaction zone I, shortening the residence time of the heavy and inferior wax oil in contact with the active center. It is necessary to increase the temperature of the hydrorefining reaction zone I to compensate for the saturation of aromatics. However, increasing the temperature of the hydrorefining reaction zone I will shorten the operating cycle of the hydrorefining reaction zone I.

[0207] In Comparative Example 3, when the ratio of the active metal component content in the hydrorefining catalyst II to the hydrocracking catalyst is not within the range of 1.30-1.55:1, on the one hand, it is necessary to increase the temperature of the hydrorefining reaction zone II to compensate for the aromatic saturation reaction capacity. At the same time, due to the increase in the temperature of the hydrorefining reaction zone II, the temperature difference between the hydrorefining reaction zone I and the hydrorefining reaction zone II is reduced, resulting in a decrease in the thermal efficiency of the reaction directly utilizing the hydrorefining reaction zone I, thereby increasing energy consumption, and the high operating temperature affects the operating cycle of the hydrorefining reaction zone II. On the other hand, due to insufficient aromatic saturation capacity, the concentration of polycyclic aromatic hydrocarbons in the product is high, and it is necessary to increase the tail oil dumping to control the concentration of polycyclic aromatic hydrocarbons, resulting in a decrease in the yield of the target product heavy naphtha.

[0208] In Comparative Example 4, the desulfurization rate of the reaction effluent I was reduced to 76%. Although this significantly reduced the reaction severity of the hydrorefining reaction zone I, due to the low aromatic saturation rate and desulfurization rate in the hydrorefining reaction zone I, it was necessary to increase the reaction temperature of the hydrorefining reaction zone II to compensate for the aromatic saturation. Such temperature operation made it impossible to reasonably utilize the reaction heat of the hydrorefining reaction zones I and II, resulting in high operating energy consumption and mismatching of the operating cycles of the hydrorefining reaction zones I and II.

[0209] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A hydrocracking method for producing high-yield reforming material, characterized in that: The method is carried out in a device containing a hydrofining reaction zone and a hydrocracking reaction zone, wherein the hydrofining reaction zone contains a hydrofining reaction zone I and a hydrofining reaction zone II. The method comprises: (1) introducing the heavy low-quality wax oil into the hydrorefining reaction zone I filled with the hydrorefining catalyst I to carry out a first reaction to obtain a reaction effluent I; and sequentially subjecting the reaction effluent I to gas-liquid separation and gas impurity removal to obtain a mixture I1; (2) introducing the mixture I1 into the hydrotreating reaction zone II filled with a hydrotreating catalyst II to carry out a second reaction to obtain a reaction effluent II; controlling the conditions of the second reaction so that the total aromatic saturation rate in the reaction effluent II is 55%-70%; (3) introducing the reaction effluent II into the hydrocracking reaction zone filled with a hydrocracking catalyst to carry out a third reaction to obtain a reaction effluent III; the hydrocracking catalyst contains a carrier III and an active metal component III supported on the carrier III; and the weight ratio of the content of the active metal component II calculated as oxide to the content of the active metal component III calculated as oxide is 1.30-1.55:1; (4) Separating the reaction effluent III to obtain a light naphtha fraction, a heavy naphtha fraction, and a tail oil fraction; recycling the tail oil fraction to step (2) for the second reaction; controlling the conditions of the third reaction so that the yield of the tail oil fraction is 40%-60%; and the initial boiling point of the tail oil fraction is 165°C-175°C; The heavy low-quality wax oil has a 95% distillation temperature of 580° C. to 700° C. according to ASTM D-1160, a nitrogen content of 1800 μg / g to 3500 μg / g, and a sum of two-ring or higher cycloalkanes and two-ring or higher aromatics of 50 wt % to 80 wt %. The mixture I1 contains the liquid phase material obtained after the gas-liquid separation and the hydrogen obtained after the gas impurity removal; The hydrorefining catalyst I contains a carrier I and an active metal component I supported on the carrier I, and the hydrorefining catalyst II contains a carrier II and an active metal component II supported on the carrier II, and the weight ratio of the content of the active metal component I calculated as oxide to the content of the active metal component II calculated as oxide is 1.30-1.45:1; The conditions of the first reaction are controlled so that the desulfurization rate of the heavy low-quality wax oil is 85%-92%, and the total aromatic saturation rate in the reaction effluent I is 10%-25%.

2. The method according to claim 1, wherein In step (1) and step (2), the loading volume ratio of the hydrotreating catalyst I to the hydrotreating catalyst II is 1:0.2-1.

5.

3. The method according to claim 1 or 2, wherein: In step (1), in the hydrorefining catalyst I, the carrier I is alumina or silica-alumina, and the active metal component I contains at least one metal element selected from Group VIII non-precious metal elements and Group VIB non-precious metal elements; and the content of the active metal component I calculated as oxide is 40 wt% to 60 wt% based on the total weight of the hydrorefining catalyst I.

4. The method according to claim 3, wherein: In step (1), in the hydrorefining catalyst I, the Group VIII non-noble metal element is selected from at least one of nickel and cobalt, and the Group VIB non-noble metal element is a combination of molybdenum and tungsten.

5. The method according to claim 4, wherein In step (1), based on the total weight of the hydrorefining catalyst I, the content of the non-noble metal elements of Group VIII calculated as oxides is 1 wt%-15 wt%, and the content of the non-noble metal elements of Group VIB calculated as oxides is 5 wt%-45 wt%.

6. The method according to claim 1 or 2, wherein: In step (1), in the hydrorefining catalyst I, in the carrier I, the ratio of the total volume of pores with a pore diameter greater than or equal to 10 nm to the total pore volume is 0.6-0.8:

1.

7. The method according to claim 6, wherein: In step (1), in the hydrorefining catalyst I, in the carrier I, the ratio of the mesopore area to the total specific surface area is 0.3-0.7:

1.

8. The method according to claim 1 or 2, wherein: In step (2), in the hydrorefining catalyst II, the carrier II is alumina or silica-alumina, and the active metal component II contains at least one metal element selected from Group VIII non-precious metal elements and Group VIB non-precious metal elements; and the content of the active metal component II calculated as oxide is 25wt%-35wt% based on the total weight of the hydrorefining catalyst II.

9. The method according to claim 8, wherein In step (2), in the hydrorefining catalyst II, the Group VIII non-noble metal element is selected from at least one of nickel and cobalt, and the Group VIB non-noble metal element is selected from at least one of molybdenum and tungsten.

10. The method according to claim 8, wherein Based on the total weight of the hydrorefining catalyst II, the content of the Group VIII non-noble metal elements is 1 wt%-6 wt%, and the content of the Group VIB non-noble metal elements calculated as oxides is 5 wt%-30 wt%.

11. The method according to claim 1, wherein In step (3), in the hydrocracking catalyst, the carrier III contains a heat-resistant inorganic oxide and an acidic component, the heat-resistant inorganic oxide is selected from at least one of silicon oxide and aluminum oxide, and the acidic component contains a Y-type molecular sieve; the active metal component III contains at least two metal elements selected from Group VIB metal elements and Group VIII metal elements; and based on the total weight of the hydrocracking catalyst, the content of the Group VIB metal element calculated as oxide is 15wt%-27wt%, and / or the content of the Group VIII metal element calculated as oxide is 2wt%-8wt%.

12. The method according to claim 11, wherein Based on the total weight of the carrier III, the content of the acidic component is 40 wt%-75 wt%.

13. The method according to claim 1 or 2, wherein: In step (1), the hydrorefining reaction zone I is filled with a hydrogenation protection catalyst and a hydrodemetallization catalyst.

14. The method according to claim 13, wherein In step (1), the hydrogenation protected catalyst contains a carrier IV and an active metal component IV supported on the carrier IV, the carrier IV is selected from at least one of aluminum oxide, silicon oxide and titanium oxide, and the active metal component IV contains at least one metal element selected from Group VIII non-noble metal elements and Group VIB metal elements; and the content of the active metal component IV in terms of oxide is 0.1 wt% to 15 wt% based on the total weight of the hydrogenation protected catalyst.

15. The method according to claim 14, wherein The linear average particle size of the hydrogenation protection catalyst is 0.5 mm to 50.0 mm, and the bulk density is 0.3 g / cm 3 -1.2g / cm 3 , with a specific surface area of 50m 2 / g-300m 2 / g.

16. The method according to claim 13, wherein: In step (1), the hydrodemetallization catalyst contains a carrier V and an active metal component V supported on the carrier V, the carrier V is selected from at least one of aluminum oxide, silicon oxide and titanium oxide, and the active metal component V contains at least one metal element selected from Group VIII non-noble metal elements and Group VIB metal elements; and the content of the active metal component V calculated as oxide is 3 wt% to 30 wt% based on the total weight of the hydrodemetallization catalyst.

17. The method according to claim 16, wherein The linear average particle size of the hydrodemetallization catalyst is 0.2 mm to 6.0 mm, and the bulk density is 0.3 g / cm 3 -0.8g / cm 3 , with a specific surface area of 100m 2 / g-250m 2 / g.

18. The method according to claim 1 or 2, wherein: In step (1) and step (2), the conditions of the first reaction and the second reaction independently include: hydrogen partial pressure of 10.0 MPa-20.0 MPa, reaction temperature of 280°C-400°C, liquid hourly space velocity of 0.5 h -1 -6h -1 , the hydrogen-to-oil volume ratio is 300-2000.

19. The method according to claim 1 or 2, wherein: In step (3), the conditions of the third reaction include: hydrogen partial pressure of 6.0MPa-20.0MPa, reaction temperature of 290℃-420℃, liquid hourly space velocity of 0.3h -1 -5h -1 , the hydrogen-to-oil volume ratio is 300-2000.

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