Hydrocracking method for increasing yield of reforming material

Abstract

The invention relates to the technical field of heavy inferior wax oil processing, and discloses a hydrocracking method for producing a high-yield reforming material. The method comprises the following steps: introducing heavy inferior wax oil into a hydrofining reaction zone I filled with a hydrofining catalyst I, and carrying out a first reaction to obtain a reaction effluent I; sequentially carrying out gas-liquid separation and gas impurity removal on the reaction effluent I to obtain a mixture I1; the mixture I1 is introduced into a hydrofining reaction zone II filled with a hydrofining catalyst II for a second reaction, and a reaction effluent II is obtained; the reaction effluent II is introduced into a hydrocracking reaction zone for a third reaction, and a reaction effluent III is obtained; separating the reaction effluent III to obtain a light naphtha fraction, a heavy naphtha fraction and a tail oil fraction; and circulating the tail oil fraction to perform the second reaction. By adopting the method provided by the invention, the heavy inferior wax oil raw material can be converted into heavy naphtha to the maximum extent.

Description

Technical Field

[0001] The 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, the apparent consumption of aromatics in China has increased year by year. In order to meet the market demand for aromatics, the hydrocracking unit of the refinery has gradually increased the processing depth to produce more heavy naphtha that can be used as reforming material. At the same time, with the annual increase in crude oil production, the supply of high-quality crude oil and conventional crude oil has decreased year by year and the price has risen; at the same time, the supply of heavy and inferior crude oil has increased year by year and the price is relatively low. Although the processing of heavy and inferior crude oil is difficult, the development of hydrocracking technology that can directly convert low-priced and abundantly supplied heavy and inferior crude oil into high-value and market-demand reforming material has the opportunity to obtain higher economic benefits.

[0003] In order to meet the demand for deep conversion of heavy and inferior crude oil, in recent years, delayed coking technology for lightening of heavy oil, slurry bed, ebullating bed, and suspended bed heavy oil hydrocracking technology have been further developed. However, heavy oil delayed coking, slurry bed, ebullating bed, and suspended bed heavy oil hydrocracking technology will produce a considerable proportion of wax oil fractions or heavy distillate oils in the process of lightening of 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 of heavy and inferior crude oil have the characteristics of high density, high dry point, high sulfur content, high nitrogen content, and high residual carbon value, among which the density at 20℃ 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 very 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. The method realizes the production of conventional hydrocracking products by processing heavy straight-run wax oil raw materials with low nitrogen content but complex nitrogen-containing compound structure through two-stage denitrogenation means.

[0005] CN104611053A discloses a high-drying point raw material hydrocracking process, which adopts a two-stage denitrification method, and by setting a gas-liquid countercurrent contact reaction zone and a gas-liquid separation zone in one stage, it is possible to process heavy and inferior deep-pulled 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 inferior 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 with two fractionation units to achieve conversion of inferior raw oil with a nitrogen content greater than 2000 μg / g and a final distillation point of about 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 raw material. The method realizes the conversion of the high-nitrogen raw material 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. The method realizes the conversion of heavy and inferior raw materials with a final distillation point of 580°C-620°C into conventional clean oil products and chemical raw materials by arranging a gas-liquid separation in the second refining reaction zone equipped with a bulk catalyst.

[0011] CN104611022A discloses a two-stage hydrocracking method for inferior heavy distillate oil. The method realizes the conversion of heavy inferior raw materials with a nitrogen content of 2000 μg / g-15000 μg / 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 realizes 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 highly nitrogen-resistant hydrocracking catalysts in the cracking reaction zone.

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

[0014] On the one hand, the raw materials processed by the existing hydrocracking technology are not of low quality and it is difficult to match the processing needs of low-quality raw materials; on the other hand, the 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 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 difficult conversion of heavy and inferior wax oil raw materials and relatively single product route in the prior art, and to provide a method for producing heavy naphtha in maximum quantity from heavy and inferior wax oil.

[0017] In order to achieve the above object, the present invention provides a hydrocracking method for producing more reforming materials, which 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, and the method comprises:

[0018] (1) introducing the heavy low-quality wax oil into the hydrotreating reaction zone I filled with the hydrotreating catalyst I to carry out 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 carry out 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 carry out 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) to perform the second reaction;

[0022] The 95% distillation temperature of the heavy low-quality wax oil according to ASTM D-1160 is 580° C.-700° C., the nitrogen content is 1800 μg / g-3500 μg / g, and the sum of the content of cycloalkanes with two or more rings and aromatics with two or more rings is 50 wt %-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 sequentially introduces heavy low-quality wax oil into a hydrorefining reaction zone I and a hydrorefining reaction zone II to carry out a two-stage hydrorefining reaction, and simultaneously controls the weight ratio of metal active components contained in the hydrorefining catalyst I and the hydrorefining catalyst II, coordinates the process conditions of the hydrorefining reaction, and all the obtained tail oil is recycled to the hydrorefining reaction zone II for the hydrorefining reaction, thereby being able to convert a maximum amount of heavy low-quality wax oil raw material into heavy naphtha. DETAILED DESCRIPTION

[0027] The endpoints and any values ​​of the ranges disclosed in this article 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 endpoint values ​​of each range, the endpoint values ​​of each range and the 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 as specifically disclosed in this article.

[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 more aromatic hydrocarbons in the heavy low-quality wax oil=the mass of two-ring or more 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 chain alkanes, cycloalkanes and aromatic hydrocarbons, and the chain 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 95wt% 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) of SH / T 0572-1993, and the pore volume is tested with reference to the zeolite specific surface area and micropore volume determination method in catalyst of NB / SH / T 0571-2021.

[0037] In the present invention, the mesopore area and specific surface area are tested with reference to the method for measuring specific surface area and micropore volume of zeolite in catalysts in NB / SH / T 0571-2021 and the method for measuring surface area of ​​catalysts and adsorbents in GB / T 5816-1995.

[0038] As mentioned above, the present invention provides a hydrocracking method for producing more reforming materials, which 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, and the method comprises:

[0039] (1) introducing the heavy low-quality wax oil into the hydrotreating reaction zone I filled with the hydrotreating catalyst I to carry out 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 carry out 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 carry out 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 to step (2) to perform the second reaction;

[0043] The 95% distillation temperature of the heavy low-quality wax oil according to ASTM D-1160 is 580° C.-700° C., the nitrogen content is 1800 μg / g-3500 μg / g, and the sum of the content of cycloalkanes with two or more rings and aromatics with two or more rings is 50 wt %-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] The inventors of the present invention have discovered during the course of their research that by using different hydrotreating catalysts having a metal active component content ratio within the above-mentioned range, on the one hand, the metal cost of the catalyst can be reduced, and on the other hand, the number of active centers of the catalyst can be reduced, thereby controlling the aromatic saturation rate in the hydrotreating reaction zone II 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 aromatics in the circulating oil and reducing the catalyst deactivation rate.

[0048] At the same time, the inventors of the present invention also found during the research process that, after carrying out desulfurization reaction and light aromatic saturation in the hydrorefining reaction zone I, on the one hand, the competitive adsorption reaction of 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 sulfided active center of the catalyst in the hydrorefining reaction zone II and the hydrocracking reaction zone, thereby ensuring the stability of the active center of the catalyst.

[0049] Preferably, the conditions of the second reaction are controlled so that the total aromatic saturation rate in the reaction effluent II is 55%-70%. The inventors of the present invention have found that under this preferred condition, the heavy low-quality wax oil feedstock can be highly selectively converted into a reforming material, while avoiding excessive conversion of aromatics in the reforming material into cycloalkanes, thereby achieving both product selectivity and reduced reaction 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 found that by controlling the yield of the tail oil fraction, that is, the amount of tail oil recycled back to the hydrofining reaction zone II, on the one hand, the severity of the cracking reaction can be reduced, the generation of by-product liquefied gas and gas can be reduced, and the product heavy naphtha selectivity can be improved. At the same time, the temperature rise distribution of the reaction bed can be optimized, which is conducive to a more stable operation of the device.

[0051] Preferably, in step (3), 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. The inventors of the present invention have found that this preferred case can achieve lower hydrogen consumption under the premise of mass production of heavy naphtha.

[0052] Preferably, in step (4), the initial distillation 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 based on the total weight of the hydrorefining catalyst I, the content of the active metal component I in terms of oxide is 40wt%-60wt%.

[0055] Further preferably, in step (1), in the hydrotreating catalyst I, the Group VIII non-precious metal element is selected from at least one of nickel and cobalt, and the Group VIB non-precious 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-precious metal elements of Group VIII calculated as oxides is 1wt%-15wt%, and the content of the non-precious metal elements of Group VIB calculated as oxides is 5wt%-45wt%.

[0057] Preferably, in step (1), in the hydrotreating catalyst I, in the carrier I, the ratio of the total volume of pores with a pore size 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 hydrotreating 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 hydrotreating 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 based on the total weight of the hydrotreating catalyst II, the content of the active metal component II in terms of oxide is 25wt%-35wt%.

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

[0061] Furthermore, based on the total weight of the hydrotreating catalyst II, the content of the non-noble metal elements of Group VIII is 1 wt%-6 wt%, and the content of the non-noble metal elements of Group VIB in terms of oxide 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, based on the total weight of the carrier III, the content of the acidic component is 40wt%-75wt%. The inventors of the present invention have found that under this preferred condition, the 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 hydrotreating reaction zone I is filled with a hydroprotection catalyst and a hydrodemetallization catalyst.

[0065] Preferably, in step (1), the hydrogenation protection 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 non-precious metal elements of Group VIII and metal elements of Group VIB; and the content of the active metal component IV in terms of oxide is 0.1 wt%-15 wt% based on the total weight of the hydrogenation protection catalyst.

[0066] Preferably, the linear average particle size of the hydrogenation protection catalyst is 0.5 mm-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 non-precious metal elements of Group VIII and metal elements of Group VIB; and the content of the active metal component V in terms of oxide is 3 wt%-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-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 volume ratio of hydrogen to oil is 300-2000.

[0070] According to another preferred embodiment, in step (3), the conditions of the third reaction include: hydrogen partial pressure of 6.0 MPa-20.0 MPa, reaction temperature of 290°C-420°C, liquid hourly space velocity of 0.3 h -1 -5h -1 , the volume ratio of hydrogen to oil 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 by way of 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 an outer 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 an alumina carrier I1;

[0077] 200 g of carrier I1 was placed in a polytetrafluoroethylene-lined self-pressure sealed autoclave, 100 g of deionized water was added to seal, and the autoclave was subjected to constant temperature hydrothermal treatment at 90° C. for 12 h, and then filtered. 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 then filtered for 1h. 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 soaked for 1h, then filtered, and 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 C1-C4 gas separated / the mass of heavy low-quality wax oil × 100%;

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

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

[0083] raw material:

[0084] Hydrotreating catalysts:

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

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

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

[0088] Hydrogenation protection catalyst:

[0089] Protective CAT3: Brand 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 RG-201, carrier IV is alumina, calculated as oxide, the content of molybdenum is 1.2wt%, the content of nickel 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 RG-30A, carrier IV is alumina, calculated as oxide, the content of molybdenum is 2.5wt%, the content of nickel 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] Protection CAT6: Brand RG-30B, carrier IV is alumina, calculated as oxide, molybdenum content is 5.5wt%, nickel content is 1.0wt%, linear average particle size is 3.0mm, 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 molybdenum content is 7.5wt%, the nickel content 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: The grade is RHC-210F, the content of molybdenum is 15.5wt%, the content of nickel is 4.5wt%, and the balance is carrier III, based on the total weight of carrier III; the content of acidic component (Y-type molecular sieve) is 45wt%, and the balance is alumina;

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

[0098] Cracking CAT10: The brand is RHC-210. Calculated as oxide, the tungsten content is 27.0wt%, the nickel content is 2.7wt%, and the balance is carrier III; calculated 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 the hydrotreating catalyst I to carry out 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 carry out 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 carry out 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) to perform 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 condition 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 in this embodiment:

[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 tail oil fraction yield is 50.0%;

[0115] The tail oil fraction with a temperature of >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 in this embodiment:

[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 tail oil fraction yield is 60.0%;

[0124] The tail oil fraction discarded >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 in this embodiment:

[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 in this embodiment:

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

[0137] In the hydrocracking reaction zone, an equal volume of cracking CAT8 is 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 with a temperature of >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 in this embodiment:

[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 tail oil fraction yield 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 in this embodiment:

[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 carry out 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 carry out 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 carry out 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) to perform the second reaction;

[0163] The specific process condition 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 in this comparative example:

[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 tail oil fraction yield 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 in this comparative example:

[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 is replaced by 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 tail oil fraction yield 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 in this comparative example:

[0185] The reaction temperature of the first reaction was 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 is 13.0%, and the desulfurization rate is 76.0%; the nitrogen mass fraction in the reaction effluent II is 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+Demetallized CAT7+Refined CAT1 means that according to the flow direction of liquid materials, protection CAT3, protection CAT4, protection CAT5, protection CAT6, demetallized CAT7 and refined CAT1 are loaded in sequence;

[0196] 2. The column of packing volume ratio refers to the packing 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 be 85%-92%, and the total aromatic saturation rate in the reaction effluent I is controlled to be 10%-25%; and the weight ratio of the active metal components in the hydrorefining catalyst I and the hydrorefining catalyst II in terms of oxide 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 47wt% can be obtained, which can be used as a high-quality reforming material;

[0201] In Example 4, a hydrocracking catalyst having a Y-type molecular sieve content of not 40wt%-75wt% is used in the hydrocracking reaction zone. Accordingly, the cracking activity of the catalyst is greatly reduced. To achieve a conversion depth similar to that of Example 1, the hydrocracking reaction temperature needs to be increased to 398°C, which will shorten the operation 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, so that the yield of by-product gas and light naphtha is increased, and the yield and aromatic potential content of the target product heavy naphtha are reduced;

[0203] In Example 6, the total aromatic saturation rate in the reaction effluent II is increased to 83.2%. On the one hand, this will lead to 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 will lead to excessive ring-opening cracking, poor selectivity of the reaction product, increased hydrogen consumption, and reduced aromatic potential of the product heavy naphtha.

[0204] In Example 7, the tail oil fraction yield was controlled to 20.0%, which reduced the amount of tail oil circulated 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. Under the conditions of gas-liquid separation and gas impurity removal, affected by the reaction atmosphere and competitive adsorption, under the harsh hydrotreating reaction conditions, the total aromatic saturation rate of the reaction effluent II is still relatively low, only 49.22%, which will increase the difficulty of the hydrocracking reaction conversion. -1 Under the condition of hydrocracking reaction temperature of 410°C, 10% of tail oil needs to be dumped to achieve 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 inferior wax oil raw materials into heavy naphtha products;

[0206] In Comparative Example 2, the tail oil is recycled back to the hydrofining reaction zone I, which increases the liquid hourly space velocity of the hydrofining reaction zone I, shortening the residence time of the heavy inferior wax oil in contact with the active center. It is necessary to increase the temperature of the hydrofining reaction zone I to compensate for the saturation of aromatics. However, increasing the temperature of the hydrofining reaction zone I will shorten the operation cycle of the hydrofining 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 using the hydrorefining reaction zone I, thereby increasing energy consumption, and the high operating temperature affects the operation 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 is reduced to 76%. Although the reaction severity of the hydrorefining reaction zone I can be significantly reduced, since the aromatic saturation rate and desulfurization rate of the hydrorefining reaction zone I are low, it is necessary to increase the reaction temperature of the hydrorefining reaction zone II to compensate for the aromatic saturation. Such temperature operation makes it impossible to reasonably utilize the reaction heat of the hydrorefining reaction zone I and the hydrorefining reaction zone II, resulting in high operating energy consumption and mismatching of the operating cycles of the hydrorefining reaction zone I and the hydrorefining reaction zone II.

[0209] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A hydrocracking method for producing high-yield reforming materials, 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 hydrotreating reaction zone I filled with the hydrotreating catalyst I to carry out 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; (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; (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; (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) to perform the second reaction; The 95% distillation temperature of the heavy low-quality wax oil according to ASTM D-1160 is 580° C.-700° C., the nitrogen content is 1800 μg / g-3500 μg / g, and the sum of the content of cycloalkanes with two or more rings and aromatics with two or more rings is 50 wt %-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 (2), the conditions of the second reaction are controlled so that the total aromatic saturation rate in the reaction effluent II is 55%-70%.

3. The method according to claim 1 or 2, wherein: In step (3), the conditions of the third reaction are controlled so that the yield of the tail oil fraction is 40%-60%.

4. The method according to any one of claims 1 to 3, wherein: In step (3), 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.

5. The method according to any one of claims 1 to 4, wherein: In step (4), the initial distillation point of the tail oil fraction is 165°C-175°C.

6. The method according to any one of claims 1 to 5, 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.

7. The method according to any one of claims 1 to 6, 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 the non-precious metal elements of Group VIII and the non-precious metal elements of Group VIB; and the content of the active metal component I in terms of oxide is 40 wt% to 60 wt% based on the total weight of the hydrorefining catalyst I; Preferably, in step (1), in the hydrotreating catalyst I, the non-precious metal element of Group VIII is selected from at least one of nickel and cobalt, and the non-precious metal element of Group VIB is a combination of molybdenum and tungsten; Preferably, in step (1), based on the total weight of the hydrotreating catalyst I, the content of the non-precious metal elements of Group VIII calculated as oxides is 1wt%-15wt%, and the content of the non-precious metal elements of Group VIB calculated as oxides is 5wt%-45wt%.

8. The method according to any one of claims 1 to 7, wherein: In step (1), in the hydrotreating 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; Preferably, in step (1), in the hydrotreating catalyst I, in the carrier I, the ratio of the mesopore area to the total specific surface area is 0.3-0.7:

1.

9. The method according to any one of claims 1 to 8, wherein: In step (2), in the hydrorefining catalyst II, the carrier II is alumina or silicon oxide-alumina, and the active metal component II contains at least one metal element selected from the non-precious metal elements of Group VIII and the non-precious metal elements of Group VIB; 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; Preferably, in step (2), in the hydrotreating catalyst II, the non-noble metal element of Group VIII is selected from at least one of nickel and cobalt, and the non-noble metal element of Group VIB is selected from at least one of molybdenum and tungsten; Preferably, based on the total weight of the hydrotreating catalyst II, the content of the non-noble metal element of Group VIII is 1 wt%-6 wt%, and the content of the non-noble metal element of Group VIB in terms of oxide is 5 wt%-30 wt%.

10. The method according to claim 4, 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%; Preferably, based on the total weight of the carrier III, the content of the acidic component is 40 wt%-75 wt%.

11. The method according to any one of claims 1 to 10, wherein: In step (1), the hydrotreating reaction zone I is filled with a hydroprotection catalyst and a hydrodemetallization catalyst.

12. The method according to claim 11, wherein: In step (1), the hydrogenation protection 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 non-precious metal elements of Group VIII and metal elements of Group VIB; 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 protection catalyst; Preferably, the linear average particle size of the hydrogenation protection catalyst is 0.5 mm-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.

13. The method according to claim 11 or 12, 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 non-precious metal elements of Group VIII and metal elements of Group VIB; 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; Preferably, the linear average particle size of the hydrodemetallization catalyst is 0.2 mm-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.

14. The method according to any one of claims 1 to 13, wherein: 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 volume ratio of hydrogen to oil is 300-2000.

15. The method according to any one of claims 1 to 14, 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 volume ratio of hydrogen to oil is 300-2000.

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