A hydrocracking method for heavy and inferior wax oil

Abstract

The present invention relates to the technical field of heavy and low-quality wax oil processing, and discloses a hydrocracking method for heavy and low-quality wax oil. The method is carried out in an apparatus containing a hydrorefining reaction zone and a hydrocracking reaction zone, and comprises: introducing the heavy and low-quality wax oil into the hydrorefining reaction zone filled with a bulk-like hydrorefining catalyst to perform a first reaction to obtain a reaction effluent I; introducing the reaction effluent I into the hydrocracking reaction zone filled with a hydrocracking catalyst to perform a second reaction to obtain a reaction effluent II; and separating the reaction effluent II to obtain a light naphtha fraction, a heavy naphtha fraction, an intermediate distillate, and a tail oil fraction. The method provided by the present invention can convert heavy and low-quality wax oil feedstock into clean fuel and high-quality chemical feedstock.

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 heavy and inferior wax oil. Background Art

[0002] In recent years, with the continued development of the international energy and chemical industries, crude oil production has increased annually. However, as a non-renewable resource, the supply of high-quality and conventional crude oil has decreased and its price has risen with increasing production. Meanwhile, the supply of heavy and low-quality crude oil has increased annually, and its price has remained relatively low. Although heavy and low-quality crude oil is difficult and costly to process, refineries can achieve significant economic returns by selecting appropriate refining technologies and product solutions, processing this inexpensive and abundant source of crude oil.

[0003] To meet the processing needs of heavy, low-quality crude oil, delayed coking technologies, slurry bed, ebullating bed, and suspension bed heavy oil hydrocracking technologies have been further developed in recent years as a means of lightening heavy oil. However, these technologies, including 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 wax oil raw materials obtained from conventional crude oil fractionation, the heavy low-quality wax oil fractions or wide-fraction heavy low-quality wax oils obtained from lightening heavy, low-quality 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 approximately 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, the above existing hydrocracking technology mainly has the following problems:

[0014] On the one hand, the raw materials processed by existing hydrocracking technology are not of low quality and cannot meet 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, and there is little research on the conversion of heavy and low-quality wax oil and product route development.

[0015] Furthermore, the deterioration of feedstock typically leads to an increase in the BMCI value of the hydrocracked tail oil, which serves as a steam cracking feedstock, and a deterioration in quality. Steam crackers typically strive to minimize the BMCI value of the hydrocracked tail oil to achieve a high triene yield and optimal economics. However, processing heavy, low-quality wax oil feedstocks results in an increase in the BMCI value of the hydrocracked tail oil, leading to a deterioration in quality. This contradicts the refinery's goal of reducing the BMCI value of the tail oil to increase triene production.

[0016] To this end, the development of hydrocracking technology that can process heavy and inferior wax oil raw materials and produce tail oil with low BMCI value is of great significance for refining and chemical companies to achieve high-value conversion and value enhancement of heavy and inferior crude oil. Summary of the Invention

[0017] The purpose of the present invention is to solve the problems of difficulty in converting heavy and low-quality wax oil raw materials and relatively single product routes in the prior art, and to provide a method for converting heavy and low-quality wax oil into clean fuel and high-quality chemical raw materials.

[0018] To achieve the above object, the present invention provides a method for hydrocracking heavy low-quality wax oil, which is carried out in a device containing a hydrorefining reaction zone and a hydrocracking reaction zone, and comprises:

[0019] (1) introducing the heavy low-quality wax oil into the hydrotreating reaction zone filled with a bulk-like hydrotreating catalyst to carry out a first reaction to obtain a reaction effluent I;

[0020] (2) introducing the reaction effluent I into the hydrocracking reaction zone filled with a hydrocracking catalyst to perform a second reaction to obtain a reaction effluent II;

[0021] (3) separating the reaction effluent II to obtain a light naphtha fraction, a heavy naphtha fraction, a middle distillate oil, and a tail oil fraction;

[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 bulk-phase hydrorefining catalyst comprises a carrier I and an active metal component I supported on the carrier I, wherein the carrier I is alumina or silica-alumina, and the active metal component I comprises at least one metal element selected from Group VIII non-noble metal elements and Group VIB non-noble metal elements; the content of the active metal component I, calculated as oxide, is 35 wt% to 55 wt% based on the total weight of the bulk-phase hydrorefining catalyst; and in the carrier I, a ratio of the total volume of pores having a pore diameter greater than or equal to 10 nm to the total pore volume is 0.6 to 0.8;

[0024] The conditions of the first reaction are controlled so that the saturation rate of two-ring or higher aromatic hydrocarbons in the reaction effluent I is 70%-95%; and the conditions of the second reaction are controlled so that the yield of the tail oil fraction is 20%-38%.

[0025] The present invention adopts a bulk-phase hydrorefining catalyst and cooperates with the process conditions of the hydrorefining reaction to control the saturation rate of two-ring and higher aromatic hydrocarbons in the product obtained after hydrorefining to be within the range of 70%-95%. At the same time, the process conditions of the hydrocracking reaction are coordinated to control the yield of the tail oil fraction in the product obtained after the hydrocracking reaction to be within the range of 20%-38%. Heavy and low-quality wax oil raw materials can be converted into clean fuels and high-quality chemical raw materials. DETAILED DESCRIPTION

[0026] 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.

[0027] 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%.

[0028] 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%.

[0029] In the present invention, the hydrocarbon family includes alkanes, cycloalkanes and aromatic hydrocarbons, and the alkanes include straight-chain alkanes and branched-chain alkanes.

[0030] In the present invention, the saturation rate of two-ring or larger aromatic hydrocarbons = (the content of two-ring or larger aromatic hydrocarbons in the heavy inferior wax oil - the content of two-ring or larger aromatic hydrocarbons in the reaction effluent I) / the content of two-ring or larger aromatic hydrocarbons in the heavy inferior wax oil × 100%.

[0031] In the present invention, the yield of the tail oil fraction = the weight of the separated tail oil fraction / the weight of the heavy inferior wax oil × 100%.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] As mentioned above, the present invention provides a method for hydrocracking heavy low-quality wax oil, which is carried out in a device containing a hydrofining reaction zone and a hydrocracking reaction zone, and comprises:

[0036] (1) introducing the heavy low-quality wax oil into the hydrotreating reaction zone filled with a bulk-like hydrotreating catalyst to carry out a first reaction to obtain a reaction effluent I;

[0037] (2) introducing the reaction effluent I into the hydrocracking reaction zone filled with a hydrocracking catalyst to perform a second reaction to obtain a reaction effluent II;

[0038] (3) separating the reaction effluent II to obtain a light naphtha fraction, a heavy naphtha fraction, a middle distillate oil, and a tail oil fraction;

[0039] 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 %.

[0040] The bulk-phase hydrorefining catalyst comprises a carrier I and an active metal component I supported on the carrier I, wherein the carrier I is alumina or silica-alumina, and the active metal component I comprises at least one metal element selected from Group VIII non-noble metal elements and Group VIB non-noble metal elements; the content of the active metal component I, calculated as oxide, is 35 wt% to 55 wt% based on the total weight of the bulk-phase hydrorefining catalyst; and in the carrier I, a ratio of the total volume of pores having a pore diameter greater than or equal to 10 nm to the total pore volume is 0.6 to 0.8:1;

[0041] The conditions of the first reaction are controlled so that the saturation rate of two-ring or higher aromatic hydrocarbons in the reaction effluent I is 70%-95%; and the conditions of the second reaction are controlled so that the yield of the tail oil fraction is 20%-38%.

[0042] It should be noted that the total pore volume is the total pore volume of the carrier I.

[0043] The inventors of the present invention have discovered that the bulk-like hydrotreating catalyst can improve the conversion efficiency of reactants in the hydrocracking zone.

[0044] The inventors of the present invention have also discovered that controlling the conditions of the first reaction so that the saturation rate of two-ring or higher aromatic hydrocarbons in the reaction effluent I is 70%-95% can promote the ring-opening cracking of cyclic hydrocarbon molecules in the heavy, low-quality wax oil feedstock, not only achieving the conversion of high-BMCI cyclic hydrocarbon molecules into low-BMCI single-ring long side chains or paraffins, but also suppressing the formation of condensed-ring aromatic hydrocarbons, thereby extending the operating cycle. Simultaneously, controlling the conditions of the second reaction so that the yield of the tail oil fraction is 20%-38% can achieve sufficient conversion of cyclic hydrocarbon molecules, achieving a high tail oil yield while also reducing the BMCI value of the tail oil.

[0045] Preferably, in step (1), in the bulk-phase hydrorefining catalyst, 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.

[0046] Preferably, in step (1), based on the total weight of the bulk-phase hydrorefining catalyst, 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%-40 wt%.

[0047] Preferably, in step (1), in the bulk-phase hydrorefining catalyst, 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.

[0048] According to a preferred embodiment, the hydrocracking catalyst contains a carrier II and an active metal component II supported on the carrier II, the carrier II 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 II 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%-33wt%, and / or the content of the Group VIII metal element calculated as oxide is 2wt%-8wt%.

[0049] Further preferably, based on the total weight of the carrier II, the content of the acidic component is 40 wt%-75 wt%.

[0050] More preferably, the content of the Y-type molecular sieve is 60wt%-100wt% based on the total weight of the acidic components. The inventors of the present invention have found that under this preferred condition, a higher quality tail oil fraction can be obtained and the operation cycle of the device is longer.

[0051] Preferably, in step (1), the conditions of the first reaction are controlled so that the saturation rate of two-ring or higher aromatic hydrocarbons in the reaction effluent I is 74%-90%.

[0052] Preferably, in step (2), the initial boiling point of the tail oil fraction is 300° C.-350° C. The inventors of the present invention have found that under this preferred condition, middle distillate oil and tail oil fraction of better quality can be obtained.

[0053] According to another preferred embodiment, in step (1), according to the flow direction of the liquid phase material, in the hydrorefining reaction zone, a hydrogenation protection catalyst is loaded upstream of the bulk-phase hydrorefining catalyst, and optionally, at least one catalyst selected from a hydrodemetallization catalyst and a hydroremoval of carbon residue catalyst is loaded between the hydrogenation protection catalyst and the bulk-phase hydrorefining catalyst.

[0054] More preferably, in step (1), a hydrodemetallization catalyst and a hydrodecarbonization catalyst are loaded between the hydroprotection catalyst and the bulk-phase hydrorefining catalyst, and the hydrodemetallization catalyst is loaded upstream of the hydrodecarbonization catalyst.

[0055] Further preferably, in step (1), based on the total volume of the catalyst in the hydrorefining reaction zone, the loading volume content of the hydrogenation protection catalyst is 3%-10%, the loading volume content of the hydrodemetallization catalyst is 0.01%-20%, the loading volume content of the hydroremoval of carbon residue catalyst is 0.01%-20%, and the loading volume content of the bulk-phase hydrorefining catalyst is 50%-96%.

[0056] Particularly preferably, based on the total volume of the catalyst in the hydrotreating reaction zone, the loading volume content of the bulk-phase hydrotreating catalyst is 60%-96%.

[0057] Preferably, in step (1), the hydrogenation protected catalyst contains a carrier III and / or an active metal component III supported on the carrier III, the carrier III is selected from at least one of aluminum oxide, silicon oxide and titanium oxide, and the active metal component III 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 III calculated as oxide is 0.1 wt% to 15 wt% based on the total weight of the hydrogenation protected catalyst.

[0058] Preferably, in step (1), 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.

[0059] Preferably, in step (1), the hydrodemetallization 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 3 wt% to 30 wt% based on the total weight of the hydrodemetallization catalyst.

[0060] Preferably, in step (1), 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.

[0061] Preferably, in step (1), the hydrodecarbonization 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 33 wt% based on the total weight of the hydrodecarbonization catalyst.

[0062] Preferably, in step (1), the linear average particle size of the hydroremoval of carbon residue catalyst is 0.2 mm to 3.0 mm, and the bulk density is 0.3 g / cm 3 -0.7g / cm 3 , with a specific surface area of 100m 2 / g-250m 2 / g.

[0063] According to a preferred embodiment, in step (1), the conditions of the first reaction include: hydrogen partial pressure of 6.0 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.

[0064] According to another preferred embodiment, in step (2), the conditions of the second 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 hydrogen-to-oil volume ratio is 300-2000.

[0065] Preferably, the heavy low-quality wax oil is selected from at least one of straight-run wax oil and secondary processed oil.

[0066] More 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.

[0067] The present invention will be described in detail below through examples.

[0068] In the following examples, unless otherwise specified, all raw materials used were commercially available.

[0069] In the following examples, the preparation method of purified CAT1 is as follows:

[0070] Weigh 1000g of pseudo-boehmite (purchased from Sinopec Catalyst Changling Branch, with a dry basis of 0.73 and a specific surface area of 300m2 / 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;

[0071] 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;

[0072] 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.

[0073] In the following example,

[0074] The yield of the light naphtha fraction is defined as: the weight of the separated light naphtha fraction (<65°C) / the weight of the heavy inferior wax oil × 100%;

[0075] The yield of the heavy naphtha fraction is defined as: the weight of the separated heavy naphtha fraction (65°C-165°C) / the weight of the heavy inferior wax oil × 100%;

[0076] The yield of the diesel fraction is defined as: the weight of the separated middle distillate oil (165°C - T1°C) / the weight of the heavy inferior wax oil × 100%; T1 is the initial distillation point of the tail oil fraction.

[0077] raw material:

[0078] Hydrorefining catalyst:

[0079] Refined CAT1: Support I is alumina, calculated as oxide, the content of molybdenum is 5.6wt%, the content of tungsten is 32wt%, 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 support I to the total pore volume is 0.693:1, and the surface area of support I is 71.68m 2 / g, and the ratio of the total specific surface area is 0.3106:1;

[0080] Refined CAT2-1: Brand RN-32V, carrier I is alumina, calculated as oxide, the tungsten content is 23.0wt%, the molybdenum content is 2.3wt%, and the nickel content is 2.4wt%. In carrier II, the ratio of the total volume of pores with a pore diameter greater than or equal to 10nm to the total pore volume is 0.5675:1;

[0081] Refined CAT2-2: Brand RN-510, carrier I is alumina, calculated as oxide, the molybdenum content is 26.5wt%, and the nickel content is 5.0wt%;

[0082] Hydrogenation protection catalyst:

[0083] Protective CAT3: Brand is RG-200, carrier III is alumina, does not contain active components, linear average particle size is 16mm, specific surface area is 100m 2 / g, bulk density is 0.65g / cm 3 ;

[0084] Protective CAT4: Brand is RG-201, carrier III 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 ;

[0085] Protection CAT5: Brand is RG-30A, carrier III 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 ;

[0086] Protection CAT6: Brand is RG-30B, carrier III 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 ;

[0087] Hydrodemetallization catalyst:

[0088] Demetallized CAT7: The brand is RAM-100, the carrier IV is alumina, the content of molybdenum oxide is 7.5wt%, the content of nickel oxide 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 ;

[0089] Hydrocracking catalyst:

[0090] Cracking CAT8: RHC-210, with a tungsten content of 27.0 wt% and a nickel content of 2.7 wt% based on oxides, with the balance being Support II; an acidic component content of 65 wt% based on the total weight of Support II, with the balance being alumina; and a Y-type molecular sieve content of 100 wt% based on the total weight of the acidic components;

[0091] Cracking CAT9: The brand is RHC-133. Calculated as oxides, the tungsten content is 24.5wt%, the nickel content is 6.5wt%, and the balance is carrier II; calculated based on the total weight of carrier II, the acidic component content is 20wt%, and the balance is alumina; calculated based on the total weight of the acidic components, the Y-type molecular sieve content is 50wt%, and the balance is amorphous silica-alumina.

[0092] In the following examples, the properties of the heavy low-quality wax oil used are shown in Table 1.

[0093] Table 1

[0094]

[0095] Example 1

[0096] (1) introducing the heavy low-quality wax oil into a hydrotreating reaction zone filled with a bulk-like hydrotreating catalyst to carry out a first reaction to obtain a reaction effluent I;

[0097] (2) introducing the reaction effluent I into a hydrocracking reaction zone filled with a hydrocracking catalyst to carry out a second reaction to obtain a reaction effluent II;

[0098] (3) separating the reaction effluent II to obtain a light naphtha fraction, a heavy naphtha fraction, a middle distillate oil, and a tail oil fraction;

[0099] The specific process parameters are shown in Table 2, and the yield and property parameters of the product are shown in Table 3.

[0100] Example 2

[0101] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0102] The reaction temperature of the second reaction was 370°C.

[0103] The remaining process parameters are the same as those in Example 1.

[0104] In this embodiment, the tail oil fraction yield is 23.40%.

[0105] The yield and property parameters of the product are shown in Table 3.

[0106] Example 3

[0107] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0108] The reaction temperature of the second reaction was 365°C.

[0109] The remaining process parameters are the same as those in Example 1.

[0110] In this embodiment, the tail oil fraction yield is 30.00%.

[0111] The yield and property parameters of the product are shown in Table 3.

[0112] Example 4

[0113] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0114] The reaction temperature of the second reaction was 372°C.

[0115] The remaining process parameters are the same as those in Example 1.

[0116] In this embodiment, the tail oil fraction yield is 20.00%.

[0117] The yield and property parameters of the product are shown in Table 3.

[0118] Example 5

[0119] This example was carried out in the same manner as in Example 1, except that in this example: the reaction temperature of the second reaction was 369°C.

[0120] The remaining process parameters are the same as those in Example 1.

[0121] In this embodiment, the tail oil fraction yield is 25.00%.

[0122] The yield and property parameters of the product are shown in Table 3.

[0123] Example 6

[0124] This example was carried out in the same manner as in Example 1, except that in this example: the reaction temperature of the second reaction was 362°C.

[0125] The remaining process parameters are the same as those in Example 1.

[0126] In this embodiment, the tail oil fraction yield is 35.00%.

[0127] The yield and property parameters of the product are shown in Table 3.

[0128] Example 7

[0129] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0130] The reaction temperature of the second reaction was 387 °C and the liquid hourly space velocity was 0.83 h -1 ;

[0131] In the hydrocracking reaction zone, an equal volume of cracking CAT8 is replaced by cracking CAT9.

[0132] The remaining process parameters are the same as those in Example 1.

[0133] In this embodiment, the tail oil fraction yield is 23.10%.

[0134] The yield and property parameters of the product are shown in Table 3.

[0135] Example 8

[0136] This embodiment is carried out in the same manner as in embodiment 1, except that:

[0137] The reaction temperature of the second reaction was 372°C;

[0138] The initial distillation point of the tail oil fraction is 260℃.

[0139] The remaining process parameters are the same as those in Example 1.

[0140] In this embodiment, the tail oil fraction yield is 34.28%.

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

[0142] Comparative Example 1

[0143] This comparative example was carried out in the same manner as in Example 1, except that:

[0144] The reaction temperature for the first reaction was 375°C;

[0145] The reaction temperature of the second reaction was 376°C.

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

[0147] The nitrogen mass fraction of the reaction effluent I in this example is 90.0 μg·g -1 , the saturation rate of two-ring and above aromatic hydrocarbons is 67.66%;

[0148] The yield of tail oil fraction is 28.50%.

[0149] The yield and property parameters of the product are shown in Table 3.

[0150] Comparative Example 2

[0151] This comparative example was carried out in the same manner as in Example 1, except that:

[0152] The reaction temperature of the second reaction was 353°C.

[0153] The remaining process parameters are the same as those in Example 1.

[0154] In this embodiment, the tail oil fraction yield is 48.67%.

[0155] The yield and property parameters of the product are shown in Table 3.

[0156] Comparative Example 3

[0157] This comparative example was carried out in the same manner as in Example 1, except that:

[0158] The reaction temperature for the first reaction was 395°C;

[0159] In the hydrofining reaction zone, an equal volume of refined CAT1 was replaced with refined CAT2-1;

[0160] The reaction temperature of the second reaction was 387 °C and the liquid hourly space velocity was 0.83 h -1 ;

[0161] In the hydrocracking reaction zone, an equal volume of cracking CAT8 is replaced by cracking CAT9.

[0162] The remaining process parameters are the same as those in Example 1.

[0163] The nitrogen mass fraction of the reaction effluent I in this example is 12.0 μg·g -1 , the saturation rate of two-ring or higher aromatic hydrocarbons is 84.00%;

[0164] The yield of tail oil fraction is 25.00%.

[0165] The yield and property parameters of the product are shown in Table 3.

[0166] Comparative Example 4

[0167] This comparative example was carried out in the same manner as in Example 1, except that:

[0168] The reaction temperature for the first reaction was 395°C;

[0169] In the hydrofining reaction zone, an equal volume of refined CAT1 was replaced with refined CAT2-1;

[0170] The remaining process parameters are the same as those in Example 1.

[0171] The nitrogen mass fraction of the reaction effluent I in this example is 12.0 μg·g -1, the saturation rate of two-ring or higher aromatic hydrocarbons is 84.00%;

[0172] The yield of tail oil fraction is 40.50%.

[0173] The yield and property parameters of the product are shown in Table 3.

[0174] Comparative Example 5

[0175] This comparative example was carried out in the same manner as in Example 1, except that:

[0176] The reaction temperature of the first reaction was 398°C and the liquid hourly space velocity was 0.50h -1 ;

[0177] In the hydrofining reaction zone, an equal volume of refined CAT1 was replaced with refined CAT2-2;

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

[0179] The nitrogen mass fraction of the reaction effluent I in this example is 15.0 μg·g -1 , the saturation rate of two-ring or higher aromatic hydrocarbons is 78.00%;

[0180] The yield of tail oil fraction is 47.00%.

[0181] The yield and property parameters of the product are shown in Table 3.

[0182] Table 2

[0183]

[0184] Note: Protection CAT3+Protection CAT4+Protection CAT5+Protection CAT6+Demetallization CAT7+Refined CAT1 means that Protection CAT3, Protection CAT4, Protection CAT5, Protection CAT6, Demetallization CAT7 and Refined CAT1 are loaded in sequence according to the direction of liquid material flow.

[0185] Table 3

[0186]

[0187]

[0188] From the data in Table 2 and Table 3, we can see that:

[0189] In Examples 1 to 6, when the saturation rate of two-ring or higher aromatic hydrocarbons was controlled to 87.00% and the yield of the tail oil fraction was controlled to be within the range of 20%-38%, the BMCI value of the obtained tail oil was no higher than 11.70. Therefore, it can be seen that the method provided by the present invention can obtain high-quality tail oil with a low BMCI value;

[0190] In Example 7, the hydrocracking catalyst in the hydrocracking reaction zone uses a catalyst with an acid component content, especially a Y-type molecular sieve content, which is not within the range of 60wt%-90wt%. Due to its insufficient conversion capacity of heavy and inferior wax oil feedstock, it is necessary to significantly reduce the liquid hourly space velocity to 0.83h -1 , and the reaction temperature in the hydrocracking reaction zone is 387℃, high-quality tail oil with a low BMCI value can be obtained;

[0191] In Example 8, when the initial boiling point of the tail oil fraction is controlled to be 260° C. and the yield of the tail oil fraction is 34.28%, although the yield of the tail oil fraction is within the range of 20%-38% required by the present invention, since the initial boiling point of the tail oil fraction is not within the range of 300° C.-350° C., on the one hand, the BMCI value of the tail oil is 13.8, and on the other hand, the cetane index of the diesel fraction is 45.4, the product quality will be relatively poor. It can be seen that controlling the initial boiling point of the tail oil fraction within the range of 300° C.-350° C. can obtain better tail oil fractions and middle distillates;

[0192] In Comparative Example 1, the saturation rate of two-ring and larger aromatics was controlled to 67.66%, and the nitrogen content in the reaction effluent I was 90.0 μg / g. On the one hand, the reaction temperature in the hydrocracking reaction zone needed to be increased to compensate for the effects of denitrification and insufficient saturation depth of two-ring and larger aromatics. On the other hand, the BMCI value of the tail oil increased significantly, which was detrimental to product quality. In addition, a higher nitrogen content would accelerate the deactivation rate of the hydrocracking catalyst, which was detrimental to the long-term operation of the device.

[0193] In Comparative Example 2, when the yield of the tail oil fraction was controlled to be 48.67%, the BMCI value of the tail oil was 13.8. It can be seen that when the yield of the tail oil fraction (hydrocracking conversion rate) required by the present invention is within the range of 20%-38%, it is difficult to obtain a good tail oil quality.

[0194] In Comparative Example 3, when the bulk-phase hydrorefining catalyst and the hydrocracking catalyst having a Y-type molecular sieve content not in the range of 8wt%-35wt% in the present invention are not used, when the yield of the tail oil fraction is 25%, not only the BMCI value of the tail oil is 11.1, but also the reaction temperature of the hydrorefining reaction zone reaches 395°C, the reaction temperature of the hydrocracking reaction zone is 387°C, and the liquid hourly space velocity is 0.83h -1 The reaction conditions are too harsh. On the one hand, it is difficult to meet the long-term operation requirements of the unit. On the other hand, it is difficult to convert heavy and low-quality wax oil into high-quality tail oil under the conditions of the existing hydrocracking unit.

[0195] In Comparative Example 4, the hydrorefining catalyst in the hydrorefining reaction zone does not use a bulk-like hydrorefining catalyst, but uses a conventional hydrorefining catalyst. Due to the low content of active metal components in the conventional hydrorefining catalyst and the small number of macropores (pores with a pore diameter greater than or equal to 10 nm) in the carrier, the number and accessibility of active centers capable of converting the heavy low-quality wax oil feedstock macromolecular aromatic compounds are reduced. In order to achieve the same denitrogenation depth as in Example 4, the reaction temperature of the hydrorefining reaction zone needs to be increased to 395° C., and the aromatic saturation rate is still relatively insufficient, with a saturation rate of two-ring or higher aromatics of only 84%. This, on the one hand, reduces the conversion performance of the cracking reaction and increases the tail oil yield. At the same time, due to the difficulty in converting macromolecular aromatic compounds, the tail oil BMCI value is relatively high.

[0196] In Comparative Example 5, the hydrorefining catalyst in the hydrorefining reaction zone does not use a bulk-like hydrorefining catalyst, but a catalyst with significantly reduced active metal components. Due to the lack of active centers of the catalyst, even if the liquid hourly space velocity is reduced to 0.50h -1 To achieve a conversion depth similar to that in the embodiment, the reaction temperature of the hydrotreating reaction zone needs to be increased to 398°C, and the saturation rate of two-ring and higher aromatic hydrocarbons is only 78.00%, which leads to a decrease in the conversion performance of the cracking reaction, an increase in the tail oil yield, and a deterioration in the tail oil BMCI.

[0197] 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 heavy low-quality wax oil, characterized in that: The method is carried out in a device containing a hydrofining reaction zone and a hydrocracking reaction zone, and comprises: (1) introducing the heavy low-quality wax oil into the hydrotreating reaction zone filled with a bulk-like hydrotreating catalyst to carry out a first reaction to obtain a reaction effluent I; (2) introducing the reaction effluent I into the hydrocracking reaction zone filled with a hydrocracking catalyst to perform a second reaction to obtain a reaction effluent II; (3) separating the reaction effluent II to obtain a light naphtha fraction, a heavy naphtha fraction, an intermediate distillate oil, and a tail oil fraction; the initial boiling point of the tail oil fraction is 300° C.-350° 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 bulk-phase hydrorefining catalyst comprises a carrier I and an active metal component I supported on the carrier I, wherein the carrier I is alumina or silica-alumina, and the active metal component I comprises at least one metal element selected from Group VIII non-noble metal elements and Group VIB non-noble metal elements; and the content of the active metal component I, calculated as oxide, is 35 wt% to 55 wt% based on the total weight of the bulk-phase hydrorefining catalyst. 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 to 0.8:1; The conditions of the first reaction are controlled so that the saturation rate of two-ring or higher aromatic hydrocarbons in the reaction effluent I is 70%-95%; and the conditions of the second reaction are controlled so that the yield of the tail oil fraction is 20%-38%; In step (2), the hydrocracking catalyst comprises a carrier II and an active metal component II supported on the carrier II, the carrier II comprises 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 comprises a Y-type molecular sieve; the active metal component II comprises 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 15 wt% to 33 wt%, and / or the content of the Group VIII metal element calculated as oxide is 2 wt% to 8 wt%; Based on the total weight of the carrier II, the content of the acidic component is 40wt%-75wt%; Based on the total weight of the acidic components, the content of the Y-type molecular sieve is 60wt%-100wt%.

2. The method according to claim 1, wherein In step (1), in the bulk-phase hydrorefining catalyst, 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.

3. The method according to claim 2, wherein: In step (1), based on the total weight of the bulk-phase hydrorefining catalyst, 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%-40 wt%.

4. The method according to claim 2, wherein: In step (1), in the bulk-phase hydrorefining catalyst, in the carrier I, the ratio of the mesopore area to the total specific surface area is 0.3-0.7:

1.

5. The method according to any one of claims 1 to 4, wherein: In step (1), the conditions of the first reaction are controlled so that the saturation rate of two-ring or higher aromatic hydrocarbons in the reaction effluent I is 74%-90%.

6. The method according to any one of claims 1 to 4, wherein: In step (1), according to the flow direction of the liquid phase material, in the hydrorefining reaction zone, a hydrogenation protection catalyst is loaded upstream of the bulk-phase hydrorefining catalyst, and optionally, at least one catalyst selected from the group consisting of a hydrodemetallization catalyst and a hydroremoval of carbon residue catalyst is loaded between the hydrogenation protection catalyst and the bulk-phase hydrorefining catalyst.

7. The method according to claim 6, wherein: In step (1), a hydrodemetallization catalyst and a hydrodecarbonization catalyst are loaded between the hydroprotection catalyst and the bulk-phase hydrorefining catalyst, and the hydrodemetallization catalyst is loaded upstream of the hydrodecarbonization catalyst.

8. The method according to claim 7, wherein: In step (1), based on the total volume of the catalyst in the hydrorefining reaction zone, the loading volume content of the hydroprotected catalyst is 3%-10%, the loading volume content of the hydrodemetallization catalyst is 0.01%-20%, the loading volume content of the hydroremoval of carbon residue catalyst is 0.01%-20%, and the loading volume content of the bulk-phase hydrorefining catalyst is 50%-96%.

9. The method according to claim 6, wherein: In step (1), the hydrogenation protected catalyst contains a carrier III and an active metal component III supported on the carrier III, the carrier III is selected from at least one of aluminum oxide, silicon oxide and titanium oxide, and the active metal component III 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 III calculated as oxide is 0.1 wt% to 15 wt% based on the total weight of the hydrogenation protected catalyst.

10. The method according to claim 9, wherein: In step (1), 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.

11. The method according to claim 6, wherein: In step (1), the hydrodemetallization 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 3 wt% to 30 wt% based on the total weight of the hydrodemetallization catalyst.

12. The method according to claim 11, wherein In step (1), 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.

13. The method according to claim 6, wherein: In step (1), the hydrodecarbonization 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 33 wt% based on the total weight of the hydrodecarbonization catalyst.

14. The method according to claim 13, wherein In step (1), the linear average particle size of the hydrogenation carbon removal catalyst is 0.2 mm to 3.0 mm, and the bulk density is 0.3 g / cm 3 -0.7g / cm 3 , with a specific surface area of 100m 2 / g-250m 2 / g.

15. The method according to any one of claims 1 to 4, wherein: In step (1), the conditions of the first reaction include: hydrogen partial pressure of 6.0 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.

16. The method according to any one of claims 1 to 4, wherein: In step (2), the conditions of the second 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 hydrogen-to-oil volume ratio is 300-2000.

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