A hydrocracking catalyst, its preparation method and application

Abstract

This invention provides a hydrocracking catalyst. Catalyst I is a support formed by mixing Y molecular sieve, alumina, and a binder, on which nickel and tungsten are loaded. Catalyst II is a support formed by mixing ZSM-5 molecular sieve, alumina, and a binder, on which cobalt and tungsten are loaded. The hydrocracking catalyst is obtained by mixing catalyst I and catalyst II. This invention loads cobalt and tungsten onto ZSM-5 molecular sieves to reduce the influence of aromatics on the adsorption reaction of alkanes, enhances the bond breaking and isomerization reactions of alkanes, significantly reduces the pour point of transformer oil, and increases the yield of transformer oil. Loading nickel and tungsten onto Y molecular sieves enhances the ring-opening cracking reaction of aromatics, which can significantly reduce the aromatic content in transformer oil and improve its stability and color. The composite catalyst addresses both the aromatic content and pour point indicators of transformer oil, and can achieve partitioned enhancement of the ring-opening reaction of aromatics and the bond breaking and isomerization reaction of alkanes, directly producing qualified transformer oil products.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrocracking, and particularly relates to a preparation method of a hydrocracking catalyst. BACKGROUND

[0002] The aromatic hydrocarbon content of the hydrocracking diesel product is low, and the heavy components thereof can be used as transformer oil products with higher added value and market prospects. Therefore, it is of great significance to optimize process parameters and reduce the yield of diesel product of a hydrocracking device, so as to improve the comprehensive economic benefit of the device.

[0003] The transformer oil in special oil products requires low aromatic hydrocarbon content and high isoparaffin content, and a conventional hydrocracking catalyst often uses a single molecular sieve component, which is difficult to simultaneously consider the ring-opening of aromatic hydrocarbons and the isomerization performance of paraffins, and the produced transformer oil may face the problems of high aromatic hydrocarbon content or pour point.

[0004] Therefore, it is of great significance to develop a hydrocracking catalyst that simultaneously considers the ring-opening of aromatic hydrocarbons and the isomerization performance of paraffins, so as to simultaneously reduce the aromatic hydrocarbon content and n-paraffin content in the components of the transformer oil produced by hydrocracking, and thus produce qualified transformer oil products.

[0005] CN114181758A discloses a transformer oil and a preparation method thereof. The synthetic ester type base oil is heated to a set temperature, an antioxidant is added to obtain a mother liquor mixture, the mother liquor mixture is fully stirred, mineral type base oil is added and fully stirred, and the stirred mixture is vacuum filtered. The transformer oil prepared by using 90-95 parts of mineral type base oil, 5-10 parts of synthetic ester type base oil and 0.2-0.3 parts of antioxidant can not only meet the requirements of various indexes, but also can still meet the requirements of a breakdown voltage higher than 40 kV and improved electrical performance under a water content exceeding 30 mg / kg.

[0006] CN107619706A discloses a transformer oil and a preparation method thereof. The transformer oil is prepared by using naphthenic and paraffin-based vacuum distillate oil as raw materials, through a three-stage high-pressure hydrogenation production process, and by adding a combined aromatic hydrocarbon additive and an antioxidant. The components are as follows in terms of mass percentage: 15% to 25% of paraffin-based base oil fraction, 4% to 7% of the combined aromatic hydrocarbon additive, 0.3%±0.05% of the antioxidant, and the balance of naphthenic base oil. The transformer oil provided by the application has excellent carbon type structure and anti-gas separation performance, and the low-temperature performance and the antioxidant performance are higher than those of existing products on the market. However, the method has strict requirements on the composition of raw oil, the process flow is complex, and the production cost of the transformer oil is high. SUMMARY

[0007] In view of the deficiencies of the prior art, the application provides a preparation method of a hydrocracking catalyst, so as to produce qualified transformer oil products.

[0008] The present application provides a preparation method of a hydrocracking catalyst, comprising the following steps:

[0009] (1) mixing Y zeolite, alumina and a binder to form a carrier I, loading nickel and tungsten on the carrier I, drying, and calcining to obtain a catalyst I;

[0010] (2) mixing ZSM-5 zeolite, alumina and a binder to form a carrier II, loading cobalt and tungsten on the carrier II, drying, and calcining to obtain a catalyst II;

[0011] (3) mixing the catalyst I and the catalyst II to obtain the hydrocracking catalyst.

[0012] Further, the loading of the active components in (1) and (2) is carried out by impregnation, including equal volume impregnation, excess volume impregnation and steam impregnation, and the specific operation method is known to those skilled in the art.

[0013] Further, the drying temperature in (1) and (2) is 70-120°C, and the calcining temperature is 350-500°C, preferably 400-500°C.

[0014] Further, based on the total weight of the catalyst I, the alumina accounts for 30.0-40.0wt%, the Y zeolite accounts for 30.0-50.0wt%, the nickel accounts for 4.0-12.0wt% as an oxide, and the tungsten accounts for 12.0-25.0wt% as an oxide.

[0015] Further, based on the total weight of the catalyst II, the alumina accounts for 50.0-60.0wt%, the ZSM-5 zeolite accounts for 5.0-20.0wt%, the cobalt accounts for 2.0-8.0wt% as an oxide, and the tungsten accounts for 6.0-20.0wt% as an oxide.

[0016] Further, the weight ratio of the catalyst I and the catalyst II is 1:0.2-1:4, preferably 1:0.5-1:1.

[0017] Further, the specific surface area of the hydrocracking catalyst is 120.0-500.0m 2 / g, the average pore size is 2.0-12.0nm, the pore volume is 0.16-0.65cm 3 / g, and the acid amount is 0.20-0.80mmol / g.

[0018] Further, the shape of the obtained hydrocracking catalyst can be clover, four-leaf clover, cylinder, and tooth ball.

[0019] The technical purpose of the second aspect of the present application is to provide the hydrocracking catalyst prepared by the above preparation method.

[0020] The hydrocracking catalyst of the present application loads cobalt-tungsten active metal on ZSM-5 molecular sieve, reduces the influence of aromatic hydrocarbon on adsorption reaction of paraffin, strengthens the bond breaking and isomerization of paraffin, loads nickel-tungsten active metal on Y molecular sieve, strengthens the ring-opening cracking reaction of aromatic hydrocarbon, and can significantly reduce the content of aromatic hydrocarbon in transformer oil.

[0021] The technical purpose of the third aspect of the present application is to provide the application of the above hydrocracking catalyst, and the above hydrocracking catalyst is used for preparing transformer oil by oil product hydrocracking.

[0022] Further, the oil product is vacuum gas oil, coking gas oil and the like raw materials. 3 , the initial boiling point is 220-260 DEG C, the dry point is 500-580 DEG C, the sulfur content is 0.5wt%-3.0wt%, and the nitrogen content is 200-2000 μg·g -1 .

[0023] Further, the temperature of the hydrocracking reaction is 320-450 DEG C, preferably 360-390 DEG C, the reaction pressure is 12.0-20.0 MPa, preferably 14.0-17.0 MPa, and the hydrocracking segment volume space velocity is 0.2-2.0 h -1 , preferably 0.5-2.0 h -1 .

[0024] The technical purpose of the fourth aspect of the present application is to provide a method for producing transformer oil, and the oil product is sequentially passed through the bed layers filled with the hydrofining catalyst and the hydrocracking catalyst to produce transformer oil.

[0025] Further, the reaction pressure of the hydrofining is 12.0-20.0 MPa, preferably 14.0-17.0 MPa, the reaction temperature is 340-420 DEG C, preferably 360-400 DEG C, and the hydrofining volume space velocity is 0.2-2.0 h -1 , preferably 0.5-1.5 h -1 .

[0026] Further, the temperature of the hydrocracking reaction is 320-450 DEG C, preferably 360-390 DEG C, the reaction pressure is 12.0-20.0 MPa, preferably 14.0-17.0 MPa, and the hydrocracking segment volume space velocity is 0.2-2.0 h -1 , preferably 0.5-2.0 h -1 .

[0027] Compared with the prior art, the method has the following beneficial effects:

[0028] (1) The present application loads cobalt-tungsten active metal on ZSM-5 molecular sieve, reduces the influence of aromatic hydrocarbon on the adsorption reaction of paraffin, strengthens the bond breaking and isomerization reaction of paraffin, significantly reduces the pour point of transformer oil, and improves the yield of transformer oil. The nickel-tungsten active metal loaded on Y molecular sieve can strengthen the ring-opening cracking reaction of aromatic hydrocarbon, can significantly reduce the content of aromatic hydrocarbon in transformer oil, and improve its stability and color. After compounding, the indicators of the content of aromatic hydrocarbon and the pour point of transformer oil can be considered, the partition strengthening of aromatic ring-opening reaction and paraffin bond-breaking isomerization reaction can be realized, and then the content of aromatic hydrocarbon in hydrocracking diesel and the pour point are reduced, so that the conventional hydrocracking means can directly produce qualified transformer oil products.

[0029] (2) The hydrogenation catalyst system prepared by the method of the present application can realize selective hydrogenation and directional conversion of polycyclic aromatic hydrocarbon, not only low hydrogen consumption of the device, but also good quality of the produced transformer oil.

[0030] (3) The catalyst prepared by the method of the present application has simple preparation process, good reaction activity and selectivity, low required reaction temperature, and can significantly prolong the operation period of the device. DETAILED DESCRIPTION

[0031] The following embodiments will further illustrate the preparation method of the hydrogenation cracking catalyst provided by the present application, and the effect and advantages of the hydrogenation cracking method of the present application will be compared and embodied, but the present application is not limited thereto.

[0032] In the following examples, the experimental methods are conventional methods in the art unless otherwise specified. The experimental materials used in the following examples are purchased from conventional biochemical reagent stores unless otherwise specified.

[0033] In the present application, unless otherwise specified, the percentage refers to the mass fraction.

[0034] Example 1

[0035] Preparation of composite hydrogenation cracking catalyst HC-1

[0036] (1) 40.0wt% Y molecular sieve and 35.0wt% alumina are mechanically mixed, then a binder is added and sufficiently rolled and pressed to form, and then dried at 80℃ to obtain a catalyst carrier; an equal volume impregnation method is used to impregnate nickel-tungsten active metal, wherein the mass fraction of nickel as NiO is 5.2wt%, and the mass fraction of tungsten as WO3 is 19.8wt%. After drying at 80℃ and calcining at 450℃, catalyst I is obtained.

[0037] (2) 20.0% ZSM-5 molecular sieve and 58.0 wt% alumina are mechanically mixed, a binder is added, and the mixture is sufficiently rolled and shaped, and then dried at 80°C to obtain a catalyst carrier; the catalyst carrier is impregnated with a solution containing cobalt-tungsten active metal components, and cobalt-tungsten active metal is impregnated by using the equal-volume impregnation method, wherein the mass fraction of cobalt, calculated as CoO, is 4.5 wt%, and the mass fraction of tungsten, calculated as WO3, is 17.5 wt%. After drying at 70°C and calcination at 500°C, catalyst II is obtained.

[0038] (3) Finally, catalyst I and catalyst II are mechanically mixed at a weight ratio of 2:1 to obtain a composite hydrocracking catalyst HC-1.

[0039] The specific surface area of the composite hydrocracking catalyst HC-1 is 421.0 m 2 / g, the average pore size is 5.2 nm, the pore volume is 0.60 cm 3 / g, and the acid amount is 1.20 mmol / g.

[0040] Example 2

[0041] Preparation of a composite hydrocracking catalyst HC-2

[0042] (1) 45.0 wt% Y molecular sieve and 30.0 wt% alumina are mechanically mixed, a binder is added, and the mixture is sufficiently rolled and shaped, and then dried at 80°C to obtain a catalyst carrier; nickel-tungsten active metal is impregnated by using the equal-volume impregnation method, wherein the mass fraction of nickel, calculated as NiO, is 5.5 wt%, and the mass fraction of tungsten, calculated as WO3, is 19.5 wt%. After drying at 80°C and calcination at 420°C, catalyst I is obtained.

[0043] (2) 15 wt% ZSM-5 molecular sieve and 60 wt% alumina are mechanically mixed, a binder is added, and the mixture is sufficiently rolled and shaped, and then dried at 80°C to obtain a catalyst carrier; the catalyst carrier is impregnated with a solution containing cobalt-tungsten active metal components, and cobalt-tungsten active metal is impregnated by using the equal-volume impregnation method, wherein the mass fraction of cobalt, calculated as CoO, is 6.0 wt%, and the mass fraction of tungsten, calculated as WO3, is 19.0 wt%. After drying at 70°C and calcination at 550°C, catalyst II is obtained.

[0044] (3) Finally, catalyst I and catalyst II are mechanically mixed at a weight ratio of 3:1 to obtain a composite hydrocracking catalyst HC-2.

[0045] The specific surface area of the composite hydrocracking catalyst HC-2 is 425.0 m 2 / g, the average pore size is 5.5 nm, the pore volume is 0.65 cm 3 / g, and the acid amount is 1.31 mmol / g.

[0046] Example 3

[0047] Preparation of composite hydrocracking catalyst HC-3

[0048] (1) 38.0 wt% Y molecular sieve and 37.0 wt% alumina were mechanically mixed, a binder was added, and the mixture was sufficiently rolled and then formed to obtain a catalyst carrier which was dried at 80°C. An equal volume impregnation method was used to impregnate nickel-tungsten active metals, wherein the mass fraction of nickel was 4.5 wt% as NiO, and the mass fraction of tungsten was 20.5 wt% as WO3. After drying at 80°C and calcination at 470°C, catalyst I was obtained.

[0049] (2) 18.0 wt% ZSM-5 molecular sieve and 57.0 wt% alumina were mechanically mixed, a binder was added, and the mixture was sufficiently rolled and then formed to obtain a catalyst carrier which was dried at 80°C. The catalyst carrier was impregnated with a solution containing cobalt-tungsten active metal components, and an equal volume impregnation method was used to impregnate cobalt-tungsten active metals, wherein the mass fraction of nickel species was 5.0 wt% as CoO, and the mass fraction of tungsten was 20.0 wt% as WO3. After drying at 70°C and calcination at 500°C, catalyst II was obtained.

[0050] (3) Finally, catalyst I and catalyst II were mechanically mixed in a weight ratio of 1:1 to obtain composite hydrocracking catalyst HC-3.

[0051] The specific surface area of composite hydrocracking catalyst HC-3 was 434.3 m 2 / g, the average pore size was 5.4 nm, the pore volume was 0.50 cm 3 / g, and the acid amount was 1.00 mmol / g.

[0052] Example 4

[0053] Preparation of composite hydrocracking catalyst HC-4

[0054] (1) 40.0 wt% Y molecular sieve and 35.0 wt% alumina were mechanically mixed, a binder was added, and the mixture was sufficiently rolled and then formed to obtain a catalyst carrier which was dried at 80°C. An equal volume impregnation method was used to impregnate nickel-tungsten active metals, wherein the mass fraction of nickel was 5.5 wt% as NiO, and the mass fraction of tungsten was 19.5 wt% as WO3. After drying at 80°C and calcination at 450°C, catalyst I was obtained.

[0055] (2) 20.0 wt% ZSM-5 molecular sieve and 58.0 wt% alumina are mechanically mixed, then a binder is added and the mixture is sufficiently rolled and shaped, and then dried at 80°C to obtain a catalyst carrier; the catalyst carrier is impregnated with a solution containing cobalt-tungsten active metal components, and cobalt-tungsten active metal is impregnated by using the equal-volume impregnation method, wherein the mass fraction of nickel species calculated as CoO is 5.5 wt%, and the mass fraction of tungsten calculated as WO3 is 16.5 wt%. After drying at 70°C and calcination at 500°C, catalyst II is obtained.

[0056] (3) Finally, catalyst I and catalyst II are mechanically mixed in a weight ratio of 2:1 to obtain a composite hydrocracking catalyst HC-4.

[0057] The specific surface area of the composite hydrocracking catalyst HC-4 is 416.5 m 2 / g, the average pore size is 5.5 nm, the pore volume is 0.53 cm 3 / g, and the acid amount is 1.05 mmol / g.

[0058] Two reactors in series are used, and a hydrofining catalyst and the hydrocracking catalyst prepared in the application are sequentially loaded, i.e., a hydrofining catalyst FHUDS-5 is loaded in the first reactor, and the hydrocracking catalysts of Examples 1-4 are loaded in the second reactor. The feedstock oil in Table 1 is used as the raw material, and a 2000h process evaluation experiment is carried out according to the process reaction conditions in Table 3.

[0059] Comparative Example 1

[0060] Preparation of the hydrocracking catalyst:

[0061] (1) 40.0 wt% Y molecular sieve and 35.0 wt% alumina are mechanically mixed, then a binder is added and the mixture is sufficiently rolled and shaped, and then dried at 80°C to obtain a catalyst carrier; nickel-tungsten active metal is impregnated by using the equal-volume impregnation method, wherein the mass fraction of nickel calculated as NiO is 5.5 wt%, and the mass fraction of tungsten calculated as WO3 is 19.5 wt%. After drying at 80°C and calcination at 450°C, catalyst I is obtained.

[0062] (2) 20.0 wt% ZSM-5 molecular sieve and 58.0 wt% alumina are mechanically mixed, then a binder is added and the mixture is sufficiently rolled and shaped, and then dried at 80°C to obtain a catalyst carrier; nickel-tungsten active metal is impregnated by using the equal-volume impregnation method, wherein the mass fraction of nickel calculated as NiO is 5.5 wt%, and the mass fraction of tungsten calculated as WO3 is 19.5 wt%. After drying at 80°C and calcination at 450°C, catalyst II is obtained.

[0063] (3) Finally, catalyst I and catalyst II are mechanically mixed in a weight ratio of 2:1 to obtain a composite hydrocracking catalyst HC-5.

[0064] The specific surface area of the composite hydrocracking catalyst HC-5 is 419.5 m 2 / g, the average pore size is 5.6 nm, and the pore volume is 0.56 cm 3 / g, and the acid amount is 1.15 mmol / g.

[0065] Two reactors in series were used, and the hydrogenation refining catalyst and the hydrogenation cracking catalyst prepared in the application were sequentially loaded, i.e., the first reactor was loaded with the hydrogenation refining catalyst FHUDS-5, and the second reactor was loaded with the HC-5 hydrogenation cracking catalyst. The feedstock oil in Table 1 was used as the raw material, and the process evaluation experiment was carried out for 2000 h according to the process reaction conditions in Table 3.

[0066] Comparative Example 2

[0067] The FHUDS-5 refining catalyst was loaded in the hydrogenation refining reactor, the conventional industrial FC-46 hydrogenation cracking catalyst was used instead of the hydrogenation cracking catalyst of the application and was loaded in the second reactor, the feedstock oil in Table 1 was used as the raw material, and the process evaluation experiment was carried out for 2000 h according to the process reaction conditions in Table 3.

[0068] Comparative Example 3

[0069] The FHUDS-5 refining catalyst was loaded in the hydrogenation refining reactor, the hydrogenation cracking catalyst prepared in Comparative Example 1 was used instead of the hydrogenation cracking catalyst of the application and was loaded in the second reactor, the feedstock oil in Table 1 was used as the raw material, and the process evaluation experiment was carried out for 2000 h according to the process reaction conditions in Table 3.

[0070] The feedstock oil was straight-run waxy oil, and the properties are shown in Table 1.

[0071] Table 1

[0072] Feedstock oil name Straight-run wax oil Density (20°C) / g-cm -3 ]] 0.9002 Distillation range / °C 300～530 S, wt% 2.15 [N, pg g -1 ]] 789 Aromatics, wt% 35.6

[0073] The properties of the industrial FHUDS-5 and FC-46 catalysts used in Example 5 and Comparative Example 1 are shown in Table 2.

[0074] Table 2

[0075] Industrial agent FHUDS-5 FC-46 Active metal Mo-Co W-Ni WO3, m% 20.0～25.0 MoO3, m% ≮18.0 CoO, m% ≮3.0 NiO, m% 4.8～6.2 Pore diameter / nm 2-10 nm 3-9 nm Pore volume / mL-g -1 ]] ≥0.33 ≥0.26 Specific surface area / m 2 ·g -1 ]]> ≥200 ≥360 Shape Clover Cylindrical bar Charge bulk, g / cm 3 ]]> 0.84 0.74

[0076] Table 3

[0077] Reaction pressure, MPa 16.0 hydroprocessing reaction zone volume hourly space velocity, h -1 ]]> 1.0 hydrocracking reaction zone volume hourly space velocity, h -1 ]]> 1.5 Refined oil nitrogen content, ppm 10 Hydrocracking conversion rate, % 65 Hydrofining reaction zone inlet hydrogen / oil ratio 800:1 Hydrocracking reactor inlet hydrogen / oil ratio 1200:1 Operation time, h 2000

[0078] The experimental results after running are shown in Table 4.

[0079] Table 4 Evaluation results of examples and comparative examples

[0080]

[0081] From the experimental results of the comparative examples and the examples, it can be seen that, under the condition of controlling the same conversion rate, the hydrogen consumption is low, the content of aromatic hydrocarbons and the pour point of the produced transformer oil are low, and the transformer oil is qualified 0# transformer oil. When the catalyst system under the condition of Example 1 is used, the content of polycyclic aromatic hydrocarbons of the produced 275-365°C transformer oil is the lowest, 0.10%, and the pour point is the lowest, -16°C.

Claims

1. A method of producing a transformer oil, characterized by, The oil product is sequentially passed through beds or reactors filled with a hydrofining catalyst and a hydrocracking catalyst to produce transformer oil; The hydrocracking catalyst is prepared by the following steps: (1) mixing Y molecular sieve, alumina and a binder to form a carrier I, loading nickel and tungsten on the carrier I, drying, and calcining to obtain a catalyst I; (2) mixing ZSM-5 molecular sieve, alumina and a binder to form a carrier II, loading cobalt and tungsten on the carrier II, drying, and calcining to obtain a catalyst II; (3) mixing the catalyst I and the catalyst II to obtain the hydrocracking catalyst; The weight ratio of catalyst I and catalyst II is 1:0.2-1:4; the specific surface area of the hydrocracking catalyst is 120.0-500.0m 2 / g, the average pore size is 2.0-12.0nm, the pore volume is 0.16-0.65cm 3 / g, and the acid amount is 0.20-0.80mmol / g.

2. The method of claim 1, wherein, The loading of the active components in (1) and (2) is performed by impregnation, including isovolume impregnation, excess volume impregnation or steam impregnation.

3. The method of claim 1, wherein, The drying temperature in (1) and (2) is 70-120°C, and the calcining temperature is 350-500°C.

4. The method of claim 1, wherein, Based on the total weight of the catalyst I, the alumina accounts for 30.0-40.0wt%, the Y molecular sieve accounts for 30.0-50.0wt%, the nickel accounts for 4.0-12.0wt% as an oxide, and the tungsten accounts for 12.0-25.0wt% as an oxide.

5. The method of claim 1, wherein, Based on the total weight of the catalyst II, the alumina accounts for 50.0-60.0wt%, the ZSM-5 molecular sieve accounts for 5.0-20.0wt%, the cobalt accounts for 2.0-8.0wt% as an oxide, and the tungsten accounts for 6.0-20.0wt% as an oxide.

6. The method of claim 1, wherein, The weight ratio of the catalyst I to the catalyst II is 1:0.5-1:

1.

7. The method of claim 1, wherein, The temperature of the hydrocracking reaction is 320-450℃, the reaction pressure is 12.0-20.0MPa, the hydrocracking section volume space velocity is 0.2-2.0h -1 .

8. The method of claim 1, wherein, The reaction pressure of the hydrofining is 12.0-20.0 MPa, the reaction temperature is 340-420 ℃, the hydrofining volume space velocity is 0.2-2.0 h -1 .

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