Hydrocracking catalyst as well as preparation method and application thereof

Abstract

The invention provides a hydrocracking catalyst, which is characterized in that a catalyst I is formed by mixing a Y molecular sieve, alumina and an adhesive to serve as a carrier and is loaded with nickel and tungsten, a catalyst II is formed by mixing a ZSM-5 molecular sieve, alumina and an adhesive to serve as a carrier and is loaded with cobalt and tungsten, and the catalyst I and the catalyst II are mixed to obtain the hydrocracking catalyst. Cobalt and tungsten are loaded on the ZSM-5 molecular sieve, so that the influence of aromatic hydrocarbon on alkane adsorption reaction is reduced, bond breaking and isomerization reaction of alkane are enhanced, the pour point of the transformer oil is remarkably reduced, and the yield of the transformer oil is increased; nickel and tungsten are loaded on the Y molecular sieve, so that the ring-opening cracking reaction of aromatic hydrocarbon is enhanced, the aromatic hydrocarbon content in the transformer oil can be remarkably reduced, and the stability and chromaticity of the transformer oil are improved. The composite catalyst gives consideration to indexes of the aromatic hydrocarbon content and the pour point of the transformer oil, can realize partitioned reinforcement of an aromatic hydrocarbon ring-opening reaction and a paraffin bond-breaking isomerization reaction, and can directly produce a qualified transformer oil product.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrocracking, and in particular relates to a method for preparing a hydrocracking catalyst. Background Art

[0002] With the adjustment of domestic economic structure and the slowdown of economic growth, as well as the promotion and application of clean alternative fuels such as LNG, the growth rate of diesel consumption has slowed down, and it will become normal for it to be lower than the growth rate of gasoline consumption. The continuous decline in the diesel-gasoline ratio has led to a gradual deviation from the adjustment range of the diesel-gasoline ratio, resulting in an oversupply of diesel production capacity. The hydrocracking diesel product has a low aromatic content, and its heavy components can be used as a transformer oil product with more added value and market prospects. Therefore, it is of great significance to improve the comprehensive economic benefits of the unit by optimizing process parameters and reducing the diesel product yield of the hydrocracking unit.

[0003] Among special oil products, transformer oil requires low aromatic and high isoparaffin content, while conventional hydrocracking catalysts often use a single molecular sieve component, which makes it difficult to take into account both the ring opening of aromatics and the isomerization of paraffins. The transformer oil produced will face the problem of too high aromatic content or pour point.

[0004] Therefore, it is of great significance to develop a hydrocracking catalyst that takes into account both the ring-opening of aromatics and the isomerization ability of paraffins, so as to simultaneously reduce the content of aromatics and normal alkanes in the transformer oil components produced by hydrocracking, thereby producing qualified transformer oil products.

[0005] CN114181758A discloses transformer oil and its preparation method. The invention heats the synthetic ester base oil to a set temperature; adds an antioxidant to obtain a mother liquor mixture; fully stirs the mother liquor mixture; adds a mineral base oil and fully stirs; and vacuum filters the stirred mixture. The transformer oil prepared by using 90-95 parts of mineral base oil, 5-10 parts of synthetic ester base oil, and 0.2-0.3 parts of antioxidant can not only ensure that the oil meets various index requirements, but also can meet the breakdown voltage of more than 40kV when the moisture content exceeds 30mg / kg, thereby improving the electrical performance of the oil.

[0006] CN107619706A discloses a transformer oil and a preparation method thereof. The transformer oil is prepared by using cycloalkyl and paraffinic vacuum distillate oil as raw materials, undergoing a three-stage high-pressure hydrogenation production process, and adding a combined aromatic additive and an antioxidant. The components are calculated by mass percentage, and the paraffinic base oil fraction accounts for 15% to 25%, the combined aromatic additive accounts for 4 to 7%, the antioxidant accounts for 0.3% ± 0.05%, and the balance is cycloalkyl base oil; the transformer oil provided by the transformer oil has excellent carbon structure and anti-gassing performance, and its low temperature performance and antioxidant performance are higher than those of existing products on the market. However, this method has strict requirements on the composition of the raw oil, a complex process flow, and a high production cost of the transformer oil. Summary of the invention

[0007] In view of the deficiencies of the prior art, the present invention provides a method for preparing a hydrocracking catalyst to produce qualified transformer oil products.

[0008] The present invention provides a method for preparing a hydrocracking catalyst, comprising the following steps:

[0009] (1) Y molecular sieve, alumina and a binder are mixed and formed to obtain a carrier I, nickel and tungsten are loaded on the carrier I, dried and calcined to obtain a catalyst I;

[0010] (2) ZSM-5 molecular sieve, alumina and a binder are mixed and molded to obtain carrier II, cobalt and tungsten are loaded on carrier II, dried and calcined to obtain catalyst II;

[0011] (3) Catalyst I and catalyst II are mixed to obtain the hydrocracking catalyst.

[0012] Furthermore, the active components in (1) and (2) are loaded by an impregnation method, including an equal volume impregnation method, an excess volume impregnation method, and a steam impregnation method, etc. The specific operation method is well known to those skilled in the art.

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

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

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

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

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

[0018] Furthermore, the obtained hydrocracking catalyst may have a shape of a three-leaf clover, a four-leaf clover, a cylinder, a toothed ball, or the like.

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

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

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

[0022] Furthermore, the oil product is a raw material such as vacuum wax oil, coking wax oil, etc. The density is 0.88-0.94g / cm 3 , initial distillation point is 220-260℃, dry point is 500-580℃, sulfur content is 0.5wt%-3.0wt%, nitrogen content is 200-2000μg·g -1 .

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

[0024] The technical purpose of the fourth aspect of the present invention is to provide a method for producing transformer oil, wherein the oil product is sequentially passed through a bed layer loaded with a hydrorefining catalyst and the hydrocracking catalyst to produce transformer oil.

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

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

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

[0028] (1) The present invention loads cobalt tungsten active metal on ZSM-5 molecular sieve, reduces the influence of aromatics on the adsorption reaction of paraffins, strengthens the bond breaking and isomerization reaction of paraffins, significantly reduces the pour point of transformer oil, and improves the yield of transformer oil. The nickel tungsten active metal is loaded on the Y molecular sieve, which can strengthen the ring-opening cracking reaction of aromatics, significantly reduce the aromatic content in transformer oil, and improve its stability and chromaticity. After the two are compounded, the indicators of the aromatic content and pour point of transformer oil can be taken into account, and the partitioning strengthening of the aromatic ring-opening reaction and the chain alkane bond breaking isomerization reaction can be achieved, thereby reducing the aromatic content and pour point in hydrocracking diesel, so that conventional hydrocracking means can directly produce qualified transformer oil products.

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

[0030] (3) The catalyst prepared by the method of the present invention has a simple preparation process, good reaction activity and selectivity, and requires a low reaction temperature, which can significantly extend the operation cycle of the device. DETAILED DESCRIPTION

[0031] The following is a further description of a method for preparing a hydrocracking catalyst provided by the present invention in conjunction with examples to compare and embody the effects and advantages of the hydrocracking method of the present invention, but the present invention is not limited thereto.

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

[0033] In the present invention, unless otherwise specified, percentages refer to mass fractions.

[0034] Example 1

[0035] Preparation of composite hydrocracking catalyst HC-1

[0036] (1) After mechanically mixing 40.0wt% Y molecular sieve and 35.0wt% alumina, a binder was added and fully rolled to form, and then dried at 80°C to obtain a catalyst carrier; nickel and tungsten active metals were impregnated by an equal volume impregnation method, wherein the mass fraction of nickel in terms of NiO was 5.2wt% and the mass fraction of tungsten in terms of WO3 was 19.8wt%. Catalyst I was obtained after drying at 80°C and calcining at 450°C.

[0037] (2) After mechanically mixing 20.0% ZSM-5 molecular sieve and 58.0wt% alumina, a binder was added and fully rolled to form, and then dried at 80°C to obtain a catalyst carrier; the catalyst carrier was impregnated with a solution containing cobalt and tungsten active metal components, and the cobalt and tungsten active metals were impregnated by an equal volume impregnation method, wherein the mass fraction of cobalt calculated as CoO was 4.5wt%, and the mass fraction of tungsten calculated as WO3 was 17.5wt%. After drying at 70°C and calcining at 500°C, Catalyst II was obtained.

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

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

[0040] Example 2

[0041] Preparation of composite hydrocracking catalyst HC-2

[0042] (1) After mechanically mixing 45.0wt% Y molecular sieve and 30.0wt% alumina, a binder was added, fully rolled and formed, and then dried at 80°C to obtain a catalyst carrier; nickel and tungsten active metals were impregnated by an equal volume impregnation method, wherein the mass fraction of nickel in terms of NiO was 5.5wt%, and the mass fraction of tungsten in terms of WO3 was 19.5wt%. Catalyst I was obtained after drying at 80°C and calcining at 420°C.

[0043] (2) After mechanically mixing 15wt% ZSM-5 molecular sieve and 60wt% alumina, a binder was added and fully rolled to form, and then dried at 80°C to obtain a catalyst carrier; the catalyst carrier was impregnated with a solution containing cobalt and tungsten active metal components, and the cobalt and tungsten active metals were impregnated by an equal volume impregnation method, wherein the mass fraction of cobalt calculated as CoO was 6.0wt%, and the mass fraction of tungsten calculated as WO3 was 19.0wt%. After drying at 70°C and calcining at 550°C, Catalyst II was obtained.

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

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

[0046] Example 3

[0047] Preparation of composite hydrocracking catalyst HC-3

[0048] (1) After mechanically mixing 38.0wt% Y molecular sieve and 37.0wt% alumina, a binder was added, fully rolled and formed, and then dried at 80°C to obtain a catalyst carrier; nickel and tungsten active metals were impregnated by an equal volume impregnation method, wherein the mass fraction of nickel in terms of NiO was 4.5wt%, and the mass fraction of tungsten in terms of WO3 was 20.5wt%. Catalyst I was obtained after drying at 80°C and calcining at 470°C.

[0049] (2) After mechanically mixing 18.0wt% ZSM-5 molecular sieve and 57.0wt% alumina, a binder was added and fully rolled to form, and then dried at 80°C to obtain a catalyst carrier; the catalyst carrier was impregnated with a solution containing cobalt and tungsten active metal components, and the cobalt and tungsten active metals were impregnated by an equal volume impregnation method, wherein the mass fraction of cobalt in terms of CoO and nickel species was 5.0wt%, and the mass fraction of tungsten in terms of WO3 was 20.0wt%. After drying at 70°C and calcining 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 a composite hydrocracking catalyst HC-3.

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

[0052] Example 4

[0053] Preparation of composite hydrocracking catalyst HC-4

[0054] (1) After mechanically mixing 40.0wt% Y molecular sieve and 35.0wt% alumina, a binder was added and fully rolled to form, and then dried at 80°C to obtain a catalyst carrier; nickel and tungsten active metals were impregnated by an equal volume impregnation method, wherein the mass fraction of nickel in terms of NiO was 5.5wt%, and the mass fraction of tungsten in terms of WO3 was 19.5wt%. Catalyst I was obtained after drying at 80°C and calcining at 450°C.

[0055] (2) After mechanically mixing 20.0wt% ZSM-5 molecular sieve and 58.0wt% alumina, a binder was added and fully rolled to form, and then dried at 80°C to obtain a catalyst carrier; the catalyst carrier was impregnated with a solution containing cobalt and tungsten active metal components, and the cobalt and tungsten active metals were impregnated by an equal volume impregnation method, wherein the mass fraction of cobalt in terms of CoO and the mass fraction of tungsten in terms of WO3 was 5.5wt%, and the mass fraction of tungsten in terms of WO3 was 16.5wt%. After drying at 70°C and calcining at 500°C, catalyst II was obtained.

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

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

[0058] Two reactors connected in series were used, and the hydrofining catalyst and the hydrocracking catalyst prepared by the present invention were sequentially loaded, that is, the first reactor was loaded with the hydrofining catalyst FHUDS-5, and the second reactor was loaded with the hydrocracking catalyst of Examples 1 to 4. The crude oil in Table 1 was used as the raw material, and a 2000h process evaluation experiment was carried out according to the process reaction conditions in Table 3.

[0059] Comparative Example 1

[0060] Preparation of hydrocracking catalyst:

[0061] (1) After mechanically mixing 40.0wt% Y molecular sieve and 35.0wt% alumina, a binder was added and fully rolled to form, and then dried at 80°C to obtain a catalyst carrier; nickel and tungsten active metals were impregnated by an equal volume impregnation method, wherein the mass fraction of nickel in terms of NiO was 5.5wt%, and the mass fraction of tungsten in terms of WO3 was 19.5wt%. Catalyst I was obtained after drying at 80°C and calcining at 450°C.

[0062] (2) After mechanically mixing 20.0wt% ZSM-5 molecular sieve and 58.0wt% alumina, a binder was added and fully rolled to form, and then dried at 80°C to obtain a catalyst carrier; nickel and tungsten active metals were impregnated by an equal volume impregnation method, wherein the mass fraction of nickel in terms of NiO was 5.5wt%, and the mass fraction of tungsten in terms of WO3 was 19.5wt%. Catalyst II was obtained after drying at 80°C and calcining at 450°C.

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

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

[0065] Two reactors connected in series were used, and the hydrofining catalyst and the hydrocracking catalyst prepared by the present invention were sequentially loaded, that is, the first reactor was loaded with the hydrofining catalyst FHUDS-5, and the second reactor was loaded with the HC-5 hydrocracking catalyst. The crude oil in Table 1 was used as the raw material, and a 2000h process evaluation experiment was carried out according to the process reaction conditions in Table 3.

[0066] Comparative Example 2

[0067] The FHUDS-5 refining catalyst was loaded into the hydrorefining reactor, and the conventional industrial FC-46 hydrocracking catalyst was used instead of the hydrocracking catalyst of the present invention and loaded into the second reactor. The crude oil in Table 1 was used as the raw material, and a 2000h process evaluation experiment was carried out according to the process reaction conditions in Table 3.

[0068] Comparative Example 3

[0069] The FHUDS-5 refining catalyst was loaded into the hydrorefining reactor, and the hydrocracking catalyst prepared in Comparative Example 1 was used instead of the hydrocracking catalyst of the present invention and loaded into the second reactor. The crude oil in Table 1 was used as the raw material, and a 2000h process evaluation experiment was carried out according to the process reaction conditions in Table 3.

[0070] The raw material oil is straight-run wax oil, and its properties are shown in Table 1.

[0071] Table 1

[0072] Raw oil name Straight run wax oil <![CDATA[Density (20 °C) / g·cm -3 > 0.9002 Distillation range / ℃ 300～530 S, wt% 2.15 <![CDATA[N,μg·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 Agents FHUDS-5 FC-46 Active Metals Mo-Co W-Ni <![CDATA[WO3,,m%]]> 20.0～25.0 <![CDATA[MoO3,m%]]> ≮18.0 CoO, m% ≮3.0 NiO, m% 4.8～6.2 Pore ​​diameter / nm 2~10nm 3~9nm <![CDATA[Pore volume / mL·g -1 > ≥0.33 ≥0.26 <![CDATA[Specific surface area / m 2 ·g -1 > ≥200 ≥360 shape Shamrock Cylindrical Bar <![CDATA[Loading heap ratio, g / cm 3 > 0.84 0.74

[0076] Table 3

[0077] Reaction pressure, MPa 16.0 <![CDATA[Hydrofining reaction zone volumetric space velocity, h -1 > 1.0 <![CDATA[Hydrocracking reaction zone volumetric space velocity, h -1 > 1.5 Nitrogen content of refined oil, ppm 10 Hydrocracking conversion rate, % 65 Hydrogen to oil ratio at the inlet of hydrotreating reaction zone 800:1 Hydrogen to oil ratio at the inlet of hydrocracking reactor 1200:1 Running 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] It can be seen from the experimental results of the comparative examples and the embodiments that, under the condition of controlling the same conversion rate, the hydrocracking method of the present invention not only has low hydrogen consumption, but also has low aromatic content and pour point of the transformer oil produced, and is a qualified 0# transformer oil. When the catalyst system under the conditions of Example 1 is adopted, the polycyclic aromatic hydrocarbon content of the transformer oil produced at 275-365°C is the lowest, which is 0.10%, and the pour point is the lowest at -16°C.

Claims

1. A method for preparing a hydrocracking catalyst, comprising the following steps: (1) Y molecular sieve, alumina and a binder are mixed and formed to obtain carrier I, nickel and tungsten are loaded on carrier I, dried and calcined to obtain catalyst I; (2) ZSM-5 molecular sieve, alumina and a binder are mixed and formed to obtain carrier II, cobalt and tungsten are loaded on carrier II, dried and calcined to obtain catalyst II; (3) Catalyst I and catalyst II are mixed to obtain the hydrocracking catalyst.

2. The preparation method according to claim 1, characterized in that: The active components in (1) and (2) are loaded by an impregnation method, including an equal volume impregnation method, an excess volume impregnation method or a steam impregnation method.

3. The preparation method according to claim 1, characterized in that: The drying temperature in (1) and (2) is 70-120°C, and the calcining temperature is 350-500°C.

4. The preparation method according to claim 1, characterized in that: Based on the total weight of catalyst I, alumina accounts for 30.0-40.0wt%, Y molecular sieve accounts for 30.0-50.0wt%, nickel accounts for 4.0-12.0wt% in terms of oxide, and tungsten accounts for 12.0-25.0wt% in terms of oxide.

5. The preparation method according to claim 1, characterized in that: Based on the total weight of Catalyst II, alumina accounts for 50.0-60.0wt%, ZSM-5 molecular sieve accounts for 5.0-20.0wt%, cobalt accounts for 2.0-8.0wt% in terms of oxide, and tungsten accounts for 6.0-20.0wt% in terms of oxide.

6. The preparation method according to claim 1, characterized in that: The weight ratio of the catalyst I to the catalyst II is 1:0.2-1:4, preferably 1:0.5-1:

1.

7. The preparation method according to claim 1, characterized in that: The specific surface area of ​​the hydrocracking catalyst is 120.0-500.0m 2 / g, average pore diameter of 2.0-12.0nm, pore volume of 0.16-0.65cm 3 / g, and the acid content is 0.20-0.80mmol / g.

8. The hydrocracking catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the hydrocracking catalyst according to claim 8 for preparing transformer oil by hydrocracking of oil products.

10. The use according to claim 9, characterized in that: The temperature of the hydrocracking reaction is 320-450°C, the reaction pressure is 12.0-20.0 MPa, and the volume space velocity of the hydrocracking stage is 0.2-2.0 h -1 .

11. A method for producing transformer oil, characterized in that: The oil product is sequentially passed through a bed or reactor filled with a hydrorefining catalyst and the hydrocracking catalyst to produce transformer oil.

12. The method according to claim 11, characterized in that The reaction pressure of hydrofining is 12.0-20.0MPa, the reaction temperature is 340-420℃, and the volumetric space velocity of hydrofining is 0.2-2.0h -1 .

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