A hydrocracking method for producing raw materials for lubricating oil base oil

Abstract

The present invention discloses a hydrocracking method for producing raw materials of lubricating oil base oil, which is characterized in that: the feedstock sequentially passes through a hydrofining reaction zone and a hydrocracking reaction zone. The hydrofining reaction zone is filled with a hydrofining catalyst, and the hydrocracking reaction zone is filled with a hydrocracking catalyst. The hydrocracking catalyst includes a hydrogenation active metal component and a carrier. The carrier includes a modified ZSM-22 molecular sieve and a Y molecular sieve. The molar ratio of SiO2 / Al2O3 on the outer surface of the modified ZSM-22 molecular sieve is 500 to 1000, and the molar ratio of SiO2 / Al2O3 in the bulk phase is 50 to 150. The total pyridine infrared acid amount is 0.1 to 0.5 mmol / g, and the total infrared acid amount of di-tert-butylpyridine is 0.001 to 0.03 mmol / g. By processing the hydrocracking feedstock with the method, a hydrocracking tail oil with a high viscosity index, a low content of n-paraffins and good low-temperature fluidity can be obtained, which is used as a high-quality raw material for lubricating oil base oil.

Description

Technical Field

[0001] The present invention relates to the field of hydrocracking, and particularly to a method for producing high-quality tail oil as a raw material for lubricating base oil by hydrocracking. Background Art

[0002] Due to the characteristics of strong raw material adaptability, flexible operation scheme, green and environmental protection in the production process, high selectivity and good quality of target products, hydrocracking technology has become one of the important processing means for producing high-quality chemical raw materials and clean fuel oils from inferior petroleum raw materials. In the hydrocracking reaction process, the polycyclic aromatic hydrocarbons contained in the feedstock oil undergo hydrogenation saturation, ring-opening conversion and other reactions, and the generated paraffins are enriched in the tail oil product, which can be used as high-quality raw materials for producing lubricating base oil.

[0003] The viscosity index of lubricating base oil is closely related to the hydrocarbon structure and composition it contains. Cyclic hydrocarbons with long side chains and isoparaffins with short branched chains are ideal components of lubricating base oil. Although normal paraffins have a very high viscosity index, due to their high pour point, the low-temperature flow performance of lubricating oil is affected, and it is necessary to convert them into isoparaffins.

[0004] The hydrocracking catalyst is a bifunctional catalyst composed of an active metal as a hydrogenation component and a molecular sieve with acidity or amorphous silica-alumina as a cracking component.

[0005] CN102145307A discloses a method for producing lubricating base oil with a high viscosity index. This method uses a silica-alumina composite material as the cracking component of the cracking catalyst, and the catalyst shows excellent hydrogenation activity and middle distillate selectivity. However, due to the weak acidity of the silica-alumina composite material, the catalyst activity is low, and the viscosity index of the lubricating base oil obtained by hydrocracking can only reach about 86.

[0006] Y-type molecular sieve is the most commonly used cracking component in hydrocracking catalysts. It has a strong ring-opening conversion function for polycyclic cyclic hydrocarbons, but its isomerization performance is weak. The content of straight-chain paraffins in the tail oil obtained by hydrocracking is relatively high, which affects its low-temperature flow performance. Therefore, using molecular sieves with appropriate cracking performance and strong isomerization performance as acidic cracking components together can strengthen the isomerization performance of the catalyst while ensuring the ring-opening conversion ability of the catalyst, thereby effectively reducing the content of normal paraffins in the hydrocracking tail oil and obtaining a lubricating base oil raw material with a high viscosity index and good low-temperature flow performance.

[0007] US7300900B2 discloses a method for producing hydrocracked tail oil with a high viscosity index. The hydrocracking catalyst used in this method employs one or several of molecular sieves such as ZBM-30, ZSM-48, and EU-1 in combination with Y molecular sieve as the cracking component. The viscosity index of the hydrocracked tail oil obtained under the same process conditions is 5 units higher than that obtained using only Y molecular sieve as the cracking component.

[0008] Both CN107344108A and CN106669801A use Y and ZSM-48 composite molecular sieves together as the acidic components of the cracking catalyst. Through the modification treatment of the molecular sieves, the prepared catalyst has good ring-opening conversion activity and isomerization performance, and can produce hydrocracked tail oil products with a low content of straight-chain alkanes and a high viscosity index as raw materials for lubricating oil base oil. Summary of the Invention

[0009] In view of the deficiencies of the prior art, the present invention provides a hydrocracking method for producing raw materials for lubricating oil base oil. The method can process hydrocracking raw materials to obtain hydrocracked tail oil with a high viscosity index, a low content of normal alkanes, and good low-temperature flow performance, as high-quality raw materials for lubricating oil base oil.

[0010] A hydrocracking method for producing raw materials for lubricating oil base oil, wherein the raw material oil sequentially passes through a hydrotreating reaction zone and a hydrocracking reaction zone. The hydrotreating reaction zone is filled with a hydrotreating catalyst, and the hydrocracking reaction zone is filled with a hydrocracking catalyst. The hydrocracking catalyst includes a hydrogenation active metal component and a carrier. The carrier includes a modified ZSM-22 molecular sieve and a Y molecular sieve. The molar ratio of SiO2 / Al2O3 on the outer surface of the modified ZSM-22 molecular sieve is 500 - 1000, and the molar ratio of SiO2 / Al2O3 in the bulk phase is 50 - 150. The total pyridine infrared acid amount is 0.1 - 0.5 mmol / g, and the total infrared acid amount of di-tert-butylpyridine is 0.001 - 0.03 mmol / g.

[0011] In the method of the present invention, the raw material oil is one or several of vacuum gas oil, coker wax oil, solvent-refined deasphalted oil, and Fischer-Tropsch synthesis oil.

[0012] In the method of the present invention, the hydrotreating catalyst can adopt a conventional hydrotreating catalyst, generally using an alumina-based carrier, with Group VIB and Group VIII metals as the hydrogenation active metal components. The Group VIB metal is preferably molybdenum and / or tungsten, and the Group VIII metal is preferably cobalt and / or nickel. Based on the weight of the catalyst, the content of the Group VIB metal (calculated as the oxide) is 15.0% - 30.0%, and the content of the Group VIII metal (calculated as the oxide) is 4.0% - 8.0%.

[0013] In the method of the present invention, the hydrocracking reaction conditions are as follows: the reaction pressure is 12.0 - 18.0 MPa, the temperature is 350 - 435 °C, the hydrogen-oil volume ratio is 1000:1 - 2000:1, and the liquid hourly space velocity is 0.5 - 5.0 h -1 .

[0014] In the method of the present invention, the hydrofining reaction conditions are as follows: the reaction pressure is 12.0 - 18.0 MPa, the temperature is 350 - 435 °C, the hydrogen-oil volume ratio is 1000:1 - 2000:1, and the liquid hourly space velocity is 0.5 - 5.0 h -1 .

[0015] In the method of the present invention, the molar ratio of SiO2 / Al2O3 on the outer surface of the modified ZSM-22 molecular sieve is 600 - 900, the molar ratio of SiO2 / Al2O3 in the bulk phase is 60 - 120; the total pyridine infrared acid amount is 0.15 - 0.25 mmol / g; the total di-tert-butylpyridine infrared acid amount is 0.01 - 0.025 mmol / g.

[0016] In the method of the present invention, the properties of the Y molecular sieve are as follows: the relative crystallinity is 110% - 150%, the molar ratio of SiO2 / Al2O3 is 10 - 100, preferably 15 - 70, the unit cell parameter is 2.425 - 2.445 nm, the total pore volume is 0.55 - 1.0 mL / g, preferably 0.6 - 1.0 mL / g, and the mesopore volume accounts for more than 70% of the total pore volume, preferably 80% - 90%.

[0017] In the method of the present invention, the carrier further contains macroporous alumina, and the properties of the macroporous alumina are as follows: the pore volume is 0.7 - 1.0 mL / g, and the specific surface area is 200 - 500 m 2 / g.

[0018] In the method of the present invention, based on the weight of the hydrocracking catalyst, the content of the hydrogenation active metal component in terms of oxide is 14% - 38%, and the content of the carrier is 60% - 85%.

[0019] In the hydrocracking catalyst of the present invention, based on the weight of the carrier, the content of the modified ZSM-22 molecular sieve is 10% - 50%, the content of the Y molecular sieve is 10% - 40%, and the content of the macroporous alumina is 10% - 80%.

[0020] In the hydrocracking catalyst of the present invention, it further includes a binder, such as small-pore alumina, etc., and based on the weight of the catalyst, the content of the binder is 0.1% - 2%.

[0021] In the method of the present invention, in the hydrocracking catalyst, the hydrogenation active metal is a metal of Group VIB and / or Group VIII. The metal of Group VIB is preferably molybdenum and / or tungsten, and the metal of Group VIII is preferably cobalt and / or nickel. In the catalyst of the present invention, based on the weight of the catalyst, the content of the Group VIB metal (calculated as the oxide) is 10.0% - 30.0%, and the content of the Group VIII metal (calculated as the oxide) is 4.0% - 8.0%.

[0022] In the method of the present invention, the specific surface area of the hydrocracking catalyst is 250 - 450m 2 / g, and the pore volume is 0.30 - 0.60 mL / g.

[0023] In the method of the present invention, the preparation of the hydrocracking catalyst includes the preparation of the support and the loading of the hydrogenation active metal component; among them, the preparation process of the support is as follows: mixing the modified ZSM-22 molecular sieve, Y molecular sieve, and macroporous alumina, forming, and then drying and calcining to make the support.

[0024] Further, in the preparation process of the support, the drying and calcining can adopt conventional conditions, generally drying at 100°C - 150°C for 1 - 12 h, and then calcining at 450°C - 550°C for 3.0 - 6.0 h.

[0025] The Y molecular sieve can be prepared according to the prior art, such as obtained by the method of CN201610289588.6.

[0026] Further, the catalyst support is loaded with the hydrogenation active metal component by a conventional method, such as the kneading method, impregnation method, etc. In the present invention, the impregnation method is preferably used to load the hydrogenation active metal component, and then the hydrocracking catalyst is obtained by drying and calcining. The impregnation method can be saturated impregnation, excess impregnation or complex impregnation, that is, impregnating the catalyst support with a solution containing the required active component, and the impregnated support is dried at 100°C - 150°C for 1 - 12 h, and then calcined at 450°C - 550°C for 3.0 - 6.0 h to obtain the final catalyst.

[0027] Further, the preparation method of the modified ZSM-22 molecular sieve includes:

[0028] (1) Preparing ZSM-22 molecular sieve without removing the template agent;

[0029] (2) Mixing the ZSM-22 molecular sieve obtained in step (1) with the dealumination and silicon supplementation reagent for dealumination and silicon supplementation;

[0030] (3) Subjecting the material obtained in step (2) to steam treatment;

[0031] (4) Treat the material obtained in step (3) with a buffer solution to obtain a modified ZSM-22 molecular sieve.

[0032] Further, in step (1), the ZSM-22 molecular sieve without removing the template agent can be prepared by hydrothermal synthesis. For example: Feed the silicon source, aluminum source, template agent, alkali source, and water according to the following molar ratios: SiO2: (0.006 - 0.03) Al2O3: (0.2 - 4.0) R (template agent): (0.01 - 10) K2O: (10 - 200) H2O. After crystallizing the mixed material at 150 - 180 °C for 2 - 5 days, wash the product until the pH value is 7 - 8, and then filter and dry at 80 - 120 °C to obtain the ZSM-22 molecular sieve without removing the template agent.

[0033] Further, in the preparation process of the ZSM-22 molecular sieve, the silicon source is selected from one or more of silica sol, fumed silica, tetraethyl orthosilicate, etc.; the aluminum source is selected from one or more of aluminum sulfate octadecahydrate, aluminum isopropoxide, pseudoboehmite, potassium metaaluminate, etc.; the template agent is selected from one or more of 1,6-hexanediamine, n-butylamine, diethylamine, imidazole-based bisquaternary ammonium salts, etc.; the alkali source is potassium hydroxide; and the water is deionized water.

[0034] Further, in step (2), the dealumination and silicon supplementation reagent is at least one of ammonium hexafluorosilicate solution, tetraethyl orthosilicate solution, etc.

[0035] Further, in step (2), the molar concentration of the dealumination and silicon supplementation reagent is 0.5 - 1.5 mol / L. The mass ratio of the ZSM-22 molecular sieve obtained in step (1) to the dealumination and silicon supplementation reagent is 1:2 - 1:8.

[0036] Further, in step (2), the specific operation process of dealumination and silicon supplementation is as follows: Mix the ZSM-22 molecular sieve obtained in step (1) with water evenly, heat it up to 60 - 100 °C, and continuously stir. Dropwise add the dealumination and silicon supplementation reagent. After the addition is completed, continue to stir for 60 - 120 min, filter while it is hot, wash the obtained filter cake with water, filter again and dry. Among them, the liquid-solid volume ratio of water to the ZSM-22 molecular sieve obtained in step (1) is 2:1 - 8:1 mL / g.

[0037] Further, in step (3), the conditions for steam treatment are: temperature is 400 - 700 °C, preferably 500 - 600 °C; pressure is 0.01 - 0.3 MPa, preferably 0.1 - 0.2 MPa; time is 0.5 - 6 h, preferably 1 - 4 h.

[0038] Further, in step (4), the buffer solution is one or more of oxalic acid - ammonium oxalate solution and acetic acid - ammonium acetate solution. The pH value of the buffer solution is 4.5 - 6.5, preferably 5.0 - 6.0. In the buffer solution, the molar concentration of the organic acid root is 0.1 - 1.0 mol / L. The liquid - solid volume ratio of the buffer solution to the material obtained in step (3) is 3:1 - 10:1 mL / g.

[0039] Further, in step (4), the specific treatment process is as follows: the material obtained in step (3) is mixed with the buffer solution and stirred, the treatment temperature is 40 - 80 °C, and the treatment time is 0.5 - 3 h.

[0040] Further, in step (4), solid - liquid separation (such as suction filtration) is carried out; and the above operation is repeated 2 - 4 times, and the finally obtained material is dried to obtain the modified ZSM - 22 molecular sieve.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] 1. The modified ZSM - 22 molecular sieve used as the catalyst in the method of the present invention has a low total amount of infrared acid of di - tert - butylpyridine. While eliminating the outer - surface acid sites, it has an open and unobstructed pore structure, and the isomerization performance of the molecular sieve is strengthened. Using the modified ZSM - 22 molecular sieve and Y molecular sieve as cracking centers together not only gives full play to their respective performance characteristics but also enables the two molecular sieves to produce a synergistic catalytic effect. That is, the Y molecular sieve provides the appropriate cracking performance of the catalyst, causing the ring - shaped hydrocarbons to open - ring and transform into chain - shaped hydrocarbons, and the ZSM - 22 molecular sieve strengthens the isomerization performance of the catalyst, converting n - paraffins into iso - paraffins. The two work together to improve the selectivity of the product while improving the low - temperature flow performance of the product. The hydrocracking catalyst of the present invention is suitable for processing VGO raw materials and can obtain hydrocracked tail oil with a high viscosity index, a low n - paraffin content, and good low - temperature flow performance, which is used as a high - quality lubricating oil base stock raw material.

[0043] 2. In the preparation method of the modified ZSM - 22 molecular sieve in the method of the present invention, first, the molecular sieve obtained by hydrothermal synthesis does not undergo a template - removing agent treatment. The organic template agent molecules in the pores act as pore - protecting agents. The acid - removing and silicon - adding method is used to selectively remove the acidic centers on the outer surface of the molecular sieve, reducing the over - cracking reaction of n - paraffins on the outer surface of the molecular sieve. The aluminum on the outer surface of the molecular sieve is replaced by non - acidic silicon atoms under the action of the acid - removing and silicon - adding reagent. Due to the presence of the template agent molecules, the acidic centers in the pores are protected. Subsequently, the method of treating with constant - pressure high - temperature water vapor is used to reduce the total acid amount of the molecular sieve and also remove the template agent molecules in the pores. Finally, a buffer solution is used to remove the non - framework aluminum generated during the hydrothermal treatment process, making the pores of the molecular sieve more open and unobstructed, and facilitating the diffusion of the intermediate products during the shape - selective isomerization reaction of n - paraffins. Specific embodiments

[0044] The functions and effects of the technical solution of the present invention will be further described below in conjunction with examples and comparative examples. However, the following examples do not limit the protection scope of the present invention.

[0045] In the present invention, the percentages involved in the examples and comparative examples are mass fractions unless otherwise specified.

[0046] In the present invention, the molar ratio of SiO2 / Al2O3 on the outer surface is measured by X-ray photoelectron spectroscopy (XPS). The elemental composition and state on the catalyst surface are determined on a Multilab2000 electron spectrometer of Thermofisher Company, USA. The excitation source is Mg Kα, and the cathode voltage and current are 13 kV and 20 mA respectively. The electron binding energy is calibrated with C1s (284.6 eV).

[0047] In the present invention, the molar ratio of bulk SiO2 / Al2O3 is obtained by X-ray fluorescence spectroscopy (XRF). A ZSX100e X-ray fluorescence spectrometer is used, the spectral line is Kα, the crystal is Li F1, the target material is Rh, the detector is SC scintillation, the timing is 20 s, and the optical path atmosphere is vacuum.

[0048] In the present invention, the pyridine infrared measurement method is as follows: The powdered ZSM-22 molecular sieve is pressed into tablets. After evacuation, it is degassed at 450 °C for 2 h. When the temperature drops to room temperature, pyridine molecules are used as probe molecules to measure the infrared spectrum of chemical desorption and calculate the adsorption amount.

[0049] In the present invention, the total amount of acid of 2,6-di-tert-butylpyridine infrared refers to the proton acid that can be contacted by 2,6-di-tert-butylpyridine molecules with a kinetic diameter of 10.5 Å. The 2,6-di-tert-butylpyridine infrared measurement method is as follows: The powdered ZSM-22 molecular sieve is pressed into tablets. After evacuation, it is degassed at 450 °C for 2 h. When the temperature drops to room temperature, 2,6-di-tert-butylpyridine molecules are used as probe molecules to measure the infrared spectrum of its chemical desorption and calculate the adsorption amount.

[0050] Example 1

[0051] Weigh 84.0 g of potassium hydroxide and dissolve it in 4950 mL of water. During stirring, successively add 43.3 g of aluminum sulfate octadecahydrate, 750.0 g of silica sol (mass fraction is 40%), and 174.0 g of 1,6 - hexanediamine (DAH) to form a mixed gel with a molar ratio of SiO₂:0.013Al₂O₃:0.3DAH:0.15K₂O:60H₂O. Load the well - mixed initial gel into a sealed reaction kettle and carry out crystallization at 160 °C for 3 days. Wash the obtained mixture product until the pH value is 7, then filter and dry it at 120 °C to obtain ZSM - 22 powder without removing the template agent. Take 120 g of the above - mentioned ZSM - 22 powder, add 720 mL of water and mix evenly. Stir and heat to 60 °C, and use a peristaltic pump to uniformly drip 360 mL of 0.5 mol / L ammonium hexafluorosilicate solution. Keep the temperature at 60 °C and continuously stir for 90 min. Filter while it is hot. Add 960 mL of water to the obtained filter cake, heat to 60 °C and keep for 20 min, filter while it is hot. Dry the filter cake at 120 °C for 8 h. Then place the dried product in a hydrothermal treatment furnace and treat it at 500 °C and 0.1 MPa for 2 h. Place the obtained material in 1200 mL of oxalic acid - ammonium oxalate solution with a pH value of 6.0, where the molar concentration of oxalate is 0.3 mol / L. Stir and heat up to 60 °C, keep for 30 min and then filter while it is hot. Repeat this process 3 times. After the obtained filter cake is dried at 120 °C for 8 h, the modified molecular sieve is named ZSM - 22 - 1.

[0052] Example 2

[0053] Same as Example 1, prepare ZSM - 22 powder without removing the template agent. Take 120 g of the above - mentioned ZSM - 22 powder, add 720 mL of water and mix evenly. Stir and heat to 60 °C, and use a peristaltic pump to uniformly drip 360 mL of 0.8 mol / L tetraethyl orthosilicate solution. Keep the temperature at 60 °C and continuously stir for 90 min. Filter while it is hot. Add 960 mL of water to the obtained filter cake, heat to 60 °C and keep for 20 min, filter while it is hot. Dry the filter cake at 120 °C for 8 h. Then place the dried product in a hydrothermal treatment furnace and treat it at 550 °C and 0.1 MPa for 2 h. Place the obtained material in 1200 mL of acetic acid - ammonium acetate solution with a pH value of 5.5, where the molar concentration of acetate is 0.4 mol / L. Stir and heat up to 60 °C, keep for 30 min and then filter while it is hot. Repeat this process 3 times. After the obtained filter cake is dried at 120 °C for 8 h, the modified molecular sieve is named ZSM - 22 - 2.

[0054] Example 3

[0055] Same as Example 1, prepare ZSM-22 powder without removing the template agent. Take 120 g of the above ZSM-22 powder, add 720 mL of water and mix evenly. Stir and heat to 60 °C, and slowly drip 360 mL of 1.0 mol / L tetraethyl orthosilicate solution with a peristaltic pump. Keep the temperature at 60 °C and continuously stir for 90 min. Filter while it is hot. Add 960 mL of water to the obtained filter cake, heat to 60 °C and keep for 20 min, filter while it is hot. Dry the filter cake at 120 °C for 8 h. Then place the dried product in a hydrothermal treatment furnace and treat it at 550 °C and 0.15 MPa for 2 h. Place the obtained material in 1200 mL of oxalic acid-ammonium oxalate solution with a pH value of 5.0, where the molar concentration of oxalate is 0.5 mol / L. Stir and heat up to 60 °C, keep for 30 min and then filter while it is hot. Repeat this process 3 times. After drying the obtained filter cake at 120 °C for 8 h, the obtained modified molecular sieve is named ZSM-22-3.

[0056] Example 4

[0057] Same as Example 1, prepare ZSM-22 powder without removing the template agent. Take 120 g of the above ZSM-22 powder, add 720 mL of water and mix evenly. Stir and heat to 60 °C, and slowly drip 360 mL of 1.0 mol / L ammonium hexafluorosilicate solution with a peristaltic pump. Keep the temperature at 60 °C and continuously stir for 90 min. Filter while it is hot. Add 960 mL of water to the obtained filter cake, heat to 60 °C and keep for 20 min, filter while it is hot. Dry the filter cake at 120 °C for 8 h. Then place the dried product in a hydrothermal treatment furnace and treat it at 600 °C and 0.2 MPa for 2 h. Place the obtained material in 1200 mL of oxalic acid-ammonium oxalate solution with a pH value of 5.0, where the molar concentration of oxalate is 0.6 mol / L. Stir and heat up to 60 °C, keep for 30 min and then filter while it is hot. Repeat this process 3 times. After drying the obtained filter cake at 120 °C for 8 h, the obtained modified molecular sieve is named ZSM-22-4.

[0058] Example 5

[0059] Same as Example 1, prepare ZSM-22 powder without removing the template agent. Take 120 g of the above ZSM-22 powder, add 720 mL of water and mix evenly. Stir and heat to 60 °C, and slowly add 360 mL of 1.2 mol / L tetraethyl orthosilicate solution with a peristaltic pump. Keep the temperature at 60 °C and continuously stir for 90 min. Filter while it is hot. Add 960 mL of water to the obtained filter cake, heat to 60 °C and keep for 20 min, filter while it is hot. Dry the filter cake at 120 °C for 8 h. Then place the dried product in a hydrothermal treatment furnace and treat it at 600 °C and 0.10 MPa for 2 h. Place the obtained material in 1200 mL of oxalic acid-ammonium oxalate solution with a pH value of 5.5, where the molar concentration of oxalate is 0.4 mol / L. Stir and heat to 60 °C, keep for 30 min and then filter while it is hot. Repeat this process 3 times. After drying the obtained filter cake at 120 °C for 8 h, the modified molecular sieve obtained is named ZSM-22-5.

[0060] Example 6

[0061] Same as Example 1, prepare ZSM-22 powder without removing the template agent. Take 120 g of the above ZSM-22 powder, add 720 mL of water and mix evenly. Stir and heat to 60 °C, and slowly add 360 mL of 1.5 mol / L ammonium hexafluorosilicate solution with a peristaltic pump. Keep the temperature at 60 °C and continuously stir for 90 min. Filter while it is hot. Add 960 mL of water to the obtained filter cake, heat to 60 °C and keep for 20 min, filter while it is hot. Dry the filter cake at 120 °C for 8 h. Then place the dried product in a hydrothermal treatment furnace and treat it at 550 °C and 0.15 MPa for 2 h. Place the obtained material in 1200 mL of acetic acid-ammonium acetate solution with a pH value of 6.5, where the molar concentration of acetate is 0.5 mol / L. Stir and heat to 60 °C, keep for 30 min and then filter while it is hot. Repeat this process 3 times. After drying the obtained filter cake at 120 °C for 8 h, the modified molecular sieve obtained is named ZSM-22-6.

[0062] Comparative Example 1

[0063] Same as Example 1, ZSM-22 powder without removing the template agent was prepared, and then the template agent-removed ZSM-22 powder was obtained by calcining at 550 °C for 6 h. Take 120 g of the above ZSM-22 powder, add 720 mL of water and mix evenly, stir and heat to 60 °C, and slowly drip 360 mL of 0.8 mol / L ammonium hexafluorosilicate solution with a peristaltic pump. Keep the temperature at 60 °C and continue stirring for 90 min. Filter while it is hot. Add 960 mL of water to the obtained filter cake, heat to 60 °C and keep for 20 min, filter while it is hot, and dry the filter cake at 120 °C for 8 h. Then place the dried product in a hydrothermal treatment furnace and treat it at 500 °C and 0.1 MPa for 2 h. Place the obtained material in 1200 mL of oxalic acid-ammonium oxalate solution with a pH value of 6.0, where the molar concentration of oxalate is 0.4 mol / L. Stir and heat up to 60 °C, keep for 30 min and then filter while it is hot. Repeat this process 3 times. After drying the obtained filter cake at 120 °C for 8 h, the modified molecular sieve obtained is named ZSM-22-D1.

[0064] Comparative Example 2

[0065] Same as Example 1, ZSM-22 powder without removing the template agent was prepared. Take 120 g of the above ZSM-22 powder and place it in a hydrothermal treatment furnace, treat it at 600 °C and 0.15 MPa for 2 h. Place the obtained material in 1200 mL of oxalic acid-ammonium oxalate solution with a pH value of 5.0, where the molar concentration of oxalate is 0.3 mol / L. Stir and heat up to 60 °C, keep for 30 min and then filter while it is hot. Repeat this process 3 times. After drying the obtained filter cake at 120 °C for 8 h, the modified molecular sieve obtained is named ZSM-22-D2.

[0066] Table 1 Characterization results of the modified molecular sieves obtained in the examples and comparative examples

[0067]

[0068] Example 7

[0069] 30.9 g of modified molecular sieve ZSM-22-3 (dry basis 97 wt%), 77.8 g of Y molecular sieve (relative crystallinity 130%, SiO2 / Al2O3 molar ratio 62, unit cell parameter 2.440 nm, total pore volume 0.71 mL / g, mesopore volume accounting for 83% of the total pore volume, dry basis 90 wt%), 142.9 g of macroporous alumina (pore volume 1.0 ml / g, specific surface area 400 m 2(70 wt% dry basis) was put into a rolling mill for mixing and rolling, and a dilute binder (concentration of small-pore alumina: 2.2 g / 100 mL) was added. It was rolled into a paste, extruded into strips, and the extruded strips were dried at 120 °C for 6 h, then calcined at 550 °C for 4 h to obtain a support. The support was impregnated with an impregnation solution containing tungsten and nickel at room temperature for 2 h, dried at 120 °C for 6 h, and calcined at 500 °C with a programmed temperature increase for 4 h to obtain catalyst CAT-1. The properties of the catalyst are shown in Table 2.

[0070] Example 8

[0071] 41.2 g of modified zeolite ZSM-22-3 (97 wt% dry basis), 66.7 g of Y zeolite (the same as in Example 7), and 142.9 g of macroporous alumina (pore volume 1.0 ml / g, specific surface area 400 m 2 (70 wt% dry basis) was put into a rolling mill for mixing and rolling, and a dilute binder (concentration of small-pore alumina: 2.2 g / 100 mL) was added. It was rolled into a paste, extruded into strips, and the extruded strips were dried at 120 °C for 6 h, then calcined at 550 °C for 4 h to obtain a support. The support was impregnated with an impregnation solution containing molybdenum and nickel at room temperature for 2 h, dried at 120 °C for 6 h, and calcined at 500 °C with a programmed temperature increase for 4 h to obtain catalyst CAT-2. The properties of the catalyst are shown in Table 2.

[0072] Example 9

[0073] 51.5 g of modified zeolite ZSM-22-4 (97 wt% dry basis), 55.6 g of Y zeolite (the same as in Example 7), and 142.9 g of macroporous alumina (pore volume 1.0 ml / g, specific surface area 400 m 2 (70 wt% dry basis) was put into a rolling mill for mixing and rolling, and a dilute binder (concentration of small-pore alumina: 2.2 g / 100 mL) was added. It was rolled into a paste, extruded into strips, and the extruded strips were dried at 120 °C for 6 h, then calcined at 550 °C for 4 h to obtain a support. The support was impregnated with an impregnation solution containing tungsten and nickel at room temperature for 2 h, dried at 120 °C for 6 h, and calcined at 500 °C with a programmed temperature increase for 4 h to obtain catalyst CAT-3. The properties of the catalyst are shown in Table 2.

[0074] Example 10

[0075] 61.9 g of modified zeolite ZSM-22-4 (97 wt% dry basis), 44.4 g of Y zeolite (the same as in Example 7), and 142.9 g of macroporous alumina (pore volume 1.0 ml / g, specific surface area 400 m 2(70 wt% on dry basis) was put into a rolling mill for mixing and milling, and a dilute binder (concentration of small-pore alumina: 2.2 g / 100 mL) was added. It was rolled into a paste, extruded into strips, and the extruded strips were dried at 120 °C for 6 h, then calcined at 550 °C for 4 h to obtain a support. The support was impregnated with an impregnation solution containing molybdenum and nickel at room temperature for 2 h, dried at 120 °C for 6 h, and calcined at 500 °C with a programmed temperature increase for 4 h to obtain catalyst CAT-4. The properties of the catalyst are shown in Table 2.

[0076] Comparative Example 3

[0077] 41.2 g of modified molecular sieve ZSM-22-D1 (97 wt% on dry basis), 66.7 g of Y molecular sieve (the same as in Example 7), and 142.9 g of macroporous alumina (pore volume: 1.0 ml / g, specific surface area: 400 m 2 / g, 70 wt% on dry basis) was put into a rolling mill for mixing and milling, and a dilute binder (concentration of small-pore alumina: 2.2 g / 100 mL) was added. It was rolled into a paste, extruded into strips, and the extruded strips were dried at 120 °C for 6 h, then calcined at 550 °C for 4 h to obtain a support. The support was impregnated with an impregnation solution containing tungsten and nickel at room temperature for 2 h, dried at 120 °C for 6 h, and calcined at 500 °C with a programmed temperature increase for 4 h to obtain catalyst CAT-D1. The properties of the catalyst are shown in Table 2.

[0078] Comparative Example 4

[0079] 61.9 g of modified molecular sieve ZSM-22-D2 (97 wt% on dry basis), 44.4 g of Y molecular sieve (the same as in Example 7), and 142.9 g of macroporous alumina (pore volume: 1.0 ml / g, specific surface area: 400 m 2 / g, 70 wt% on dry basis) was put into a rolling mill for mixing and milling, and a dilute binder (concentration of small-pore alumina: 2.2 g / 100 mL) was added. It was rolled into a paste, extruded into strips, and the extruded strips were dried at 120 °C for 6 h, then calcined at 550 °C for 4 h to obtain a support. The support was impregnated with an impregnation solution containing molybdenum and nickel at room temperature for 2 h, dried at 120 °C for 6 h, and calcined at 500 °C with a programmed temperature increase for 4 h to obtain catalyst CAT-D2. The properties of the catalyst are shown in Table 2.

[0080] Table 2 Catalyst Composition and Physicochemical Properties

[0081]

[0082] Example 11

[0083] This example describes the evaluation method and results of the method of the present invention. Catalysts CAT-1, CAT-2, CAT-3, CAT-4, CAT-D1, and CAT-D2 were evaluated on a fixed-bed hydrogenation test device under the same process conditions. The evaluation conditions were: hydrogen-oil volume ratio of 1200:1, reaction pressure of 14.7 MPa, and volume space velocity of 1.0 h when refining the reaction liquid-1 When cracking the reaction liquid, the volume space velocity is 1.5 h -1 , the conversion rate is 70%, and a one-stage series once-through process flow is adopted, where the refining catalyst is the commercial catalyst FF-36. The feedstock oil used for evaluation is vacuum gas oil, and its properties are shown in Table 3. The evaluation results are listed in Table 4.

[0084] It can be seen from the evaluation results that the hydrocracked tail oil prepared by the method of the present invention has a lower content of n-paraffins, a higher viscosity index, and better low-temperature fluidity, and is a very high-quality raw material for lubricating base oil.

[0085] Table 3 Properties of feedstock oil

[0086]

[0087] Table 4 Comparative evaluation results of catalyst performance in examples and comparative examples

[0088]

Claims

1. A hydrocracking method for producing a lubricating base oil raw material, characterized in that: The feedstock oil passes through a hydrofining reaction zone and a hydrocracking reaction zone in sequence. The hydrofining reaction zone is filled with a hydrofining catalyst, and the hydrocracking reaction zone is filled with a hydrocracking catalyst. The hydrocracking catalyst includes a hydrogenation active metal component and a carrier. The carrier includes a modified ZSM-22 molecular sieve, a Y molecular sieve, and macroporous alumina. The molar ratio of SiO2 / Al2O3 on the outer surface of the modified ZSM-22 molecular sieve is 500-1000, and the molar ratio of SiO2 / Al2O3 in the bulk phase is 50-150. The total pyridine infrared acid amount is 0.1-0.5 mmol / g, and the total infrared acid amount of di-tert-butylpyridine is 0.001-0.03 mmol / g. The properties of the Y molecular sieve are as follows: the relative crystallinity is 110%-150%, the molar ratio of SiO2 / Al2O3 is 10-100, the unit cell parameter is 2.425-2.445 nm, the total pore volume is 0.55-1.0 mL / g, and the mesoporous pore volume accounts for more than 70% of the total pore volume. In the hydrocracking catalyst, based on the weight of the carrier, the content of the modified ZSM-22 molecular sieve is 10%-50%, the content of the Y molecular sieve is 10%-40%, and the content of macroporous alumina is 10%-80%.

2. The method according to claim 1, wherein: The feedstock oil is one or more of vacuum gas oil, coker wax oil, solvent-refined deasphalted oil, and Fischer-Tropsch synthesis oil.

3. The method according to claim 1, wherein: The hydrofining catalyst uses an alumina-based carrier, and the hydrogenation active metal components are metals of Group VIB and Group VIII. The metal of Group VIB is molybdenum and / or tungsten, and the metal of Group VIII is cobalt and / or nickel. Based on the weight of the catalyst, the content of the metal of Group VIB in terms of oxide is 15.0%-30.0%, and the content of the metal of Group VIII in terms of oxide is 4.0%-8.0%.

4. The method according to claim 1, characterized in that: The hydrocracking reaction conditions are as follows: the reaction pressure is 12.0 - 18.0 MPa, the temperature is 350 - 435 °C, the hydrogen-to-oil volume ratio is 1000:1 - 2000:1, and the liquid hourly space velocity is 0.5 - 5.0 h -1 .

5. The method according to claim 1, wherein: The hydrofining reaction conditions are as follows: the reaction pressure is 12.0 - 18.0 MPa, the temperature is 350 - 435 °C, the hydrogen-oil volume ratio is 1000:1 - 2000:1, and the liquid hourly space velocity is 0.5 - 5.0 h -1 .

6. The method according to claim 1, characterized in that: The molar ratio of SiO2 / Al2O3 on the outer surface of the modified ZSM-22 molecular sieve is 600-900, and the molar ratio of SiO2 / Al2O3 in the bulk phase is 60-120. The total pyridine infrared acid amount is 0.15-0.25 mmol / g. The total infrared acid amount of di-tert-butylpyridine is 0.01-0.025 mmol / g.

7. The method according to claim 1, wherein: The properties of the Y molecular sieve are as follows: the molar ratio of SiO2 / Al2O3 is 15-70, the total pore volume is 0.6-1.0 mL / g, and the mesoporous pore volume accounts for 80%-90% of the total pore volume.

8. The method according to claim 1, wherein: The properties of the macroporous alumina are as follows: the pore volume is 0.7 to 1.0 mL / g, and the specific surface area is 200 to 500 m 2 / g.

9. The method according to claim 1, characterized in that: Based on the weight of the hydrocracking catalyst, the content of the hydrogenation active metal component in terms of oxide is 14%-38%, and the content of the carrier is 60%-85%.

10. The method according to claim 1, characterized in that: In the hydrocracking catalyst, a binder is included. Based on the weight of the catalyst, the content of the binder is 0.1%-2%.

11. The method according to claim 1, wherein: In the hydrocracking catalyst, the hydrogenation active metal is a metal of Group VIB and / or Group VIII. The metal of Group VIB is molybdenum and / or tungsten, and the metal of Group VIII is cobalt and / or nickel.

12. The method according to claim 11, wherein: In the hydrocracking catalyst, based on the weight of the catalyst, the content of Group VIB metal calculated as the oxide is 10.0% - 30.0%, and the content of Group VIII metal calculated as the oxide is 4.0% - 8.0%.

13. The method according to claim 1, characterized in that: The specific surface area of the hydrocracking catalyst is 250-450 m 2 / g, and the pore volume is 0.30-0.60 mL / g.

14. The method according to claim 1, wherein: The preparation of the hydrocracking catalyst includes the preparation of the support and the loading of the hydrogenation active metal components; among them, the preparation process of the support is as follows: Mix the modified ZSM-22 molecular sieve, Y molecular sieve, and macroporous alumina, form them, and then dry and calcine to make the support.

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