Method for producing white oil through hydrogenation

Abstract

The invention discloses a method for producing white oil by hydrogenation, which comprises the following steps: (1) mixing raw oil and hydrogen, feeding into a hydroisomerization reaction zone, and contacting with a hydroisomerization catalyst for reaction; (2) feeding the reaction effluent obtained in the step (1) into a separation system to obtain gt; distillate oil at 320 DEG C; (3) gt is obtained in the step (2); and mixing the distillate oil at 320 DEG C with hydrogen, feeding the mixture into a post-treatment reaction zone, and reacting in the presence of a post-treatment catalyst to obtain a final white oil product. The method is especially suitable for processing cycloalkyl high-viscosity raw materials containing heavy aromatics, and high-quality food-grade white oil can be produced.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry and relates to a method for producing white oil by hydrogenation. Background Art

[0002] White oil can be categorized into industrial, cosmetic, pharmaceutical, and food grades based on characteristics such as impurity content and color. Currently, my country still relies on imports for high-grade white oils, including cosmetic, pharmaceutical, and food grades. Food-grade white oil is the most highly refined and has the most stringent quality requirements. The most commonly used industrial method for producing high-grade white oil is hydrogenation. The process involves using hydrotreated distillate and hydrocracking tail oil as feedstocks, conducting an isomerization dewaxing reaction in the presence of hydrogen and a hydroisomerization catalyst. The liquid phase of the reaction effluent undergoes post-treatment and fractional distillation to yield the desired white oil product. The post-treatment process primarily achieves deep hydrogenation and saturation of aromatics, meeting the stringent aromatic content requirements for high-grade white oil. This requires the post-treatment catalyst to have a high capacity for deep aromatic removal and good selectivity, ensuring minimal changes in the viscosity, pour point, and flash point of the hydrorefined product.

[0003] CN100400625C discloses a two-stage hydrogenation method for producing food-grade white oil. This method employs a two-stage process involving low-pressure hydroisomerization and supplemental hydrorefining. The feedstock first enters a low-pressure hydroisomerization reactor to lower the pour point. After gas-liquid separation of the isomerized product, the fraction above 320°C enters a supplemental hydrorefining reactor for deep aromatic saturation, achieving food-grade white oil specifications. This method utilizes a conventional supplemental hydrorefining catalyst, which has limited adaptability to the feedstock. Furthermore, the resulting food-grade white oil product, such as viscosity and Saybolt color, requires further improvement. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a method for producing white oil by hydrogenation. The method is particularly suitable for processing high-viscosity cycloalkyl feedstocks containing heavy aromatics and can produce high-quality food-grade white oil.

[0005] According to a first aspect of the present invention, the present invention provides a method for producing white oil by hydrogenation, comprising the following steps:

[0006] (1) The feedstock oil and hydrogen are mixed and enter the hydroisomerization reaction zone, where they come into contact with the hydroisomerization catalyst to react;

[0007] (2) the reaction effluent obtained in step (1) enters a separation system to obtain a distillate oil >320°C;

[0008] (3) The distillate oil with a temperature greater than 320° C. obtained in step (2) is mixed with hydrogen and then enters a post-treatment reaction zone, where the mixture reacts in the presence of a post-treatment catalyst to obtain a final white oil product; the post-treatment catalyst comprises an active metal component and a carrier, and the carrier comprises a modified Y-type molecular sieve; the total molar content of 0-NNN aluminum and 1-NNN aluminum in the modified Y-type molecular sieve is 94% to 96%, based on the total molar amount of X-NNN aluminum; and the molar ratio of the 0-NNN aluminum to the 1-NNN aluminum is 3.5 to 4.4.

[0009] In the method of the present invention, the raw oil in step (1) is one or more of cycloalkyl high-viscosity white oil and hydrocracking tail oil; the raw oil has the following properties: nitrogen content <10ppm, sulfur content <10ppm, aromatic content 8-20wt%, viscosity (40℃) 15-40mm 2 / s.

[0010] In the method of the present invention, the hydroisomerization reaction zone in step (1) is provided with one or more fixed-bed hydrogenation reactors connected in series; when multiple fixed-bed hydrogenation reactors are provided in series, a cooler is provided after each reactor.

[0011] In the method of the present invention, the hydroisomerization catalyst in step (1) can be a conventional hydroisomerization catalyst, and the hydroisomerization catalyst includes a carrier and an active metal component, the carrier includes one or more of ZSM-22, ZSM-23, SAPO-11, SAPO-31 and SAPO-41 molecular sieves, and the active metal component is one or more of Pt, Pd, Ru and Rh; the hydroisomerization catalyst can be prepared according to existing technology, or a commercial hydroisomerization catalyst can be selected, such as the hydroisomerization catalyst with the trade name FIW-12 developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd.

[0012] In the method of the present invention, the reaction conditions of the hydroisomerization reaction zone in step (1) are as follows: reaction temperature 250-370°C, reaction pressure 1.0-2.5 MPa, hydrogen-to-oil volume ratio 500-2000, liquid hourly volume space velocity 0.3-3.0 h -1 .

[0013] In the method of the present invention, the separation system in step (2) includes a gas-liquid separation unit and a fractionation unit, the gas-liquid separation unit includes a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator and a cold low-pressure separator; the fractionation unit includes a distillation tower.

[0014] In the method of the present invention, in the post-treatment catalyst described in step (3), the total molar content of 0-NNN aluminum and 1-NNN aluminum in the modified Y-type molecular sieve and the molar ratio of 0-NNN aluminum to 1-NNN are determined by solid-state NMR nuclear magnetic resonance spectroscopy using a peak area corresponding to X-NNN aluminum, and then calculated. For example, the total molar content of 0-NNN aluminum and 1-NNN aluminum is calculated as follows: the sum of the peak areas corresponding to 0-NNN aluminum and 1-NNN aluminum is divided by the sum of the peak areas corresponding to all X-NNN aluminum.

[0015] In the method of the present invention, in the post-treatment catalyst in step (3), the modified Y-type molecular sieve has a skeleton structure shown in structural formula I,

[0016]

[0017] There are 9 positions in the adjacent position of the Al atom, any of which can be occupied by an Al atom or a Si atom. According to the number of Al atoms, it can be marked as X-NNN aluminum, where X can be any integer from 0 to 9. If all 9 positions are occupied by silicon, it is recorded as 0-NNN aluminum. If any one of the 9 positions is occupied by aluminum and the remaining 8 positions are occupied by silicon, it is recorded as 1-NNN aluminum. If any two of the 9 positions are occupied by aluminum and the remaining 7 positions are occupied by silicon, it is recorded as 2-NNN aluminum. By analogy, it can be marked until all 9 positions are replaced by Al, which is recorded as 9-NNN aluminum.

[0018] In the method of the present invention, in the post-treatment catalyst in step (3), the average diameter of the modified Y-type molecular sieve particles is 100-500 nm, preferably 200-400 nm, and the mesopore volume of 4-8 nm accounts for more than 70% of the total pore volume, preferably more than 72%.

[0019] In the method of the present invention, in the post-treatment catalyst in step (3), the modified Y-type molecular sieve has a relative crystallinity of ≥95%, preferably ≥98%; and a unit cell constant of 2.428 to 2.430 nm.

[0020] In the method of the present invention, in the post-treatment catalyst in step (3), the modified Y-type molecular sieve SiO2 / A12O3 (molar ratio) is 50-60; the specific surface area is 900-1200m 2 / g; pore volume 0.50~0.80mL / g.

[0021] In the method of the present invention, in the post-treatment catalyst in step (3), the content of the active metal component in terms of elemental mass is 0.3-1.3 wt%, the carrier content is 98.7-99.7 wt%, and the content of the modified Y-type molecular sieve is 10 wt%-25 wt%, based on the mass of the catalyst.

[0022] In the method of the present invention, in the post-treatment catalyst in step (3), the carrier further contains amorphous silica-alumina; the properties of the amorphous silica-alumina are as follows: a pore volume of 0.7 to 1.2 mL / g, preferably 0.8 to 1.0 mL / g, a specific surface area of ​​300 to 500 m 2 / g, preferably 350 to 500 m 2 / g; based on the mass of the catalyst, the content of amorphous silicon and aluminum is 60wt% to 85wt%, preferably 65wt% to 70wt%.

[0023] In the method of the present invention, in the post-treatment catalyst in step (3), the carrier further contains a binder; the binder can be a commonly used adhesive in the art, preferably a small-pore alumina, the pore volume of the small-pore alumina is 0.3 to 0.5 mL / g, and the specific surface area is 200 to 400 m 2 / g; based on the mass of the catalyst, the binder content is 10wt% to 30wt%.

[0024] In the method of the present invention, the active metal components in the post-treatment catalyst in step (3) are Pd and / or Pt; based on the mass of the catalyst, the Pt content is 0.1wt% to 0.5wt%, and the Pd content is 0.2wt% to 0.8wt%.

[0025] In the method of the present invention, the specific surface area of ​​the post-treatment catalyst in step (3) is 300 to 700 m 2 / g, and the pore volume is 0.5~1.0mL / g.

[0026] In the method of the present invention, the preparation method of the post-treatment catalyst in step (3) comprises: kneading, shaping, drying and calcining the modified Y-type molecular sieve with amorphous silica-alumina and a binder to obtain a catalyst carrier; loading Pd and / or Pt on the catalyst carrier by an impregnation method, and then drying and calcining the catalyst carrier twice to obtain the post-treatment catalyst.

[0027] In the method of the present invention, the primary drying temperature is 100-130°C and the time is 6-14 hours; the primary roasting temperature is 450-550°C and the time is 3-8 hours; the secondary drying temperature is 100-130°C and the time is 10-14 hours; and the secondary roasting temperature is 500-500°C and the time is 3-10 hours.

[0028] In the method of the present invention, the reaction conditions of the post-treatment reaction zone in step (3) are as follows: reaction temperature 180-250°C, reaction pressure 6-15 MPa, hydrogen-to-oil volume ratio 500-2000, liquid hourly volume space velocity 0.5-5.0h -1 .

[0029] According to the second aspect of the present invention, the present invention provides white oil obtained by the above method, wherein the white oil is food grade white oil with a viscosity (40°C) of 39 to 43 mm 2 ·s -1 , flash point 220~242℃, Saybolt color 31~35.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] In the process of hydrogenating white oil to produce white oil, the present invention adopts a novel post-treatment catalyst, which contains a modified Y-type molecular sieve with an appropriate content and ratio of 0-NNN aluminum:1-NNN aluminum, a small grain size, and a high proportion of effective mesopores of 4-8 nm. The catalyst is particularly suitable for the hydrogenation and dearomatization process of raw oil such as hydrocracking tail oil, and can achieve excellent reaction effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the pore size distribution diagram of the Y-2 molecular sieve in Example 2. DETAILED DESCRIPTION

[0033] In order to better illustrate the present invention, the present invention is further illustrated below in conjunction with Examples and Comparative Examples. However, the scope of the present invention is not limited to the scope of these Examples.

[0034] In the present invention, specific surface area and pore volume were measured using the ASAP2405 low-temperature liquid nitrogen physical adsorption method, and the relative crystallinity and unit cell constant of the molecular sieve were determined by X-ray powder diffraction (XRD). The relative crystallinity of the raw material NH4NaY was 100%, and the relative crystallinity of other samples was compared with this. The silicon-aluminum molar ratio was measured using chemical titration.

[0035] In the present invention, the total molar content of 0-NNN aluminum and 1-NNN aluminum and the molar ratio of 0-NNN aluminum to 1-NNN are obtained by measuring the peak area corresponding to X-NNN aluminum by a solid-state NMR nuclear magnetic resonance spectrometer and then calculating. For example, the total molar content of 0-NNN aluminum and 1-NNN aluminum is calculated as follows: the sum of the peak areas corresponding to 0-NNN aluminum and 1-NNN aluminum is divided by the sum of the peak areas corresponding to all X-NNN aluminums.

[0036] In the present invention, wt% refers to mass fraction, and v% refers to volume fraction.

[0037] In the present invention, the preparation process of the modified Y-type molecular sieve comprises the following steps:

[0038] 1) performing a hydrothermal treatment on an NH4NaY molecular sieve, wherein the average crystal diameter of the NH4NaY molecular sieve is 200-500 nm;

[0039] 2) treating the molecular sieve obtained in step 1) with a buffer solution;

[0040] 3) performing a secondary hydrothermal treatment on the molecular sieve obtained in step 2);

[0041] 4) treating the molecular sieve obtained in step 3) with an acidic solution, performing solid-liquid separation, washing, and drying to obtain the final modified Y-type molecular sieve;

[0042] The temperature of the secondary hydrothermal treatment in step 3) is controlled to be 20-40° C. lower than that of the primary hydrothermal treatment; and the water vapor pressure of the secondary hydrothermal treatment is at least 0.2 MPa higher than that of the primary hydrothermal treatment, preferably 0.3-0.5 MPa higher.

[0043] Furthermore, in the above-mentioned preparation method of the modified Y-type molecular sieve, the SiO2 / Al2O3 (molar ratio) of the NH4NaY molecular sieve in step 1) is 4-8, and the Na2O content is ≤2.5wt%. The NH4NaY molecular sieve can be purchased from the market or prepared by existing methods in the art.

[0044] Furthermore, in the preparation method of the modified Y-type molecular sieve, the primary hydrothermal treatment temperature in step 1) is 600°C to 670°C, preferably 630°C to 660°C, the water vapor pressure is 0.01 to 0.20 MPa, preferably 0.08-0.14 MPa, and the treatment time is 1.0 to 4.0 h.

[0045] Furthermore, in the preparation method of the modified Y-type molecular sieve, the buffer solution in step 2) contains an ammonium salt and an acid, the ammonium salt is one or more of ammonium chloride, ammonium nitrate, ammonium carbonate, ammonium sulfate, ammonium acetate, ammonium oxalate and ammonium citrate; the acid is an inorganic acid and / or an organic acid, the inorganic acid is one or more of hydrochloric acid, nitric acid and sulfuric acid, and the organic acid is one or more of acetic acid, oxalic acid and citric acid.

[0046] Furthermore, in the preparation method of the modified Y-type molecular sieve, the NH4 + The concentration is 1-3 mol / L, H + The concentration is 0.1-0.4mol / L.

[0047] Furthermore, in the preparation method of the modified Y-type molecular sieve, the specific operation process of treating the molecular sieve obtained in step (1) with a buffer solution in step 2) is as follows: the molecular sieve obtained in step (1) is mixed with the buffer solution, the mother liquor is removed, and then washed with water and dried; the mass ratio of the molecular sieve to the buffer solution is 1:5 to 1:20; the mixing temperature is 70 to 120°C, and the mixing time is 0.5 to 4.0; the above steps can be repeated 1 to 4 times until the SiO2 / Al2O3 (molar ratio) of the molecular sieve is 10.0 to 15.0.

[0048] Furthermore, in the preparation method of the modified Y-type molecular sieve, the secondary hydrothermal treatment temperature in step 3) is 570-640°C, preferably 600-630°C, the water vapor pressure is 0.3-1.0 MPa, preferably 0.25-0.7 MPa, and the treatment time is 1.0-4.0 hours.

[0049] Furthermore, in the above-mentioned preparation method of modified Y-type molecular sieve, the acid contained in the acidic solution in step 4) is an inorganic acid and / or an organic acid, the inorganic acid is one or more of hydrochloric acid, nitric acid and sulfuric acid, and the organic acid is one or more of acetic acid, oxalic acid and citric acid.

[0050] Furthermore, in the above-mentioned preparation method of modified Y-type molecular sieve, the concentration of the acidic solution in step 4) is generally 0.1 to 3.0 mol / L, and the mass ratio of the molecular sieve to the acidic solution is 1:5 to 1:20.

[0051] Furthermore, in the above-mentioned preparation method of modified Y-type molecular sieve, the treatment temperature in step 4) is generally 60-110° C., and the treatment time is generally 0.5-5 h.

[0052] Furthermore, in the above-mentioned method for preparing the modified Y-type molecular sieve, the method for solid-liquid separation in step 4) is not limited, and any solid-liquid separation method known in the art can be used. Specifically, in the present invention, any of static separation, filtration separation, and centrifugal separation can be used, with filtration separation being preferred.

[0053] The specific embodiments of the present invention are described in detail below. However, it should be noted that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims in the appendix.

[0054] Example 1

[0055] (1) Molecular sieve modification

[0056] Take 100g of NH4NaY (average grain diameter 350nm, unit cell parameter 2.465nm, crystallinity 100%, Na2O content 2.4wt%, SiO2 / Al2O3 (molar ratio) = 5.0) produced by Shanghai Xinnian Petrochemical Additive Co., Ltd. and place it in a heat treatment furnace. Control the heating rate of 500℃ / h and raise the temperature to 640℃ while maintaining the water vapor pressure of the system at 0.12MPa. Treat for 2 hours, cool down, and take out the sample. The obtained molecular sieve is mixed with 1000mL of a mixed aqueous solution of ammonium nitrate and nitric acid (NH4 + The concentration is 1.5 mol / L, H + The mixture was slurried and mixed evenly, and stirred at 80 ° C for 2 h, filtered and washed with water until the solution was close to neutral; the wet filter cake was placed in a heat treatment furnace, the temperature was raised to 615 ° C, the water vapor pressure was controlled at 0.45 MPa, the temperature was kept constant for 2 hours, the temperature was lowered, and the sample was taken out; finally, the mixture was treated with H + The sample was contacted with 850 mL of a 0.45 mol / L nitric acid solution and stirred, treated at 85°C for 2 hours, filtered, washed with water, and dried to obtain a small-grain Y molecular sieve product Y-1. The physicochemical properties of the product Y-1 are shown in Table 1.

[0057] (2) Catalyst preparation

[0058] Based on the final catalyst mass, Y-1 molecular sieve accounting for 12% of the catalyst weight, amorphous silica-alumina (pore volume 0.85 mL / g, specific surface area 350 m 2 / g, silica weight content 12%), and 15% of the catalyst weight of small pore alumina (pore volume 0.30mL / g, specific surface area 325m 2 / g) and 10% dilute nitric acid (HNO3 / small-pore Al2O3 molar ratio of 0.20), placed in a roller compactor, mixed and ground, water was added, and rolled into a paste, which was extruded into strips. The extruded strips were dried at 110°C for 4 hours and then calcined at 550°C for 4 hours to obtain carrier TC-1.

[0059] The conventional equal volume impregnation method was used to impregnate solutions of PdC12 (analytical grade) and Pt(NH4)4C12 (analytical grade) onto the formed support in steps according to the final catalyst metal amount. The mixture was allowed to stand for 12 h, dried at 110°C for 6 h, and calcined at 480°C for 4 h to obtain catalyst C-1. The corresponding catalyst properties are shown in Table 2.

[0060] Example 2

[0061] (1) Molecular sieve modification

[0062] Take 100g of NH4NaY (average grain diameter 350nm, unit cell parameter 2.465nm, crystallinity 100%, Na2O content 2.4wt%, SiO2 / Al2O3 (molar ratio) = 5.0) produced by Shanghai Xinnian Petrochemical Additive Co., Ltd. and place it in a heat treatment furnace. Control the heating rate of 500℃ / h and raise the temperature to 640℃ while maintaining the water vapor pressure of the system at 0.12MPa. Treat for 2 hours, cool down, and take out the sample. The obtained molecular sieve is mixed with 1000mL of a mixed aqueous solution of ammonium nitrate and nitric acid (NH4 + The concentration is 1.5 mol / L, H + The mixture was slurried and mixed evenly, and stirred at 80 ° C for 2 h, filtered and washed with water until the solution was close to neutral; the wet filter cake was placed in a heat treatment furnace, the temperature was raised to 615 ° C, the water vapor pressure was controlled at 0.48 MPa, the temperature was kept constant for 2 hours, the temperature was lowered, and the sample was taken out; finally, the mixture was treated with H + 850 mL of a 0.48 mol / L nitric acid solution was contacted with the sample and stirred, then treated at 85°C for 2 hours, filtered, washed with water, and dried to obtain a small-grain Y molecular sieve product, Y-2. The physicochemical properties of the product Y-2 are shown in Table 1.

[0063] (2) Catalyst preparation

[0064] Based on the final catalyst mass, Y-1 molecular sieve accounting for 14% of the catalyst weight, amorphous silica-alumina (pore volume 0.85 mL / g, specific surface area 350 m 2 / g, silica weight content 12%), and 15% of the catalyst weight of small pore alumina (pore volume 0.30mL / g, specific surface area 325m 2 / g) and 10% dilute nitric acid (HNO3 / small-pore Al2O3 molar ratio of 0.20), placed in a roller compactor, mixed and ground, water was added, and rolled into a paste, which was extruded into strips. The extruded strips were dried at 110°C for 4 hours and then calcined at 550°C for 4 hours to obtain carrier TC-2.

[0065] The support was impregnated with an impregnation solution containing tungsten and nickel at 25°C for 2 hours, dried at 120°C for 4 hours, and calcined at 500°C for 4 hours to obtain catalyst C-2. The corresponding catalyst properties are shown in Table 2.

[0066] Example 3

[0067] (1) Molecular sieve modification

[0068] Take 100g of NH4NaY (average grain diameter 350nm, unit cell parameter 2.465nm, crystallinity 100%, Na2O content 2.4wt%, SiO2 / Al2O3 (molar ratio) = 5.0) produced by Shanghai Xinnian Petrochemical Additive Co., Ltd. and place it in a heat treatment furnace. Control the heating rate of 500℃ / h and raise the temperature to 645℃ while maintaining the water vapor pressure of the system at 0.11MPa. Treat for 2 hours, cool down, and take out the sample. The obtained molecular sieve is mixed with 1000mL of a mixed aqueous solution of ammonium nitrate and nitric acid (NH4 + The concentration is 1.5 mol / L, H + The mixture was slurried and mixed evenly, and stirred at 80 ° C for 2 h, filtered and washed with water until the solution was close to neutral; the wet filter cake was placed in a heat treatment furnace, the temperature was raised to 620 ° C, the water vapor pressure was controlled at 0.50 MPa, the temperature was kept constant for 2 hours, the temperature was lowered, and the sample was taken out; finally, the mixture was treated with H + 800 mL of a 0.50 mol / L nitric acid solution was placed in contact with the sample and stirred, then treated at 85°C for 2 hours. The sample was then filtered, washed with water, and dried to obtain a small-grain Y molecular sieve product, Y-3. The physicochemical properties of the product Y-3 are shown in Table 1.

[0069] (2) Catalyst preparation

[0070] Based on the final catalyst mass, Y-1 molecular sieve accounting for 16% of the catalyst weight, amorphous silica-alumina (pore volume 0.85 mL / g, specific surface area 350 m 2 / g, silica weight content 12%), and 15% of the catalyst weight of small pore alumina (pore volume 0.30mL / g, specific surface area 325m 2 / g) and 10% dilute nitric acid (HNO3 / small-pore Al2O3 molar ratio of 0.20), placed in a roller compactor, mixed and ground, water was added, and rolled into a paste, which was extruded into strips. The extruded strips were dried at 110°C for 4 hours and then calcined at 550°C for 4 hours to obtain carrier TC-2.

[0071] The support was impregnated with an impregnation solution containing tungsten and nickel at 25°C for 2 hours, dried at 120°C for 4 hours, and calcined at 500°C for 4 hours to obtain catalyst C-3. The corresponding catalyst properties are shown in Table 2.

[0072] Example 4

[0073] (1) Molecular sieve modification

[0074] Take 100g of NH4NaY (average grain diameter 350nm, unit cell parameter 2.465nm, crystallinity 100%, Na2O content 2.4wt%, SiO2 / Al2O3 (molar ratio) = 5.0) produced by Shanghai Xinnian Petrochemical Additive Co., Ltd. and place it in a heat treatment furnace. Control the heating rate of 500℃ / h and raise the temperature to 645℃ while maintaining the water vapor pressure of the system at 0.10MPa. Treat for 2 hours, cool down, and take out the sample. The obtained molecular sieve is mixed with 1000mL of a mixed aqueous solution of ammonium nitrate and nitric acid (NH4 + The concentration is 1.4 mol / L, H + The mixture was slurried and mixed evenly, and stirred at 80 ° C for 2 h, filtered and washed with water until the solution was close to neutral; the wet filter cake was placed in a heat treatment furnace, the temperature was raised to 620 ° C, the water vapor pressure was controlled at 0.53 MPa, the temperature was kept constant for 2 hours, the temperature was lowered, and the sample was taken out; finally, the mixture was treated with H + 800 mL of a 0.52 mol / L nitric acid solution was placed in contact with the sample and stirred, then treated at 85°C for 2 hours. The sample was then filtered, washed with water, and dried to obtain a small-grain Y molecular sieve product, Y-4. The physical and chemical properties of the product Y-4 are shown in Table 1.

[0075] (2) Catalyst preparation

[0076] Based on the final catalyst mass, Y-1 molecular sieve accounting for 18% of the catalyst weight, amorphous silica-alumina (pore volume 0.85 mL / g, specific surface area 350 m 2 / g, silica weight content 12%), and 15% of the catalyst weight of small pore alumina (pore volume 0.30mL / g, specific surface area 325m 2 / g) and 10% dilute nitric acid (HNO3 / small-pore Al2O3 molar ratio of 0.20), placed in a roller compactor, mixed and ground, water was added, and rolled into a paste, which was extruded into strips. The extruded strips were dried at 110°C for 4 hours and then calcined at 550°C for 4 hours to obtain carrier TC-4.

[0077] The support was impregnated with an impregnation solution containing tungsten and nickel at 25°C for 2 hours, dried at 120°C for 4 hours, and calcined at 500°C for 4 hours to obtain catalyst C-4. The corresponding catalyst properties are shown in Table 2.

[0078] Comparative Example 1

[0079] (1) Molecular sieve modification

[0080] Take 100g of NH4NaY (average grain diameter 350nm, unit cell parameter 2.465nm, crystallinity 100%, Na2O content 2.4wt%, SiO2 / Al2O3 (molar ratio) = 5.0) produced by Shanghai Xinnian Petrochemical Additive Co., Ltd. and place it in a heat treatment furnace. Control the heating rate of 500℃ / h and raise the temperature to 615℃ while maintaining the water vapor pressure of the system at 0.07MPa. Treat for 2 hours, cool down, and take out the sample. The obtained molecular sieve is mixed with 800mL of a mixed aqueous solution of ammonium nitrate and nitric acid (NH4 + The concentration is 1.5 mol / L, H + The mixture was slurried and mixed evenly, and stirred at 80 ° C for 2 h, filtered and washed with water until the solution was close to neutral; the wet filter cake was placed in a heat treatment furnace, the temperature was raised to 585 ° C, the water vapor pressure was controlled at 0.15 MPa, the temperature was kept constant for 2 hours, the temperature was lowered, and the sample was taken out; finally, the mixture was treated with H + 800 mL of a 0.4 mol / L nitric acid solution was placed in contact with the sample and stirred, then treated at 85°C for 2 hours, filtered, washed with water, and dried to obtain product CY-1. The physicochemical properties of product CY-1 are shown in Table 1.

[0081] (2) Catalyst preparation

[0082] The preparation method of CC-1 catalyst is the same as step (2) of Example 1, except that Y-1 molecular sieve is replaced by CY-1. The corresponding catalyst properties are shown in Table 2.

[0083] Comparative Example 2

[0084] (1) Molecular sieve modification

[0085] Take 100g of NH4NaY (average grain diameter 350nm, unit cell parameter 2.465nm, crystallinity 100%, Na2O content 2.4wt%, SiO2 / Al2O3 (molar ratio) = 5.0) produced by Shanghai Xinnian Petrochemical Additive Co., Ltd. and place it in a heat treatment furnace. Control the heating rate of 500℃ / h and raise the temperature to 620℃ while maintaining the water vapor pressure of the system at 0.06MPa. Treat for 2 hours, cool down, and take out the sample. The obtained molecular sieve is mixed with 700mL of a mixed aqueous solution of ammonium chloride and hydrochloric acid (NH4 + The concentration is 1.8 mol / L, H + The mixture was slurried and mixed evenly, and stirred at 90 ° C for 2 h, filtered and washed with water until the solution was close to neutral; the wet filter cake was placed in a heat treatment furnace, the temperature was raised to 590 ° C, the water vapor pressure was controlled at 0.06 MPa, the temperature was kept constant for 2 hours, the temperature was lowered, and the sample was taken out; finally, the mixture was treated with H +800 mL of a 0.45 mol / L hydrochloric acid solution was placed in contact with the sample and stirred, then treated at 90°C for 2 hours, filtered, washed with water, and dried to obtain product CY-2. The physicochemical properties of product CY-2 are shown in Table 1.

[0086] (2) Catalyst preparation

[0087] The preparation method of CC-2 catalyst is the same as step (2) of Example 2, except that Y-2 molecular sieve is replaced by CY-2. The corresponding catalyst properties are shown in Table 2.

[0088] Comparative Example 3

[0089] (1) Molecular sieve modification

[0090] Take 100g of NH4NaY (average grain diameter 350nm, unit cell parameter 2.465nm, crystallinity 100%, Na2O content 2.4wt%, SiO2 / Al2O3 (molar ratio) = 5.0) produced by Shanghai Xinnian Petrochemical Additive Co., Ltd. and place it in a heat treatment furnace. Control the heating rate of 500℃ / h and raise the temperature to 655℃ while maintaining the water vapor pressure of the system at 0.1MPa. Treat for 2 hours, cool down, and take out the sample. The obtained molecular sieve is mixed with 700mL of a mixed aqueous solution of ammonium chloride and hydrochloric acid (NH4 + The concentration is 1.8 mol / L, H + The mixture was slurried and mixed evenly, and stirred at 90 ° C for 2 h, filtered and washed with water until the solution was close to neutral; the wet filter cake was placed in a heat treatment furnace, the temperature was raised to 645 ° C, the water vapor pressure was controlled at 0.40 MPa, the temperature was kept constant for 2 hours, the temperature was lowered, and the sample was taken out; finally, the mixture was treated with H + 800 mL of a 0.45 mol / L hydrochloric acid solution was placed in contact with the sample and stirred, then treated at 90°C for 2 hours, filtered, washed with water, and dried to obtain product CY-3. The physicochemical properties of product CY-3 are shown in Table 1.

[0091] (2) Catalyst preparation

[0092] The preparation method of CC-3 catalyst is the same as step (2) of Example 2, except that Y-2 molecular sieve is replaced by CY-3. The corresponding catalyst properties are shown in Table 2.

[0093] Comparative Example 4

[0094] (1) Molecular sieve modification

[0095] Take 100g of NH4NaY (average grain diameter 350nm, unit cell parameter 2.465nm, crystallinity 100%, Na2O content 2.4wt%, SiO2 / Al2O3 (molar ratio) = 5.0) produced by Shanghai Xinnian Petrochemical Additive Co., Ltd. and place it in a heat treatment furnace. Control the heating rate of 500℃ / h and raise the temperature to 650℃ while maintaining the water vapor pressure of the system at 0.10MPa. Treat for 2 hours, cool down, and take out the sample. The obtained molecular sieve is mixed with 700mL of a mixed aqueous solution of ammonium chloride and hydrochloric acid (NH4 + The concentration is 1.8 mol / L, H + The mixture was slurried and mixed evenly, and stirred at 90 ° C for 2 h, filtered and washed with water until the solution was close to neutral; the wet filter cake was placed in a heat treatment furnace, the temperature was raised to 650 ° C, the water vapor pressure was controlled to 0.10 MPa, the temperature was kept constant for 2 hours, the temperature was lowered, and the sample was taken out; finally, the mixture was heated with H + 800 mL of a 0.45 mol / L hydrochloric acid solution was placed in contact with the sample and stirred, then treated at 90°C for 2 hours, filtered, washed with water, and dried to obtain product CY-4. The physicochemical properties of product CY-4 are shown in Table 1.

[0096] (2) Catalyst preparation

[0097] The preparation method of CC-4 catalyst is the same as step (2) of Example 2, except that Y-2 molecular sieve is replaced by CY-4. The corresponding catalyst properties are shown in Table 2.

[0098] Table 1 Properties of modified Y-type molecular sieves

[0099]

[0100]

[0101] As can be seen from Table 1, the modified small-grain Y molecular sieve prepared by the present invention has a larger specific surface area and pore volume than the comparative example. At the same time, the proportion of 4-8 nm secondary mesopore volume to the total pore volume is high, the total content of 0-NNN aluminum and 1-NNN aluminum is high, and the molar ratio of 0-NNN aluminum to 1-NNN is large.

[0102] Table 2 Physicochemical properties of catalysts

[0103] Catalyst No. C-1 C-2 C-3 C-4 CC-1 CC-2 CC-3 CC-4 Pt, wt% 0.18 0.20 0.19 0.22 0.19 0.20 0.19 0.20 Pd, wt% 0.61 0.59 0.60 0.59 0.61 0.59 0.60 0.59

[0104] The catalysts of the present invention and the comparative example catalysts were subjected to activity evaluation tests. The tests were conducted on a 200 mL small-scale hydrogenation unit. The properties of the feedstock oil (hydrocracking tail oil) used are shown in Table 3. The feedstock oil and hydrogen were mixed and introduced into a hydroisomerization reactor. The reaction took place in contact with a hydroisomerization catalyst, trade name FIW-12, developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. The reaction conditions were as follows: reaction temperature of 314°C, hydrogen partial pressure of 1.8 MPa, hydrogen-to-oil volume ratio of 700, and volume space velocity of 1.0 h-1 / h. -1 The reaction effluent enters the separation system to obtain a fraction of oil >320°C, which is then mixed with hydrogen and then enters the post-treatment reaction zone. The reaction is carried out in the presence of the post-treatment catalyst prepared in the examples and comparative examples. The reaction conditions are as follows: hydrogen partial pressure of 12.9 MPa, hydrogen-to-oil volume ratio of 1200, and volume space velocity of 1.4 h -1 The final food grade white oil product was obtained. The evaluation test results are shown in Table 4.

[0105] Table 3 Hydrocracking tail oil properties

[0106] Analysis Project <![CDATA[Density (20 °C) / kg·m -3 > 867.4 Distillation range / ℃ 321-526 <![CDATA[Sulfur / μg·g -1 > 4.6 <![CDATA[Nitrogen / μg·g -1 > 1.8 Pour point / ℃ 23 <![CDATA[Viscosity (100 °C) / mm 2 ·s -1 > 4.801 <![CDATA[Viscosity (40 °C) / mm 2 ·s -1 > 24.11 Carbon residue, wt% 0.02 Aromatics, wt% 16.1

[0107] Table 4 Catalyst activity evaluation results

[0108] Catalyst No. C-1 C-2 C-3 C-4 CC-1 CC-2 CC-3 CC-4 Reaction temperature, °C 221 223 224 225 223 225 226 227 Liquid yield, wt% 99.3 99.4 99.5 99.6 98.3 98.0 98.9 98.7 <![CDATA[Viscosity (40 °C), mm 2 ·s -1 > 39.57 40.98 41.95 42.78 37.76 38.02 37.86 35.79 Flash point, ℃ 224 228 232 241 210 205 208 204 Saybolt color / number +31.1 +32.3 +33.4 +34.5 +30.2 +29.3 +29.4 +28.7

[0109] It can be seen from the evaluation results of the catalysts in Table 4 that the key technical indicators of the food-grade white oil produced by the catalyst prepared by the present invention are better than those of the comparative example.

Claims

1. A method for producing white oil by hydrogenation, characterized in that: The steps include: (1) The feedstock oil and hydrogen are mixed and enter the hydroisomerization reaction zone, where they come into contact with the hydroisomerization catalyst to react; (2) the reaction effluent obtained in step (1) enters a separation system to obtain a distillate oil >320°C; (3) The distillate oil with a temperature greater than 320° C. obtained in step (2) is mixed with hydrogen and then enters a post-treatment reaction zone, where the mixture reacts in the presence of a post-treatment catalyst to obtain a final white oil product; the post-treatment catalyst comprises an active metal component and a carrier, and the carrier comprises a modified Y-type molecular sieve; the total molar content of 0-NNN aluminum and 1-NNN aluminum in the modified Y-type molecular sieve is 94% to 96%, based on the total molar amount of X-NNN aluminum; and the molar ratio of the 0-NNN aluminum to the 1-NNN aluminum is 3.5 to 4.

4.

2. The method according to claim 1, wherein: The raw oil in step (1) has the following properties: nitrogen content <10ppm, sulfur content <10ppm, aromatic content 8-20wt%, viscosity (40℃) 15-40mm 2 / s.

3. The method according to claim 1, wherein: The hydroisomerization reaction zone in step (1) is provided with one or more fixed-bed hydrogenation reactors connected in series; when multiple fixed-bed hydrogenation reactors are connected in series, a cooler is provided after each reactor.

4. The method according to claim 1, wherein: The hydroisomerization catalyst in step (1) includes a carrier and an active metal component, the carrier includes one or more of ZSM-22, ZSM-23, SAPO-11, SAPO-31 and SAPO-41 molecular sieves, and the active metal component is one or more of Pt, Pd, Ru and Rh.

5. The method according to claim 1, wherein: The reaction conditions of the hydroisomerization reaction zone in step (1) are as follows: reaction temperature 250-370°C, reaction pressure 1.0-2.5 MPa, hydrogen-to-oil volume ratio 500-2000, liquid hourly volume space velocity 0.3-3.0 h -1 .

6. The method according to claim 1, wherein: The separation system in step (2) includes a gas-liquid separation unit and a fractionation unit, the gas-liquid separation unit includes a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator and a cold low-pressure separator; the fractionation unit includes a fractionation tower.

7. The method according to claim 1, wherein: In the post-treatment catalyst in step (3), the average diameter of the modified Y-type molecular sieve grains is 100-500 nm, preferably 200-400 nm, and the pore volume of mesopores of 4-8 nm accounts for more than 70% of the total pore volume, preferably more than 72%.

8. The method according to claim 1, wherein: In the post-treatment catalyst in step (3), the modified Y-type molecular sieve SiO2 / A12O3 (molar ratio) is 50-60; the specific surface area is 900-1200m 2 / g; pore volume 0.50~0.80mL / g.

9. The method according to claim 1, wherein: In the post-treatment catalyst described in step (3), based on the mass of the catalyst, the content of the active metal component as a single substance is 0.3-1.3 wt%, the carrier content is 98.7-99.7 wt%, and the content of the modified Y-type molecular sieve is 10 wt%-25 wt%.

10. The method according to claim 1, wherein: In the method of the present invention, the active metal components in the post-treatment catalyst in step (3) are Pd and / or Pt; based on the mass of the catalyst, the Pt content is 0.1wt% to 0.5wt%, and the Pd content is 0.2wt% to 0.8wt%.

11. The method according to claim 1, wherein: The specific surface area of ​​the post-treatment catalyst in step (3) is 300 to 700 m 2 / g, and the pore volume is 0.5~1.0mL / g.

12. The method according to claim 1, wherein: The preparation method of the post-treatment catalyst described in step (3) comprises: kneading, shaping, drying and calcining the modified Y-type molecular sieve with amorphous silica-alumina and a binder to obtain a catalyst carrier; loading Pd and / or Pt on the catalyst carrier by an impregnation method, and then drying and calcining the catalyst carrier twice to obtain the post-treatment catalyst.

13. The method according to claim 12, wherein: The primary drying temperature is 100-130°C, and the time is 6-14 hours; the primary roasting temperature is 450-550°C, and the time is 3-8 hours; the secondary drying temperature is 100-130°C, and the time is 10-14 hours; the secondary roasting temperature is 500-500°C, and the time is 3-10 hours.

14. The method according to claim 1, wherein: The reaction conditions of the post-treatment reaction zone in step (3) are as follows: reaction temperature 180-250°C, reaction pressure 6-15 MPa, hydrogen-to-oil volume ratio 500-2000, liquid hourly volume space velocity 0.5-5.0 h -1 .

15. White oil obtained by the method according to any one of claims 1 to 14.

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