A process for the production of a base oil

Abstract

The application discloses a production method of base oil, which comprises the following steps: carrying out a hydroisomerization reaction on a lubricating oil base oil raw material under the action of at least one metal phosphide catalyst to obtain base oil, characterized in that the metal phosphide catalyst comprises a metal component and a carrier, the metal phosphide catalyst is subjected to twice modification treatment, the first modification is to introduce a first modification aid alkali metal and / or an acidic compound into the carrier, and the second modification is to introduce a second modification aid polyhydroxy organic compound into the metal component. According to the production method of the base oil, the lubricating oil base oil with low condensation point and low pour point can be produced by taking wax oil as the raw material and carrying out the hydroisomerization reaction on the wax oil by using the metal phosphide catalyst, meanwhile, the lubricating oil base oil produced by the application has low aromatic hydrocarbon content and high total lubricating oil base oil yield.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of lubricating oil base oil, and particularly relates to a production method of base oil. BACKGROUND

[0002] As an important component of domestic production, lubricating oil base oil has a very wide range of applications. Wax oil is a commonly used lubricating oil base oil raw material. In addition to removing sulfur, nitrogen compound impurities and some polycyclic aromatic hydrocarbons to improve the viscosity index and oxidation stability, the solid hydrocarbons in the wax oil must also be removed to reduce the freezing point and pour point. The solid hydrocarbons contained in the lubricating oil base oil raw material are usually referred to as wax, which is composed of straight-chain alkanes and some non-straight-chain alkanes.

[0003] How to effectively convert wax molecules into branched isomers is a technical problem to be solved in the production of low freezing point lubricating oil base oil. Isomerization dewaxing (hydroisomerization) technology is the most advanced lubricating oil base oil processing technology, which has the characteristics of converting wax molecules into branched isomers, low cracking activity, and maximum production of lubricating oil base oil. The core of isomerization dewaxing technology is the isomerization dewaxing catalyst. The improvement of the catalyst has never stopped, mainly from the improvement of the metal active component and the carrier material. The existing isomerization dewaxing catalyst mainly uses noble metals Pt and Pd as the main active component. This type of catalyst is expensive, and the development of low-cost isomerization dewaxing catalyst is the general trend of development.

[0004] US Patent 4,176,050 discloses a method for preparing a catalytic dewaxing catalyst, using large crystal ZSM-5 molecular sieve as the acidic component and nickel as the hydrogenation component. The selectivity of the catalyst is improved, but the activity is poor, and the liquid yield is low.

[0005] Chinese patent CN102989492A discloses a supported composite sulfur phosphide hydroprocessing catalyst, the catalyst is composed of active metals Ni, Co or Mo, W and modified porous support material, characterized in that: the active metal exists in the form of M-P or M-P-S or M-S and is supported on the porous support material; the total amount of active metal accounts for 10-40% of the weight of the catalyst; the porous support material is molecular sieve or oxide and its binary, multi-component composite; the preparation steps are as follows: (1) the soluble transition metal salt and the soluble alkali are dissolved in water respectively, then mixed, stirred, precipitated, the obtained precipitate is filtered and washed with deionized water, the obtained filter cake is placed in deionized water, stirred and H3PO2 or H3PO2 solution is added dropwise into it until the precipitate is completely dissolved, the obtained solution is added into the complexing agent and the transition metal salt to prepare a clear solution; or the transition metal salt, the phosphorus source and the complexing agent are dissolved in water to prepare a clear solution; or the transition metal salt, ammonium phosphomolybdate or ammonium phosphotungstate and the complexing agent are dissolved in water to prepare a clear solution; or the secondary phosphite salt containing Ni or Co, the transition metal salt and the complexing agent are dissolved in water to prepare a clear solution; (2) the prepared clear solution is added into the support, impregnated for 2-8 hours, then the support impregnated with the active component is dried at 80-150°C for 2-8 hours to prepare a composite phosphide catalyst precursor; the complexing agent is citric acid, ethylenediaminetetraacetic acid or its ammonium salt, cyclohexanediaminetetraacetic acid or its ammonium salt, tartaric acid, malic acid, ethylenediamine or ethylene glycol. The phosphorus source is phosphoric acid, secondary phosphite, diammonium hydrogen phosphate, dimethyl phosphite or triphenyl phosphorus. The transition metal salt is ammonium molybdate, ammonium tungstate, ammonium phosphomolybdate, ammonium phosphotungstate, nickel nitrate, cobalt nitrate, basic nickel carbonate, basic cobalt carbonate or binary, multi-component mixture thereof. The support is SiO2, Al2O3, HZSM-5, HY, NaY zeolite, beta molecular sieve, MCM-41, SBA-15 or silica-alumina composite support, binary or multi-component composite oxide support. The catalyst is used for hydroprocessing reaction of gasoline, diesel, lubricating oil, residual oil.

[0006] Chinese patent CN101134910A discloses a method for reducing the pour point of lubricating oil distillate oil, the method adopts catalytic dewaxing process, the catalyst is composed of a carrier including ZSM-5 molecular sieve and nickel as active component, the light deasphalted oil with pour point of 9°C can be isomerized to reduce to-24°C, the obvious disadvantage of the process is that when the wax content in the raw oil is high and the pour point reduction range needs to be increased, the yield and viscosity of total 0 base oil will be greatly reduced.

[0007] Chinese patent CN110498424A discloses a Y molecular sieve modification method, the obtained NH4Y molecular sieve is contacted with a salt solution containing alkali metal ions and / or a salt solution containing alkaline earth metal ions, after filtration, washing and drying, the obtained product is contacted with an acid solution, and the product is recovered to obtain a modified Y molecular sieve; wherein the alkali metal is selected from rubidium, cesium, the alkaline earth metal is selected from strontium, barium, and the acid solution is one or more of oxalic acid, citric acid, ethylenediaminetetraacetic acid, tartaric acid, hydrochloric acid and sulfuric acid. By screening suitable alkali metal (or alkaline earth metal) ions, ion exchange method is adopted, so that the cation distribution of Y molecular sieve shows the characteristics of NH4 + , the outside is alkali metal (or alkaline earth metal) ion, the effect of stabilizing the framework by alkali metal (or alkaline earth metal) ion is utilized to protect the outer molecular sieve in dealuminization to some extent, so that the inner molecular sieve is preferentially dealuminated. By changing the type, exchange condition and other factors of alkali metal (or alkaline earth metal) ion, the exchange position and exchange amount of alkali metal (or alkaline earth metal) ion can be changed, and then the inner and outer aluminum atom distribution and acid site distribution of dealuminated Y molecular sieve can be adjusted.

[0008] Chinese patent CN105344368A discloses a preparation method of transition metal phosphide for hydrogenation dechlorination reaction, characterized by comprising the following steps: step one, dissolving soluble metal salt and diammonium hydrogen phosphate in water, and dissolving polyethylene glycol in the above solution; step two, after the aqueous solution obtained in step one is stirred at 80°C for 3h, it is evaporated to dryness at 100°C, then dried at 120°C for 12h, and calcined at 500°C for 5h to obtain an oxidation precursor; step three, grinding and tabletting the oxidation precursor obtained in step two, and sieving to obtain 20-40 mesh granular material, which is reduced by programmed temperature reduction method to obtain modified transition metal phosphide.

[0009] Chinese patent CN108246341A discloses a preparation method of a hydrodearomatization catalyst, characterized by comprising the following steps: (1) under stirring at room temperature, ammonium dihydrogen phosphate is dissolved in deionized water, after it is dissolved, nickel nitrate is added, after continuing to stir for 30 minutes, ethylene glycol is added and continues to stir for 1 hour, then a solution of nitric acid with a mass concentration of 65% to 68% is added dropwise, the pH value of the solution is adjusted to be in the range of 2 to 5, after continuing to stir for at least 30 minutes, it is impregnated into a carrier by using a preliminary wet impregnation method, then it is dried at 80 DEG C for at least 5 hours, and then it is heated to 120 DEG C until it is dried; then the sample is placed into a muffle furnace and calcined at 500 DEG C for 2 hours to obtain a precursor; wherein the molar ratio of ammonium dihydrogen phosphate to nickel nitrate is 0.5 to 2; (2) the precursor is placed into a tubular furnace, under a flowing hydrogen atmosphere, it is heated to 650 DEG C and kept for at least 1 hour; then it is cooled to room temperature, and then it is switched to a 1% O2 / N2 passivation gas chamber to be passivated at room temperature for at least 2 hours to obtain sample A; wherein the volume space velocity of hydrogen is 3000 to 5000 h -1 ; (3) using trimethylaluminum as an aluminum source, aluminum hydroxide is deposited on the surface of sample A by using an atomic layer deposition method at 150 to 180 DEG C, then the obtained product is loaded into a tubular furnace and calcined at 600 DEG C under an argon atmosphere for at least 2 hours to obtain the required hydrodearomatization catalyst; wherein the deposition layer number of aluminum hydroxide is 3 to 10 atomic layers.

[0010] Metal phosphide catalysts, as representatives of non-noble metal type hydroisomerization catalysts, have become potential hydroisomerization catalysts for producing lubricating oil base oil due to their good hydrodehydrogenation performance, but the existing metal phosphide catalysts have the problem of poor condensation point reduction effect in the process of producing low condensation point base oil from waxy oil as raw material, and still need to be improved from the aspects of lubricating oil production process and catalyst process technology. SUMMARY

[0011] The main purpose of the present application is to provide a production method of base oil, and isomerization of waxy molecules in lubricating oil base oil is the core technical problem of producing low condensation point base oil. Non-noble metal catalysts represented by metal phosphide catalysts have weak condensation point reduction effect in the production of low condensation point base oil from waxy oil as raw material, and the existing production process needs to be improved, so as to solve the problem of poor condensation point reduction effect of non-noble metal type catalyst hydroisomerization process technology.

[0012] To achieve the above objectives, the present invention discloses a method for producing base oil, the method comprising: subjecting lubricating oil base oil feedstock to a hydroisomerization reaction under the action of at least one metal phosphide catalyst to obtain base oil, wherein the metal phosphide catalyst comprises a metal component and a support, and the metal phosphide catalyst undergoes two modification treatments, the first modification being the introduction of a first modifying agent, an alkali metal and / or an acidic compound, into the support, and the second modification being the introduction of a second modifying agent, a polyhydroxy organic compound, into the metal component.

[0013] The method for producing base oil of the present invention involves reducing a metal phosphide catalyst precursor under a hydrogen atmosphere to obtain the metal phosphide catalyst precursor. The metal phosphide catalyst precursor contains a metal component, phosphorus element, support, alkali metal and / or acidic compound, and polyhydroxy organic compound. The mass ratio of polyhydroxy organic compound to support is 1~20:100, preferably 1~15:100, and most preferably 3~10:100.

[0014] The method for producing the base oil of the present invention uses wax oil as the raw material for the lubricating oil base oil, which is selected from at least one of reduced-pressure wax oil, reduced-pressure wax oil, reduced-pressure wax oil, wax paste, hydrocracking tail oil and bright oil.

[0015] The method for producing the base oil of the present invention has a wax oil with a distillation range of 300~600℃, a sulfur content of no more than 200μg / g, and a nitrogen content of no more than 100μg / g; preferably, the wax oil has a distillation range of 350~580℃, a sulfur content of no more than 100μg / g, and a nitrogen content of no more than 50μg / g; most preferably, the sulfur content is no more than 50μg / g, and the nitrogen content is no more than 30μg / g.

[0016] In the production method of the base oil of the present invention, the wax content of the wax oil is not greater than 60% by mass, preferably not greater than 50% by mass.

[0017] The method for producing base oil according to the present invention uses a carrier comprising modified molecular sieves and alumina and / or amorphous silica-alumina.

[0018] The method for producing base oil of the present invention uses modified molecular sieves obtained by modifying molecular sieves with alkali metal salts and / or acidic compounds.

[0019] The method for producing the base oil of the present invention uses pyridine infrared spectroscopy to characterize the modified molecular sieve. At 150°C, the Brønsted acid content is 0.1–0.5 mmol / g, and the molar ratio of Brønsted acid to Lewis acid is 5:1–1:1; at 350°C, the Brønsted acid content is 0.1–0.3 mmol / g, and the molar ratio of Brønsted acid to Lewis acid is 5:1–1:1, wherein the total acid content of Brønsted acid and Lewis acid is greater than the total acid content of Brønsted acid and Lewis acid at 350°C.

[0020] The base oil production method of the present application, the molecular sieve has ten-membered ring or twelve-membered ring topology, and has a straight-through pore structure; the molar ratio of Si / Al2O3 in the molecular sieve is 5-100, and the average crystal grain size is 30-150 nm.

[0021] The base oil production method of the present application, the molecular sieve is at least one of SAPO-11, ZSM-22, MCM-22, ZSM-23, ZSM-35 and ZSM-48.

[0022] The base oil production method of the present application, the alkali metal is selected from at least one of group IA or IIA metals, preferably lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium and radium; and the acidic compound is selected from at least one of nitric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, acetic acid, tartaric acid, oxalic acid, citric acid and malic acid.

[0023] The base oil production method of the present application, the polyhydroxy organic compound is selected from at least one of glycerol, ethylenediaminetetraacetic acid, citric acid, tartaric acid and OH-(CH2) n -CH2-OH, wherein n is an integer greater than or equal to 1.

[0024] The base oil production method of the present application, the metal component is selected from at least one of cobalt, nickel, molybdenum and tungsten, and the metal component exists in the form of a compound in the metal phosphide catalyst; the total content of the metal component and phosphorus element in the metal phosphide catalyst is 10-40 wt% of the mass of the metal phosphide catalyst.

[0025] The base oil production method of the present application, the molar ratio of phosphorus element to metal component in the metal phosphide catalyst is 1:5-5:1, preferably 1:3-3:1.

[0026] The base oil production method of the present application, the phosphorus element in the metal phosphide catalyst is selected from one or more of phosphate, phosphoric acid, monohydrogen phosphate, dihydrogen phosphate and hypophosphite.

[0027] The base oil production method of the present application, the temperature of the hydrogen isomerization reaction is 300-400 DEG C, the hydrogen partial pressure is 8-15 MPa, the volume space velocity is 0.5-2.0, and the lubricating oil base oil with a pour point of not more than -15 DEG C can be produced.

[0028] The base oil production method of the present application uses a non-noble metal type catalyst, a metal phosphide catalyst as a catalytic medium, and converts wax oil into low freezing point lubricating oil base oil through a hydrogen isomerization reaction, which improves the freezing point of the lubricating oil base oil produced by the traditional metal phosphide catalyst using vacuum gas oil as a raw material, and cannot meet the low temperature fluidity use requirements of the lubricating oil base oil. In the metal phosphide catalyst, the carrier contains alkali metal salt and / or acid, which improves the acid distribution and electronic structure of the carrier, and the metal component is added with a polyhydroxy organic compound, the metal component forms a complex with the polyhydroxy organic compound, the interaction force between the metal component and the carrier is weakened, the distribution state of the metal on the catalyst carrier is improved, and the metal is more evenly distributed in the catalyst. At the same time, due to the complexation of the polyhydroxy organic compound and the metal phosphide, the interaction force between the metal phosphide and the carrier is weakened, so that the catalytic activity of the finally formed metal phosphide catalyst is stronger, and when using wax oil as a raw material, low freezing point, low freezing point lubricating oil base oil can be produced. At the same time, the aromatic hydrocarbon content of the base oil is low, which meets the general lubricating oil base oil standard (Q / SY 44-2009) requirements. DETAILED DESCRIPTION

[0029] The following detailed description of the embodiments of the present application is given: The present embodiment is implemented on the premise of the technical solution of the present application, and gives a detailed implementation method and process, but the protection scope of the present application is not limited to the following embodiments. The experimental method is not specified in the following embodiments, and is usually carried out under conventional conditions.

[0030] The present application provides a base oil production method, which uses lubricating oil base oil as a raw material, a metal phosphide catalyst as a catalyst, and is loaded in a fixed bed reactor. The wax oil is heated in a heating container and mixed uniformly with hydrogen in the container to form an oil-gas mixture, which is introduced into the reactor through a pressure pump. The oil-gas mixture and the metal phosphide catalyst perform a hydrogen isomerization reaction to generate a full-range lubricating oil base oil product. The full-range lubricating oil base oil product is cut by a fractionation system to obtain a low freezing point lubricating oil base oil.

[0031] The lubricating oil base oil raw material is wax oil, which is selected from one or a mixture of two or more of reduced second line wax oil, reduced third line wax oil, reduced fourth line wax oil, hydrocracking tail oil and wax paste; the distillation range of the wax oil is 300-600℃, preferably 350-580℃; the wax content of the wax oil is not more than 60%, preferably not more than 50%; the sulfur content is not more than 200μg / g, preferably not more than 100μg / g, and further preferably not more than 50μg / g; the nitrogen content is not more than 100μg / g, preferably not more than 50μg / g, and further preferably not more than 30μg / g.

[0032] The metal phosphide catalyst is obtained by reducing a metal phosphide catalyst precursor in a hydrogen atmosphere at a reduction temperature of 300-600°C. The metal phosphide catalyst precursor contains a carrier, a metal phosphide, an alkali metal salt and / or an acidic compound additive, and a polyhydroxy organic compound additive.

[0033] The carrier contains a modified molecular sieve obtained by modifying a molecular sieve with an alkali metal salt and / or an acidic compound. The molecular sieve is selected from one or more of SAPO-11, ZSM-22, MCM-22, ZSM-23, ZSM-35, and ZSM-48, i.e. a molecular sieve with a ten-membered ring or a twelve-membered ring structure and a straight-through pore structure.

[0034] The alkali metal salt can be used as an electron additive to improve the electronic structure of the carrier, change the force mode between the carrier and the metal phosphide, and thus improve the catalytic performance of the metal phosphide catalyst. The alkali metal in the alkali metal salt is selected from one or more of Group IA and Group IIA metals, such as lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium, and radium. The alkali metal salt compound is a soluble alkali metal salt, such as an alkali metal salt containing nitrate, an alkali metal salt containing sulfate, and an alkali metal salt containing chloride. Modifying the molecular sieve with an acidic compound or an alkali metal compound can effectively improve the pore structure properties, specific surface area, and acid distribution of the carrier, and thus improve the catalytic performance of the catalyst. The acidic compound is selected from one or more of nitric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, acetic acid, tartaric acid, oxalic acid, citric acid, and malic acid.

[0035] The polyhydroxy organic compound is selected from one or more of glycerol, ethylenediaminetetraacetic acid, citric acid, tartaric acid, and OH-(CH2) n -CH2-OH, wherein n is greater than or equal to 1. The polyhydroxy organic compound is preferably one or more of ethylenediaminetetraacetic acid, ethylene glycol, and polyethylene glycol. The mass ratio of the polyhydroxy organic compound to the carrier is 1-15:100, preferably 3-10:100.

[0036] In one embodiment, the concentration of the alkali metal salt in the impregnation solution formed by the alkali metal salt is 0.1-0.5 mol / L, and the concentration of the acidic compound in the impregnation solution formed by the acidic compound is 0.1-0.4 mol / L. The volume of the acidic compound impregnation solution or the alkali metal salt compound impregnation solution used per 100 g of the molecular sieve during the impregnation process is 60-100 mL.

[0037] The molecular sieve is modified by alkali metal salt and / or acid to obtain a modified molecular sieve. The modified molecular sieve is characterized by pyridine infrared, and the B acid content of the modified molecular sieve is 0.1-0.5 mmol / g at 150°C, and the B acid:L acid ratio is 5:1-1:1; the B acid content is 0.1-0.3 mmol / g at 350°C, and the B acid:L acid ratio is 5:1-1:1. The total acid amount (i.e. the acid amount of B acid+L acid) at 150°C is greater than the total acid amount (i.e. the acid amount of B acid+L acid) at 350°C. Thus, the transition metal phosphide catalyst prepared by using the molecular sieve is used for producing a lubricating oil base oil with low freezing point, and the produced base oil has the advantages of low freezing point and low pour point, and high liquid yield and low aromatic content.

[0038] In an embodiment, the catalyst carrier of the present application further comprises alumina and / or amorphous silica-alumina, and thus the modified molecular sieve and the alumina and / or amorphous silica-alumina form a composite carrier. The metal active component of the catalyst of the present application can be a transition metal element, such as one or more of nickel, molybdenum, tungsten, cobalt, iron and zirconium; and the phosphorus element can be one or more of phosphate, phosphoric acid, monohydrogen phosphate, dihydrogen phosphate and hypophosphite. In another embodiment, the content of the carrier in the catalyst is 60-90 wt% based on the total mass of the catalyst, and the content of the metal active component and the phosphorus element is 10-40 wt% in total, and further, the content of the molecular sieve in the carrier is, for example, 40-90 wt%, and the content of the alumina or the alumina and amorphous silica-alumina in the carrier is, for example, 10-60 wt%.

[0039] The type of the molecular sieve and the modification method have been described in detail above, and thus will not be described again.

[0040] The technical solutions of the present application will be further described below by means of specific examples.

[0041] Examples 1-6

[0042] (1) Preparation of the modified molecular sieve

[0043] In Examples 1-6, the ZSM-22, SAPO-11, MCM-22, ZSM-23, ZSM-35 and ZSM-48 are commercially available or prepared by any existing method, preferably with a Si / Al203molar ratio of 5-100 and an average crystal size of 30-150 nm. The molecular sieve is modified by a solution of an alkali metal or an acidic solution, wherein the alkali metal is selected from Group IA or IIA metals and the acid is selected from one or more of nitric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, acetic acid, tartaric acid, oxalic acid, citric acid or malic acid, and the modification process is to impregnate the molecular sieve with a solution of the Group IA or IIA metal salt or the above acid solution at a concentration of 0.1-0.3 mol / L, with a ratio of the mass of the molecular sieve (in g) to the volume of the impregnation liquid (in mL) being 100:60-100. In the case of 100 g of the original molecular sieve powder, the A1, B1, C1, D1, E1 and F1 samples are the original molecular sieve powder without modification, and the Si02 / Al203molar ratio, average crystal size, modification reagent used and amount are shown in Table 1.

[0044] Table 1 Properties of the molecular sieve and modification reagent

[0045]

[0046] (2) Characterization of the modified molecular sieve and preparation of the metal phosphide catalyst

[0047] The modified molecular sieve in Table 1 is dried at 120°C for 2 hours and calcined at 500°C for 4 hours, and then used for pyridine infrared (Py-IR) characterization and preparation of the metal phosphide catalyst.

[0048] The sample is pretreated by vacuum pumping in a pyridine sample cell, then adsorbed in a pyridine sample cell in an ice bath at 0°C, and then characterized by pyridine desorption at 150°C and 350°C. The amounts of B acid and L acid at the two desorption temperatures of 150°C and 350°C are calculated, and the characterization results are shown in Table 2.

[0049] Table 2 Py-IR characterization results of the molecular sieve

[0050]

[0051] Example 7

[0052] The A2 sample in the above examples, i.e. the modified ZSM-35 molecular sieve, is mixed with 20 g of alumina powder (dry basis) and then extruded into a wet strip, which is dried at 150°C for 2 hours and calcined at 500°C for 6 hours to prepare the carrier.

[0053] The molar ratio of molybdenum (Mo) to phosphorus (P) in the catalyst is 1:1, and the total loading of molybdenum and phosphorus elements is 20%. Take 27.86g of ammonium molybdate ((NH4)6Mo7O 24 ·4H2O) and 20.94g of diammonium hydrogen phosphate ((NH4)2HPO4) and dissolve them in 100mL of 3mol / L ammonia water to obtain solution A. Dissolve 8g of glycerol and 4g of polyethylene glycol in 30mL of deionized water to obtain solution B. Slowly add solution B to solution A to obtain mixed solution C. Heat and dilute solution C to 80mL to obtain solution D, which is ready for use.

[0054] Dip solution D into the catalyst carrier, immerse for 4h at 30℃, then dry at 60℃ for 4h to obtain catalyst precursor A.

[0055] Example 8

[0056] Take the B2 sample in the above examples, i.e. 36g of modified ZSM-48 molecular sieve (dry basis), mix with 32g of alumina powder (dry basis) and 22g of amorphous silica-alumina powder (dry basis, silica content 30%), and knead, then pass through the extruder to form a wet strip. Dry the wet strip at 120℃ for 4h and calcine at 500℃ for 8h to prepare the carrier.

[0057] The molar ratio of tungsten (W) to phosphorus (P) in the catalyst is 1:1, and the total loading of tungsten and phosphorus elements is 10%. Take 11.54g of ammonium metatungstate ((NH4)6W 12 O 39 ·2H2O) and 5.37g of ammonium dihydrogen phosphate (NH4H2PO4) and dissolve them in 100mL of deionized water to obtain solution A. Dissolve 2g of ethylene glycol and 3g of tartaric acid in 30mL of deionized water to obtain solution B. Slowly add solution B to solution A to obtain solution C. Heat and dilute solution C to 70mL to obtain solution D, which is ready for use.

[0058] Dip solution D into the catalyst carrier, immerse for 4h at 25℃ (room temperature), then dry at 120℃ for 6h to obtain catalyst precursor B.

[0059] Example 9

[0060] Take the C2 and D2 samples in the above examples, i.e. 40g of modified SAPO-11 molecular sieve (dry basis) and 23g of modified ZSM-23 molecular sieve (dry basis), mix with 13g of alumina powder (dry basis) and 14g of amorphous silica-alumina powder (dry basis, silica content 30%), and knead, then pass through the extruder to form a wet strip. Dry the wet strip at 120℃ for 4h and calcine at 500℃ for 6h to prepare the carrier.

[0061] The catalyst contains nickel (Ni) and phosphorus (P) in a molar ratio of 2:1, with a total nickel and phosphorus loading of 30%. 118g of nickel nitrate (Ni(NO3)2·6H2O) and 23.6g of ammonium hypophosphite ((NH4)2HPO3) were dissolved in 250mL of deionized water to obtain solution A. 7g of citric acid and 4g of ethylene glycol were added to 40mL of deionized water to obtain solution B. Solution B was slowly added dropwise to solution A to obtain solution C. Solution C was heated to a final volume of 70mL to obtain solution D. Solution D was then heated to a final volume of 200mL for later use.

[0062] The solution was impregnated onto the catalyst support twice, 100 mL each time. After each impregnation, the solution was impregnated at 25°C for 4 h, and then dried at 120°C for 3 h to obtain the catalyst precursor C.

[0063] Comparative Example 1

[0064] The difference from Example 9 is that the step of adding 7g of citric acid and 4g of ethylene glycol to 40mL of deionized water was omitted in the preparation of the impregnation solution. The remaining steps are the same as in Example 9, and the catalyst precursor obtained is DC.

[0065] Example 10

[0066] Take sample E2 from the above examples, namely 59g (dry basis weight) of modified MCM-22 molecular sieve, 18g of alumina powder (dry basis weight) and 8g of amorphous silica-alumina powder (dry basis weight, silica content of 40%), mix them together, form them by extrusion machine, and prepare the carrier by drying the wet strip at 120℃ for 4 hours and calcining at 500℃ for 6 hours.

[0067] The catalyst contains nickel (Ni) and phosphorus (P) in a molar ratio of 1:5, with a total nickel and phosphorus loading of 15%. 20.4 g of nickel nitrate (Ni(NO3)2·6H2O) and 40.8 g of ammonium hypophosphite ((NH4)2HPO3) were dissolved in 150 mL of deionized water to obtain solution A. 3 g of ethylene glycol was added to 20 mL of deionized water to obtain solution B. Solution B was slowly added dropwise to solution A to obtain solution C. Solution C was heated to a final volume of 80 mL to obtain solution D, which was then set aside.

[0068] Solution D was impregnated onto the catalyst support. After each impregnation, the solution was impregnated at 40°C for 4 hours and then dried at 100°C for 3 hours to obtain the catalyst precursor D.

[0069] Example 11

[0070] The difference between Example 10 is that the molar ratio of nickel (Ni) to phosphorus (P) in the catalyst is 5:1, and the total loading of nickel and phosphorus elements is 15%, taking 67.7g of nickel nitrate (Ni(NO3)2·6H2O) and 5.4g of ammonium hypophosphite ((NH4)2HPO3), and the remaining steps are the same, finally obtaining catalyst precursor E.

[0071] Comparative Example 2

[0072] The same as Example 11, taking the unmodified E2 sample, and the remaining steps are the same as Example 11, obtaining catalyst precursor DE.

[0073] Example 12

[0074] The difference between Example 11 is that the molar ratio of nickel (Ni) to phosphorus (P) in the catalyst is 1:5, and the total loading of nickel and phosphorus elements is 15%, taking 20.4g of nickel nitrate (Ni(NO3)2·6H2O) and 13.6g of ammonium hypophosphite ((NH4)2HPO3) dissolved in 150ml of deionized water, 3g of ethylene glycol is 10g of glycerol, and the remaining steps are the same, finally obtaining catalyst precursor F.

[0075] Example 13

[0076] Taking the F2 sample in the above examples, i.e. 35g of modified ZSM-22 molecular sieve (dry basis), 30g of alumina powder (dry basis) and 20g of amorphous silica-alumina powder (dry basis, silica content 50%) are kneaded, and the carrier is prepared after being formed by an extruder, dried at 150°C for 2 hours and calcined at 500°C for 6 hours.

[0077] The molar ratio of nickel (Ni) to phosphorus (P) in the catalyst is 3:1, and the total loading of nickel and phosphorus elements is 15%, taking 42.78g of nickel nitrate (Ni(NO3)2·6H2O) and 8.5g of ammonium hypophosphite ((NH4)2HPO3) dissolved in 150ml of deionized water to obtain solution A, 6g of polyethylene glycol is added to 20ml of deionized water to obtain solution B, solution B is slowly added to solution A to obtain solution C, solution C is heated to constant volume to 85ml to obtain solution D, and is ready for use.

[0078] Solution D is impregnated on the catalyst carrier, and after each impregnation, it is impregnated at 25°C for 4h, and then dried at 100°C for 2h, finally obtaining catalyst precursor G.

[0079] Comparative Example 3

[0080] The same as example 13, except that the unmodified G1 sample was used, and the step of adding 6 g of polyethylene glycol to 20 mL of deionized water was not performed in the preparation of the impregnation solution, and the remaining steps were the same as those of example 13, to obtain a catalyst precursor DG.

[0081] Example 14

[0082] The metal phosphide catalyst precursors obtained in examples 7 to 13 and comparative examples 1 to 3 were each loaded into a fixed bed reactor, and after being kept at a constant temperature of 450°C for 6 h under a hydrogen atmosphere at a hydrogen pressure of 2 MPa and a hydrogen flow rate of 50 L / h, the temperature was lowered to 60°C, and nitrogen was blown through at the same pressure and flow rate for 4 h, to obtain metal phosphide catalysts A-cat, B-cat, C-cat, D-cat, E-cat, F-cat, G-cat, DC-cat, DE-cat, and DG-cat.

[0083] Example 15

[0084] The catalysts prepared in example 14 were selected for hydrogenation evaluation. Six catalysts, C-cat, E-cat, G-cat, DC-cat, DE-cat, and DG-cat, were selected for hydrogenation performance evaluation. A fixed bed reactor was loaded with 100 mL of the metal phosphide catalyst, and the lubricating oil base stock feedstock was preheated to 100°C and mixed uniformly with hydrogen in an oil-gas mixing tank to obtain a mixed oil-gas, which was then introduced into the fixed bed reactor to perform hydrogenation isomerization with the metal phosphide. The hydrogenation evaluation process conditions are shown in Table 3.

[0085] Table 3 Hydrogenation evaluation process conditions

[0086]

[0087] The feedstock oil used for evaluation was a four-line cut wax oil, and the properties of the feedstock oil are shown in Table 4.

[0088] Table 4 Properties of the lubricating oil base stock feedstock

[0089]

[0090] The full-range lubricating oil base stock product produced after hydrogenation evaluation was cut by vacuum distillation to obtain lubricating oil base stocks of different viscosity grades, and the total base oil yield and the properties of the lubricating oil base stock product greater than 350°C are shown in Table 5.

[0091] Table 5 Hydrogenation evaluation results

[0092]

[0093] Example 16

[0094] The catalyst prepared in Example 14 was selected for hydrogenation evaluation, and six catalysts, C-cat, E-cat, G-cat, DC-cat, DE-cat and DG-cat were selected for hydrogenation performance evaluation. A fixed bed reactor was filled with 100 mL of the metal phosphide catalyst, and the lubricating oil base stock was preheated to 60 DEG C and mixed with hydrogen in the pipeline to obtain a mixed oil gas, which was then introduced into the fixed bed reactor for hydrogenation isomerization reaction with the metal phosphide. The hydrogenation evaluation process conditions are shown in Table 6.

[0095] Table 6 Hydrogenation evaluation process conditions

[0096]

[0097] The feedstock oil for evaluation was a hydrocracking tail oil, and the properties of the feedstock oil are shown in Table 7.

[0098] Table 7 Properties of the lubricating oil base stock

[0099]

[0100] The full-range lubricating oil base stock product produced after hydrogenation evaluation was subjected to vacuum distillation cutting to obtain lubricating oil base stocks of different viscosity grades, and the total base oil yield and the properties of the lubricating oil base stock product greater than 330 DEG C are shown in Table 8.

[0101] Table 8 Hydrogenation evaluation results

[0102]

[0103] The production method of the base oil provided by the present application can produce lubricating oil base stocks with low freezing point and low pour point when using waxy oil as the raw material and using a metal phosphide catalyst for hydrogenation isomerization reaction, and the lubricating oil base stock produced by the present application has low aromatic content and high total lubricating oil base stock yield.

[0104] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications should all belong to the protection scope of the claims of the present application.

Claims

1. A method of producing a base oil, comprising: A lubricating oil base stock is produced by hydroisomerization of a base stock feed in the presence of at least one metal phosphide catalyst, characterized in that the metal phosphide catalyst comprises a metal component and a support comprising a modified molecular sieve, the metal phosphide catalyst is modified twice, the first modification is to introduce a salt of a first modifying metal and / or an acidic compound into the molecular sieve by impregnation to obtain a modified molecular sieve, the second modification is to impregnate the modified molecular sieve after mixing a second modifying polyhydroxy organic compound with a compound comprising the metal component and a compound comprising phosphorus; the first modifying metal is selected from the group consisting of Group IA or Group IIA metals; the acidic compound is selected from at least one of nitric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, acetic acid, tartaric acid, oxalic acid, citric acid and malic acid; the polyhydroxy organic compound is selected from at least one of glycerol, ethylenediaminetetraacetic acid, citric acid, tartaric acid and OH-(CH2) n -CH2-OH, where n is an integer greater than or equal to 1. The modified molecular sieve is characterized by pyridine infrared, at 150 DEG C, the B acid content is 0.1-0.5 mmol / g, the molar ratio of B acid:L acid is 5:1-1:1; at 350 DEG C, the B acid content is 0.1-0.3 mmol / g, the molar ratio of B acid:L acid is 5:1-1:1, wherein the total acid amount of B acid and L acid > the total acid amount of B acid and L acid at 350 DEG C.

2. The method for producing base oil according to claim 1, characterized by, The metal phosphide catalyst is prepared by reducing a metal phosphide catalyst precursor in a hydrogen atmosphere; the metal phosphide catalyst precursor contains a metal component, a phosphorus element, a carrier, a first modified auxiliary metal and / or an acidic compound, and a polyhydroxy organic compound; the mass ratio of the polyhydroxy organic compound to the carrier is 1-20:

100.

3. The method of producing base oil according to claim 2, characterized by, The mass ratio of the polyhydroxy organic compound to the carrier is 1-15:

100.

4. The method of producing base oil according to claim 3, characterized by, The mass ratio of the polyhydroxy organic compound to the carrier is 3-10:

100.

5. The method of producing base oil according to claim 1, characterized by, The lubricating oil base stock is at least one selected from the group consisting of a second vacuum gas oil, a third vacuum gas oil, a fourth vacuum gas oil, a wax paste, a hydrocracking tail oil, and a bright stock.

6. The method of producing base oil according to claim 5, characterized by, The lubricating oil base stock has a distillation range of 300-600 DEG C, a sulfur content of not more than 200 mu g / g, and a nitrogen content of not more than 100 mu g / g; the lubricating oil base stock has a wax content of not more than 60% by mass.

7. The method of producing base oil according to claim 6, characterized by, The lubricating oil base stock has a distillation range of 350-580 DEG C, a sulfur content of not more than 100 mu g / g, and a nitrogen content of not more than 50 mu g / g.

8. The method of producing base oil according to claim 6, characterized by, The lubricating oil base stock has a sulfur content of not more than 50 mu g / g, and a nitrogen content of not more than 30 mu g / g.

9. The method of producing base oil according to claim 6, characterized by, The lubricating oil base stock has a wax content of not more than 50% by mass.

10. The method of producing base oil according to claim 1, characterized by, The carrier further comprises alumina and / or amorphous silica-alumina.

11. The method of producing base oil according to claim 1, characterized by, The molecular sieve has a ten-membered ring or a twelve-membered ring topology and has a straight-through pore structure; the molar ratio of Si / Al2O3 in the molecular sieve is 5-100, and the average crystal grain size is 30-150 nm.

12. The method of producing base oil according to claim 1, characterized by, The molecular sieve is at least one selected from the group consisting of SAPO-11, ZSM-22, MCM-22, ZSM-23, ZSM-35, and ZSM-48.

13. The method of producing base oil according to claim 1, characterized by, The first modified auxiliary metal is at least one selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium, and radium.

14. The method of producing base oil according to claim 2, characterized by, The metal component is at least one selected from the group consisting of cobalt, nickel, molybdenum, and tungsten, and the metal component exists in the metal phosphide catalyst in a combined state; The total content of the metal component and the phosphorus element in the metal phosphide catalyst accounts for 10-40 wt% of the mass of the metal phosphide catalyst.

15. The method of producing base oil according to claim 2, characterized by, The molar ratio of the phosphorus element to the metal component is 1:5-5:

1.

16. The method of producing base oil according to claim 15, characterized by, The molar ratio of the phosphorus element to the metal component is 1:3-3:

1.

17. The method of producing base oil according to claim 2, characterized by, The phosphorus element in the metal phosphide catalyst is derived from one or more of a phosphate and phosphoric acid.

18. The method of producing base oil according to claim 2, characterized by, The phosphorus element in the metal phosphide catalyst is derived from one or more of monohydrogen phosphate, dihydrogen phosphate, and hypophosphite.

19. The method of producing base oil according to claim 1, characterized by, The temperature of the hydroisomerization reaction is 300-400℃, the volume space velocity is 0.5-2.0h -1 .

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