CN115851314A

CN115851314A - Lubricating oil base oil and preparation method thereof

Info

Publication number: CN115851314A
Application number: CN202211427002.XA
Authority: CN
Inventors: 郭守敬; 李景; 白天忠; 李�浩; 安良成; 朱加清; 张安贵; 刘粟侥; 苏星宇; 邢爱华; 李艳; 胡云剑; 范娜娜; 燕艺楠; 郑舒丹
Original assignee: National Institute of Clean and Low Carbon Energy; National Energy Group Ningxia Coal Industry Co Ltd
Current assignee: National Institute of Clean and Low Carbon Energy; National Energy Group Ningxia Coal Industry Co Ltd
Priority date: 2022-11-15
Filing date: 2022-11-15
Publication date: 2023-03-28
Anticipated expiration: 2042-11-15

Abstract

The invention provides lubricating oil base oil and a preparation method thereof. The preparation method comprises the following steps: s1, performing centrifugal separation on the cracking tail oil to obtain an oil phase and a wax phase, wherein the cracking tail oil is coal-based hydrocracking tail oil; s2, enabling the oil phase and the wax phase to enter an isomerization reactor through different parts to perform an isomerization dewaxing reaction to obtain an isomerization product, wherein the wax phase enters from the top of the isomerization reactor, and the oil phase enters from the middle part of the isomerization reactor; and S3, carrying out normal pressure distillation, supplementary refining and reduced pressure distillation on the isodewaxing product to obtain the lubricating oil base oil. By applying the technical scheme, the centrifugal separation and isomerization dewaxing process is matched, so that the energy consumption is favorably reduced, the reaction condition is mild, and the production cost of the lubricating oil base oil is favorably reduced.

Description

Lubricating oil base oil and preparation method thereof

Technical Field

The invention relates to the field of coal chemical industry, in particular to lubricating oil base oil and a preparation method thereof.

Background

The coal indirect liquefaction process is a process of generating oil products and chemicals by coal gasification, transformation, purification and Fischer-Tropsch synthesis reaction. The Fischer-Tropsch synthesis intermediate product is rich in olefin, mainly comprises straight-chain alkane after hydrogenation saturation, has high saturated hydrocarbon content (more than or equal to 90 percent) in hydrofining and hydrocracking tail oil, basically has no impurities such as aromatic hydrocarbon, sulfur, nitrogen and the like, and is suitable for producing high-quality and high-added-value lubricating oil base oil products.

The lubricating oil as a high-end oil product mainly comprises base oil and additives, wherein the performance of the base oil plays a decisive role in the lubricating oil. The base oil raw material is mainly petroleum base, and the lubricating oil base oil is produced by processes such as solvent dewaxing, catalytic dewaxing or isomerization dewaxing. The prior patents are more in the aspect of isodewaxing catalysts, and the reports on deep processing of coal-based cracking tail oil raw materials are less.

The raw material pretreatment mainly adopts a physical method, namely, wide fraction is changed into narrow fraction, such as atmospheric and vacuum distillation, and CN102041029A discloses a comprehensive utilization method of hydrocracking tail oil, wherein the hydrocracking tail oil is subjected to vacuum fractionation, and the fractionated hydrocracking tail oil light fraction and hydrocracking tail oil heavy fraction are obtained; CN103305267A discloses a method for producing high-grade lubricating oil base oil by hydrogenating hydrocracking tail oil, which takes the hydrocracking tail oil as a raw material, and the distillate is fractionated at the temperature of more than 430 ℃ and less than or equal to 430 ℃ by vacuum pre-fractionation. Second, wax oil separation, such as solvent dewaxing. CN1175620A reports a method for producing food-grade paraffin and lubricant base oil by using hydrocracking tail oil as a raw material and adopting a solvent dewaxing-clay refining process; CN104560196A discloses a method for preparing deoiled wax by solvent dewaxing.

The coal-based cracking tail oil is mainly saturated hydrocarbon and has wide distillation range, wherein the ratio of isomeric hydrocarbon is higher than that of normal hydrocarbon, but the isomerization degree is low. The method combines the properties of coal-based cracking tail oil raw materials, adopts a proper method for pretreatment, is matched with an isomerization dewaxing process, and produces the lubricating oil base oil with high yield and high performance, thereby becoming the key of industrial production.

The prior main technology is as follows: the reduced pressure distillation cuts narrow fractions, low system pressure, high heating temperature and certain number of separation tower plates are required, and the production cost is relatively high; the whole fraction is directly fed, and when the performance of the base oil meets the index requirement, higher reaction temperature is needed, so that the yield of the base oil is reduced; most solvents for solvent dewaxing are organic solvents, the dosage is large, the solvents are harmful to human bodies and pollute the environment, and in addition, the equipment investment and the operation cost are also high.

Disclosure of Invention

The invention mainly aims to provide lubricating oil base oil and a preparation method thereof, and aims to solve the problem that the yield, the performance and the cost of the base oil are difficult to be considered in the production of the lubricating oil base oil by coal-based cracking tail oil in the prior art.

In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing a lubricant base oil, the method comprising: step S1, carrying out centrifugal separation on the cracking tail oil to obtain an oil phase and a wax phase, wherein the cracking tail oil is coal-based hydrocracking tail oil; s2, enabling the oil phase and the wax phase to enter an isomerization reactor through different parts to perform an isomerization dewaxing reaction to obtain an isomerization product, wherein the wax phase enters from the top of the isomerization reactor, and the oil phase enters from the middle part of the isomerization reactor; and S3, carrying out normal pressure distillation, supplementary refining and reduced pressure distillation on the isodewaxing product to obtain the lubricating oil base oil.

The cracking tail oil comes from a vacuum tower bottom distillation section of a hydrocracking unit, the distillation range is 300-720 ℃, the content of saturated hydrocarbon in the coal-based hydrocracking tail oil is preferably not less than 98 percent, and the proportion of normal alkane is not more than 10 percent.

Further, the centrifugal separation uses a two-phase centrifugal device.

Further, the rotation speed of centrifugal separation is 2000-15000 rpm, preferably 3000-12000 rpm;

preferably, the total time of centrifugal separation is 15 to 60min, more preferably 20 to 55min;

preferably, the temperature of centrifugal separation is 0to 40 ℃, more preferably 5 to 35 ℃;

more preferably, the oil phase has a pour point no higher than 21 ℃ and the wax phase has a pour point no higher than 21 ℃.

Further, in step S2, the isomerization reactor is a trickle bed reactor, preferably, the trickle bed reactor comprises three reaction beds, the wax phase is fed from the top of the reactor, and the oil phase is fed from the second bed; more preferably, the catalyst loadings of the three reaction beds: the first bed layer is larger than the third bed layer and is not larger than the second bed layer.

Further, the isomerization dewaxing catalyst is a one-dimensional medium-pore molecular sieve loaded with metals, the metals comprise noble metals and/or non-noble metals, and preferably, the molecular sieve is selected from any one or more of ZSM molecular sieves and SAPO series molecular sieves;

preferably, the noble metal comprises any one or more of Pt and Pd, and the non-noble metal comprises any one or more of Ni, mg, fe and Ce; more preferably, the metals include at least one noble metal and at least one non-noble metal;

preferably, the temperature of the isomerization dewaxing is 260-340 ℃, more preferably 280-320 ℃;

preferably, the partial pressure of the isodewaxing hydrogen is 1 to 10MPa, more preferably 2to 8MPa;

preferably, the volume space velocity of the hydrogen for isodewaxing is 0.1-2 h ^-1 More preferably 0.3 to 1.6 hours ^-1 ；

Preferably, the isodewaxing hydrogen oil volume ratio is (50-1500): 1, more preferably (100-1200): 1.

Further, atmospheric distillation comprises: cutting out fraction with final distilling point no more than 190 deg.C to obtain naphtha, cutting out fraction with distilling range of 190-320 deg.C to obtain isoparaffin solvent, and collecting fraction with distilling range of > 320 deg.C as raw material for additional refining.

Further, the post-refined catalyst comprises a hydrogenation metal catalyst and a carrier, wherein the hydrogenation metal catalyst comprises any one or more of Pt, pd, ni, mg, fe and Co, and the carrier comprises any one or more of alumina and silica;

preferably, the temperature for the additional purification is 200 to 260 ℃, the hydrogen partial pressure is 2to 8MPa,

preferably, the space velocity of the complementary refining is 0.3-1.6 h ^-1 The hydrogen-oil ratio is (500-1200) to 1.

According to another aspect of the present application, there is provided a lubricant base oil prepared by the preparation method of any one of the above.

Further, the grades of the lubricant base oil include 2cSt, 3cSt, 4cSt, 6cSt, 10cSt, and 30cSt, and the content of saturated hydrocarbons in the lubricant base oil is not less than 99%.

By applying the technical scheme of the invention, according to the characteristics that coal-based cracking tail oil has high saturated hydrocarbon content, has certain fluidity at room temperature and is heterogeneous, a centrifugal process is adopted to carry out wax-oil two-phase pre-separation on the cracking tail oil, according to the characteristics of an oil phase and a wax phase, the oil is respectively fed from different parts of an isomerization reactor, and hydroisomerization reaction conditions matched with the oil phase and the wax phase are selected to improve the yield of an isomerization product, and through normal-pressure distillation, light components can be cut out to obtain naphtha and isoparaffin solvent oil, which is beneficial to reducing the load of subsequent refining supplement and reducing the production cost, and finally, lubricating oil base oil is cut out through vacuum rectification. The preparation method combines the centrifugal separation and the isomerization dewaxing process, is favorable for reducing energy consumption, has mild reaction conditions, and is favorable for reducing the production cost of the lubricating oil base oil.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows a hydroisomerization reactor block diagram in accordance with the present invention;

FIG. 2 shows a process flow diagram for producing lube base oil from coal-based hydrocracked tail oil according to the present invention.

Wherein the figures include the following reference numerals:

01. a buffer area; 02. a gas-liquid distributor; 03. a catalyst zone; 04. a catalyst support zone; 10. a first bed layer; 20. a second bed layer; 30. a third bed layer; 100. a wax phase; 200. an oil phase; 300. and (3) isomerizing the product.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

As analyzed by the background of the present application, there are problems in the prior art: firstly, the cracking tail oil is directly used as a raw material, and the low yield and the product performance of the base oil are difficult to be considered; secondly, the cracked tail oil is cut into different fraction sections for feeding, so that the grades of the produced base oil products are few; thirdly, solvent dewaxing requires an organic solvent and low temperature conditions, the process is complex and high-quality base oil is difficult to obtain; fourthly, the pressure of the complementary refining system is different from that of the hydroisomerization system, the pressure is higher (more than 8 MPa), and the flow and the process are relatively complex. In order to solve the problem, the present application provides a lubricant base oil and a preparation method thereof.

According to an exemplary embodiment of the present application, there is provided a method of preparing a lubricant base oil, the method comprising: step S1, carrying out centrifugal separation on the cracking tail oil to obtain an oil phase and a wax phase, wherein the cracking tail oil is coal-based hydrocracking tail oil; s2, enabling the oil phase and the wax phase to enter an isomerization reactor through different parts to perform isomerization dewaxing reaction to obtain an isomerization product, wherein the wax phase enters from the top of the isomerization reactor, and the oil phase enters from the middle part of the isomerization reactor; and S3, carrying out normal pressure distillation, supplementary refining and reduced pressure distillation on the isodewaxing product to obtain the lubricating oil base oil.

According to the method, the coal-based cracking tail oil has the characteristics of high saturated hydrocarbon content, certain fluidity at room temperature and heterogeneous appearance, the cracking tail oil is subjected to wax-oil two-phase pre-separation by adopting a centrifugal process, the raw materials are respectively fed from different parts of an isomerization reactor according to the characteristics of an oil phase and a wax phase, the hydro-isomerization reaction conditions matched with the raw materials are selected, the yield of an isomeric product is improved, light components can be cut out through normal-pressure distillation to obtain naphtha and isoparaffin solvent oil, the load of subsequent supplement refining is favorably reduced, the production cost is reduced, and finally the lubricating oil base oil is cut out through vacuum rectification. The preparation method combines the centrifugal separation and the isomerization dewaxing process, is favorable for reducing energy consumption, has mild reaction conditions, and is favorable for reducing the production cost of the lubricating oil base oil.

In some typical embodiments of the present application, the cracking tail oil comes from a vacuum tower bottom distillation section of a hydrocracking unit, the distillation range is 300-720 ℃, preferably, the content of saturated hydrocarbon in the coal-based cracking tail oil is not less than 98%, the normal alkane content is not more than 10%, and the performance of the lubricating base oil obtained by separation is better.

The device for the centrifugal separation treatment is not particularly required, and may be selected from conventional devices. In some embodiments of the present application, the centrifugation employs a two-phase centrifuge to facilitate pre-separation of the oil phase and the wax phase, further improving separation efficiency and yield of the hydroisomerized product.

In some embodiments of the present application, the rotation speed of the centrifugal separation is 2000-15000 rpm, preferably 3000-12000 rpm, which may improve the efficiency of the centrifugal separation and may be, for example, 3000rpm, 4000rpm, 5000rpm, 6000rpm, 7000rpm, 8000rpm, 9000rpm, 1000rpm, 11000rpm, 12000rpm or a range therebetween, for which the separation apparatus is easy to implement.

The time for the centrifugal separation is related to the rotational speed of the centrifugal treatment, and the lower the rotational speed, the longer the time required for the centrifugal treatment, and the higher the rotational speed, the shorter the time required for the centrifugal treatment. In some embodiments of the present application, the total time of the centrifugation is 15 to 60min, preferably 20 to 55min, and illustratively, the time of the centrifugation is 25min, 30min, 35min, 40min, 45min, 50min, 55min or a range between any two of them, and the centrifugation can be performed in multiple times for convenience, such as 2to 10 times.

The coal-based cracking tail oil chamber has the characteristic of being heterogeneous at room temperature, and the centrifugal separation can be performed at room temperature, so that researches of researchers in the application find that good wax-oil separation effect can be realized under the condition of 0-40 ℃, the centrifugal separation effect is good when the separation is performed at 5-35 ℃, the operation environment is good, the separation method is more beneficial to being performed, and the wax-oil pre-separation efficiency is more beneficial to being improved. In some preferred embodiments, the pour point of the oil phase is no more than 21 ℃, and the pour point of the wax phase is no less than 21 ℃, facilitating subsequent isodewaxing.

Respectively carrying out hydroisomerization reaction on the oil phase and the wax phase obtained by centrifugal separation, wherein the hydroisomerization comprises the following steps: the wax phase is fed from the top of the isomerization reactor, the oil phase is fed from the middle bed layer of the isomerization reactor, and the hydroisomerization reaction condition is adjusted under the action of the isomerization catalyst to obtain an isomerization product. The raw materials for isomerization and dewaxing are an oil phase and a wax phase obtained through centrifugal separation, the isomerization degree of the oil phase is higher than that of the wax phase, two raw materials are fed from different positions of an isomerization reactor, and the hydroisomerization reaction conditions are matched with the properties of the raw materials, so that the isomerization yield can be improved. In some exemplary embodiments of the present application, the isomerization reactor is a trickle bed reactor, and preferably, the trickle bed reactor includes three reaction beds, as shown in fig. 1, from top to bottom, a first bed 10, a second bed 20, and a third bed 30, each bed includes a buffer zone 01, a gas-liquid distributor 02, a catalyst zone 03, and a catalyst support zone 04, which are arranged from top to bottom, a wax phase 100 and a part of hydrogen are fed from the top of the reactor, i.e., above the first bed 10, an oil phase 200 and another part of hydrogen are fed from the second bed 20, the wax phase and the oil phase move downward during the reaction, and flow out from the lower outlet of the reactor through the third bed 30 to obtain an isomerization product 300. In some preferred embodiments, in order to improve the isomerization hydrogenation efficiency and the catalyst utilization rate, the catalyst loading of the three reaction beds is as follows: the first bed layer 10 is more than the third bed layer 30 and is less than or equal to the second bed layer 20. The specific catalyst loading can be determined according to the reactor and the composition of the raw materials, and illustratively, the loading of the first bed layer is 40-70% of that of the second bed layer, and the loading of the third bed layer is 70-100% of that of the second bed layer, based on the loading of the catalyst of the second bed layer.

In some embodiments herein, the isodewaxing catalyst is a metal-loaded unidimensional mesoporous molecular sieve, preferably, the molecular sieve is selected from any one or more of ZSM molecular sieves, preferably any one or more of ZSM-22, ZSM-23 and ZSM-48, and SAPO molecular sieves, preferably any one or more of SAPO-11 and SAPO-31; the metal comprises noble metal and/or non-noble metal catalyst, preferably, the noble metal used as the isomerization dewaxing catalyst is selected from one or more of Pt and Pd, the non-noble metal comprises one or more of Ni, mg, fe and Ce, more preferably, the metal catalyst comprises at least one of the noble metal and at least one of the non-noble metal, the catalyst effect on the isomerization raw material is better, and the isomerization dewaxing efficiency can be obviously improved.

In some embodiments herein, the isomerization dewaxing temperature is from 260 to 340 c,more preferably 280-320 ℃, and the isomerization effect is better, when the trickle bed reactor with a plurality of beds is adopted, the temperature of each bed is preferably gradually reduced, namely the temperature of the upper bed is higher than that of the lower bed, which is beneficial to improving the efficiency of isomerization hydrogenation and considering energy consumption saving. Illustratively, the temperature of the first bed is 310-320 ℃, the temperature of the second bed is 295-310 ℃ and the temperature of the third bed is 280-300 ℃. In some embodiments, the partial pressure of the hydrogen for isodewaxing is 1 to 10MPa, a better isodewaxing effect can be obtained under the pressure, preferably 2to 8MPa, for example, the hydrogen pressure is 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa or any range therebetween, a better isomerization effect can be achieved, the hydrogen partial pressure of the reaction is obviously reduced, the requirement on equipment is obviously reduced, and the equipment investment can be obviously reduced. Preferably, the volume space velocity of the hydrogen is 0.1-2 h ^-1 More preferably 0.3 to 1.6 hours ^-1 . Preferably, the hydrogen to oil volume ratio is (50-1500): 1, more preferably (100-1200): 1.

The method and conditions for atmospheric distillation can be applied to the prior art, have no special requirements and are not described in detail. And the hydroisomerized product is rectified by normal pressure to obtain a light component with a lower boiling point, so that the quality of the final lubricating oil base oil can be improved, the load of subsequent complementary refining can be reduced, and the light component can be respectively used as naphtha and isoparaffin solvent oil. Preferably, cut out the fraction with final boiling point no more than 190 ℃ to obtain naphtha, cut out the fraction with boiling range of 190-320 ℃ to obtain isoparaffin solvent, collect the fraction with boiling point more than 320 ℃, namely the tower bottom oil as the raw material for additional refining.

The post-refining comprises reacting the distilled isomerized product with hydrogen under the action of hydrogenation catalyst to obtain a post-refined product, and the post-refining method can be referred to the prior art. In some embodiments of the present application, the post-refined catalyst comprises a hydrogenation metal catalyst, preferably the hydrogenation metal catalyst comprises any one or more of Pt, pd, ni, mg, fe, co, and a support, preferably the hydrogenation catalyst is Al, more preferably the support comprises any one or more of alumina, silica ₂ O ₃ /Pt、Al ₂ O ₃ /Pt-Pd、Al ₂ O ₃ Any one or more of Pt-Ni has higher catalytic efficiency, is more suitable for performing supplementary refining on the isomerization dewaxing product of the application, and has higher catalytic efficiency.

In some embodiments of the present application, the temperature of the supplemental refining reaction is 200 to 260 ℃, the hydrogen partial pressure is 2to 8MPa, and the overall refining efficiency is high.

And (4) performing reduced pressure distillation on the product obtained by the supplementary refining to cut fractions with different distillation ranges, thereby obtaining the lubricating oil base oil with different viscosities. The method and conditions for the vacuum distillation can be adopted by the prior art, have no special requirements and are not described in detail.

In some exemplary embodiments of the present application, a process flow of producing lubricating base oil from coal-based hydrocracking tail oil is shown in fig. 2, collecting bottom fraction of a hydrocracking unit to obtain hydrocracking tail oil with a distillation range of 300 to 720 ℃, performing centrifugal separation on the hydrocracking tail oil to obtain an oil phase and a wax phase, allowing the oil phase and the wax phase to enter a hydroisomerization device through different positions respectively for hydroisomerization, performing atmospheric pressure rectification on the obtained isomerized product, separating out naphtha with a lower distillation point, isoparaffin solvent oil and components with a higher distillation point as raw materials for additional refining, performing vacuum rectification after additional refining to obtain main products of lubricating base oil, naphtha by-product, and isoparaffin solvent oil, and improving an additional value of coal indirect liquefied cracking tail oil.

According to another exemplary embodiment of the present application, there is provided a lubricant base oil produced by any of the above-described production methods, wherein the lubricant base oil has a brand number comprising 2cSt, 3cSt, 4cSt, 6cSt, 10cSt, and 30cSt, and a saturated hydrocarbon content of not less than 99%. The lubricating oil base oil obtained by the method has high yield and good performance, and has relatively low preparation cost due to high preparation efficiency, thereby having better application and popularization values.

The following will further explain advantageous effects that can be achieved by the present application in conjunction with examples and comparative examples.

Example 1

Taking coal-based cracked tail oil with the distillation range of 310-700 ℃ as an initial raw material, centrifuging for 6 times at 20 ℃ at 4000rpm for 15min, 13min, 11min, 9min, 7min and 5min in sequence, and respectively taking an upper oil phase and a lower wax phase as raw materials for producing base oil to perform isodewaxing after the centrifugation is finished; adopting a trickle bed reactor, feeding a wax phase from the top end of the reactor, feeding an oil phase from the upper part of a second bed layer of the reactor, selecting ZSM-23/Pt-Fe as an isomerizing agent, wherein the first bed layer of the reactor is filled with 2.8kg, the reaction temperature is 310 ℃, the second bed layer is filled with 4kg, the reaction temperature is 300 ℃, the third bed layer is filled with 3.2kg, the reaction temperature is 295 ℃, and the volume airspeed is 0.6h ^-1 Carrying out isomerization reaction under the conditions that the hydrogen partial pressure is 6MPa and the volume ratio of hydrogen to oil is 500. The isomerization product is rectified at normal pressure to cut naphtha (less than 190 ℃) and isoparaffin solvent oil (190-320 ℃), the bottom oil of the normal pressure tower is supplemented and refined, and the catalyst for supplementing and refining is Al ₂ O ₃ Pt, reaction temperature 240 ℃, hydrogen partial pressure 6MPa, the refined product (base oil full fraction) was tested.

Example 2

Taking coal-based cracked tail oil with the distillation range of 340-700 ℃ as an initial raw material, centrifuging for 5 times at the speed of 5000rpm at the temperature of 15 ℃ for 9min each time, and respectively taking an upper oil phase and a lower wax phase as raw materials of production base oil to perform isodewaxing after the centrifugation is finished; adopting a trickle bed reactor, feeding a wax phase from the top end of the reactor, feeding an oil phase from the upper part of a second bed layer of the reactor, selecting ZSM-48/Pt-Ce as an isomerizing agent, loading 2kg of agent in the first bed layer of the reactor, the reaction temperature of 300 ℃, loading 4kg of agent in the second bed layer, the reaction temperature of 290 ℃, loading 4kg of agent in a third bed layer, the reaction temperature of 290 ℃, and the volume airspeed of 0.8h ^-1 Carrying out isomerization reaction under the conditions that hydrogen partial pressure is 4MPa and hydrogen-oil volume ratio is 1000. The isomerization product is rectified at normal pressure to cut naphtha (less than 190 ℃) and isoparaffin solvent oil (190-320 ℃), the bottom oil of the normal pressure tower is supplemented and refined, and the catalyst for supplementing and refining is Al ₂ O ₃ Pt-Pd, reaction temperature 240 ℃, hydrogen partial pressure 4MPa, the refined product (base oil whole fraction) was tested.

Example 3

Taking coal-based cracked tail oil with the distillation range of 330-700 ℃ as an initial raw material, selecting 6000rpm, 25 ℃, centrifuging for 5 times, wherein the centrifuging time is 12min, 10min, 8min, 6min and 4min in sequence, and respectively taking an upper oil phase and a lower wax phase as raw materials for producing base oil to perform isodewaxing after the centrifugation is finished; adopting a trickle bed reactor, feeding a wax phase from the top end of the reactor, feeding an oil phase from the upper part of a second bed layer of the reactor, selecting ZSM-22/Pt-Mg as an isomerizing agent, wherein the first bed layer of the reactor is filled with 2kg, the reaction temperature is 305 ℃, the second bed layer is filled with 4.4kg, the reaction temperature is 300 ℃, the third bed layer is filled with 3.6kg, the reaction temperature is 295 ℃, and the volume space velocity is 0.8h ^-1 Carrying out isomerization reaction under the conditions that the hydrogen partial pressure is 3MPa and the volume ratio of hydrogen to oil is 1200. Performing atmospheric distillation on the isomerization product to cut naphtha (less than 190 ℃) and isoparaffin solvent oil (190-320 ℃), and performing supplementary refining on the bottom oil of the atmospheric tower, wherein the catalyst for supplementary refining is Al ₂ O ₃ Pt-Pd, reaction temperature 260 ℃, hydrogen partial pressure 3MPa, the refined product (base oil whole fraction) was tested.

Example 4

Taking coal-based cracked tail oil with the distillation range of 305-700 ℃ as an initial raw material, selecting 8000rpm, 20 ℃, centrifuging for 4 times, each time for 8min, and respectively taking an upper oil phase and a lower wax phase as raw materials of production base oil to perform isodewaxing after the centrifugation is finished; adopting a trickle bed reactor, feeding a wax phase from the top end of the reactor, feeding an oil phase from the upper part of a second bed layer of the reactor, selecting SAPO-11/Pt-Ni as an isomerizing agent, wherein the first bed layer of the reactor is filled with 2.4kg, the reaction temperature is 315 ℃, the second bed layer is filled with 4kg, the reaction temperature is 310 ℃, the third bed layer is filled with 3.6kg, the reaction temperature is 300 ℃, and the volume space velocity is 1h ^-1 And hydrogen partial pressure of 6MPa and hydrogen-oil volume ratio of 750. The isomerization product is rectified at normal pressure to cut naphtha (less than 190 ℃) and isoparaffin solvent oil (190-320 ℃), the bottom oil of the normal pressure tower is supplemented and refined, and the catalyst for supplementing and refining is Al ₂ O ₃ Pt, reaction temperature 240 ℃, hydrogen partial pressure 6MPa, the refined product (base oil full fraction) was tested.

Example 5

Taking coal-based cracked tail oil with the distillation range of 315-700 ℃ as an initial raw material, centrifuging for 3 times at 10000rpm and 15 ℃, wherein the centrifuging time is 8min, 6min and 5min in sequence, and respectively taking an upper oil phase and a lower wax phase as raw materials of production base oil to perform isodewaxing after the centrifugation is finished; adopting a trickle bed reactor, feeding a wax phase from the top end of the reactor, feeding an oil phase from the upper part of a second bed layer of the reactor, selecting SAPO-31/Pt as an isomerizing agent, wherein the first bed layer of the reactor is filled with 2.6kg, the reaction temperature is 305 ℃, the second bed layer is filled with 3.7kg, the reaction temperature is 300 ℃, the third bed layer is filled with 3.7kg, the reaction temperature is 290 ℃, and the volume airspeed is 0.6h ^-1 Carrying out isomerization reaction under the conditions that hydrogen partial pressure is 4MPa and hydrogen-oil volume ratio is 1000. The isomerization product is rectified at normal pressure to cut naphtha (less than 190 ℃) and isoparaffin solvent oil (190-320 ℃), the bottom oil of the normal pressure tower is supplemented and refined, and the catalyst for supplementing and refining is Al ₂ O ₃ Pt-Pd, reaction temperature 260 ℃, hydrogen partial pressure 4MPa, and the refined product (base oil full fraction) was tested.

Example 6

The difference from example 2 is that: continuously carrying out centrifugal separation for 45min, wherein the centrifugal rotating speed is 5000rpm.

Example 7

The difference from example 2 is that: centrifugation was carried out at 5 ℃.

Example 8

The difference from example 2 is that: centrifugation was carried out at 40 ℃.

Example 9

The difference from example 2 is that: centrifugation was carried out at 35 ℃.

Example 10

The difference from example 2 is that: the temperature of the isomerization reaction was 260 ℃.

Example 11

The difference from example 2 is that: the isomerization temperature was 340 ℃.

Example 12

The difference from example 2 is that: the partial pressure of hydrogen in the isomerization reaction was 9MPa.

Example 13

The difference from example 2 is that: the catalyst for the isomerization reaction is ZSM-5/Pt-Ni.

Example 14

The difference from example 2 is that: the catalyst for supplementary refining is cobalt molybdenum nickel oxide.

Example 15

The difference from example 2 is that: the initial raw material is coal-based cracking tail oil with the distillation range of 370-550 ℃.

Example 16

Taking coal-based cracked tail oil with the distillation range of 340-700 ℃ as an initial raw material, centrifuging for 5 times at the speed of 5000rpm at the temperature of 15 ℃ for 9min each time, and respectively taking an upper oil phase and a lower wax phase as raw materials of production base oil to perform isodewaxing after the centrifugation is finished; adopting a trickle bed reactor, feeding a wax phase from the top end of the reactor, feeding an oil phase from the upper part of a second bed layer of the reactor, selecting ZSM-48/Pt-Ce as an isomerizing agent, and carrying out the reaction at the temperature of 300 ℃ in the first bed layer, 290 ℃ in the second bed layer, 290 ℃ in the third bed layer and 0.8h of volume space velocity ^-1 Carrying out isomerization reaction under the conditions that hydrogen partial pressure is 4MPa and hydrogen-oil volume ratio is 1000. Performing atmospheric distillation on the isomerization product to cut naphtha (less than 190 ℃) and isoparaffin solvent oil (190-320 ℃), and performing supplementary refining on the bottom oil of the atmospheric tower, wherein the catalyst for supplementary refining is Al ₂ O ₃ Pt-Pd, the reaction temperature is 240 ℃, the hydrogen partial pressure is 4MPa, and the refined product is cut by vacuum rectification to obtain the lubricating oil base oil with different viscosities. And (3) normal-pressure rectification cutting conditions: the pressure at the top of the tower is 0.08MPa (G), the pressure at the bottom of the tower is 0.11MPa (G), the temperature at the bottom of the tower is 340-345 ℃, the fraction at the top of the tower is less than 190 ℃, and the fraction at the side of the tower is 190-320 ℃. And (3) vacuum rectification cutting conditions: the pressure of a decompression system is 10Torr, the temperature of a tower kettle is controlled to be 235-300 ℃, and 320-380 ℃ cut section base oil is extracted from the tower top; the pressure of a decompression system is 2Torr, the temperature of a tower bottom is controlled to be 190-345 ℃, and the segmented base oil is extracted from the top of the tower at 380-420 ℃, 420-460 ℃, 460-510 ℃, 510-550 ℃ and more than 550 ℃ in sequence.

Comparative example 1

Coal-based cracking tail oil with the distillation range of 340-700 ℃ is directly used as a raw material for producing base oil, ZSM-22/Pt is selected as an isomerizing agent, the reaction temperature is 280 ℃, and the volume space velocity is 0.6h ^-1 Hydrogen partial pressure 6MPa, hydrogen-oil volume ratio 500. The supplementary refining agent is Al ₂ O ₃ Pt, reaction temperature 230 ℃, hydrogen partial pressure 6MPa, the refined product (base oil full fraction) was tested.

Comparative example 2

The method comprises the steps of selecting a ketone-benzene organic solvent from coal-based cracking tail oil raw material with the distillation range of 340-700 ℃, dissolving at a low temperature, adding a diluent, filtering, cold washing to separate oil and wax, and then distilling to separate the oil from the organic solvent. Separating oil phase, selecting ZSM-23/Pt as an isomerizing agent, and reacting at 290 ℃ at a volume space velocity of 1h ^-1 Hydrogen partial pressure 4MPa, hydrogen-oil volume ratio 1000. The supplementary refining agent is Al ₂ O ₃ Pt, reaction temperature 240 ℃, hydrogen partial pressure 8MPa, the refined product (base oil full fraction) was tested.

Comparative example 3

The cracking tail oil with the distillation range of 340-700 ℃ is cut by adopting atmospheric and vacuum, the cutting point is 450 ℃, the distillation section is the initial distillation point-450 ℃, and the cutting point is used as a raw material for separating and preparing the lubricating oil base oil. ZSM-48/Pt is respectively selected as an isomerizing agent, the isomerization reaction temperature is 300 ℃, and the volume space velocity is 0.8h ^-1 Hydrogen partial pressure 8MPa, hydrogen-oil volume ratio 1200. The supplementary refining agent is Al ₂ O ₃ Pt, reaction temperature 260 ℃, hydrogen partial pressure 8MPa, the refined product (base oil whole fraction) was tested.

Comparative example 4

The difference from the comparative example 3 is that the raw material used is cracked tail oil with a cut of 450-540 ℃.

Comparative example 5

Coal-based cracked tail oil with the distillation range of 310-700 ℃ is used as an initial raw material, and isodewaxing is directly carried out; adopting a trickle bed reactor, feeding raw materials from the top end of the reactor, selecting ZSM-23/Pt-Fe as an isomerizing agent, loading 2.8kg of a first layer of the reactor, reacting at the temperature of 310 ℃, loading 4kg of a second layer of the reactor, reacting at the temperature of 300 ℃, loading 3.2kg of a third layer of the reactor, reacting at the temperature of 295 ℃,volume space velocity of 0.6h ^-1 Carrying out isomerization reaction under the conditions that the hydrogen partial pressure is 6MPa and the volume ratio of hydrogen to oil is 500. Performing atmospheric distillation on the isomerization product to cut naphtha (less than 190 ℃) and isoparaffin solvent oil (190-320 ℃), and performing supplementary refining on the bottom oil of the atmospheric tower, wherein the catalyst for supplementary refining is Al ₂ O ₃ Pt, reaction temperature 240 ℃, hydrogen partial pressure 6MPa, the refined product (base oil full fraction) was tested.

Comparative example 6

Coal-based cracked tail oil with the distillation range of 310-700 ℃ is used as an initial raw material, and isodewaxing is directly carried out; adopting a trickle bed reactor, feeding 60wt% of raw materials from the top end of the reactor, feeding the rest 40% of raw materials from the upper part of a second bed layer of the reactor, selecting ZSM-23/Pt-Fe as an isomerizing agent, wherein the first layer of the reactor is filled with 2.8kg of raw materials, the reaction temperature is 310 ℃, the second layer is filled with 4kg of raw materials, the reaction temperature is 300 ℃, the third layer is filled with 3.2kg of raw materials, the reaction temperature is 295 ℃, and the volume space velocity is 0.6h ^-1 Carrying out isomerization reaction under the hydrogen partial pressure of 6MPa and the hydrogen-oil volume ratio of 500. The isomerization product is rectified at normal pressure to cut naphtha (less than 190 ℃) and isoparaffin solvent oil (190-320 ℃), the bottom oil of the normal pressure tower is supplemented and refined, and the catalyst for supplementing and refining is Al ₂ O ₃ Pt, reaction temperature 240 ℃, hydrogen partial pressure 6MPa, the refined product (base oil full fraction) was tested.

The properties of the cracked tail oils and the yields of the separated wax oils of examples 1 to 16 and comparative examples 1 to 6 are shown in Table 1, and the properties of the lubricating base oils (i.e., refined products having a boiling range > 320 ℃ C.) obtained in examples 1 to 15 and comparative examples 1 to 6 are shown in Table 2, wherein the yields of the lubricating base oils are calculated based on the oils subjected to isomerization, and the physical properties of the various products obtained in example 16 are shown in Table 3.

TABLE 1

TABLE 2

/>

TABLE 3

/>

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects: the method adopts a centrifugal process to carry out wax-oil two-phase pre-separation on the cracked tail oil, an oil phase and a wax phase are respectively used as raw materials for producing the lubricating oil base oil, and the lubricating oil base oil with high performance can be produced in high yield through hydroisomerization, normal pressure rectification, complementary refining and vacuum rectification, and naphtha and isoparaffin solvent oil are by-products. After the coal-based cracking tail oil is centrifugally separated, the wax phase and the oil phase are fed from different positions of an isomerization reactor, and the hydroisomerization reaction conditions matched with the wax phase and the oil phase are selected, so that the yield of the hydroisomerization product is improved. Naphtha and isoparaffin solvent oil are cut out by atmospheric distillation, the high-value utilization of the cracking tail oil is improved, and only the atmospheric tower kettle oil is supplemented and refined, so that the hydrofining load is reduced, and the production cost is reduced.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A preparation method of lubricating oil base oil is characterized by comprising the following steps:

step S1, carrying out centrifugal separation on cracking tail oil to obtain an oil phase and a wax phase, wherein the cracking tail oil is coal-based hydrocracking tail oil;

s2, enabling the oil phase and the wax phase to enter an isomerization reactor through different parts to perform an isomerization dewaxing reaction to obtain an isomerization product, wherein the wax phase enters from the top of the isomerization reactor, and the oil phase enters from the middle part of the isomerization reactor;

and S3, carrying out normal pressure distillation, supplementary refining and reduced pressure distillation on the isodewaxing product to obtain the lubricating oil base oil.

2. The preparation method according to claim 1, wherein the cracked tail oil is from a vacuum tower bottom distillation section of a hydrocracking unit, the distillation range is 300-720 ℃,

preferably, the content of saturated hydrocarbon in the coal-based hydrocracking tail oil is not less than 98 percent, and the content of normal alkane is not more than 10 percent.

3. The method of claim 1, wherein the centrifugation is performed using a two-phase centrifuge.

4. The method according to claim 1, wherein the rotational speed of the centrifugal separation is 2000 to 15000rpm, preferably 3000 to 12000rpm;

preferably, the total time of the centrifugal separation is 15-60 min, and more preferably 20-55 min;

preferably, the temperature of the centrifugal separation is 0-40 ℃, and more preferably 5-35 ℃;

more preferably, the oil phase has a pour point no less than 21 ℃ and the wax phase has a pour point no less than 21 ℃.

5. The production method according to claim 1, wherein in the step S2, the isomerization reactor is a trickle bed reactor,

preferably, the trickle bed reactor comprises three reaction beds, the wax phase being fed from the top of the reactor and the oil phase being fed from the second bed;

more preferably, the catalyst loading of the three reaction beds: the first bed layer is larger than the third bed layer and is not larger than the second bed layer.

6. The preparation method according to claim 1, wherein the isodewaxing catalyst is a unidimensional mesoporous molecular sieve loaded with metals, the metals comprise noble metals and/or non-noble metals, preferably, the molecular sieve is selected from any one or more of ZSM molecular sieves and SAPO series molecular sieves;

preferably, the noble metal comprises any one or more of Pt and Pd, and the non-noble metal comprises any one or more of Ni, mg, fe and Ce; more preferably, the metals include at least one of the noble metals and at least one of the non-noble metals;

preferably, the partial pressure of the hydrogen for the isodewaxing is 1 to 10MPa, more preferably 2to 8MPa;

Preferably, the isodewaxed hydrogen oil volume ratio is (50-1500): 1, more preferably (100-1200): 1.

7. The method of claim 1, wherein the atmospheric distillation comprises: cutting out a fraction with an end point of no more than 190 ℃ to obtain naphtha, cutting out a fraction with a distillation range of 190-320 ℃ to obtain an isoparaffin solvent, and collecting the fraction with a temperature of more than 320 ℃ as the raw material for the additional refining.

8. The preparation method of claim 1, wherein the post-refining catalyst comprises a hydrogenation metal catalyst and a carrier, the hydrogenation metal catalyst comprises any one or more of Pt, pd, ni, mg, fe and Co, and the carrier comprises any one or more of alumina and silica;

preferably, the temperature of the supplementary refining is 200-260 ℃, the hydrogen partial pressure is 2-8 MPa,

preferably, the space velocity of the supplementary refining is 0.3-1.6 h ^-1 The hydrogen-oil ratio is (500-1200) to 1.

9. A lubricant base oil characterized by being produced by the production method according to any one of claims 1 to 8.

10. The lubricant base oil of claim 9, wherein the lubricant base oil grades comprise 2cSt, 3cSt, 4cSt, 6cSt, 10cSt, 30cSt, and the lubricant base oil has a saturated hydrocarbon content of no less than 99%.