CN114437796B

CN114437796B - Method for producing high-viscosity index lubricating oil base oil through hydrogenation

Info

Publication number: CN114437796B
Application number: CN202011620190.9A
Authority: CN
Inventors: 赵威; 姚春雷; 全辉; 张志银; 孙国权; 刘林东
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2020-10-31
Filing date: 2020-12-31
Publication date: 2024-02-02
Anticipated expiration: 2040-12-31
Also published as: CN114437796A

Abstract

The invention discloses a method for producing high-viscosity index lubricating oil base oil through hydrogenation. The method comprises the following steps: mixing wax-containing oil with hydrogen, and firstly contacting with a noble metal hydrocracking catalyst; the hydrocracking effluent enters a precious metal supplementing and refining reaction zone; separating the reaction effluent of the supplementary refining reaction to obtain a light lubricating oil base oil product and a heavy base oil component; returning all or part of the obtained heavy base oil components to a hydroisomerization dewaxing reaction zone for hydroisomerization reaction; the hydroisomerization effluent and the hydrocracking product enter a complementary refining reaction zone together; the reaction effluent enters a fractionation system. The method can obtain the light and heavy lubricant base oil with high quality, and simultaneously produces a special oil product with high quality, and has simple process and low operation energy consumption.

Description

Method for producing high-viscosity index lubricating oil base oil through hydrogenation

Technical Field

The invention relates to a method for producing high-viscosity index lubricating oil base oil by hydrogenation. In particular to a method for producing high-viscosity index lubricating oil base oil by taking wide-fraction high-wax-content oil as a raw material and adopting a noble metal hydrocracking-isomerization dewaxing/supplementary refining reverse-sequence series process.

Background

The traditional production of the base oil of the lubricating oil adopts a solvent refining process, and the main two steps are that the solvent refining is adopted to remove non-ideal components such as aromatic hydrocarbon and the like and the solvent dewaxing is adopted to ensure the low-temperature flow property of the base oil. In addition, clay or hydrofinishing is generally performed.

Increasingly stringent environmental regulations and rapid developments in the mechanical industry place increasing demands on the performance of lubricating oil base oils. Meanwhile, the crude oil quantity suitable for producing lubricating oil is gradually reduced due to the worldwide crude oil degradation. Therefore, the hydrogenation process for producing lubricating oil has been developed very rapidly. The hydrogenation process is the process of producing base oil of lubricating oil by adopting a hydrocracking process or a hydrotreating-isomerization dewaxing-hydrofining combined process, and has the advantages of high raw material flexibility, high base oil yield, high byproduct value and the like.

One disadvantage of conventional hydroisomerization dewaxing processes is that it is difficult to simultaneously achieve both a light lubricant oil component and a heavy lubricant oil component meeting the pour point and viscosity index requirements when using a full or wide range waxy oil as the feed. In general, when the pour point of the heavy lubricating oil component is acceptable, the viscosity index loss of the light lubricating oil component is large, and it is difficult to produce an API III light base oil product with the viscosity index of more than 120; and when the viscosity index of the light lubricating oil component is acceptable, the heavy component cannot be used as an acceptable lubricating oil component.

Aiming at the problems, the prior art adopts the steps of prefractionating wax-containing oil and then taking each narrow fraction as the feeding material of hydroisomerization dewaxing, thereby solving the problem of producing the high-viscosity index light lubricating oil base oil. US5,580,442 proposes a process for the production of high viscosity index lubricant base oils from hydrocracked tail oils. Firstly, the hydrocracking tail oil is subjected to pressure reduction prefractionation, and 100 viscosity is cut into 3mm respectively ² /s、4mm ² /s、6 mm ² S and 8mm ² Four narrow fractions of/s, which are separately hydrodewaxed to produce a viscosity index>130 has a 100 viscosity of 3mm respectively ² /s、4mm ² /s、6 mm ² S and 8mm ² Four lubricating base oil products per second.

US7,198,710 proposes a process for producing a high viscosity index lubricant base oil from fischer-tropsch wax. The Fischer-Tropsch wax is fractionated to obtain a light component and a heavy component, and hydroisomerization dewaxing is performed to reduce the pour point of the raw material, so that the light lubricating oil base oil with the pour point meeting the requirement can be obtained. The pour point of the heavy component is further reduced by adopting a solvent dewaxing method due to disqualification of the pour point of the heavy component, and finally the heavy lubricant base oil product with the pour point meeting the requirement is obtained.

The method for producing the light and heavy high-viscosity index lubricating oil base oil can be solved by adopting the narrow fraction waxy oil as a feeding method for hydroisomerization dewaxing, but a plurality of raw material tanks are required to be arranged, so that the construction investment of the device is increased; in addition, raw materials are frequently switched and technological parameters are frequently adjusted in actual production, so that the operation difficulty of the device is greatly increased and a large amount of unqualified products are produced.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a production method of high-viscosity index lubricating oil base oil. One or more wax-containing oils in hydrotreated light deoiling, hydrotreated cerate, hydrotreated lower wax oil or Fischer-Tropsch synthetic wax heavy fraction are used as raw oil, and the high-viscosity index lubricating oil base oil is produced through a noble metal hydrocracking-isomerization dewaxing/supplementary refining reverse-sequence tandem process.

The invention relates to a production method of high-viscosity index lubricating oil base oil, which comprises the following steps:

(1) Taking wax-containing oil as raw oil, mixing with hydrogen, firstly entering a hydrocracking reaction zone, contacting with a noble metal hydrocracking catalyst, performing hydrocracking reaction, reducing the molecular weight of reactants, and performing shallow isomerism reaction;

(2) The reaction effluent obtained in the step (1) enters a precious metal supplementing and refining reaction zone, and the reaction zone is saturated with olefin and aromatic hydrocarbon;

(3) The reaction effluent obtained in the step (2) enters a separation and fractionation system to obtain a light lubricating oil base oil product with pour point meeting the requirement and high viscosity index and a heavy base oil component;

(4) Returning all or part of the heavy base oil component obtained in the step (3) to a hydroisomerization dewaxing reaction zone, and carrying out hydroisomerization reaction under proper conditions to obtain a heavy lubricating oil base oil product with pour point meeting the requirement and high viscosity index;

(5) The reaction effluent obtained in the step (4) and the hydrocracking product enter a hydrofining reaction zone together for deep hydrofining reaction;

(6) And (3) introducing the reaction effluent obtained in the step (5) into a fractionation system to obtain a light lubricating oil base oil product and a heavy base oil component.

In the method of the invention, the wax-containing oil can be one or more of hydrotreated light deoiling, hydrotreated cerate, hydrotreated lower wax oil or Fischer-Tropsch synthetic wax heavy fraction, and the sulfur content of the raw materials is required to be lower than 30 mug/g, preferably lower than 15 mug/g; the nitrogen content is required to be less than 5 mug/g, preferably less than 2 mug/g, so as to meet the requirements of the noble metal catalyst used for hydrocracking, isodewaxing and refining as well as the impurity content of the raw materials. The light deoiling, the hydrotreatment of the cerate and the oil under the wax are all conventional methods in the field, and generally non-noble metal catalysts are used, so that the main purpose is to deeply remove sulfur, nitrogen and other impurities. The initial boiling point of the raw oil is generally 200 to 400 ℃ and the final boiling point is generally 500 to 700 ℃. In the invention, the wax-containing oil in the step (1) is selected from one or more of hydrotreated light deoiling, hydrotreated cerate, hydrotreated lower wax oil or Fischer-Tropsch synthetic wax heavy fraction.

In the method, in the initial stage of device start-up, the pour point of the heavy lubricant base oil product does not meet the index requirement, all the heavy lubricant base oil components obtained in the step (3) are required to be recycled back to the isomerization dewaxing reactor, and after the isomerization dewaxing reactor operates stably, the proper recycle proportion of the heavy lubricant base oil is maintained, so that the heavy lubricant base oil product with qualified pour point and viscosity index can be obtained. In general, the mass ratio of the heavy base oil component from step (3) to the cycle oil returned to the hydroisomerization dewaxing reaction zone as part of the product is 0.2:1 to 5:1, preferably 0.5: 1-2: 1, can be specifically determined according to the properties of raw materials and the quality index of products.

In the method of the invention, the viscosity indexes of the obtained light lubricating oil base oil product (1-2 side products obtained by distillation) and the obtained heavy lubricating oil base oil product (1 side products obtained by distillation and a bottom product) are both more than 120 and generally 120-170. The pour point of both the light lubricant base oil product and the heavy lubricant base oil product is below-10 ℃, preferably below-15 ℃. The pour point of the light lubricating oil base oil product is-10 to-30 ℃, preferably-15 to-27 ℃; the pour point of the heavy lubricant base oil product is-10 to-25 ℃, preferably-12 to-21 ℃.

The temperature of the division point of the light base oil product and the heavy base oil component obtained in the step (6) is 450-520 ℃, namely, the distillation division temperature (real boiling point temperature) of the light base oil product and the heavy base oil component is 450-520 ℃ in a reduced pressure distillation tower, the base oil with the boiling point lower than the division point is the light base oil, and the base oil component with the boiling point higher than the division point enters an isomerization dewaxing reactor for further reaction and fractionation to obtain the heavy base oil.

The noble metal hydrocracking catalyst in the step (1) is a noble metal hydrocracking catalyst containing amorphous silica-alumina, and the existing hydrocracking catalyst in the field can be selected, for example, a commercial hydrocracking catalyst can be used, and can also be prepared according to the general knowledge in the field. Further, the carrier of the noble metal hydrocracking catalyst contains 20 to 80wt% of amorphous silica-alumina, preferably 40 to 70wt% of amorphous silica-alumina. Furthermore, the carrier also contains beta molecular sieve, and the beta molecular sieve accounts for 20-80 wt% of the weight of the carrier. The specific surface area of the hydrocracking catalyst is 200-500 m ² Per gram, the pore volume is 0.15-0.90 mL/g, and the infrared acidity is generally 0.30-0.50 mmol/g; preferably a specific surface area of 300 to 400m ² Per g, the pore volume is 0.40-0.70 mL/g. The hydrocracking catalyst contains at least one precious metal hydrogenation component, preferably platinum and/or palladium. The total content of the noble metal hydrogenation components is 0.10 wt% to 1.0. 1.0 wt wt%, preferably 0.20wt% to 0.80wt%.

The isodewaxing catalyst used in the hydroisomerization dewaxing reaction zone in step (3) may beLubricating oil hydroisomerization catalysts commonly used in the art are selected. Such as commercial hydroisomerization dewaxing catalysts, may be used, or they may be prepared as is commonly known in the art. The hydroisomerization dewaxing catalyst carrier is typically an NU-10 molecular sieve, ZSM-22, ZSM-23 molecular sieve, ZSM-48 molecular sieve, etc., of alumina and TON structure, preferably ZSM-22 molecular sieve. The content of the molecular sieve in the hydroisomerization dewaxing catalyst is 30-80 wt%, preferably 40-70 wt%, and partial silicon oxide can be added into the carrier; the active metal component is one or more of Pt, pd, ru and Rh, and the content of the active metal component in the catalyst is 0.1-5.0 wt%. The optional auxiliary agent component is one or more of boron, fluorine, chlorine and phosphorus, and the content of the auxiliary agent component in the catalyst is 0.1-5.0 wt%; the specific surface area of the hydroisomerization dewaxing catalyst is 150-500 m ² Per g, the pore volume is 0.15-0.60 mL/g.

The supplementary refining catalyst used in the supplementary refining reaction zone in the step (2) is a conventional reduced hydrofining catalyst, wherein the active metal is one or two of Pt and Pd or the active metal is a reduced nickel catalyst, the weight content of the active metal in the noble metal catalyst is generally 0.05-1%, the active metal of the reduced nickel catalyst is 30-80% by weight of oxide, and the catalyst carrier is generally Al ₂ O ₃ Or Al ₂ O ₃ -SiO ₂ An auxiliary agent such as P, ti, B, zr may be contained. The catalyst is used for conventional reduction, so that the hydrogenation active metal is ensured to be in a reduced state in the reaction process. The catalyst can be selected from common commercial catalysts in the field or prepared according to common methods in the field.

The reaction conditions of the hydrocracking reaction zone are as follows: the reaction temperature is 300-400 ℃, preferably 320-360 ℃, the hydrogen partial pressure is 2.0-18.0 MPa, preferably 10.0-15.0 MPa, and the volume space velocity is 0.4-6.0 h ^-1 Preferably 0.6 to 1.8h ^-1 The volume ratio of hydrogen oil is 400:1-1500:1, preferably 600:1-1000:1. The hydrocracking process requires control of the proper cracking severity, typically controlling > 370 ℃ conversion to 50wt% to 70wt%.

The reaction conditions of the isomerization dewaxing zone are as follows: the temperature is 300-380 ℃, preferably 310-340 ℃, the hydrogen partial pressure is 2.0-18.0 MPa,preferably 10.0-15.0 MPa, and the volume space velocity of the raw oil is 0.2h ^-1 ～6.0h ^-1 Preferably 0.4. 0.4 h ^-1 ～1.0h ^-1 The volume ratio of hydrogen oil is 400:1-1500:1, preferably 600:1-800:1.

The reaction conditions of the complementary refining reaction zone are as follows: the temperature is 200-300 ℃, preferably 210-280 ℃, the hydrogen partial pressure is 6.0-18.0 MPa, preferably 10.0-15.0 MPa, and the volume space velocity is 0.3h ^-1 ～3.0h ^-1 Preferably 0.6h ^-1 ～1.2h ^-1 The volume ratio of hydrogen oil is 400:1-1500:1, preferably 600:1-800:1.

In the method, the hydrocracking reactor, the isomerization dewaxing reactor and the refining supplementing reactor share one distillation system, so that the investment and the occupied area can be greatly saved.

Compared with the prior art, the method for producing the high-viscosity index lubricating oil base oil by the hydrocracking-isomerization dewaxing/supplementary refining reverse-sequence tandem process has the following advantages:

1. the method adopts the noble metal hydrocracking catalyst, solves the sulfur loss problem of the vulcanized hydrocracking catalyst, does not need to frequently supplement sulfur, can stably operate for a long period, can share a new hydrogen system, a circulating hydrogen system and a distillation system, and saves investment, occupied area and operation cost.

2. The noble metal hydrocracking catalyst containing beta molecular sieve has certain isomerization reaction while reducing the molecular weight of the material, light product with qualified condensation point and heavy product with lowered condensation point, and through fractional distillation system, the heavy product is partially circulated back to the isomerization dewaxing reactor to solve the selectivity problem of the isomerization dewaxing reactor in treating wide fraction material, optimize the condensation point, viscosity index and yield of light and heavy lubricant base oil and improve the cloud point of heavy lubricant base oil greatly.

3. The heavy product passes through the supplementary refining reactor twice, so that the trace amount of polycyclic aromatic hydrocarbon containing nitrogen atoms with the greatest influence on color and stability can be deeply saturated under the condition of less loading of noble metal supplementary refining catalyst, the carbon deposition tendency of the feeding material of the isomerization dewaxing reactor can be reduced, and the service life of the isomerization dewaxing catalyst can be prolonged.

4. The process simultaneously produces a series of light white oil meeting the technical index requirements of the light white oil (II) in NB/SH/T0913-2015 and industrial white oil meeting the technical index requirements of the industrial white oil (II) in NB/SH/T0006-2017.

Drawings

FIG. 1 is a schematic process flow diagram of the method of the present invention.

Detailed Description

The technical scheme of the invention is described in more detail below with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1, the method for producing the high viscosity index lubricating base oil according to the present invention comprises: the wax oil-containing raw oil 1, the new hydrogen 2 and the recycle hydrogen 3 are mixed and firstly enter a noble metal hydrocracking reaction zone 4 to complete a hydrocracking reaction with proper depth; the hydrocracking product 5 and the isomerism dewaxing reaction product 16 enter a precious metal supplementing refining reaction zone 6 together, and the olefins and the aromatic hydrocarbon are saturated; the finishing reaction effluent 7 enters a separation system 8, wherein the separation system 8 generally comprises a high-pressure separator and a low-pressure separator, the gas phase 3 obtained by separation returns to the hydrocracking reaction zone 4 as circulating hydrogen, and the liquid phase product 9 enters a fractionation system to obtain light white oil II and industrial white oil II 11. The light lubricating oil base oil product 12 with the pour point meeting the requirement and high viscosity index, the heavy base oil fraction 13 with the pour point being higher, and the heavy base oil fraction 14 with the pour point being higher returns to the hydroisomerization dewaxing reaction zone 16 completely or partially, and the hydroisomerization reaction with deeper depth is completed under proper conditions, so that the heavy lubricating oil base oil product with the pour point meeting the requirement and high viscosity index is obtained. The isomerization dewaxing reaction effluent 17 and the hydrocracking product 5 enter a hydrogenation replenishing refining reaction zone 6 together to carry out deep replenishing refining reaction, so that the stability of the product is ensured. The circulation amount of the heavy lubricant base oil circulation oil 14 is adjusted according to the product properties until the whole system reaches balance, and a heavy lubricant base oil product 15 with pour point meeting the requirements and high viscosity index is obtained.

The details and effects of the method according to the invention are described below by means of specific examples.

The following examples further illustrate the methods provided by the present invention, but are not intended to limit the scope of the invention. The properties of the raw materials treated by the method are shown in Table 1, and the physicochemical properties of the catalyst used are shown in Table 2.

Table 1 example feedstock properties

TABLE 2 catalyst physicochemical Properties

Examples 1 to 3

In examples 1-3, the raw materials are 3 raw materials listed in Table 1 respectively, the physical and chemical properties of the catalyst are shown in Table 2, the principle flow chart is shown in FIG. 1, and the obtained results are specifically shown in tables 3-4.

Comparative examples 1 to 3

Comparative examples 1 to 3 used the same raw materials as examples 1 to 3, used the same catalysts as in examples 1 to 3, and were conventional isodewaxing-finishing processes without using a noble metal hydrocracking catalyst, with partial recycle of the tail oil, and the process conditions and results shown in tables 3 to 4, respectively.

Table 3 process conditions for examples and comparative examples

Table 4 the results of the examples and comparative examples.

As can be seen from the examples and comparative examples in tables 3-4, it is difficult to achieve a balance of light and heavy lube base oil pour point, viscosity index and yield at the same time for a feedstock of high wax content, high molecular weight, wide distillation range, which is a hydrotreated light deoiling, hydrotreated cerate, hydrotreated lower wax oil or Fischer-Tropsch wax heavy fraction, to directly enter isomerization dewaxing without hydrocracking treatment at a low temperature without reacting, high temperature, severe cracking, and formation of a large amount of gas and naphtha.

Claims

1. A method for producing high-viscosity index lubricating oil base oil through hydrogenation comprises the following steps:

(1) Taking wax-containing oil as raw oil, mixing with hydrogen, firstly entering a hydrocracking reaction zone, and contacting with a noble metal hydrocracking catalyst to carry out hydrocracking reaction;

(4) Returning all or part of the heavy base oil components obtained in the step (3) to a hydroisomerization dewaxing reaction zone for hydroisomerization reaction to obtain a heavy lubricating oil base oil product with pour point meeting requirements and high viscosity index;

(5) The reaction effluent obtained in the step (4) and the hydrocracking product obtained in the step (1) enter a precious metal hydrofining reaction zone together for a hydrofining reaction;

(6) The reaction effluent obtained in the step (5) enters a fractionation system to obtain a light lubricating oil base oil product and a heavy base oil component;

the sulfur content of the wax-containing oil is lower than 30 mug/g, and the nitrogen content is lower than 5 mug/g; the initial distillation point of the wax-containing oil is 200-400 ℃ and the final distillation point is 500-700 ℃.

2. The method according to claim 1, wherein the wax-containing oil has a sulphur content of less than 15 μg/g and a nitrogen content of less than 2 μg/g.

3. The process of claim 1, wherein the heavy base oil fraction obtained in step (3) is returned to the hydroisomerization dewaxing reaction zone in which the mass ratio of recycle oil returned to the hydroisomerization dewaxing reaction zone to product fraction is 0.2:1 to 5:1.

4. the method of claim 1, wherein the viscosity index of the resulting light lubricating oil base oil product and heavy base oil component are each 120 or more; the pour point of both the light lubricant base oil product and the heavy lubricant component is below-10 ℃.

5. The method according to claim 4, wherein the viscosity index of the obtained light lubricating oil base oil product and heavy base oil component is 120 to 170; the pour point of both the light lubricant base oil product and the heavy lubricant component is below-15 ℃.

6. The process according to claim 1, wherein the split point temperature of the light base oil product and the heavy base oil component obtained in step (6) is 450 to 520 ℃.

7. The method according to claim 1, wherein the noble metal hydrocracking catalyst is a noble metal hydrocracking catalyst containing amorphous silica-alumina, and the catalyst carrier contains 20-80 wt% of amorphous silica-alumina.

8. The method of claim 7, wherein the carrier further comprises a beta molecular sieve, the beta molecular sieve comprising 10wt% to 50wt% of the weight of the carrier.

9. The process of claim 1 wherein the hydroisomerization dewaxing catalyst used in the hydroisomerization dewaxing reaction zone has a carrier of at least one of NU-10 molecular sieve, ZSM-22, ZSM-23 molecular sieve, ZSM-48 molecular sieve of alumina and TON structure, the molecular sieve being present in the hydroisomerization dewaxing catalyst in an amount of 30wt% to 80wt%; the active metal component is one or more of Pt, pd, ru and Rh, and the content of the metal component in the catalyst is 0.1-5.0 wt%.

10. The method of claim 9, wherein the molecular sieve is present in the hydroisomerization dewaxing catalyst in an amount of 40 wt.% to 70 wt.%.

11. The process according to claim 1, wherein the noble metal-based catalyst used in the finishing reaction zone contains one or both of Pt and Pd as the active metal, and the active metal is contained in an amount of 0.05 to 1% by weight based on the catalyst, and the catalyst carrier is Al ₂ O ₃ Or Al ₂ O ₃ -SiO ₂ 。

12. The process of claim 1 wherein the reaction conditions in said hydrocracking reaction zone are: the reaction temperature is 300-400 ℃, the hydrogen partial pressure is 2.0-18.0 MPa, and the volume airspeed is 0.4-6.0 h ^-1 The volume ratio of hydrogen to oil is 400:1-1500:1.

13. The process of claim 11 wherein the hydrocracking process is controlled to > 370 ℃ with a conversion of 50wt% to 70wt%.

14. The process of claim 1 wherein the reaction conditions in the isodewaxing zone are: the temperature is 300-380 ℃, the hydrogen partial pressure is 2.0-18.0 MPa, and the liquid hourly space velocity is 0.2h ^-1 ～6.0h ^-1 The volume ratio of hydrogen to oil is 400:1-1500:1.

15. The process of claim 1 wherein the reaction conditions in said finishing reaction zone are: the temperature is 200-300 ℃, the hydrogen partial pressure is 6.0-18.0 MPa, and the volume airspeed is 0.3h ^-1 ～3.0h ^-1 The volume ratio of hydrogen to oil is 400:1-1500:1.

16. The process of claim 1 wherein the reaction conditions in said finishing reaction zone are: the hydrogen partial pressure is 10.0-15.0 MPa.