阅读说明：本技术 一种对光亮油细分和提质的超临界萃取分离方法 (Supercritical extraction separation method for subdividing and upgrading bright oil ) 是由 王伟 盛奎龙 鲁佳 汪恩阳 于 2020-06-10 设计创作，主要内容包括：本发明涉及一种对光亮油细分和提质的超临界萃取分离方法,属于润滑油基础油的制备领域。对光亮油细分和提质的超临界萃取分离方法包括以下步骤：以丙烷为溶剂,对光亮油原料进行超临界流体萃取,得到100℃运动粘度不同的窄馏程组分油品。该方法可实现对光亮油原料的进一步细分和提质,可得到的色度、氧化安定性、粘度指数等指标均得到改善的光亮油细分产品,可直接作为或经常规精制处理后作为高品质调合组分使用。(The invention relates to a supercritical extraction separation method for subdividing and upgrading bright oil, belonging to the field of preparation of lubricating oil base oil. The supercritical extraction separation method for subdividing and upgrading the bright oil comprises the following steps: the method takes propane as a solvent to carry out supercritical fluid extraction on the bright oil raw material to obtain the oil product with narrow distillation range components with different kinematic viscosities at 100 ℃. The method can realize the further subdivision and quality improvement of the bright oil raw material, and the obtained bright oil subdivided product with improved indexes such as chromaticity, oxidation stability, viscosity index and the like can be directly used as or used as a high-quality blending component after conventional refining treatment.)

1. A supercritical extraction separation method for subdividing and upgrading bright oil is characterized by comprising the following steps: the method takes propane as a solvent to carry out supercritical fluid extraction on the bright oil raw material to obtain the components with narrow distillation ranges and different kinematic viscosities at 100 ℃.

2. The supercritical extraction separation process for the subdivision and upgrading of bright oils according to claim 1 wherein supercritical fluid extraction is carried out in an extractive distillation column and the narrow boiling range component is separated by changing the solvent power of the extraction solvent by adjusting the working pressure to increase or decrease at the working temperature.

3. The supercritical extraction separation process for the subdivision and upgrading of bright oil as claimed in claim 1 or 2, characterized in that the temperature of the supercritical fluid extraction is 100-140 ℃ and the pressure is 4.5-8 MPa.

4. The supercritical extraction separation process for bright oil subdivision and upgrading of claim 1, characterized in that the kinematic viscosity at 100 ℃ of the bright oil feedstock is 16mm²The kinematic viscosity is less than or equal to 50mm at the temperature of less than or equal to 100 DEG C²/s。

5. The supercritical extraction separation process for bright oil refinement and upgrading of claim 1, wherein the bright oil feedstock is a light dewaxed oil, or a refined light dewaxed oil.

Technical Field

The invention belongs to the field of preparation of lubricating oil base oil, and particularly relates to a supercritical extraction separation method for subdividing and upgrading bright oil.

Background

Bright stock is a heavy lubricant base oil of the type specified for the greatest kinematic viscosity, used as a blending component in internal combustion engine oils, or as a major component in automotive and industrial gear oils.

The kinematic viscosity of bright stock at 100 ℃ is generally in the range from 17 to 34mm²Between/s, the viscosity is divided into 90BS, 120BS and 150BS, wherein the 100 ℃ kinematic viscosity range of 90BS bright stock is 17-22mm²The kinematic viscosity range of 120BS bright stock is 22-28mm²The kinematic viscosity range of 150BS bright stock is 28-34mm²The higher the kinematic viscosity, the wider the range of bright stock applications.

Conventional methods for bright stock production generally include the following steps: the light deasphalted oil is obtained after propane deasphalting of the vacuum residue of the paraffin base (main body) crude oil, the light deasphalted oil is subjected to solvent refining and solvent dewaxing to obtain light dewaxed oil, and the light dewaxed oil is subjected to clay refining (or supplementary hydrogenation) to obtain a bright stock product. Solvent refining often uses a furfural refining process and solvent dewaxing often uses a benzol dewaxing process. The process is the 'three sets' of old technology for producing traditional lubricating oil. While the heavy base oil produced by hydrogenation or isomerization dewaxing mode can not reach the viscosity grade above 90 BS.

Bright stock produced by the 'old three sets' process often has obvious defects in the aspects of indexes such as chromaticity, rotary oxygen bomb, viscosity index and the like due to the reasons of raw material heaviness, process condition limitation and the like, and the quality of the obtained bright stock needs to be further improved.

Disclosure of Invention

The invention aims to provide a supercritical propane extraction separation method for subdividing and upgrading bright oil, so as to solve the problem that the quality of the bright oil produced by the traditional process needs to be improved.

The production process scheme of the invention is as follows:

a supercritical extraction separation method for subdividing and upgrading bright oil comprises the following steps: the method takes propane as a solvent to carry out supercritical fluid extraction on the bright oil raw material to obtain the components with narrow distillation ranges and different kinematic viscosities at 100 ℃.

In a specific supercritical region, the solubility of the solute of the mixture to be separated can be changed in a considerable range under the condition of small change of temperature and pressure, so that the separation and purification purposes can be achieved. The separation result of the bright oil raw material shows that the bright oil raw material shows good subdivision cutting capability, can be separated into different components according to the viscosity, and can obtain oil products meeting different qualities and market requirements by yield adjustment according to the regular characteristics.

The bright oil raw material is subjected to propane supercritical fluid extraction, so that the bright oil raw material can be further subdivided and upgraded, and a subdivided bright oil product with improved indexes such as chromaticity, oxidation stability, viscosity index and the like is obtained by yield adjustment and can be directly used as a high-quality blending component or used as a high-quality blending component after conventional refining treatment. In general, the higher the kinematic viscosity at 100 ℃ of bright stock, the wider its industrial application range and the greater its industrial value.

The process can carry out full distillation range fine separation on the bright oil raw material; the individual components are extracted with any distillation range width. Including 17mm²The kinematic viscosity is less than 22mm at the temperature of less than or equal to 100 DEG C²/s、22mm²The kinematic viscosity is less than 28mm at the temperature of less than or equal to 100 DEG C²And/s corresponding 90BS, 120BS viscosity grades of heavy base oil.

Supercritical fluid extraction is carried out in an extraction rectifying tower, and the narrow distillation range component is separated out by adjusting the working pressure to increase or decrease and changing the dissolving capacity of an extraction solvent at a certain working temperature.

Experiments preferably show that the extraction temperature required by the process is 100-140 ℃, and the pressure is 4.5-8 MPa.

From the prior art, the fine separation of the bright oil is difficult to achieve through the traditional rectification mode, and the product quality and the yield can not be flexibly adjusted.

The kinematic viscosity of the bright stock at 100 ℃ is 16mm²The kinematic viscosity is less than or equal to 50mm at the temperature of less than or equal to 100 DEG C²And/s can be light dewaxed oil or refined light dewaxed oil. The refined light dewaxed oil is an oil product obtained by subjecting the light dewaxed oil to clay refining (or supplementary hydrogenation) process.

The method is especially suitable for the kinematic viscosity of 16mm at 100 DEG C²/s≤100The kinematic viscosity at the temperature of less than or equal to 50mm²(s), oxidation stability, viscosity index and color require improved heavy base oils.

Drawings

FIG. 1 is a schematic diagram of a supercritical fluid extraction apparatus used in an embodiment of the present invention;

FIG. 2 is a comparison of color of various cumulative yield components and bright stock in example 1 of the present invention;

FIG. 3 is a graph showing the relationship between the yield of extracted oil and the pressure at different temperature gradients and initial pressures for the examples of the present invention;

in the figure, 1-an extractive distillation tower, 10-a distillation column, 11-an extraction kettle, 2-a separator, 3-a feed pump, 4-a supercritical fluid input pipeline, 5-a low-temperature bath, 6-a circulating pump, 7-a separator feed pipeline, 8-an extraction product discharge pipeline, 9-a solvent discharge pipeline, 12-an emptying pipeline, 13-a solvent circulation pipeline and 14-a pressure adjusting pipeline.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings.

In the following embodiments, the apparatus used for supercritical fluid extraction is shown in fig. 1, and includes an extractive distillation column 1 and a separator 2, where the extractive distillation column 1 includes a distillation column 10 and an extraction kettle 11 which are arranged up and down, the extraction kettle 11 is connected with a feed pump 3, and the feed pump 3 is connected with a light dewaxed oil storage tank for pumping raw oil (i.e. raw bright stock oil) into the extraction kettle 11.

The bottom of the extraction kettle 11 is connected with a supercritical fluid input pipeline 4, a low-temperature bath 5 and a circulating pump 6 are arranged on the supercritical fluid input pipeline 4, and the low-temperature bath 5 and the circulating pump 6 are sequentially arranged in the supercritical fluid input direction.

The top of rectifying column 10 is provided with the extraction material export, and the extraction material export passes through separator feed line 7 and links to each other with separator 2, and the bottom of separator 2 is connected with extraction product discharging line 8, and the top of separator 2 is connected with solvent discharging line 9, and solvent discharging line 9 reposition of redundant personnel is into blow-down pipeline 12 and solvent circulation pipeline 13, and solvent circulation pipeline 13 links to each other (connects the upper reaches at low temperature bath 5) with supercritical fluid input pipeline 4. A pressure regulating line 14 for regulating the pressure of the extractive distillation column is also connected between the separator feed line 7 and the solvent discharge line 9.

The volume of the extraction kettle 11 is 500ml, the height of the rectifying tower 10 is 120cm, the inner diameter is 25mm, and the tower is filled with theta-shaped filler with the diameter of 3 mm. The extraction kettle 11, the lower part, the middle part and the upper part of the rectifying tower 10 and the separator 2 are provided with jackets, and the temperature of each part is controlled by constant temperature water bath.

The basic working process of supercritical fluid extraction by using the device comprises the following steps: pressurizing raw materials and a solvent, then feeding the pressurized raw materials and the solvent into the bottom of an extraction kettle, carrying out primary contact in the extraction kettle, and further carrying out contact dissolution in an extraction rectification column with a filler arranged at the upper part; then flows through a top outlet pressure regulating valve, the pressure is reduced, the solubility is reduced, and dissolved matters are separated in a separating tank, so that the extract under the condition corresponding to the pressure of the rectifying column is obtained. The extraction process is a semi-continuous process. The rectification tower is maintained with certain temperature gradient, and the solvent is heated and pressurized for reuse.

Specifically, the method comprises the following steps: the raw material of the oil product to be separated is pumped into an extraction kettle 11 by a one-step pump 3, then a circulating pump 6 is started, a propane solvent continuously passes through the extraction kettle 11 and contacts with the raw material of the oil product to be separated in the extraction kettle 11, the propane solvent dissolves the components in the raw material of the oil product to be separated, the solvent dissolved with the raw material rises and enters a rectifying tower 10, a certain temperature gradient is kept in the rectifying tower 10 (the temperature at the bottom of the tower is low and the temperature at the top of the tower is high), the solvent dissolved with the raw material is heated along the direction of the height of the tower, the temperature is increased, the dissolving capacity of the solvent is reduced, so that part of the components dissolved in the solvent of the raw material can be re-separated out due to the reduction of the dissolving capacity of the solvent, the first separated out component is a relatively insoluble component, the separated out component flows down along the tower and contacts with the rising solvent in countercurrent to generate heat and mass exchange (internal, the pressure of the solvent is reduced, the solvent loses the dissolving capacity, the extracted fractions are obtained at the bottom of the separator, the solvent is recovered at the top of the separator 2 and is recycled to the low-temperature bath 5, the distillate oil in the separator 2 is collected in sections to obtain different fractions for property analysis, the pressure in the separation process is increased according to a certain program, and the dissolving capacity of the supercritical fluid is improved along with the increase of the pressure, so that the raw material can be separated into different fractions according to the solubility in order through the change of the pressure.

In the following examples, the bright stock used for supercritical fluid extraction was produced by the Zhongpetrochemical Nanyang energy chemical Co. The light dewaxed oil is produced with the vacuum residuum of paraffin base crude oil and through propane deasphalting to produce light deasphalted oil, and the light deasphalted oil is further solvent refined and dewaxed to obtain the light dewaxed oil. The solvent refining adopts a furfural refining process, and the solvent dewaxing adopts a ketone-benzene dewaxing process. The light dewaxing oil preparation process corresponds to the first two sets of the traditional three sets of the old technological process.

The properties of the light dewaxed oil are shown in Table 1.

TABLE 1 light dewaxed oil Properties

First, the specific embodiment of the supercritical extraction separation method for subdividing and upgrading bright oil