JPH0144238B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for economically producing a lubricating base oil with excellent high-temperature oxidation stability and high-temperature detergency and a high viscosity index even from paraffin-base or mixed-base crude oils in a high yield. In recent years, measures have been taken to improve thermal efficiency, miniaturize, increase output, and save energy for internal combustion engines, and the production of lubricating oils such as crankcase oil and cylinder oil used in these engines requires high-temperature oxidation stability and high-temperature cleanliness. There is a need for a base oil that has excellent properties and a high viscosity index.
On the other hand, industrial lubricants such as hydraulic oil, bearing oil,
The production of turbine oil and compressed machine oil requires a base oil with a higher degree of refinement than that for internal combustion engine oil. Therefore, in the lubricating base oil manufacturing industry, there is a desire to develop a technology that can simultaneously produce base oils according to their uses, with high yields, and with less energy. Conventionally, in order to produce lubricating base oil from the crude oil, a method has been adopted in which hydrorefining, solvent extraction refining, and dewaxing refining are combined in series as shown in FIG. The disadvantages of this method are that although highly refined base oils can be obtained, there are difficulties in improving yield and reducing refining costs, and it is difficult to meet the demands for producing base oils with different properties. Moreover, highly refined base oils have the disadvantage that they tend to form deposits when used under severe conditions such as lubricating oils for internal combustion engines. Conventionally, as a method for producing lubricating base oil with improved oxidation stability from naphthenic crude oil, a method of mixing non-hydrorefined oil with hydrorefined oil was disclosed (USP 3759817, USP 3000807, Japanese Patent Publication No. 1983-
12961), but this type of crude oil is difficult to obtain in Japan, and no consideration has been taken to increase the viscosity index to 90 or higher. The present inventor has studied a method for simultaneously and economically producing base oil for internal combustion engine lubricating oil and base oil for industrial lubricating oil using paraffin base or mixed base crude oil as a raw material, and has completed the present invention. . The main product produced by the method of the present invention is base oil for internal combustion engine lubricating oil, which is used in particularly large amounts among all base oils. The performance required for this base oil is that it is resistant to oxidation (oxidation stability) during long-term use under high-temperature conditions, and it also prevents the formation of deposits or lubricious substances on lubricated metal parts such as engine pistons and cylinder liners. It is difficult to cause such problems (cleanliness), and furthermore, the viscosity changes little with respect to temperature changes (high viscosity index). The present inventor has determined that the sulfur content in the base oil should be improved for high-temperature oxidation stability.
Sulfur content should be 0.15 to 0.7wt%, preferably 0.2 to 0.6wt%, and 0.2wt for high temperature cleanliness.
% or more, preferably 0.25 wt% or more is effective. Figure 2 is an experimental example showing these grounds. The viscosity index of the internal combustion engine lubricant base oil is at least 90 or more preferably 92
If the above is the case, there will be no problem. That is, a base oil having the above-mentioned sulfur content and viscosity index is the object of production in the method of the present invention. In addition, compared to the internal combustion engine,
Highly refined base oils can also be simultaneously produced in the process of the invention. That is, the object of the present invention is to produce a lubricating base oil having high temperature oxidation stability, high temperature detergency, and a high viscosity index from paraffin base or mixed base crude oil with high yield and with less energy. The goal is to provide a way to do so. By the method of the present invention, the yield per unit of feedstock oil is several percent higher than that of conventional methods, and the energy consumption can be reduced by about 50,000 Kcal per 1 Kl of base oil production. The present invention will be explained in detail below. The present invention uses a lubricating oil fraction separated from paraffin base or mixed base crude oil by distillation means as a raw material oil, and produces from it a lubricating base oil containing 0.2 to 0.7 wt% sulfur content and having a viscosity index of 90 or more. In the method, (a) the raw material oil is subjected to solvent extraction and refinement using a furfural solvent under conditions of a raffinate yield of 65 to 80% by volume to obtain a first refined oil containing 1.0 to 1.6 wt% of sulfur; (b) Next, a portion of the first refined oil is heated in the presence of a hydrorefining catalyst at a hydrogen partial pressure of 50 to 150 Kg/cm ² (gauge pressure), a temperature of 330 to 380°C, and a liquid hourly space velocity of 0.5 to 1.
Hydrorefining by contacting under the conditions of 2.0 h ^-1 ,
a second refined oil containing 0.03 to 1.10% by weight of sulfur; (c) both refined oils are solvent dewaxed before or after mixing; (d) both refined oils are mixed in an appropriate ratio and mixed. A method for producing lubricating base oil, which comprises adjusting the sulfur content in oil to 0.2 to 0.7 wt%. The raw material oil used in the present invention is obtained by atmospheric distillation of one or more types of crude oil produced in the Middle East, such as Arabian Light, Arabian Heavy, Basra Light, Kuwait, and Iranian Light, and the residual oil is further vacuum distilled and separated. Bright stock oil is obtained by deasphalting from light, medium, and heavy distillate oils and residual oils, which are classified by viscosity. Among these, oils of various viscosities except light distillate oils are particularly suitable as raw material oils in the present invention. Among them, medium and heavy oils, i.e. 80-150 neutral oil, 400-500
It has a great advantage in yield improvement for the production of neutral grade base oil. The raw material oil has a sulfur content of approximately 2.0~
It contains about 3.5 wt%, is a boiling point fraction of about 400°C or more in terms of normal pressure, and has a viscosity of about 4 to about 30 cSt (100°C). Since the raw material oil contains various sulfur compounds, nitrogen compounds, and other hydrocarbons unsuitable as a lubricating oil base oil, it is refined by the following method. The purification process used in the present invention is shown in Figures 3 and 4.
It is shown in the figure and explained based on these. FIG. 5 shows another embodiment of the invention. The raw material oil is subjected to solvent extraction and refining (hereinafter abbreviated as EX treatment) to become a first refined oil. At this time, known solvents, such as furfural, N-methyl-2-pyrrolidone, and phenol, are used, and after contact in an extraction device, they are separated into a raffinate component and an extract component, and the solvent contained in the raffinate is distilled. removed. In the present invention, extraction should be performed under relatively mild conditions, and the goal is to reduce the sulfur content in the resulting first refined oil to about 1.0 to 1.6 wt%, preferably 1.1 to 1.6 wt%.
%, particularly preferably 1.2 to 1.5 wt%. The numerical limit for the sulfur content is determined from the comprehensive viewpoint of the properties of the second refined oil obtained in the subsequent operations, ensuring the performance of the target lubricating base oil obtained by mixing, improving yield, and saving thermal energy during production. It was done. To explain in more detail, increasing the proportion of solvent during extraction and purification results in a decrease in yield and an increase in refining energy, although highly refined oil with an increased viscosity index can be obtained. For example, a base oil that is extracted and refined under severe conditions to have a sulfur content of 0.6 to 0.7 wt%, hydrorefined to produce a refined oil with a sulfur content of 0.1 to 0.2 wt%, and then mixed to have a sulfur content of 0.4 wt%. Although it has a viscosity index of 94 to 96, the yield is about 6% compared to the method of the present invention.
% decrease, and the refining energy also increases by about 8%. On the other hand, solvent extraction and purification are carried out very mildly, for example, to remove sulfur content.
A base oil with a sulfur content of 0.3wt% cannot be secured by using a refined oil of 1.8wt%, which is hydrorefined to a refined oil with a sulfur content of 0.1 to 0.2wt%, and a mixture of both refined oils with a sulfur content of 0.3wt%. . A preferable example of the conditions for obtaining the first refined oil used in the present invention is a furfural solvent/oil ratio of 150 to
220vol%, preferably 150-200vol%, extraction temperature
60~90℃, the yield of roughinate is about 60~
The solvent ratio is selected to be 85 vol%, preferably 65-80 vol%. The first refined oil contains sulfide-type sulfur compounds that have not been affected by heat or hydrogenation at all as a sulfur content of 50% or more of the total sulfur content, that is, about 0.3 to about 1.0 wt%. It exerts an effective effect when mixed with the refined oil in step 2. A portion of the obtained first refined oil is subjected to hydrorefining (hereinafter abbreviated as HF treatment) under severe conditions to become a second refined oil. The sulfur content in the refined oil is
It should be between 0.02 and 0.15 wt%, preferably between 0.02 and 0.12 wt%, and more preferably between 0.03 and 0.10 wt%. The basis for setting the sulfur content is the sulfur content, viscosity index, and target base oil properties of the first refined oil, the viscosity index of the second refined oil, and furthermore, It is based on the perspective of obtaining industrial lubricant base oil with a high degree of refinement. In other words, by HF treatment to achieve the above sulfur content, the dewaxed oil can have a viscosity index of 95 or more, and the first refined oil can be reduced to 10 to 50 vol.
% mixing, the desired viscosity index and sulfur content can be stably ensured. If the sulfur content is 0.01 wt% or less, ultra-severe refining will cause hydrogenolysis, resulting in a decrease in yield, while mild refining will make it difficult to improve the viscosity index. After studying various desulfurization rates and viscosity indexes, the viscosity index was 95% by increasing the desulfurization rate to approximately 90% or more, preferably 92 to 97%, through HF treatment.
The above (after removing wax) can be stably secured. The HF treatment is performed in the presence of a known hydrorefining catalyst in which about 0.2 to about 15 wt% of one or more of Ni, Co, Mo, W, etc. is supported on a carrier such as silica, alumina, or silica/alumina. So, the hydrogen partial pressure is 50~150Kg/
cm ² (G), preferably 70-100Kg/cm ² (G), temperature 330-
380℃, preferably 350~380℃, LHSV0.5~
Conducted in contact with oil at 2.0hr ^-1 . Both refined oils are dewaxed to lower their pour points. Solvent dewaxing means are suitable for this purpose. By dewaxing, 10 to 20 wt% of the wax content is removed, and as a result, the sulfur content in the dewaxed oil increases slightly and the viscosity index decreases. The base oil obtained by independently solvent dewaxing refining the second refined oil shown in FIGS. 3 and 4 is preferably used as an industrial lubricant base oil. The first refined oil and the second refined oil are mixed as shown in FIGS. 3 and 4. FIG. 3 shows an example in which dewaxing is performed after mixing, and FIG. 4 is an example in which each is individually mixed after dewaxing. In either case, the final sulfur content should be 0.2 to 0.7 wt%,
Mixing of the first and second refined oils is from 10:90 to 50:50.
(capacity ratio). In order to increase the viscosity index, it is preferable to increase the second mixing amount. The mixing ratio was determined based on the sulfur content and viscosity index of the target lubricating oil and the sulfur content and viscosity index of both refined oils themselves. Naturally, improvement in yield and reduction in refining energy are also involved, and overall balance is taken into consideration. The most preferred sulfur content of the base oil after mixing is 0.3-0.6wt%, which includes 20:
A ratio of 80 to 35:65 (capacity ratio) is appropriate. For example, the first
Of the 100 parts of refined oil, 80 parts are subjected to HF treatment, and the
By mixing 60 parts of the 80 parts of the second refined oil with the remaining 20 parts of the first refined oil, a lubricating base oil for internal combustion engines is produced.
80 parts can be produced, and the remaining 20 parts of the second refined oil can be used as industrial lubricant base oil. The method of the present invention has a yield of 2% compared to the conventional method.
~7vol% improvement, and mild solvent refining reduces solvent savings and refining energy required for solvent recovery, etc., is 5~10%
It is possible to reduce Furthermore, it becomes possible to simultaneously produce two or more types of base oils with different degrees of refinement, making it possible to produce lubricating oils with performance depending on the application.
FIG. 5 shows an example of the case where two types of raw material oils with different viscosities are used. The contents and effects of the present invention will be explained below based on Examples and Comparative Examples. Example 1 Boiling point separated by distillation from Arabian Light crude oil
Lubricating oil fraction (viscosity
15cSt100℃, sulfur content 2.70wt%) as raw material oil,
It was refined in the following steps to obtain a first refined oil No. 1A and a second refined oil No. 2A. Production of first refined oil No. 1A Purification was performed using the RDC furfural solvent extraction device as follows. Furfural/oil ratio: 190% Feedstock oil feed rate: 50.3 Kl/Hr Temperature: 95°C The refining results were as follows. Roughinate fraction yield: 68.3 vol% Refining energy: 225×10 ³ Kcal (per 1 Kl of refined oil) Production of second refined oil No. 2A The first refined oil was refined as follows using a hydrorefining apparatus. Catalyst: Ni 1.0wt%, Co on alumina carrier
3.0wt%, Mo 12.0wt% supported hydrogenation catalyst Hydrogen partial pressure: 98Kg/cm ² (G) Temperature: 378℃ LHSV: 1.0hr ^-1 Oil feed rate: 34.3Kl/Hr Highly desulfurized using the above method The second refined oil No.
2A was obtained in a yield of 98.9vol%. Dewaxing refining The first refined oil No. 1A and the second refined oil No. 2A were each treated separately with a mixed solvent of methyl ethyl ketone/toluene (1:1 volume ratio) per 100 parts by volume of oil.
Using 350 parts by volume, it was cooled to -20°C and the precipitated wax was filtered out to obtain dewaxed oils No. 1A-D and No. 2A-D. The properties of each are shown in Table 1.

【table】

[Table] By mixing both refined oils, 500 neutral grade lubricating oil base oils No. 1 to No. 6 were obtained. The performance of each base oil is shown in Table 2. As is clear from Tables 1 and 2, both refined oils No. 1A-D and No. 2A-D were mixed and the sulfur content was reduced to 0.2~
High temperature oxidation stability by controlling to 0.7wt%,
Excellent high temperature cleanliness and viscosity index of 92
A base oil having the above properties was obtained. 2 shown in Table 1
Refined oils No. 2A-D can be used as industrial lubricant base oils.

[Table] Comparative Example 1 The raw material oil used in Example 1 was refined as follows using the furfural solvent extraction device and hydrorefining device used in Example 1 based on the flow shown in Figure 1 to obtain lubricant base oil No. 7. Obtained. Solvent extraction and purification solvent; furfural solvent amount: 230% (furfural/oil) = 230/100 parts by volume) Raw material oil feed rate: 50.3 Kl/Hr Temperature: 95°C Raffinate yield: 62.7 vol% The refining results are as follows: It was as follows. Refining energy: 310×10 ³ kcal (per 1 Kl of refined oil) Properties of refined oil: Sulfur content: 1.04 wt% The obtained solvent refined oil was then hydrorefined. Catalyst: Same as Example 1 Reaction temperature: 330°C Hydrogen partial pressure: 98.9Kg/(G) LHSV: 1.0hr ^-1 Oil feed rate: 34.4Kl/Hr The above conditions were set at a desulfurization rate of 60%. can be,
The sulfur content in the obtained hydrotreated oil was 0.45 wt%. Next, solvent dewaxing was performed in the same manner as in Example 1 to obtain lubricating base oil No. 7. The properties of the oil are shown in Table 2. As shown in Table 2, base oil No. 7 obtained by harsh solvent extraction and mild hydrorefining without mixing is different from base oil No. 3 obtained by the method of the present invention.
Although it has approximately the same sulfur content as No. 4, it has a low viscosity index and lacks high-temperature oxidation stability and cleaning performance. Moreover, the yield in solvent purification is about 5% lower than in Example 1, and the purification energy is 85×
10 ³ Kcal/Kl more is required. Example 2 Lubricant base oil No. 8 shown in Table 3 was created by mixing the first refined oil No. 1A-D 25 vol% shown in Table 1 and the second refined oil No. 2A-D 75 vol%. . A detergent dispersant, antioxidant, etc. were blended with the base oil to create diesel engine oil No. 8D, and a 120-hour continuous test (1G2 test) was conducted using this engine oil using the Caterpillar L-1 engine. , performance tested.
The results are shown in Table 4. Comparative Example 2 Among the hydrorefining conditions shown in Comparative Example 1, the temperature was
The same raw material oil was refined in the same manner as in Comparative Example 1, except that it was purified at 350°C with a desulfurization rate of 90%, and lubricant base oil No. 1 with a sulfur content of 0.11 wt% and a viscosity index of 98 as shown in Table 3 was obtained. I got a .9. The same amount of the same additive as used in Example 3 was added to the base oil to prepare diesel engine oil No. 9D, and the same test as in Example 3 was conducted. The results are shown in Table 4.

【table】

【table】

【table】

[Table] As shown in Tables 3 and 4, the lubricating base oil produced by the method of the present invention has excellent high-temperature detergency, and the diesel engine oil produced by this method also has excellent high-temperature detergency. It turns out that cleanliness in hot parts within the engine is highly desirable.

[Brief explanation of drawings]

Figure 1 shows the conventional manufacturing flow, Figure 2 shows the relationship between sulfur content in lubricant base oil, oxidation stability and cleanliness, and Figures 3 to 5 show the manufacturing flow of the present invention. .

Claims (1)

[Claims] 1. From a lubricating oil fraction containing 2.0 to 3.5% by weight of sulfur separated from paraffin group or mixed group crude oil,
In a method for producing a lubricating base oil having a viscosity index of 90 or more and excellent high-temperature oxidation stability and high-temperature cleanliness, (a) the above-mentioned fraction is treated with a furfural solvent at a raffinate yield of 65 to 80% by volume. A first refined oil containing 1.0 to 1.6% by weight of sulfur is obtained by solvent extraction and refining, and (b) a portion of the first refined oil is heated to a hydrogen partial pressure of 50 to 50% by weight in the presence of a hydrorefining catalyst.
A second product containing 0.03 to 0.10% by weight of sulfur is hydrorefined by contacting under the conditions of 150 Kg/cm ² (cage pressure), temperature 330 to 380°C, and liquid hourly space velocity of 0.5 to 2.0 h ^-1 .
(c) Both refined oils are mixed or mixed and then solvent dewaxed and purified, (d) The first refined oil and the second refined oil are then mixed in a volume ratio of 10:90 to 50:50. A method for producing lubricating base oil, which comprises mixing and adjusting the sulfur content to 0.2 to 0.7% by weight. 2. The method for producing a lubricating base oil according to claim 1, wherein the first refined oil is a mineral oil containing at least 0.3 wt% of sulfide type sulfur. 3. The method for producing a lubricating base oil according to claim 1, wherein the lubricating oil fraction used is a mineral oil having a viscosity of 4 cSt (◎100°C) or more. 4. The method for producing a lubricating base oil according to claim 1, wherein the target lubricating base oil has a viscosity index of 92 to 96 and is a base oil for internal combustion engine lubricating oil. 5. The refined mineral oil obtained after dewaxing the second refined oil is an industrial lubricating oil manufacturing base oil having a viscosity index of 95 or more and containing 0.12 wt% or less of sulfur. Method for producing lubricating base oil.