JPS6121511B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing naphthenic lubricant base oil from lubricant crude raw materials obtained from paraffinic crude oil or mixed crude oil. Generally, naphthenic lubricating base oils have a lower viscosity index than paraffinic lubricating base oils, but they have high solubility due to the large number of aromatic rings in the naphthenic rings.
Characteristics include that the deteriorated precipitated carbon is soft.
For this reason, naphthenic lubricating base oils are used for relatively special purposes such as insulating oils, cable oils, refrigeration oils, and compressor oils. Conventionally, this type of naphthenic lubricating base oil is produced through the following steps. First, a special naphthenic crude oil with a very low wax content is selected, and the light components are removed by atmospheric distillation.The resulting atmospheric distillation residue is then subjected to vacuum distillation to produce a light lubricating oil fraction and a medium lubricating oil fraction. Divided into oil fraction, heavy lubricating oil fraction and vacuum residue (asphalt). Each fraction, excluding the vacuum residue, is processed by sulfuric acid treatment, clay treatment, solvent extraction refining method, and if a particularly high quality oil is required depending on the application, refining process such as hydrogenation treatment is performed. Lubricating base oils are produced. However, special naphthenic crude oil tends to be depleted worldwide, and it is becoming increasingly difficult to secure such crude oil in Japan, and it is becoming impossible to stably supply naphthenic lubricant base oil. In order to deal with these situations, various alternatives to naphthenic lubricant base oils are being studied, and one of these is the use of aromatic components of 60% by weight or more obtained during the production of paraffinic lubricant base oils using solvent refining methods. and an extract containing 2% by weight or more of sulfur is hydrogenated at high temperature and pressure in the presence of a special catalyst,
Method for producing naphthenic lubricating base oil
-10082 and Japanese Patent Publication No. 53-47243) have been proposed. However, such a method requires treatment under fairly harsh conditions, such as a two-stage hydrogenation treatment, has economical problems, and does not necessarily yield a lubricating base oil that is fully satisfactory in terms of quality. There are some problems such as: As a result of intensive studies to solve these problems, the present inventors found that the roughinate obtained by treating the extract obtained in the solvent extraction step during the production of lubricant base oil with an extraction solvent again. It has been discovered that an extremely high quality naphthenic base oil can be obtained by passing through a commonly used lubricating oil refining process. The present invention has been made based on this knowledge. That is, in the present invention, a lubricating oil crude raw material obtained from paraffinic crude oil or mixed crude oil is treated in a first extraction zone with an extraction solvent that has a preferential dissolving power for aromatic components. of a roughinate and a first extract, and then treating said first extract in a second extraction zone with an extraction solvent having preferential dissolving power for aromatic components to obtain a second roughinate. and a second extract is obtained, and the second roughinate is purified. The present invention will be specifically described below. The lubricating oil crude raw materials used in the present invention include light lubricating oil fractions, medium lubricating oil fractions, and heavy lubricating oil fractions obtained by vacuum distillation of the atmospheric distillation residue of paraffinic crude oil or mixed crude oil. Alternatively, it is possible to use deasphalted oil from a vacuum distillation residue, or further, hydrorefining or dewaxing of each fraction and deasphalted oil. Generally, it is economically advantageous to apply each fraction obtained by vacuum distillation or deasphalted oil to the present invention. These lubricating oil crude raw materials are introduced into the first extraction step, which consists of a commonly used liquid-liquid extraction device such as a packed bed type, rotating disk type, or centrifugal type, to obtain preferential dissolving power for aromatic components. in countercurrent contact with an extraction solvent having a The extraction solvent used in the present invention that has a preferential dissolving power for aromatic components means a selective dissolving power for aromatic components and components other than aromatic components such as naphthenes, olefins, and other unstable hydrocarbons. It is also a solvent that selectively removes compounds containing nitrogen, sulfur, oxygen, etc., and organometallic compounds. For example, it is a solvent that selectively removes compounds containing nitrogen, sulfur, oxygen, etc. -Methyl-2-pyrrolidone, nitrobenzene, β-β-dichloroether, dimethyl sulfoxide, and the like. These can be used alone or in a mixture of two or more. Furfural and phenols are particularly preferred. This first
The extraction conditions for the extraction process are a temperature of 50 to 140℃;
The amount of the extraction solvent is determined by volume relative to the crude raw material.
The amount is appropriately selected from 0.5 to 5 times. moreover,
In this first extraction step, the extraction solvent is removed from the extracted and separated first roughinate layer and first extract layer to obtain a first roughinate layer and a first extract. At this time, the extraction solvent in the first extract does not necessarily have to be completely removed. The first roughinate layer obtained in this first extraction step is mainly composed of saturated components, and is transferred to the next step and subjected to normal refining treatment to become a paraffinic lubricating base oil. This first
The first extract rich in aromatic components obtained in the extraction step is introduced into a second extraction step, and the extract is subjected to milder conditions than those in the first extraction step, such as lower extraction temperature or less extraction. In addition, the amount of the second liquid can be adjusted by adjusting the amount of the solvent, an extraction solvent that has a low ability to selectively dissolve aromatic components, etc., and a combination thereof.
Perform liquid extraction. Of course, the first extract obtained from the first extraction step may contain an extraction solvent to an extent that does not interfere with obtaining the second raffinate in the second extraction step. Not even. The conditions for this second extraction step are appropriately selected depending on the composition of the crude raw material or first extract. As for the extraction device and the extraction solvent that has preferential dissolving power for aromatic components, those described in the first extraction step can be used.
The extraction solvent used in the first extraction step and the second extraction step may be the same or different. Furthermore, in this second extraction step, the extraction solvent is removed from the extracted and separated second roughinate layer and second extract layer to obtain a second roughinate and a second extract. This second
The second roughinate obtained from the extraction process is
Contains moderate amounts of saturated and aromatic components,
This second roughinate is subjected to commonly used refining treatments such as hydrorefining, solvent refining, dewaxing,
A naphthenic lubricating base oil can be obtained by appropriately combining treatments such as clay and acid washing. These purification treatments preferably include hydrorefining treatment, followed by dewaxing treatment, and if necessary, clay treatment. Hydrorefining treatment can be applied to, for example, nickel, molybdenum, cobalt,
Using a catalyst in which one or more types of tungsten, etc. are supported on a carrier made of alumina, silica, etc., 250
Reaction temperature of ~450℃, reaction pressure of 20~250Kg/ ^cm2 ,
Liquid hourly space velocity of 0.1-3.0hr ^-1 , 100-3000l-H ₂ /l
- It can be processed under the conditions of hydrogen gas supply rate of oil. In the dewaxing treatment, a dewaxing solvent consisting of a mixture of aliphatic ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. and aromatic hydrocarbons such as toluene, benzene, etc. is appropriately added, and the mixture is cooled to about -40 to -10°C. This can be done by removing the wax component. Further, clay treatment can be carried out by adding 1 to 6% by weight of clay to the oil to be treated and treating at a temperature of about 50 to 250°C. In addition, the second extract obtained as a by-product in the second extraction step contains a larger amount of polycyclic aromatic components than conventional extracts, making it extremely suitable as a process oil for rubber processing, etc. It is something. As described above, the method of the present invention is industrially very advantageous in that it is possible to obtain a naphthenic lubricating base oil of extremely high quality, and also to produce a high-quality process oil as a by-product. The specific effects of the present invention will be explained below with reference to Examples and Comparative Examples. Example 1 The light, medium, and heavy lubricating oil fractions obtained by vacuum distillation of the atmospheric distillation residue of Kuwait crude oil and the bright stock fraction, which is an oil obtained by deasphalting the vacuum residue with propane, were used as the first Solvent extraction was performed using furfural under the first extraction conditions in the table. The properties of the first extract obtained in this first extraction are shown in Table 2. The first extract is then added to the second extract in Table 1.
The mixture was extracted with furfural under the following extraction conditions to obtain a second roughinate as an extraction residue. This property is the third
Shown in the table.

【table】

【table】

[Table] From the properties in Table 3, it can be seen that it can be usefully used as a raw material for naphthenic lubricating oil base oil. In particular, it is clear that naphthenic lubricating base oils have a sufficient ability to solve the problem due to the low aniline points shown in Table 3. Furthermore, the nitrogen content, which has an adverse effect on stability, is significantly reduced compared to the first extract. Example 2 The medium-quality second roughinate obtained in Example 1 was
Hydrogen purification treatment was carried out under the conditions in the upper column of the table, and then solvent dewaxing treatment was carried out under the conditions in the lower column of Table 4. Table 5 shows the properties of the medium naphthenic lubricating base oil thus obtained. Further, as a comparative example, the first extract of the medium fraction obtained in Example 1 was subjected to the same treatment. The results are also shown in Table 5. For reference, the fifth
The table also lists the properties of commercially available naphthenic lubricant base oils.

【table】

【table】

[Table] Pass Fail Pass Sludge generation As is clear from Table 5, the oil of the comparative example in which the first extract was subjected to hydrorefining treatment and dewaxing treatment cannot be used as a naphthenic lubricant base oil. In comparison, it can be seen that the refined oil of Example 2 has properties and composition that are equivalent to or better than those of commercially available products. Example 3 White clay was added to the medium naphthenic lubricating base oil obtained in Example 2 in an amount of 3% by weight based on the base oil, and clay treatment was performed at 70°C for 1 hour. This clay treated oil was evaluated as a refrigerating machine oil. The results are shown in Table 6 together with the evaluation results of commercially available refrigerating machine oil.

[Table] As is clear from Table 6, by using the naphthenic lubricating base oil obtained by the present invention,
The refrigerant coexistence stability is higher than that of commercially available products, and the critical melting temperature is also comparable to that of commercially available products, making it possible to produce extremely high quality refrigerating machine oil.

Claims (1)

[Claims] 1. A lubricating oil crude raw material obtained from paraffinic crude oil or mixed crude oil is treated in a first extraction zone with an extraction solvent that has preferential dissolving power for aromatic components, and A second raffinate and a second A method for producing a naphthenic lubricating base oil, which comprises obtaining an extract and refining the second roughinate.