US2132350A - Solvent refining of hydrocarbon oil - Google Patents

Description

Patented Oct. 4, 1938 UNITED STATES PATT FFIQE Louis A. Clarke, Fishkill, N. Y., assignor to The Texas Company, New York, N, Y., a corporation of Delaware No Drawing. Application June 5, 1937, Serial No. 146,587

2 Claims.

This invention relates to refining hydrocarbon oil, and more particularly to refining mineral oil by solvent extraction.

The invention contemplates the solvent ex- 5 traction of hydrocarbon oil with a selective solvent comprising resorcinol monoacetate to separate the oil into fractions having different characteristics.

I have discovered that resorcinol monoacetate is particularly suitable as a solvent refining agent for mineral oil, and especially for the refining of lubricating oil fractions derived from petroleum.

I have also discovered that this solvent, when used for treating mineral lubricating oil, permits obtaining a high yield of high viscosity index oil having a good color as well as other desirable characteristics. In this respect, it is superior to many of the known selective solvents; that is, it is possible to obtain high viscosity index oil of good color without substantially sacrificing the yield.

Treatment of the oil with the solvent may be effected by stage or continuous countercurrent contact. In either case, the mixture of oil and solvent is separated into extract and raflinate phases. The extract phase comprises the socalled naphthenic or low viscosity index constituents of the oil dissolved in the main body of the solvent, While the raffinate phase comprises the so-called parafiinic or high viscosity index constituents of the oil mixed with a small portion of the solvent.

The two phases are separated, and the solvent removed therefrom by distillation or by some other means, for example, washing or displacing the solvent from the oil by contact with some other liquid or solvent.

As a specific example, a lubricating oil distillate obtained from Mid-Continent crude, and having the tests indicated below was extracted with resorcinol monoacetate, using three parts of solventto one part of distillate, and at a temperature of about 237 F. The mixture was separated into extract and rafiinate phases, and the rafiinate phase, upon removal of the solvent liquid, comprised about 88% by volume of the original distillate.

The tests on the distillate before extraction, and on the resulting rafiinate oil, were as follows:

50 Distillate Raffinate From the foregoing, it is observed that a relatively high yield of raflinate was obtained, namely, 88%, having a viscosity index of 70, as compared with a viscosity index of 5'7 for the original distillate.

Oil of still higher viscosity index, of course, can 5 be obtained by altering the solvent proportions and the extraction temperature, in which case a somewhat lower yield of raffinate, corresponding .to the higher viscosity index, would be obtained.

It is, therefore, contemplated that extraction temperatures, either below or above that' specified above, may be used. Likewise, the solvent dosage may be varied as, for example, from one to four parts of solvent to one of oil. These factors can be varied, depending upon the nature of the oil undergoing treatment as well as upon the degree of extraction desired.

While a distillate oil has been referred to above in the specific example, it is, of course, contemplated that residual fractions may also be treated with the solvent. The solvent is also useful in the extractive treatment of other petroleum fractions as, for example, naphtha, kerosene, etc.

When treating lubricating oil stock, the oil may be diluted with a suitable diluent such as a lowboiling petroleum hydrocarbon, and the dilute mixture subjected to extraction with the solvent.

Obviously, many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. In the refining of hydrocarbon oil containing 35 relatively parafi'inic and relatively non-paraflinic constituents to separate the oil into fractions re- 4 spectively rich in paraihnic and non-parafiinic constituents, the method which comprises mixing the oil with a selective solvent comprising resorcinol monoacetate, forming anextract phase containing non-paraifinic constituents dissolved in the solvent and a rafiinate phase comprising parafiinic constituents of the oil, and separating the two phases.

2. The method of treating mineral lubricating oil containing relatively parafiinc and relatively non-paraifinic constituents to separate the oil into fractions respectively rich in paraffinic and nonparafilnic constituents comprising mixing the oil with a selective solvent comprising r-esorcinol monoacetate, forming an extract phase containing non-paraffinic constituents dissolved in the solvent and a rafiinate phase comprising paraffinic constituents of the oil, and separating the two phases.

' LOUIS A. CLARKE.