US2020290A - Solvent refining of hydrocarbon oil - Google Patents

Description

Patented Nov. 12, 1935 SOLVENT REFININgIBF HYDROC'ARBON Louis A. Clarke, FishkilL N. Y., assignor to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing.

Application November 3, 1933,

Serial No. 696,541

2 Claims.

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

The invention contemplates the treatment and refining of mineral oil with a selective solvent whereby the oil is separated into fractions having desired characteristics.

The invention has particular reference to the extractive treatment of mineral oil with a solvent selected from the low-boiling members of the alkyl acyl derivatives of furan, such as acetyl,

propionyl and butyryl furan. 2-acetyl furan, for

example, has the following chemical structure:

The foregoing solvent liquids are suitable for extracting undesired constituents from mineral oils, and particularly from lubricating oil fractions.

Lubricating oils, such as produced from midcontinent crude, are ordinarily composed of relatively parafiinic constituents, and also relatively non-paraffinic constituents, including naphthenic, aromatic, and unsaturated hydrocarbon bodies. The solvent of my invention is adapted to extract these relatively non-paraninic bodies from the oil for the production of lubricating oil fractions which are of relatively high parafli'nic character, and therefore of relatively higher viscosity index than the untreated oil.

In the application of my invention to the treatment of mineral oils for the production of lubricating oil, one part of the oil is mixed with about two parts of solvent liquid, and this mixture is then subject to agitation and heating in order to effect solution of the undesired constituents of the oil in the solvent. The extent to which the oil is soluble in the solvent will depend upon the nature of the oil as well'as upon the condition of temperature and pressure employed. The conditions of temperature and pressure, as well as the ratio of solvent to oil, may be varied for the purpose of effecting the particular degree of extraction desired. The temperatures employed, for example, may range from about 0 F. to 200 F. or thereabouts.

Upon settling, the mixture separates into two layers, one of which comprises the constituents which it is desired to extract from the oil dissolved in the bulk of the solvent liquid, while the other layer comprises the undissolved and. relatively parafiinic oil in admixture with a relatively small amount of solvent.

The two layers are then separately withdrawn, and the solvent liquid recovered therefrom. If desired, the separated layers may be subjected 5 to treatment with additional quantities of the solvent for the purpose of obtaining a series of fractions of differing characteristics.

In order to illustrate the invention, the following specific example is given in which an oil, 10 derived from mid-continent crude, was extracted with acetyl furan at atmospheric pressure.

The acetyl furan used comprised aproduct with a boiling point of from 338 to 348 F. produced by reacting furoic and acetic acids over 15 manganous oxide at about 750 F. This material was liquid at room temperature.

This solvent was mixed with the oil to be extracted in the proportion of one part of solvent compound to one part of oil, and while main- 20 tained at a temperature of about 75 F., the mixture was permitted to separate into two layers. The resulting raflinate, or substantially insoluble portion of theoil, comprised about 87% of the original oil. The viscosity and viscosity in- 5 dex of the untreated oil and the resulting railinate were as follows:

Untrsmted Raflinate 30 Saybolt universal viscosity at 210 F... 80. 5 74 Viscosity index 51 In some instances, it may be of advantage to carry out the extraction in the presence of a modifying solvent liquid, such as benzol, or a light petroleum naphtha, or a petroleum fraction composed of propane or other similar low boiling 40 hydrocarbons, for the purpose of facilitating the extraction and further controlling the extent thereof.

The lubricating oil distillate may be subjected to the foregoing extraction treatment, either be- 45 fore or after dewaxing, or subsequent to treatment with other solvents or chemicals.

The invention is not necessarily limited to the treatment of lubricating oil fractions, since the solvent may be adapted to the refining and puri- 50 fication of various hydrocarbon or mineral oil fractions, including naphtha, cracked naphtha, kerosene, etc., as well as residual or distillate fractions, or products derived from petroleum or other sources. as

By reference to the acyl derivatives of furan in the foregoing specification and in the appended claims, it is intended to include the isomers in each instance since each species may consist of a mixture of its isomers.

non-parafiinic constituents, including naphthenic, aromatic, and unsaturated bodies, to remove undesired relatively non-parafiinic constituents therefrom, which comprises extractively treatingthe oil with a relatively low boiling member of the series of compounds comprising the aliphatic acyl derivatives of furan of the character of acetyl furan whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

2. The method of refining hydrocarbon oil containing relatively parafiinic and relatively non-paraifinic constituents, including naphthen- 1 ic, aromatic, and unsaturated bodies, to remove undesired relatively non-paraflinic constituents therefrom, which comprises extractively treating the oil with a solvent comprising acetyl furan whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

,- LOUIS A. CLARKE.