US2413482A - Diesel type fuel - Google Patents

Description

Patented Dec. 31, 1946 UNITED STATES PAT NT orncs DIESEL TYPE FUEL Benjamin '1. Anderson, Long Beach, and

Marcellus T. Flaxman, Inglewood, Calif., asslgnors to Union 011 Company of California, Los Angeles, Calif., a corporation of California No Drawing. Application April 2t, 1942, Serial No. M6348 ll cram. (oi. 44-58) This invention relates primarily to fuels for Diesel engines and the like and is a continuation in part of our previous application Serial No. 415508, now latent No. 2,397,771, dated April 2, ltd-8.

Recent productions of Diesel fuels have in.- volved heavy treatment of the Diesel fuel stocks to produce highly refined fuels having high octane rating and relative freedom from objectionable exhaust odors as distinguished from earlier Diesel fuels of objectionably low octane number and bad exhaust odor. In this application exhaust odor refers to the odor of the exhaust gases from an engine operating on the fuel in question. It has been discovered that in accomplishing these advantages, the heavy treatment has removed from the fuel, constituents which heretofore apparently have imparted lubricating qualities whereby the fuel itself lubricated the moving parts of the system used in feeding the Diesel fuel .to the engine. This removal of lubricating constituentshas resulted in seizure or excessive wear of pump and injector parts. Furthermore use of lower viscosity fuels in certain types of Diesel engines has introduced a similar lubrication problem. The particular object of this invention is to produce Diesel fuels of low viscosity and well refined Diesel fuels with high octane numbers and good exhaust odor, which at the same time will contain constituents presenting necessary lubricating qualities.

Briefly,the present invention resides in the addition to a low viscosity or highly refined Diesel engine fuel of certain materials which impart adequate lubricating properties.

The additive materials of the invention comprise organic oil-soluble" lubricity agents substantially free from objectionable corrosive characteristics, and from wear-promoting characteristics, and from the characteristics of leaving objectionable residues under the conditions of use.

These lubricity agents include the herein described preferred naphthenlc acids and phenolics I containing substituents of the types including amino, nitro, halide, sulfide, oxide, and hydroxyl groups, where the agent possesses the above indicated requirements. These discoveries could be applied also to fuels containing gasoline fractions for use in any type of internal combustion engine where lubricity characteristics in the fuel would be desirable; and the term Diesel type fuel" as used in the claim may be taken to include such gasolines or gasoline fractions.

In practicing the invention, the Diesel fuel is produced by any well-known or preferred refining method to yield a product of good exhaust odor as indicated above and having a desirably high octane number in the order of 50 or above. Such 9. Diesel fuel may for example be prepared by the recognized refinery procedure of fractional distillation to obtain the desired boiling range with subsequent solvent treatment of the correct boiling range material or by the solvent treatment of a wide boiling range out and the subsequent redistillatlon and fractionation into the lie-- sired boiling range or by any procedure recognized in the art for the preparation of such Diesel fuel. Having obtained the Diesel fuel of desired refinement, there is added to the fuel a small quantity of above indicated additive material.

As examples of the additive materials which are adapted to restore to the Diesel fuel at least sufficient of the lubricating qualities removed by the heavy treatment and to impart lubricating values to low viscosity fuels, the following are described. Acidic materials from petroleum fractions Petroleum fractions, particularly those from naphthenic type crudes as distinguished from parafllnic type crudes, and boiling above 300 F.,

contain appreciable amounts of caustlc-extractable material which is largely of two types, namely naphthenic acids and phenols. The latter usually consist predominantly of higher homologs of phenol and are characterized by a lower degree of acidity than that of the naphthenic acids of similar boiling range. Advantage is taken of this fact in the usual methods of separation of these two materials. For example, naphthenic acids suitable for the purposes of our invention were prepared by extracting kerosene, Diesel and gas oil fractions from a California crude oil with caustic soda solution. Partial neutralization of the mixed caustic extracts from the.

above three fractions to a pH of about 8 liberated the bulk of the phenols-as anoily upper layer, which was removed by decantatlon. It has also been found feasible to remove this layer by ex-.

" furic acid, and re-extracting the naphthenic acids from the light naphtha with caustic. This caustic extract was then acidified to release an oily upper layer of "semi-refined naphthenic acids, which was separated and distilled to obtain a small amount of light oil (probably entrained in the extraction process), naphthenic acid distillates of various molecular weights between 170 and about 300 and a naphthenic acid bottoms fraction consisting principally of higher molecular weight acids, 1. e., over 300 and up to about 500 or higher. It has been found that all of. these naphthenic acid fractions possess the property of imparting lubricating value to Diesel fuels deficient in lubricating quality, but that in general the acids of higher molecular weight are preferred. F'or example, an additive prepared from the bottoms fraction from the naphthenic acid distillation described above had the following characteristics Viscosity, Saybolt Universal at 210 F 157 seconds Average molecular weight; About 380 The above material in a. proportion of 0.07% by' weight was added to a low viscosity Diesel fuel which was then used, in a pump of a Diesel engine of the Cummins type. There was no sign of failure or excessive wear in any part of the pump in over six hours of operation; whereas, using the same fuel without the additive under the same conditions, the fuel pump failed because of seizure in forty minutes. Furthermore, the distributor discs and gear pump teeth were found to be heavily galled on examination after failure. Road tests on various types of Diesel engines have also shown that where injectors may show excessive wear in 25,000 miles of operation and pump parts may fail because of seizure in a few minutes of operation with no additive in the fuel, mileages in excess of 50,000 miles without indications of excessive wear or failure have been obtained by the use of 0.1% of the above additive in the fuel.

Additives prepared by extraction of heavier gas oil and lubricating oil fractions whether taken as bottoms or overhead fractions in the 4 distillation have been found to be very effective. The naphthenic acid distillates of lower molecular weight have also been shown, to be effective additives, the "phenols described above have been found to have some beneficial effect and the crude acids and mixtures ofnaphthenic acids and phenols are also effective.

Other-additives of value for our purposes comprise acidic materials of paragraphs above which contain a substituent group such as a nitro, amino, halogen, or hydroxyl; and soaps or esters of the acidic material.

Limitations must be placed on the charactertics of the above additives'in many special cases. Theymust be soluble, that is, they must dissolve or at least form very stable dispersions in the fuel under the conditions of use; they. must be substantially non-corrosive to all engine parts with which they come in contact; they should provide a type of lubrication, of moving parts of the engine with which they come in contact which will not only prevent seizure but prevent excessive rates of wear or erosion; and they must leave no objectionable residue on injector tips,

'etc. These factors may eliminate certain additives for specific applications. For example certain relatively strong organic acids may introduce corrosion problems; certain chlorinated products having value as additives for extreme pressure lubricants in preventing seizure may accelerate wear; and many soaps and also materials which are effective only in relatively large amounts, such as 1% or over, may leave objectionable residues on some types of injector tips, filters and the like. Such materials may fall under the broad claim, however, since in particular Diesel engines certain of the above limitations may not apply.

It will be obvious to those skilled in the art that numerous modifications may be employed without departing from the scope of the following claim.

We claim:

A highly refined Diesel type fuel otherwise deficient in lubricating quality containing a small proportion of a lubricity agent soluble in said fuel, said proportion of lubricity agent being sufficient to impart lubricating characteristics to the fuel but being in an amount less than about 1%, said lubricity agent comprising an extract from a petroleum fraction boiling above about MARCEILUS T. FLAXMAN. BENJAMIN T. ANDERSON.