Oil additives and compositions

Details Oil additives and compositions Oil additives and compositions

1996-06-19

1998-04-28

Medley, Margaret

Fuel and related compositions

Liquid fuels

Containing organic -c

44394, 44395, C10L 118, C10L 122

Patent

active

057439230

DESCRIPTION:

BRIEF SUMMARY
This invention relates to oil compositions, primarily to fuel oil compositions, and more especially to fuel oil compositions susceptible to wax formation at low temperatures, and to additive compositions for such fuel oil compositions.
Fuel oils, whether derived from petroleum or from vegetable sources, contain components that at low temperature tend to precipitate as large crystals of wax in such a way as to form a gel structure which causes the fuel to lose its ability to flow. The lowest temperature at which the fuel will still flow is known as the pour point.
As the temperature of the fuel falls and approaches the pour point, difficulties arise in transporting the fuel through lines and pumps. Further, the wax crystals tend to plug fuel lines, screens, and filters at temperatures above the pour point. These problems are well recognized in the art, and various additives have been proposed, many of which are in commercial use, for depressing the pour point of fuel oils. Similarly, other additives have been proposed and are in commercial use for reducing the size and changing the shape of the wax crystals that do form. Smaller size crystals are desirable since they are less likely to clog a filter. The wax from a diesel fuel, which is primarily an alkane wax, crystallizes as platelets; certain additives inhibit this, causing the wax to adopt an acicular habit, the resulting needles being more likely to pass through a filter than are platelets. The additives may also have the effect of retaining in suspension in the fuel the crystals that have formed, the resulting reduced settling also assisting in prevention of blockages.
Fuels from vegetable sources, also known as biofuels, are believed to be less damaging to the environment on combustion, and are obtained from a renewable resource. It has been reported that on combustion less carbon dioxide is formed than is formed by the equivalent quantity of petroleum distillate fuel, e.g., diesel fuel, and very little sulphur dioxide is formed. Certain derivatives of vegetable oil, for example rapeseed oil, e.g., those obtained by saponification and re-esterification with a monohydric alcohol, may be used as a substitute for diesel fuel. It has recently been reported that mixtures of a rapeseed ester, for example, rapeseed methyl ester (RME), with petroleum distillate fuels in ratios of, for example, 10:90 by volume are likely to be commercially available in the near future.
However, such mixtures may have poorer low temperature flow properties than the individual components themselves. A measure of the flowability of fuels at low temperature is the cold filter plugging point (CFPP) test, described in "Journal of the Institute of Petroleum" 52(1966), 173 to 185. In one case, described in more detail below, a mixture of equal volumes of a diesel fuel with a CFPP of -6.degree. C. and an RME with a CFPP of -13.degree. C. had a CFPP of only -5.degree. C., while a 90:10 diesel:RME mixture had a CFPP of -4.degree. C., both higher than the CFPP of either fuel alone.
A further problem encountered at temperatures low enough for wax to form in a fuel is the settlement of the wax to the lower region of any storage vessel. This has two effects: one in the vessel itself where the settled layer of wax may block an outlet at the lower end, and the second in subsequent use of the fuel. The composition of the wax-rich portion of fuel will differ from that of the remainder, and will have poorer low temperature properties than that of the homogeneous fuel from which it is derived.
There are various additives available which change the nature of the wax formed, so that it remains suspended in the fuel, achieving a dispersion of waxy material throughout the depth of the fuel in the vessel, with a greater or lesser degree of uniformity depending on the effectiveness of the additive on the fuel.
Although the way in which CFPP depressants and wax anti-settling additives function is not completely understood, there is evidence that their effectiveness depends to a significant extent on mat

REFERENCES:
patent: 3402223 (1968-09-01), Hollingsworth
patent: 3642459 (1972-02-01), Ilnyckyj
patent: 3961916 (1976-06-01), Ilnyckyj et al.
patent: 4211534 (1980-07-01), Feldman
patent: 4364743 (1982-12-01), Erner
patent: 4404000 (1983-09-01), Toyoshima et al.
patent: 4661121 (1987-04-01), Lewtas
patent: 5554200 (1996-09-01), Brod et al.

Affiliated with

Also associated with

Rating

Oil additives and compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Oil additives and compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Oil additives and compositions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1528266