US 3756794 A
Description (OCR text may contain errors)
3,756,794 EMULSIFIED HYDROCARBON FUELS Peter '1. Ford, Chester, England, assignor to Shell Oil Company, New York, N.Y.
No Drawing. Filed July 16, 1969, Ser. No. 842,399 Claims priority, application Great Britain, July 22, 1968, 34,755/ 68 Int. Cl. C10] 1/32 U.S. Cl. 44-51 6 Claims ABSTRACT OF THE DISCLOSURE Emulsified fuel compositions comprising a hydrocarbon fuel as the disperse phase, an emulsifier, water and urea or formamide as an emulsion stabilizer have improved flow and dernulsification characteristics.
This invention relates to emulsified hydrocarbon fuels. More particularly it relates to emulsified hydrocarbon fuels containing a unique water soluble non-ash forming emulsion stabilizer.
A hydrocarbon fuel or its vapor can burn in an uncontrolled manner and therefore is extremely dangerous if it escapes, for example, from a leaking fuel tank. Such a tank can be a fuel tank of an aircraft, a car, a truck or a ship. In order to reduce this hazard, it is possible to decrease the flow and vaporization rate of a hydrocarbon fuel by emulsifying it with water employing a suitable emulsifying agent. Such an emulsion must have good emulsion stability properties and must also be capable of being pumped at low temperatures, for example -29 C.
It has now been found that an emulsified fuel composition consisting essentially of a hydrocarbon fuel as the disperse phase, an emulsifier, water and urea or formamide as an emulsion stabilizer, has good flow properties and demulsification characteristics. The improved properties of the present compositions are attributed in large part to the presence of the Water soluble non-ash forming emulsion stabilizer, i.e., urea or formamide, which unexpectedly have been found to be highly efficacious in imparting stability to the emulsions of the invention. While formamide is less effective than urea, it is still better than many known stabilizers (see Example 11). The stabilizer can be employed in concentrations of from 0.3% to 10% by weight, preferably from 0.3% to by weight, more preferably from 0.3% to 0.7% by weight.
Hydrocarbon fuels which can be used in the present compositions are those suitable for engines of aircraft (for example, jet or turbojet engines), cars (for example, gasoline engines) or trucks or ships (for example, diesel engines). The fuel thus includes diesel, gasoline and kerosene type distillate fuels boiling within the range 20- 400 C. The hydrocarbon fuel component of the composition forms more than 75%, preferably more than 90% and more preferable more than 95% of the total composition by weight. A preferred maximum concentration of the hydrocarbon is 98.5%.
An excessively high proportion of water cannot be incorporated in the fuel. The water may conveniently be present in the range 0.75% to 12% by weight of the total composition, but amounts in the range 0.75% to 3% are preferred.
A wide range of emulsifiers can be employed in the present compositions. An emulsifier or emulsifier mixture 3,756,794 Patented Sept. 4, 1973 having an HLB of 11-16 (see p. 19, I. See. Cosmetic Chemists, December 1948) is preferred.
An example of a very suitable emulsifier is a condensate of an alkylphenol and an alkyleneoxide. The mole ratio of alkyleneoxide to alkylphenol can be 5:1 to 15:1. Examples of the alkylphenol are C alkylphenols, especially octylphenol, nonylphenol or dodecylphenol. Examples of the alkyleneoxide are ethyleneoxide and propyleneoxide. A particularly advantageous emulsifier is a condensate of an octylphenol and ethyleneoxide, for example, one sold under the trade mark Nonidet P or Triton X-l02. The emulsifier can be employed in concentrations of 0.3% to 5% by weight, preferably 0.5% to 1.5%, although an upper limit of 10% is practicable.
In addition to the foregoing, the emulsified fuels of the invention can also contain a water soluble non-ash forming freezing point depressant. Compounds suitable for this purpose include ammonium salts (for example, ammonium nitrate) or polyols (for example, ethylene glycol or glycerol). Ammonium nitrate has been found to be particularly advantageous in the present compositions. The proportion of depressant may be 0.1% to 10% by weight but preferably is from 0.3% to 0.7%. An emulsified fuel comprising both urea and ammonium nitrate in the preferred proportions shows particularly surprising stability.
Supplementary additives can also be present. Examples of these are anticorrosion additives and antistatic additives. Anticorrosion additives may be required particularly in view of the presence of water in the composition of the invention. Trace quantities of, for example, ethylene diamine, have been found useful in reducing corrosion of iron. Glycerol and ethylene glycol are other examples of anticorrosion agents. Proprietary anticorrosion additives such as Lubrizol 541 (dodecenyl succinic acid) may also be employed in appropriate quantities. The amount of anticorrosion agent will usually be up to 1.0% by Weight.
The invention is illustrated by the following example:
EXAMPLE An emulsified hydrocarbon fuel according to the invention (Emulsion I) had the following composition:
Percent weight/volume A second emulsified hydrocarbon fuel (Emulsion II) according to the invention had the following composition:
Percent weight/ volume Aviation turbine quality fuel 96.8 Nonidet P80 0.8
Water 1.0 Urea 0.4 Ammonium nitrate 0.4 Ethylene glycol 0.4 Lubrizol 541 (dodecenyl succinic acid) 0.2
Properties of the above emulsions are given in Table I, which also contains test results relating to the properties of reference emulsions A, D and E prepared in accordance with the invention, and B, C, F, G and H not in accordance with the invention.
Emulsion A: Percent weight/volume Aviation turbine quality fuel 97.0 Nonidet P80 1.0 Water 1.3 Urea 0.6
Emulsion B: Percent weight/volume Aviation turbine quality fuel 97.0 Nonidet P80 1.0 Water 1.0 Ammonium nitrate 1.0
Emulsion Percent weight/volume Aviation turbine quality fuel 97.0 Nonidet P80 1.0 Water 1.5 Ammonium chloride 0.5
Emulsion D: Percent weight/volume Aviation turbine quality fuel 97.0 Triton X102 (octylphenol-ethyleneoxide condensate) 1.0 Water 1.0 Urea 1.0
Emulsion E: Percent weight/volume Aviation turbine quality fuel 97.0 Triton X-102 1.0 Water 1.5 Urea 0.5
Emulsion F: Percent weight/volume Aviation turbine quality fuel 97.0 Triton X-102 1.0 Water 1.0 Acetamide 1.0
Emulsion G: Percent weight/volume Aviation turbine quality fuel 97.0 Triton X-102 1.0 Water 1.5 Ammonium chloride 0.5
Emulsion H: Percent weight/volume Aviation turbine quality fuel 97.0 Triton X-102 1.0 Water 2.0
The above compositions were made up on a percent weight/volume basis, the hydrocarbon and water being measured by volume and the other components by weight.
TABLE I.-EMULSION STABILITY Exposure to Storage air at ambient Freezing Emulsions temperature --29 C. 15 C. 55 C.
I Stable 1 Stable Stable Stable. II do. do. ..d0. Do. A Separated slowlyJ; Separated B Separated 4 Stable C do. do. D Stable 1 Separated E do. (10. F Separated rapidly. Stable B G Separated 4 do? H do. Separated 3 1 Longer than 30 days.
2 After 5 cycles of cooling from ambient temperature to 29 0. maintaining the emulsion at that temperature for a period of time and than allowing it to warm-up to ambient temperature again.
3 After one cycle.
4 Bulk fuel visible at surface Within 2 to 4 hours.
EXAMPLE II To demonstrate the superiority of urea and formamide over known emulsion stabilizers, a series of emulsion compositions were prepared and tested for emulsion stability. Each of the emulsions comprised of 97% vol. aviation turbine fuel, 1% vol. water, 1% vol. Nonidet P80, 0.5% wt. ammonium nitrate together with one of the stabilizers set out in Table II.
I claim as my invention:
1. An emulsified fuel composition consisting essentially of (1) a major amount of a hydrocarbon fuel boiling in the range of 20400 C. as the disperse phase, (2) 0.3% to 5% by weight of an emulsifier, (3) 0.75% to 12% by weight water, (4) 0.3% to 0.7% by weight of urea as emulsion stabilizer and (5) 0.3% to 0.7% by weight of ammonium nitrate.
2. The composition of claim 1 wherein the hydrocarbon fuel is present in an amount of more than by weight.
3. The composition of claim 2 wherein water is present in the amount of 0.75 to 3% by weight.
4. The composition of claim 1 wherein the emulsifier is a condensate of a C alkyl phenol and C alkyleneoxide.
5. The composition of claim 4 wherein the emulsifier is a condensation product of octylphenol and ethyleneoxide.
6. The composition of claim 2 wherein the hydrocarbon fuel is present in an amount of more than by weight.
References Cited UNITED STATES PATENTS 3,458,294 7/1969 Nixon et al 445l 2,716,068 8/ 1955 Fair et a1. 252-70 3,613,372 10/1971 Lissaut 4451 DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant Examiner US. Cl. X.R. 447l; 252312