Diesel fuel emulsion

An emulsifier composition for use in fuel emulsions, which composition comprises:

• (i) a polyester non-ionic surfactant having hydrophilic repeating units comprising polyoxyalkylene and hydrophobic repeating units comprising long chain hydrocarbon residues;
• and
• (ii) at least one component selected from:
• a) fatty acid esters or partial esters of polyhydric alcohols;
• b) alkoxylated fatty acid esters or partial esters of polyhydric alcohols;
• and
• c) alkoxylated primary alcohols;
• wherein:
• 1) the polyester non-ionic surfactant has a hydrophile/lipophile balance value of between 4 and 8, and
• 2) the emulsifier composition has an hydrophile/lipophile balance value of at least 4 and not more than 8;
• 3) the fuel emulsion is stable for at least 10,000 minutes.

A method of making a fuel emulsion which comprises a water-in-diesel emulsion containing an emulsifier composition in an amount effective to form a stable emulsion, the emulsifier composition comprising:

• (i) a polyester non-ionic surfactant having hydrophilic repeating units comprising polyoxyalkylene and hydrophobic repeating units comprising long chain hydrocarbon residues;
• and
• (ii) at least one component selected from:
• a) fatty acid esters or partial esters of polyhydric alcohols;
• b) alkoxylated fatty acid esters or partial esters of polyhydric alcohols;
• and
• c) alkoxylated primary alcohols;
• wherein:
• 1) the polyester non-ionic surfactant has a hydrophile/lipophile balance value of between 4 and 8, and the emulsifier composition has an hydrophile/lipophile balance value of at least 4 and not more than 8;
• 2) said method comprises, in a single mixing operation, introducing diesel and the emulsifier composition and then water into a mixing vessel whilst subjecting the mixture to high shear mixing at a speed and for a period sufficient to create the emulsion;
• and
• 3) the fuel emulsion is stable for at least 10,000 minutes.