Emulsions

• Water in oil emulsions are discussed in the section on Fuel Additives.
• Water itself appears to modify combustion processes in benign ways that reduce NOx formation. But the quantities of water needed are quite large, at around 30% of the volume of the fuel water mixture.
• Modified engines have been successfully run with such fuels, and have achieved NOx reductions of some 30%, and research continues to be pursued.

INDEPTH
Emulsions are not easy to make stable, so there is a choice about whether to mix the emulsion at specialised plant, and carry higher volumes of fuel, or to mix the emulsion just before use, when specialist technology and fairly pure water is needed.

One benefit sought from these technologies is for fuels to flow freely at ambient temperatures, thus avoiding the need for heating throughout the fuel feed processes.