Mixtures of bitumen and water, are cheap fuel alternatives for combustion engines. There are, however, several problems that have to be solved before these fuels can be applied in high-speed diesel engines. These are:
emulsion break up due to high temperature or high shear stress in the injection system
high content of heavy metals
high emissions of particulate matter and PAH
This investigation deals with the problem of separation due to high shear stress in the injection system. It is shown that the viscosity of the injected fuel can be used to estimate whether the emulsion has separated or not.
The method is applied to evaluate the results of injection experiments where the limits of the temperature and injection pressure/shear stress of a bitumen/water emulsion in an injection system are investigated.
Since 1998 there has been activities on applying bitumen/water emulsions (b/w emulsions) as fuels for diesel type engines going on at The Technical University of Denmark, Dep. of Mechanical Engineering. This is enhanced by the attractive price and the huge amount of fuel that will become available. At present b/w emulsions are applied to some extend in boilers. In Denmark we have 1 major power plant, Asnaes, which is based on burning Orimulsion®, which is a b/w emulsion. The next natural step will be to apply the fuel for stationary diesel engines in CHP (Combined Heat and Power) plants. However, if we can apply b/w emulsion fuels to high-speed diesel engines, and do it in an environmentally friendly way, we have fuel for the World's car fleet for many more years.