Emulsified fuel in simple terms refers to the addition of water to fuel oil in such a way that small particles of water are formed in the fuel oil to produce a stable water‐in‐fuel emulsion. The main purpose of diluting fuel oil with small quantities of water is to improve the combustion efficiency by achieving a better heat release rate and to reduce NOx emissions by cooling the combustion.
There is a finite limit to the improvements that can be made to the mixing of fuel and air in the combustion chamber due to the physical limitations of the fuel injector design, the dynamic air flow and the time available for combustion. Nevertheless, emulsified fuel offers a practical method to further improve this mixing of fuel and air without requiring any modifications to the diesel engine.
Burning emulsified fuel is not totally a new application. Emulsified fuel was burnt decades ago in boilers, primarily for the purpose of washing down the furnaces. Although the benefits of burning emulsified fuel were apparent in the reported cleanliness of the furnaces, they were neither identified nor quantified.
One of the pioneers in the development of emulsified fuels is R.V Thompson. He and his team from University of Newcastle Upon Tyne conducted detailed and extensive research work in water-in-fuel emulsion for several years with breakthrough results. Dr. Ng Kok Loon, the founder of Blue Ocean Solutions, was one of the key members of the team.
SECONDARY ATOMIZATION EFFECT OF EMULSIFIED FUEL
The BOS Emulsified Fuel System improves the combustion efficiency by producing stable water-in-fuel emulsions to improve injector fuel atomization.
Smaller fuel droplets will achieve better fuel-air mixture as more fuel-air surface will be available for combustion. Therefore, the key to achieving better combustion is to create a secondary atomization effect by adding water into the fuel. The secondary atomization effect creates even smaller fuel droplets after injection.
The microscopic water particles in the fuel are superheated to around 130°C, under pressure to prevent the water from becoming steam. When the water-in-fuel emulsion is injected into the combustion chamber, the water particles flash off immediately causing a secondary atomization effect that results in a finer fuel mist and better fuel-air mixture for combustion.
Through extensive and comprehensive research, the optimum water content and particle sizes for maximum fuel saving on marine diesel engines has been established: water content of 10% and particle sizes of 2-8 microns.
- BETTER HEAT RELEASE RATE – more complete combustion
- REDUCED EMISSIONS – cooler combustion
- LESS SMOKE – improved appearance
- CLEANER ENGINE – softer soot