More information about the combustion process
Innovations in engine design, like turbo charging and direct injection, have been steadily improving engine efficiency. However, today’s fuels have difficulty meeting the requirements of modern engines. This is mainly due to the deterioration in fuel quality.
Deterioration of marine fuel quality
In the 1950's, refineries processed crude petroleum by atmospheric distillation, producing straight run distillates and residual fuels. Since then, the quality of marine fuels has deteriorated as catalytic cracking has become standard and modern marine fuels, although their caloric value has remained the same, have poor combustion characteristics.
The catalytic prosess
Petroleum based liquid fuels contain many hydrocarbons. To convert these fuels into energy, combustion must take place. The result of a complete combustion is water and carbon dioxide. Incomplete combustion produces carbon monoxide, soot and tar.
Small and light hydrocarbon molecules, like those found in gas and naphtha, burn easily. The large and heavy hydrocarbon molecules in residual fuel oil are not easily ignited, so they need a higher temperature to achieve complete combustion. In the combustion process, creation of free radicals affects the speed of combustion. Thermal cracking occurs in molecules when a sufficient temperature is reached. The components that are created during thermal cracking are extremely reactive and immediately seek to combine with oxygen atoms. This oxidation releases heat, which leads to further thermal cracking.
A chain reaction is thereby created.
The MERGI Combustion Catalyst improves the ignition quality of fuels, so releasing more energy, reducing hydrocarbon residues and producing cleaner emissions. For instance, the catalyst is designed to reduce ignition delay and improve combustion efficiency. Better combustion leads to cleaner piston rings allowing a tighter fit between rings and liner.
MERGI includes components that undergo thermal cracking at a considerably lower temperature (approximately 200oC) than hydrocarbon molecules. The concentration of free radicals is increased in an early stage of the ignition process. This in turn improves the combustion process, causing a far more intense combustion once the oxidation begins. The result is
a more complete combustion of the fuel.
This increase in temperature allows the oxidation of soot and tar (hydrocarbons with a low content of hydrogen) which otherwise would remain to form deposits in the engine , or to be expelled with the exhaust gasses as pollution. Complete combustion reduces the carbon monoxide and increases the heat/energy released from the fuel.
The increased temperature also improves the condition of the valves and the piston rings by burning off soot and carbon deposits and so improving compression. The reduced cylinder leakage improves the effectiveness of the engine and reduces the amount of fuel consumed.