Fuel adulteration is often a secretive operation, which involves mixing higher priced fuel, such as petrol with other cheaply available hydrocarbon fuels or solvents. This changes the composition and physical properties of the base fuel. The basic reason for fuel adulteration is the financial benefit obtained from different taxes imposed on fuels. This in turns boosts the revenue petroleum dealers earn by paying less tax to the government.
In Kenya, kerosene is the main culprit for making adulterated fuel. This is because government subsidies on kerosene make it cheaper than petrol or diesel, because it is the main fuel used by low income earning people for cooking and lighting purposes.
Adulteration occurs for both petrol and diesel fuels. Petroleum adulteration is more harmful in terms of the damage than the diesel adulteration would do to compression ignition engines and its emissions.
Blending kerosene with petrol will primarily result in a fuel with heavier hydrocarbon components contributed by the kerosene and thus a fuel with reduced volatility. It particularly elevates the middle and final evaporation temperatures by the introduction of heavier hydrocarbons in the kerosene. The resulting effect of this is that more polluting hydrocarbons find their way to the atmosphere.
In addition to the emissions, the petrol adulterated with kerosene would make the fuel more susceptible to knock, an abnormal combustion phenomenon in spark ignition engines. When knock is severe and persistent, it may damage the engine components including piston rings and lands, cylinder head gasket, and piston crown.
The economic consequence of fuel adulteration is the loss in tax due to the large scale channelling of subsidised kerosene to the transport sector.
All efforts must be made to eliminate this vice of adulterated fuel, as the practice has adverse consequences on environment, and the general state of the economy.
For this, the government agencies such as the Ministry of Energy, the state-owned National Environmental Management Authority (NEMA), Energy Regulatory Commission (ERC) and Kenya Bureau of Standards (KEBS) should take the matter more seriously and come up with proper strategies to deal with fuel adulteration practices once and for all. The consumers should also be careful and choose more reliable fuel supplier for their own well being.