TERMS USED IN FUEL

            

Density

This is the mass per unit volume and is generally given as kg/m³ at 15^OC and is specifcially given as that found in a vacuum. These characteristics are important to allow proper description for commercial transactions and also for preparation ( say purifiers) and in use ( main engines). Density may also be given as specific gravity. 

Viscosity

This is a measure of a fuels resistance to flow or more specifically resistance to shear of adjacent molecules. It governs the method of handling, storage, pumping and combustion. The viscosity of a fuel generally varies considerably with temperature and this is particularly the case with resif=dual fuels. 

Flash Point

This is the temperature of a fuel at which sufficient vapour is given off that momentary ignition occurs if an external flame is introduced. This temperature si quoted as Open or Closed. The closed temperature is about 15'C lower than the open 

Pour Point

This is the temperature at which and below wax crystals begin to form. This is important for pumping 

CLOUD POINT

Temperature at which wax begins to crystallise.

CARBON RESIDUE

          Tendency of the fuel to form carbon deposits under very high temperature in the absence of air.

TOTAL EXISTANT SEDIMENT

 Combination of in-organic and hydro carbon sediments existing in a fuel. 

 

Specific energy or Calorific value 

This is the total energy chemically available by a unit fuel. Heavier fuels tend to have lower values. 

Ignition quality

Is a property related to distillated fuel and is that quality of combustibility during combustion process in a diesel engine, which causes ignition delay. It is a relative value on a scale of 0 to 100, known as cetane number. Paraffin as non-combustible substance is taken for zero and Cetane (C16H34) a highly combustible substance is taken as 100.