Electrical Conductivities of Kerosene

Electrical Conductivities of Kerosene

Kerosene jet fuel typically has 50 pS m-1 conductivity. Although the conductivity is an underlying characteristic of petroleum liquids, there is an inconsistency on the recommended procedure of conductivity measurement. Often a static dissipator additive (aka. as a conductivity improver) is used to increase the electrical conductivity so as to prevent the ignition from an electrical discharge during aircraft refueling. Some specifications require a conductivity as high as 600 pS m-1 in which case the static dissipator additive has to raise the conductivity by up an order of magnitude. The limit on the amount of static dissipator additive is 3 milligrams per liter of fuel. This is because amounts any higher would interfere with fuel tank level measurements by capacitance. A widely used static dissipator additive is Stadis 450, manufactured by Octel, the active ingredient of which is dinonylnaphthylsulfonic acid (DINNSA). Pour point depressant additives, being non-ionic, do not affect the capacitance.

lll

Tables of values for the refractive indices of liquids give values of typically 1.448 for the refractive index of kerosene.

Kerosene is a low viscosity, clear liquid formed from hydrocarbons obtained from the fractional distillation of petroleum between 150 and 275 °C (300 and 525 °F), resulting in a mixture with a density of 0.78–0.81 g/cm3 (0.45–0.47 oz/cu in) composed of carbon chains that typically contain between 10 and 16 carbon atoms per molecule. It is miscible in petroleum solvents but immiscible in water.

We saw in our discussion of the refractive index of gasoline in the previous chapter that when gasoline is contaminated with kerosene the refractive index can provide a measure of the degree of contamination. This idea was taken further when gasoline-kerosene blends in the composition range pure gasoline to pure kerosene were examined for refractive index. Up to a kerosene content of 5% balance gasoline, the refractive index is indistinguishable from that for the neat gasoline which is 1.418. With greater amounts of kerosene, there is a rise to 1.425 at 30% kerosene and to 1.440 at 100% kerosene. We note in passing that the kinematic viscosity of the blends studied rises from 1.0 to 2.2 CST across the composition range.

Pure mineral oil is a very good insulator. The conductivity of petroleum liquids measured by DC methods is time-dependent, and it also depends upon electrode configuration and applied voltage. Petrol, Diesel fuel, and kerosene are all mineral spirits and are also good insulators, but some of the additives and impurities tend to make then slightly conductive. Kerosene is widely used to power jet engines of aircraft (jet fuel) and some rocket engines and is also commonly used as a cooking and lighting fuel, and for fire toys such as poi. World total kerosene consumption for all purposes is equivalent to about 1.2 million barrels (50 million U.S. gallons; 42 million imperial gallons; 190 million liters) per day.

Share This Post