Chemical Engineering - Petroleum Refinery Engineering - Discussion

Aromatic is right answer because aromatic contributes smoke, hence removal of aromatics increases the smoke point. Naphthenes with side chain one inevitably retained to give good illumination. In India, marketable kerosene should possess a smoke point of 18mm.

Lower smoke point aromatic.

Correct answer olefins.

I think by removing olefin here we can also increase the smoke point.

The maximum flame height in millimeters (mm) at which the oil burns without smoking when tested in a standard wick-fed lamp under specified conditions is termed and smoke point.

Smoke point is important because it determines the degree of illumination possible from a given kerosene in a wick-fed lamp. Smoke point is related to the hydrocarbon composition of kerosene - it is highest with paraffins, considerably lower with naphthenes and very much lower with aromatics. The smoke point is also an indication of the tendency to smoke when the flame is smaller than the maximum stipulated size. Smoking under such conditions is usually caused by an inadequate supply of air or by a sudden draught.

Excise/Customs requirements stipulate a minimum flame height of 18 mm mainly to distinguish it from HSD. The Indian customs method for testing smoke point tends to give somewhat lower readings than the standard IP method.