Product - LPG

DEFINITION :
LPG may be defined as those hydrocarbons which are gaseous at normal atmospheric pressure, but may be condensed to the liquid state at normal temperature, by the application of moderate pressures. Although they are normally used as gases, they are stored and transported as liquids under pressure for convenience and ease of handling. Liquid LPG evaporates to produce about 250 times volume of gas. Thus, a large quantity of energy can be packed, stored, transported and used in small containers.

COMPOSITION:
LPG is a predominant mixture of propane and Butane with a small percentage of unsaturates (Propylene and Butylene) and some lighter C2 as well as heavier C5 fractions.

Included in the LPG range are propane (C3H8), Propylene(C3H6), normal and iso-butane (C4H10) and Butylene(C4H8). Commercial LP gases invariably contains traces of lighter hydrocarbons like ethane (C2H6) and ethylene (C2H4) and heavier hydrocarbons like pentane (C5H12).

MANUFACTURE OF LPG:
There are two main sources from which LP gases are produced, namely:

(A) Wet Natural Gas or Associated Gas &

(B) Refinery Operations.

LP gases prepared from wet natural gas consist entirely of "saturated" hydrocarbons i.e. propane and butane .

LP Gases produced from straight distillation process will have "saturated" hydrocarbons i.e. propane and butane (both normal and iso)

LP Gases produced by both cracking and reforming processes will have, in addition to saturated hydrocarbons, some quantities of unsaturated hydrocarbons also ( i.e. propylene and butylene)

LP Gases produced will have impurities like moisture & sulphur compounds like hydrogen sulphide and mercaptans. Moisture may lead to clogging of regulators, valves, etc. and sulphur compounds cause corrosion. Moisture and sulphur compounds are, therefore, removed by suitable treatment at the refinery.

However, to alert the user of LPG in case of a leak takes place, "ethyle mercaptan" which has a distinctive odour is added in minute quantities at the refinery.