LNG & LPG

LNG and LPG are energy sources. They are flammable, and combustion releases energy. Both are mixtures which are mainly composed of hydrocarbons. Both LNG and LPG are composed of gases, but they are converted to liquid form in order to store and transport easily. So they are stored under high pressurised conditions to maintain it as a liquid. But after vaporized into gaseous state, it is a highly flammable mixture.

LNG (Liquified Natural Gas)

Liquified natural gas is abbreviated as LNG. This is a mixture of hydrocarbons, mainly composed of methane. It also contains small amounts of butane, propane, ethane, some heavier alkanes and nitrogen. LNG is odourless, non-toxic, colourless mixture. LNG is produced from natural gas. In a LNG plant, water, hydrogen sulphide, carbon dioxide and some other compounds (which will freeze under low temperatures) are removed. The environmentally harmful emissions from LNG are higher during the production, storage, and combustion. Therefore, special infrastructure facilities are there in production plants. So one disadvantage of LNG is the high cost associated with storage, transportation facilities, and infrastructure requirements.

LPG (Liquified Petroleum Gas)

Liquified petroleum gas is abbreviated as LPG. This is a mixture of hydrocarbon gases primarily containing propane and butane. Since it mostly contains propane gas, sometime LPG is referred to as propane. It is heavier than air. LPG is a flammable mixture of gases which is used as a fuel in motor vehicles and some other heating appliances (for cooking). LPG readily burns in air which makes it a good fuel for cooking and other purposes. When it is used to power the internal combustion engines in vehicles, LPG is named as auto gas. This is a clean fuel, and upon combustion, it produces fewer amounts of harmful emissions and carbon dioxide (which is a greenhouse gas).

Moreover, it is less expensive compared to gasoline. However, on the negative side, the availability of LPG is limited and also the number of miles a car can run from a full tank of fuel is fewer. So it has lower energy content. LPG is a fossil fuel, so it is produced as a by-product of petroleum refining. Further, it can be prepared by natural gas. LPG evaporates quickly at room temperature and pressure because it has a lower boiling point (which is lower than room temperature). So LPG is supplied in pressurised steel vessels. Leaking of LPG is hazardous. These leakages can be identified due to the odor of LPG. Although naturally LPG is odourless, addition of a stanching agent gives it a distinctive, unpleasant smell.

LNG vs LPG

• LNG mainly contains methane, and LPG mainly contains propane.

• LPG is commonly used in household whereas LNG is not. LNG is mainly used for other energy requirements.

• LNG is produced from natural gas, and LPG is produced from petroleum refining.