Lng is liquefied natural gas, lpg is liquefied petroleum gas, the main component is propane, cng is compressed natural gas, and the main components of both are methane. Lng is a liquid, liquefied into gas, and then compressed into compressed natural gas through pressurization, and the two can be converted to each other.

Lng is the abbreviation of English liquefied natural gas. The main component is methane with a specific gravity of 0.65. Lng is colorless, odorless, non-toxic and non-corrosive, and its volume is about 1/600 of the same volume of gaseous natural gas. The weight of LNG is only about 45% of the same volume of water, and its calorific value is 52 mmbtu/t (1mmbtu = 2.52×108 cal). "The natural gas produced in the gas field is purified first, and then liquefied at ultra-low temperature (162℃) to form liquefied natural gas."

Lpg is the abbreviation of English LiquefiedPetroleumGas. The main components of liquefied petroleum gas are propane (above 95%) and a small amount of butane. Liquefied petroleum gas is stored in liquid state in storage tanks under appropriate pressure and is often used as cooking fuel. In foreign countries, liquefied petroleum gas has been used as fuel for light vehicles for many years.