Natural gas liquids, also called NGL, are widely used as fuel, and in manufacturing petrochemicals and other products. The chief NGL compounds, in order of increasing molecular weight, are ethane, propane, butane, pentane, hexane, and heptane. Chemical manufacturers use ethane in making ethylene, an important petrochemical. LPG is used chiefly as a heating fuel in industry and homes. Pentane, hexane, and heptane are called natural gasoline or condensate.
Refiners blend natural gasoline with other gasoline.
Natural gas liquids are classified as light hydrocarbons. Hydrocarbons, which occur in natural gas and petroleum, are a group of compounds that contain only the elements hydrogen and carbon. All hydrocarbons become liquid under certain combinations of temperature and pressure, depending on their molecular weight. Light hydrocarbons liquefy at lower temperatures and higher pressures than do heavy hydrocarbons. There are two main methods of producing NGL, condensation and absorption.