Propane (C₃H₈), with three carbon hydrocarbons, is sometimes obtained as a by-product of petroleum refining or natural gas processing.
Propane is not primarily produced but is a by-product of two other processes: natural gas processing and petroleum refining.
Unlike natural gas, propane is heavier than air (1.5 times denser). Liquid propane turns into vapor at atmospheric pressure and appears white due to water vapor forming from the surrounding air.