Natural gas primarily consists of methane, including also ethane, propane butane and carbon dioxide, nitrogen, helium and hydrogen sulphide.
When natural gas is free of hydrocarbons (pure methane) is also called dry gas. Natural gas consisting of hydrocarbons apart from methane is called liquid natural gas. Natural gas is colorless and odorless, and its artificial odor helps leakage to be detected. Natural gas belongs in the second family of gaseous fuels and is lighter than air, having specific gravity of 0.59.
Natural gas burning, compared to other fossil fuels, has less harmful effect on the environment, since it emits less carbon dioxide for every energy unit produced. Following renewable energy sources, natural gas is the cleanest source of primary energy, having less emitted pollutants than conventional fuels.
