Use of methane as a fuel and for other purposes:

Use of methane as a fuel and for other purposes:

Methane (CH4) is the simplest alkane, used as a fuel for various use. Apart from methane being principal constituent of natural gas, it is obtained from coal seams (as coal bed methane, CBM) and also it is obtained from bio-mass. At room temperature, methane is a gas less dense than air. Methane's relative abundance and clean burning process makes it a very attractive fuel. Burning one molecule of methane in the presence of O2 (oxygen) releases one molecule of CO2 (carbon dioxide) and two molecules of H2O (water). Methane being gas in ordinary temperature, its transportation and storage is difficult. Methane is a powerful greenhouse gas. Methane is over 20 times more effective in trapping heat in the atmosphere than carbon dioxide (CO₂)

Some methane is manufactured synthetically by the distillation of coal. Coal also contains hydrogen and oxygen, with small concentrations of nitrogen, chlorine, sulfur, and several metals. Coals are classified by the amount of volatile material they contain. Volatile substances released from coal when it is distilled, in addition to methane, include water, carbon dioxide, ammonia, benzene, toluene, naphthalene, and anthracene. In addition, the distillation also yields oils, tars, and sulfur-containing products. The non-volatile component of coal, which remains after distillation, is coke.

At high temperatures (700 to 1100 degree Celsius) in the presence of nickel catalyst, steam reacts with methane to yield CO (carbon monoxide) and H2 (hydrogen). This hydrogen is used for manufacturing of ammonia (NH3). In near future, one of the greatest uses of hydrogen would be for running vehicle by using environment-friendly hydrogen cell technology.

Methane is important for electrical generation by burning it as a fuel in a gas turbine or steam boiler. Compared to other hydrocarbon fuels, burning methane produces less carbon dioxide for each unit of heat released. In many cities, methane is piped into homes for domestic heating and cooking purposes. Methane in the form of compressed natural gas (CNG) is used as a fuel for vehicles, and is claimed to be more environmentally friendly than alternatives such as gasoline/petrol and diesel.

Note: NASA is developing LOX/methane engines as an option for the future rocket engine, as methane is abundant in the outer solar system.