Natural gas Some of these gases include heptane, pentane, propane and other hydrocarbons with molecular weights above methane (). The natural gas transmission lines extend to the natural gas processing plant or unit which removes the higher molecular weighted hydrocarbons to produce natural gas with energy content between . The processed natural gas may then be used for residential, commercial and industrial uses. Natural gas flowing in the distribution lines is called mid-stream natural gas and is often used to power engines which rotate compressors. These compressors are required in the transmission line to pressurize and re-pressurize the mid-stream natural gas as
Compressed natural gas the end user. CNG is being experimentally stored at lower pressure in a form known as an ANG (adsorbed natural gas) tank, where it is adsorbed at 35 bar (500 psi, the pressure of gas in natural gas pipelines) in various sponge like materials, such as activated carbon and MOFs (metal-organic frameworks). The fuel is stored at similar or greater energy density than CNG. This means that vehicles can be refueled from the natural gas network without extra gas compression, the fuel tanks can be slimmed down and made of lighter, weaker materials. Compressed natural gas is sometimes mixed with