Producing gas-to-liquids fuels (or GTL) involves a process of converting natural gas into liquid, petroleum-based fuels. Unlike syncrudes, GTL products are closer to the final stage of production. They don't need to be processed by a refinery before they are used as fuel. The most widely used method for converting gas to liquid fuels is the Fischer-Tropsch process (F-T synthesis) [source: U.S. Energy Information Administration]. In this process, natural gas is combined with air and then introduced into a chamber along with a catalyst, usually a compound containing cobalt or iron. The catalyst, along with a large amount of heat and pressure, triggers a chemical reaction that forms chains of hydrocarbons. Next, the gas is condensed into liquid. Depending on which catalysts are added, different hydrocarbon structures are created. F-T synthesis can produce diesel fuels, naphtha (which can be processed to make gasoline) and industrial lubricants [source: U.S. Energy Information Administration].
The GTL process in particular has mostly been used to produce diesel fuels, although it can also produce naphtha. GTL, like other Fischer-Tropsch fuels, produces fewer emissions when burned [source: U.S. Environmental Protection Agency]. The chemical separation process creates a more pure fuel, because impurities can be filtered out easily. Another benefit is that the chemical reactions involved in converting the gas to liquids create electricity, steam and water as byproducts. Those resources can either be funneled back into the production to save costs and reduce the environmental impact or sold on the commercial market to make the process more cost effective.