Processing Magazine

Turning natural gas into diesel fuel

May 10, 2012

NEW YORK — With prices for natural gas so low, and prices for oil-based fuels so high, the idea of building plants to convert natural gas directly into liquid diesel and jet fuel is something more companies are looking into. CNN reports, Shell is currently considering building such a plant along the U.S. Gulf Coast.

Gas-to-liquids plants, as they are known in the industry, cost billions to build. And they need access to cheap natural gas, not only for the four or five years it takes to construct the facility, but over the 20- or 30-year timeframe the plants would operate. The U.S. Energy Information Agency says that with oil at $100 a barrel, natural gas needs to be priced below $6 per million British thermal units for the process to be economic.

The technology is quite similar to making liquid fuels out of coal — a process developed nearly 100 years ago and used heavily by oil-strapped Germany in W.W. II and, later, by South Africa. But it''s only recently been applied to natural gas, which results in a fuel that''s cleaner than if it''s made out of coal.

In a very basic description of the process, natural gas, oxygen and water are fed into a reactor, which uses heat, pressure and catalysts to make a wax. The wax can then be upgraded to diesel, jet fuel and a variety of other refined products. The process cannot easily produce gasoline. But the diesel production might help lower prices for truckers and others that use the fuel.