A Texas company says that it has developed a cheaper and cleaner way to convert natural gas into gasoline and other liquid fuels, making it economical to tap natural-gas reserves that in the past have been too small or remote to develop.
The company behind the technology, Dallas-based Synfuels International, says that the process uses fewer steps and is far more efficient than more established techniques based on the Fischer-Tropsch process. This process converts natural gas into syngas, a mixture of hydrogen and carbon monoxide; a catalyst then causes the carbon and hydrogen to reconnect in new compounds, such as alcohols and fuels. Nazi Germany used the Fischer-Tropsch process to convert coal and coal-bed methane into diesel during World War II.
A Synfuels gas-to-liquids (GTL) refinery goes through several steps to convert natural gas into gasoline but claims to do so with better overall efficiency. First, natural gas is broken down, or “cracked,” under high temperatures into acetylene, a simpler hydrocarbon. A separate liquid-phase step involving a proprietary catalyst then converts 98 percent of the acetylene into ethylene, a more complex hydrocarbon. This ethylene can then easily be converted into a number of fuel products, including high-octane gasoline, diesel, and jet fuel. And the end product is free of sulfur.
“We’re able to produce a barrel of gasoline for much cheaper than Fischer-Tropsch can,” says Kenneth Hall, coinventor of the process and former head of Texas A&M University’s department of chemical engineering. Hall says that a Fischer-Tropsch plant is lucky to produce a barrel of gasoline for $35 but that a much smaller Synfuels refinery could produce the same barrel for $25. Under current fuel prices, such a plant could pay for itself in as little as four years, the company says.
Texas A&M University licensed its approach to Synfuels and partly owns the company, which has been operating a $50 million demonstration plant in Texas since 2005 and says that it is close to signing a deal for its first commercial refinery near Kuwait City.
Synfuels president Tom Rolfe says that the company has developed some proprietary components and catalysts, but he adds that much of the approach is based on off-the-shelf technologies. He says that Synfuels’ main advantage is the efficiency by which it breaks down and reassembles hydrocarbon molecules. “Nobody has achieved as high a conversion rate of natural gas into acetylene as we have,” Rolfe says.
Ali Mansoori, a professor of chemical engineering and physics at the University of Illinois at Chicago, says that the process seems far less complicated than those found in a Fischer-Tropsch plant. “The numbers reported for conversion efficiency and selectivity look quite promising,” he adds.
But Synfuels isn’t alone in trying to make GTL more economical. Gas Reaction Technologies, a spinoff from the University of California, Santa Barbara, has developed a process that converts natural gas into bromine-based compounds that are later converted into liquid fuels.