The discovery of Coal Oil

Oil is now at US$140 per barrel and steady. THe pressure is on to find viable sources of alternative energy. Recently, scientists have announced what may be a new end-run around the oil problem: producing diesel fuel from coal, natural gas, and organic material. Researchers say they have developed a way to shuffle the carbon atoms derived from cheap fuel sources like coal to form more desirable combinations, such as ethane gas and diesel fuel. The synthetic diesel "is much cleaner burning than conventional diesel, even cleaner burning than gasoline," said Rutgers University chemist Alan Goldman.

Nazi Germany

The technology might one day wring more diesel fuel and ethane gas from hydrocarbon byproducts produced by oil refineries. But the new chemistry's greatest potential may be as a follow-up to an 80-year-old technology known as Fischer Trospch (FT) synthesis. Developed by German scientists Franz Fischer and Hans Tropsch in the 1920s, FT synthesis converts carbon from coal, natural gas, or wood into hydrocarbons, including propane-like gas and diesel fuel. Nazi Germany used the technique during World War II to manufacture synthetic fuel from coal, churning out 124,000 barrels a day by 1944.

Today oil-poor South Africa uses FT synthesis to distill most of the nation's diesel from its extensive coal deposits. One downside to the process, however, is the output of so-called mid-size hydrocarbons—molecules with 4 to 8 carbon atoms—which can't be used as fuel. Hydrocarbons consist of hydrogen and carbon atoms. The number of carbon atoms (anywhere from 1 to, say, 99) determines whether a particular hydrocarbon is a gas, liquid, or solid and whether it's the proper weight to burn as fuel. The breakthrough could deliver U.S. energy independence.

Key to Energy Independence?

In the U.S. the governors of Pennsylvania and Montana, both coal-rich states, have touted FT technology as a future source of homegrown diesel fuel. Last September, Pennsylvania governor Edward Rendell said his state's government would buy fuel from a planned FT plant in the state designed to convert waste coal from mining operations into low-sulfur diesel.

"When oil was $20 a barrel, it really wasn't considered economical," Goldman, the Rutgers University chemist, said. But today's high oil prices are now tipping the scales in favor of alternative fuels.

Environmental Impact

One thorny issue is the net environmental impact of coal-based synthetic fuels. According to the U.S. Environmental Protection Agency, FT fuels are cleaner burning than petroleum-derived products, producing fewer particulates and less dangerous nitrogen oxide.

But as FT fuels burn, they also release carbon dioxide and other greenhouse gases. According to the U.S. Department of Energy's National Renewable Energy Laboratory, coal-based synthetic fuels may produce twice the greenhouse gas emissions of petroleum-based fuels. Experts say one alternative may be the use of carbon collectors derived from animal waste, plants, and other organic material, which trap carbon from the atmosphere.

Key word:

coal oil