Ever since the late 1970s, when President Jimmy Carter launched a drive to develop clean coal technologies, there has been an on-again, off-again national push to develop methods of processing and burning coal that would make it nearly as clean a fuel as natural gas.
Most recently, the coal industry fought especially hard against provisions of the Clean AirAct that require what it considers too-early decisions on how to cut sulfur emissions.For several reasons, virtually none of the new coal technologies will be used to meet the 1995 standards. The best, involving gasification of coal, are costly and require building new plants, a step not contemplated soon by the conservative utility industry, answerable to rate commissions, shareholders and rate payers.
The most promising quick fix, capturing sulfur before burning by mixing coal with a special lime, is still in development.
"High-surface hydrated lime is the closest clean coal technology to commercial use," said John M. Lytle, head of the minerals engineering section of the Illinois State Geological Survey, a pioneer organization in clean coal technologies. "Right now we're trying to interest a lime company in manufacturing 400 tons for a demonstration project. But it would require modification of the lime."
Mr. Lytle has not found takers.
Long range, these technologies will result in startling breakthroughs in reducing worldwide sulfur emissions. Scientists at the Coal Research Center at Southern Illinois University in Carbondale are working on a broad spectrum of problems, from how to break out the sulfur organically locked in coal, to
finding more uses for coal and its byproducts.
At SIU's Coal Development Park in nearby Carterville, scientists work to
break down the surprisingly complex coal compound into its parts. Each part, called a maceral, behaves in a particular way, raising a host of practical possibilities just beginning to be explored.
Other scientists study the ways sulfur is linked to coal, in visible pyrite form, the common fool's gold, or in little understood organic bonds.
"My students and I are conducting research that aims to enable scientists to selectively break the carbon-sulfur bonds present in coal, thus loosening the organic sulfur from the backbone of coal," said Mark J. Bausch, assistant professor of chemistry at SIU. Results are years away, he said.
"Utility companies are going to choose technologies they have seen in operation," said John S. Mead, director of the Coal Research Center. "And that means advanced scrubbing."
Scrubber technology, the cleansing of flue gas in a giant chemical factory built onto a power unit, has been around for a long time.
"The scrubbers of the 1970s cleaned air, but at great cost," said Mr. Mead. "They can be the largest user of electricity in the whole system."
Advanced scrubbers, such as one at the University of Illinois campus in Champaign, have many bugs worked out of them and are more efficient. They work at lower temperatures, resulting in less damage to equipment, and produce gypsum as a byproduct, which can be used to make wallboard instead of sludge.
But they still cost a lot - $6.3 million for the small Abbott plant at the university, and up to $250 million at a major plant - and result in higher maintenance costs. Six operators and three mechanics were added at Abbott, bringing the work force to 49, as a result of switching to coal and scrubbing.
"As a supervisor, I certainly would prefer to use natural gas as a primary fuel," said Donald E. Fortik, who runs the plant. "It's cleaner, and I don't have the environmental problems."