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DOE funds coal-cleaning research

By Susan Trulove

Spectrum Volume 17 Issue 09 - October 20, 1994

The U.S. Department of Energy (DOE) will award two grants totaling $1.3 million for coal-cleaning research to the Virginia Center for Coal and Minerals Processing at Virginia Tech, maintaining the university's capabilities as one of the world's premier academic laboratories for advanced coal preparation.

Congressman Rick Boucher announced the awards at a press conference at the Virginia Tech Corporate Research Center last week.

The first new grant will be added to last month's $250,000 federal research award to the Appalachian Clean Coal Technology Consortium, a partnership of Virginia Tech, the University of Kentucky, and West Virginia University.

The new research efforts will become part of the DOE's Fossil Energy coal technology program. In approving the new funding, Assistant Secretary for Fossil Energy Patricia Fry Godley said, "Virginia Tech has been a partner in the department's fossil-fuel program for 15 years, and has established a track record of excellence in developing innovative approaches for improving coal's environmental acceptability. These new contracts will ensure that the nation continues to benefit from the university's substantial expertise and creativity in coal-cleaning technology."

One of the new contracts, for $300,000, is to enhance the commercial competitiveness of the patented Microcel (TM) coal-cleaning technology. Microcel was developed by researchers in the Virginia Center for Coal and Minerals Processing, which is a Center for Innovative Technology (CIT) Technology Development Center. The CIT promotes and coordinates science, technology, and economic development initiatives in Virginia, and works with Virginia's universities to patent and license technologies.

Under the new federal contract, Roe-Hoan Yoon, director of the coal-processing center, and colleagues will examine a way of removing water from the cleaned coal using a chemical reagent. By developing a more effective dewatering approach, the researchers expect to lower costs and further boost the economic attractiveness of the technology, which is already achieving market success.

Developed in a joint program with the DOE in the 1980s, the Microcel technology is now being employed at commercial coal-cleaning installations in Virginia, West Virginia, Ohio, and Kentucky. Contracts or initial agreements are also in place for facilities in China, India, and Poland. The technology is also being used for ore processing in Arizona and Georgia, and graphite processing in Australia and Korea.

The Microcel approach uses microbubbles in a water-filled flotation column to separate mineral impurities from coal. It is particularly effective in cleaning very fine coal, smaller than grains of sand, that are too small to be cleaned by conventional processes and, as a result, are often discarded.

However, dewatering the cleaned product is energy intensive, adding expense. A lower-cost approach to dewatering would broaden the commercial appeal of the Microcel process.

The Appalachian Clean Coal Technology Consortium has also identified improved dewatering technology as one of its highest priorities for research funding and will likely use most of the $250,000 contract awarded last month to support development in this area.

The second new federal contract is a three-year, $1-million effort to develop a new generation of coal-cleaning technology. Virginia Tech will develop a high-efficiency, electrostatic approach for separating impurities from dry fine coal. Dry separation techniques avoid the need for removing moisture from the coal and potentially could be as effective as the fluid-based process.

The electrostatic process works by passing fine coal particles through an electrically charged field. Mineral impurities are attracted to positively charged plates while coal particles migrate toward the negative charge.

"I'm very confident this technology will be commercially successful, given Dr. Yoon's track record," said Boucher. "The work that he is doing at Virginia Tech holds the promise of broader markets for coal and cleaner air for our nation. The coal research center has repeatedly taken a modest investment of public and private research dollars and created the world's most advanced coal cleaning technologies, which are in use today by private industry."

Improved coal cleaning becomes especially important after the year 2000 when new clean-air laws require sharp reductions in airborne pollutants from coal plants.