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Engineering Research Could Mean Comeback for Coal
From: University Currents
Date: May 12, 2000
By: Chris Curran
Phone: (513) 556-1806
Archive: Research News

Coal has always been a cheap, abundant fuel source. The problem is what happens when you burn it.

Up to 15 percent of the waste gas is carbon dioxide, a key contributor to the greenhouse effect. Burning coal also releases nitrogen oxides which can cause smog and toxic metals such as mercury.

Try to burn high-sulfur Ohio coal, and the problem gets even more complicated. Sulfur dioxide can be converted to sulfuric acid in the atmosphere, and down comes acid rain.

image of researchers in lab

Engineering professors Timothy Keener and Soon-Jai Khang say teamwork could prove to be the solution to such a complicated problem. Keener, an environmental engineer, and Khang, a chemical engineer are part of a statewide consortium in Ohio looking for ways to use coal without harming the environment.

The effort began in the early '90s and was funded by the Ohio Coal Development Office. That resulted in an 800-page monograph detailing various technological advancements. A followup effort from 1996 is wrapping up this year and will produce a second monograph 700 pages in length.

That represents an enormous amount of research from faculty at UC and the other collaborating institutions: Ohio State, Ohio University, and Case-Western Reserve. However, it's really only the beginning according to Keener and Khang.

"It takes 10-15 years for technology to get to the practical level," explained Keener. "These (utility plants) are among the largest systems on Earth...a one billion dollar investment."

Many utilities abandoned coal in favor of natural gas to help comply with Clean Air Act regulations, but Khang believes those same utilities could return to coal as gas supplies dwindle and prices increase.

"Coal is 'old value,'" said Khang. "It's like a versus Procter & Gamble."

Together, Keener and Khang have developed and tested a new method for removing sulfur dioxide from flue gas. The system uses a wet electrostatic precipitator to capture the pollutants before they can escape into the atmosphere. Doctoral student Chao-Heng Tseng of Taiwan is developing and testing the system as part of his dissertation research.

image of lab

If the system works as planned, it should be able to attack multiple pollutant sources at the same time. It actually uses the sulfur captured to help control nitrogen oxide and mercury emissions.

Keener and Khang have also received a Cinergy Earth Day grant to develop a "scrubber" which uses magnesium hydroxide to capture carbon dioxide. The material can then be recycled for other uses. Even if the system only reduces the carbon dioxide emissions by 7 percent, that's enough to put a utility in compliance with the Kyoto Accords on global warming.

"It's a very difficult problem," admitted Keener. "We're hoping to make a little dent in it."