Air Pollution Control Equipment Services, Coal, Emissions

Corny Way to Trap Mercury?

Issue 10 and Volume 105.

A team of Illinois researchers has previously investigated pistachio shells as a medium for reducing mercury emissions from coal-fired power plants. As nutty as it sounds, the shells can absorb elemental mercury and mercuric chloride compounds, replacing activated carbon, which costs more to produce. Now the University of Illinois/Illinois State Geological Survey team thinks a corny approach is better, and outlined their findings at an Air & Waste Management Association specialty conference on mercury emissions held in Chicago late this summer.

The team reported promising results from the successful full-scale test of a substance derived from corn in a demonstration of the process that took place earlier this summer at the university’s Abbott Power Plant, a 30 MW facility that burns high-sulfur coal. The carbon-injection demonstration compared the performance of a commercial activated carbon with that of a corn-derived activated carbon that the team developed.

“This full-scale test capped a five-year collaborative effort to develop low-cost adsorbents for the removal of mercury,” said Massoud Rostam-Abadi, a chemical engineer and the head of energy and environmental engineering for the Illinois State Geological Survey. “The test also marked the first time the carbon-injection technology was applied to high-sulfur Illinois coal flue gas.”

Rostam-Abadi and his team have been working for years to come up with low-cost, highly effective materials to remove mercury from flue gases. Although old tires and pistachio shells looked promising, they were eclipsed by the potential of corn.

“Earlier this year we worked with engineers from URS Radian in Austin, Texas, to look at the effectiveness of corn-based activated carbons for removing both elemental mercury and mercuric chloride from simulated coal combustion flue gases,” he says. Initial tests indicated that activated carbon adsorbents made from corn could work as well as or better than current commercial products and might even be cheaper to produce.