In a June 14 letter, the Indiana Department of Environmental Management approved Duke Energy Indiana for a test of up to 30 days in duration of a hydrated lime system as the company looks at Maximum Achievable Control Technology (MACT) compliance options at its coal-fired Cayuga power plant.
The hydrated lime, which will be delivered by truck, will be injected into the flue gas prior to the electrostatic precipitator (ESP), the letter noted. The lime will be stored in portable silos erected at the site for this project. Particulate emissions during the loading process will be controlled by a bin vent filter. Any lime that gets through the ESP would likely be captured in the flue gas desulfurization system, the letter said.
The IDEM in December 2011 approved Duke Energy Indiana, a unit of Duke Energy (NYSE: DUK), to test two coal additives designed to cut mercury and NOx emissions at the Cayuga power plant. But, Duke Energy Indiana told the Indiana Utility Regulatory Commission April 19 that testing of refined coal with chemical additives to reduce emissions at both the Cayuga and Gibson power plants didn’t work effectively enough, so it is withdrawing its September 2011 application for approval of those projects.
“Duke Energy Indiana has conducted testing at the Cayuga and Gibson generating stations to determine the effectiveness of the refined coal process,” the utility said in a brief filing. “After analyzing the testing results, it was determined that the results did not support moving forward with the refined coal project at either generating station.”
Cayuga is a three-unit, 1,104-MW generating facility built between 1970 and 1993, said the Duke website. Units 1 and 2 have been equipped with scrubbers to reduce the station’s SO2 emissions by about 95%.