This project is proposed by a team lead by URS Group, Inc., with Gary M. Blythe, P.E. as Project Manager. The project, entitled “Full-scale Testing of a Mercury Oxidation Catalyst Upstream of a Wet FGD System,” will test a gold mercury oxidation catalyst upstream of one full-scale wet flue gas desulfurization (FGD) module on a power plant unit that fires Powder River Basin coal. Mercury oxidation across the catalyst and oxidized mercury removal by the downstream wet FGD module will be measured for a period of up to two years. The test will be conducted at the Lower Colorado River Authority's (LCRA's) Fayette Power Project, Unit 3.

Unit 3 has a nameplate generating capacity of 460-MW, and is equipped with low NOx burners for NOx control, a cold-side electrostatic precipitator for particulate control, and a wet FGD system for SO₂ control. The FGD system has three modules, two of which are normally operated. Approximately 15% of the flue gas from Unit 3 bypasses the FGD system. Thus, each FGD module treats approximately 200 MW of flue gas. The gold oxidation catalyst will be installed in a duct immediately upstream of one of the three FGD modules. For that module, an existing duct section will be removed and replaced with a catalytic reactor containing the gold catalyst. Sufficient catalyst volume will be installed to achieve mercury oxidation of 70% or greater across the catalyst. Sonic horns will be installed to keep the horizontal gas flow catalysts clear of fly ash buildup.

The project will measure mercury oxidation across the catalyst, and the percentage removal of oxidized mercury across the downstream wet FGD absorber module for a period of up to two years. This will be determined using mercury semi-continuous emissions monitors to measure flue gas mercury concentrations and speciation on a bi-monthly basis throughout the test period. Triplicate measurements by the Ontario Hydro Method will also be conducted to verify the catalyst oxidation percentage and FGD mercury capture efficiency on three different occasions over the two-year period. Coal, fly ash, FGD reagent, and FGD byproduct samples will be collected and analyzed in concert with the Ontario Hydro Method sampling to calculate mercury balances around the unit.

The project represents the next logical advancement of the catalytic oxidation technology from its current pilot scale. It will answer technical questions such as the catalyst quantity required to achieve high mercury oxidation percentages, catalyst life, the efficiency of capture of catalytically oxidized mercury in full-scale wet FGD systems, and the ability to keep the catalysts clean of fly ash buildup at full scale with sonic horns.

Project team members and co-funders will include LCRA, EPRI, Johnson Matthey, Salt River Project, the Southern Company, Tennessee Valley Authority, and Westar.