NOx reduction over metal oxide catalysts in the presence of ammonia is a proven technology which has reached the commercial stage. So-called selective catalytic reduction (SCR) is not without its problems including high cost, short life (less than two years), and high disposal costs as spent catalyst is regulated as a hazardous waste. Coal ash is chemically similar to metal oxide catalyst systems containing significant amounts of titania, vanadia, as well as iron oxide, silica, and alumina, and other pertinent constituents. Many of these constituents have demonstrated catalytic activity in the presence of ammonia. Coal ash is plentiful, and inexpensive. Although coal ash is expected to have lower surface area and catalytic activity, its low cost allows thousands of times higher catalyst loading and replacement. In addition, disposal is regulated as a non-hazardous waste. Literature and patents are cited showing the catalytic activity of coal ash constituents. The proposed work concerns the quantification of NOX reduction activity of ammonia over coal ash in a bench scale fluid bed apparatus. A fluid bed would allow easy replacement of deactivated catalyst in a commercial scenario.The potential commercial application as described by the awardee: Research will lead to the reduction of NOx at combustion sources.
