About the active phases of KNO3/MgO for catalytic soot combustion

Abstract

Reports suggest KNO 3 as the active phase for the catalytic combustion of soot, through a redox mechanism with KNO 2 . Previously, the high activity of KNO 3 for coal gasification (mechanism similar to that of soot combustion) was attributed to decomposition into active K x O y (y \ x) compounds. In this work, TGA-MS assays of carbothermic reduction using the KNO 3 /MgO catalyst showed decomposition into NO x , (to which starting of CB combustion is attributed) and potassium oxide, thus disregarding possible redox cycles KNO 3 /KNO 2 . Consecutive assays of carbothermic reduction and TPO in a fixed bed reactor showed the potassium oxides as the main active phases of these catalysts.

Effect of Potassium on Sol-Gel Cerium and Lanthanum Oxide Catalysis for Soot Combustion

“…However, the temperatures at which the gases emitted into the atmosphere are cooled between 300˚C and 400˚C, coal is burned at temperatures that range between 500˚C and 600˚C. Therefore, the catalysts used in the catalytic combustion of soot must be capable of presenting catalyst activity at low temperatures [10].…”