The increase of silver grass ash melting temperature using additives

Abstract

Some types of biomass have a high content of alkali oxides and salts and, thanks to it they feature a low ash melting temperature which may result in various combustion problems. Slag and sintered particles that are formed prevent the fuel from being supplied, restrict the access of combustion air, heat transfer in the heat exchanger and can cause corrosions. One possibility of increasing the ash melting temperature is to add additives. Some additives can change chemical composition of fuel ash, thus changing also the ash melting temperature. The paper deals with the adding of 2 % additives - kaolin, talc, lime, limestone, dolomite, bentonite to silver grass. The tested additives increased the ash content but they also changed its chemical composition, which resulted in the increase of the ash melting temperature. Best positive results were achieved with kaolin and lime which increased the ash melting temperature by approx 300 degrees C.