Relations between combustion, deposition, flue gas temperatures and corrosion in straw-fired boilers

ABSTRACT: Additives trials in three different plants, Sønderborg waste incineration plant and Ensted woodchip and straw firing boiler, are described. Both aluminium silicate containing additives and ammonium sulphate was tested. At Sønderborg, there was a drastic decrease in Cl deposition when using an aluminium silicate additive, however the relative chlorine content of the deposits was unchanged. At Ensted woodchip plant, a dosage level of additives was reached which reduced the chlorine flux. For straw firing where the chlorine level in the fuel is higher and the fuel load is greater, the chlorine flux on deposition probes was not affected by additive dosage. An indication that some chlorine had been removed could be measured by the increased HCl output during additive dosage. The importance of temperature and where the additive is dosed is discussed.