STUDIES OF FLY-ASH USING THERMAL-ANALYSIS TECHNIQUES

Improved thermoanalytical methods have been developed that are capable of quantitative identification of various components of fly ash from a laboratory-scale fluidized bed combustion system. The thermogravimet ric procedure developed can determine quantities of H2O, Ca(OH)(2), Ca CO3, CaSO4 and carbonaceous matter in fly ash with accuracy comparable to more time-consuming ASTM methods. This procedure is a modification of the Mikhail-Turcotte methods that can accurately analyze bed ash, with higher accuracy regarding the greater amount of carbonaceous matt er in fly ash. In addition, in conjunction with FTIR and SEM/EDS analy ses, the reduction mechanism of CaSO4 as CaSO4+4H(2) <-> CaS + 4H(2)O has been confirmed in this study. This mechanism is important in analy zing and evaluating sulfur capture in fluidized-bed combustion systems .