An updated acid dew point temperature estimation method for air-firing and oxy-fuel combustion processes

The updated formula shows that the main effects of the Tadp were the steam concentration, initial SO2 concentration (CSO2, ppm), ash content of raw coal (A_ar, %), fly ash proportion of the inherent coal ash (α_fly, %), main mineral contents of coal ash (Fe, Al, Ca, Mg, g/kg). The formula was then fully validated by a large amount of data obtained from laboratory-scale experiments, pilot-scale experiments and industrial scale coal-fired power plants. The results showed that, the heterogeneous effect for the conversion of SO2 to SO3 contributed to 1.33 to 20.86% of the total SO3 formed, smaller than the homogenous effect. Furthermore, the influence of the heterogeneous effect for oxy-fuel process was 1.2–1.6 times larger than that for the conventional air-fired process. The accuracy of the updated formula was proven much higher than the conventional empirical formula for air-firing combustion. The relative deviation of the calculation for oxy-fuel combustion by the updated formula was < 7.8%.