Thermodynamic Simulation for the Environmental Prediction of High-Efficiency Waste-to-Power Plant Boiler

In order to characterize the complicated corrosive environment around superheater tubes in advanced waste-to-power (WTP) boilers, thermodynamic simulation was conducted using the thermodynamic equilibrium calculation software MALT for Windows. The macroscale of thermodynamically stable compounds at an equilibrium state can be obtained using this software, which is applicable for predicting the macroscale environmental conditions in WTP plants. It was revealed from these calculations that the presence of corrosive gases such as Cl₂ derived from HCl may be a corrosive factor in an actual furnace. The calculation results were compared with actual furnace environments by means of other analytical equipment such as IC, ICP–AES, TG–DTA, and fluorescent X-ray analysis. These analytical results suggested the chemical composition, and the local distribution tendency of each element, including the presence of eutectic chloride compounds with low melting points in the ash deposited onto the WTP boiler tubes. On the basis of the comparison between the thermodynamic prediction and different kinds of analytical results, the applicability and limitation of the thermodynamics were discussed.