Abstract
The phenomenon of coal ash deposition is observed on the wall in the coal gasifier. The ash deposit interferes with heat transfer and if it is heavy, it causes unplanned shutdowns of the power plant. Therefore, ash deposition behavior on the wall in the coal gasifier should be predicted when the coal type or operational condition of gasifier might be changed. Authors have conducted on the measurement of ash liquid phase ratio to study the continuous ash melting process. The ash liquid phase ratios were calculated from the result of differential thermal analysis and they were compared with the result from thermodynamics equilibrium. And the relationship between ash melting characteristics and sintering characteristics or viscous characteristics, which were evaluated from a viscosity meter, were examined. The discrimination models for sintering and fluidizing of the ash deposit were developed. The models were introduced into the heat conduction calculation program, which calculates the deposit layer surface temperature serially in the growth process of ash deposit layer. And evaluating the thickness of powder layer, sintering layer became possible by considering the sintering temperature and the fluidizing temperature defined from the ash liquid phase ratio.
