The effect of CaO on the flow temperature and temperature of the critical viscosity of ash and solid slag form the Shell entrained-flow gasifier

摘要

The effect of CaO on the fusibility and flow properties of the ash and solid slag form the Shell entrained-flow gasifier were studied in detail. The flow temperatures and the temperature of the critical viscosity (Tcv) were measured for the ash and solid slag with addition of fluxing CaO. The computer package F*A*C*T was used to predict the proportion of solid phase and the mineral phase formed as a function of the composition and the temperature of the fluxed ash and solid slag.The results showed that the flow temperatures and the Tcv of ash are always higher than those of solid slag with increasing the CaO content. Those temperatures of ash and solid slag decrease with increasing CaO content, whereas they increase rapidly at CaO content higher than 35%, because the sub-liquidus phase transforms from the anorthite phase to the melilite phase with increasing CaO content and the mass fraction solids decrease with increasing CaO content, then increase again with increasing CaO content.