EXPERIMENTAL AND NUMERICAL STUDY ON ASH DEPOSITION MODEL IN A 35KW HORIZONTAL COAL REACTOR:APPLICATION TO COAL-FIRD BOILER

摘要

Ash deposition on heat transfer surfaces produce resistances to heat transfer that can reduce boiler efficiency. Hence,rnthe ash deposition seriously inhibits the stable boiler operation. The slagging and fouling that occur in a boiler originaternin deposition phenomena. When deposited particles melt and form a sintered layer, the result is called slagging,rnwhereas when ash particles form a layer through condensation at a relatively low temperature at a surface, it is calledrnfouling. It is possible for these two phenomena to occur simultaneously or separately, depending on the temperaturernand surrounding environment. The ash adhesion experiments for blended coal were conducted to understand thernmechanisms of growth of ash deposition. The ash deposition model was applied to estimate the ash adhesionrncharacteristics in a coal-fired boiler. For this study, we used thermo-mechanical analysis(TMA) for predicting ashrnphase transition according to the ambient temperature. And we used computational fluid dynamics(CFD) to performrna simulation of coal-fired boiler. This numerical study examined the characteristic of combustion in the boiler andrnexplored the boiler’s deposition potential.