Ash deposition characteristics in pulverized coal reaction under high temperature conditions

Ash deposition characteristics under high-temperature pulverized coal react ion conditions were studied using a horizontal pulverized coal reactor with pre-combustor to produce high-temperature vitiated air. The ash deposition experiments were performed by inserting a water-cooled tube into the react or. Burning two types of coal with different melting temperature and ash co ntent, and the ash deposition phenomena were visually and quantitatively el ucidated. As a result, the quantity of ash deposition on the tube surface increases w ith an increase of the surface temperature. This is because the burning par ticles in the upper stream of the tube are radiatively cooled down under lo w temperature condition of the tube surface. Both the structure and quantit y of ash deposition depend on coal types such as melting temperature and as h content. The deposition rate at the beginning of deposition, obtained by the peripheral width of deposition layer on the tube surface, is correlated as an Arrhenius-type equation since viscosity of the molten ash can be cor related as an Arrhenius-type equation. Hence, it suggests that the ash depo sition phenomena may relate to the viscosity of molten ash.