Ash deposition characteristics of pulverized coal under high temperature reaction conditions

摘要

Ash deposition characteristics under high temperature reaction conditions of pulverized coal were studied by 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 reactor. Burning two types of coal with different melting temperature and ash content, the ash deposition phenomena were quantitatively and visually elucidated. As a result, quantity of ash deposition on the tube surface increases with an increase of the surface temperature since it is hard for burning particles to be radiatively cooled down in the upper stream of the tube under the higher temperature condition of the tube surface. Both the structure and quantity of ash deposition depend on coal types like the melting temperature and ash content. The deposition rate at the beginning of deposition, obtained by the width of deposition layer on the tube surface, is correlated as an Arrhenius equation since the viscosity of molten ash may be sometimes correlated as an Arrhenius equation. Hence, it means that the ash deposition phenomena may relate to the viscosity of molten ash.