Analysis of adhesion behavior of waste combustion ash at high temperatures and its control by the addition of coarse particles

Abstract

In solid waste combustion, adhesion of ash on the surface of super heaters causes heater corrosion so that the efficiency of electric power generation is limited by the operation temperature avoiding such troubles. Ash adhesion is caused by the formation of a liquid phase with a relatively low melting point. In order to control ash adhesion, three types of coarse inorganic particles having different chemical compositions were selected and mixed with waste combustion ash. These coarse particles are stable and inert at temperatures as high as combustor operation temperatures and expected to reduce the cohesiveness of ash particles. The properties of ash particles with and without coarse particles were characterized by the powder bed tensile test. The tensile strength of an ash powder bed at high temperature was able to be controlled by the addition of the coarse inorganic particles and depended on the chemical composition of the coarse-particles.