Characteristics of fly ash from thermal power plants important for handling and storage systems design and its utilization

Abstract

Coal based power plants are still the major source of electricity generation in Serbia and they produce huge volumes of fly ash. Quality of fly ash generated by burning Serbian lignites is various and is mainly related to changes in the quality of coal, and it is not surprising to have high variations within single power plant. Therefore, fly ash characteristics are the most important precursor to design of handling and storage systems, as well as indicator for many possibilities on its different reutilization. More and more thermal power plants are switching to sophisticated pneumatic conveying systems and storing dry fly ash, not only because of environmental aspects, but due to high demands for this kind of by-product. All of the above determines fly ash as a product which characteristics have to be known, what requires continuous investigations and detailed analysis. This paper attempts to highlight significant fly ash characteristics important from aspect of selecting adequate and reliable handling systems and utilization of fly ash in various industrial branches. Several trials on series of fly ash samples was carried out in Laboratory for Process Engineering - Faculty of Mechanical Engineering in Belgrade. Among other analysis it was determined bulk density, particle density, average diameter, porosity, the first and the second critical velocity, permeability and chemical composition. Also, a classification for obtaining guidelines for pneumatic conveying system selection was made.