Assessment of the Slagging Tendency in Power Plant Boiler Furnaces Depending on the Physical-Chemical Characteristics of Ash and Coal

The purpose of the work is to select replacing design coal possible options for low slagging potential reasons in the furnace and on adjacent heating surfaces. Solved problems: the main slagging indices (SI) are summarized, based on considering the two main parameters of the formation of ash deposits, namely viscosity and fusibility. An analysis of existing methods for assessing slagging processes of heating surfaces in steam power boilers was carried out. The scientific goal is achieved by the proposed method of ranking coals according to their slagging tendency on power boiler heating surfaces based on their physicochemical properties. The methodology is based on the slagging potential dependence of the fusibility and viscosity ash characteristics, considering the ratio of the ash percentage content to the heating value of coal. The most important result is ranking of 28 coals of various grades (subbituminous, bituminous, anthracite) burned at Russian power plants according to their tendency to form ash deposits on the furnaces of power boilers. The significance of the results obtained lies in the identification of two coal deposits, subbituminous Irsha-Borodinsky and Berezovsky in Easten Siberia and Kuznetsky bituminous in Western Siberia, which are universal during the transition to burning non-design fuel from the slagging potential point of view. The dependences of the change in ash viscosity and SI on the SiO2 / Al2O3 and Fe2O3 / SiO2 ratios in ash for Irsha-Borodinsky and Moscow region coals were under consideration. It was concluded that the value of the SI is directly proportional to the load ash content Ar and could differ more by an order of magnitude for different coals.