ABSTRACT
Utilization of high calcium oxide fuel at the thermal power plants connected with specific problems, such as ash behavior of inorganic matter in combustion process, ash deposits formation on boiler heating surfaces and it influences on heat transfer conditions. The arise of bonded ash deposits on steam boiler heating surfaces based on calcium oxide is a result of the numerous calcium oxide compound's sulphation in ash under the influence of sulphur oxides in flue gas with formation of calcium sulphate. The essential ash component forming calcium sulphate in ash deposits is free calcium oxide. Such compound of calcium silicates, aluminates, ferrites, etc., can be able to sulphation as well, but this compounds sulphation proceeds many times more slowly compared with the sulphation of free calcium oxide. The close contact between the ash particles on heating surface tubes is a great importance in the consolidation of the deposits. The ash deposits formation intensity very strongly depends on flue gas velocity and particle size that has very complicated character and should be described below.
