Risks of boiler operation during slagging and fouling process – a new methods for the determination of ash sintering temperatures

The properties of mineral matter occurs in coal in the form of inorganic compounds leads to slagging and fouling process on boiler heating surfaces, burners and ash hopper. The deposition of ash cause many undesirable phenomena such as heat transfer deterioration, damage to internal parts of the boiler as a result of detachment of large agglomerates and finally, costly shutdowns of the boiler. Standardized method of risk assessment of agglomerates formation and sintered fly ash is determined by four melting temperatures of ash. This measurement is based on visual appraisal of ash sample deformation which is subjective and strongly depends on the experience of the person conducting the test. Especially is hard predict the first two temperatures: deformation and sintering. An article has to present three non-standardized methods for determining the sintering temperature by using physical parameters: pressure drop and minimum force of probe destruction. This type of measurement allows a quantitative way to obtain reliable and meaningful result. The experiment showed that the results of non-standard methods deviate from those set using the Leitz method. This allows to conclude that sintering processes occur at much lower temperatures and changing the shape of the initial (test method Leitz) is not the first symptom of demonstrating the melting of the ash.