SYSTEMATIC INVESTIGATION OF DEPOSITS IN THE BOILER OF A SEMI-TECHNICAL ROTARY KILN INCINERATOR - MINERALOGICAL AND CHEMICAL CHARACTERIZATION

摘要

Mineralogical and chemical characterizations of deposits from the evaporator walls in the boiler of the pilot plant THERESA indicate a correlation of increased corrosion processes with phase transformation in the mineralogical composition. The samples were taken in horizontal and vertical profiles which allow a correlation of the variations in flue gas direction (for example temperature, chemical composition) as well as a comparison of the composition in the same boiler zone. Essentially the coatings are composed of different sulfates. Phase transformation between Calcium- (Ca), Sodium- (Na), Potassium- (K), and Lead- (Pb) sulfates can be observed together with macroscopic corrosion damages at the evaporator walls. These findings should help to give a prognosis over the most endangered areas in the boiler and therefore to minimize the expenditure for boiler maintenance.