CORROSIVE - MECHANICAL DAMAGE OF THE PRESSURE PARTS OF HEAT ENERGY EQUIPMENT

Abstract

Corrosion mechanical damage of the economizer pipe of the biomass boiler was analysed. Macroscopic, microscopic and SEM-EDX analysis were used for the analysis of steel samples. The results of the analyses showed a strong degradation effect of a high, up to 30% solids fraction in the flowing flue gas on the surface of the heat exchange tubes. The high amount of aggressive components, in particular Cl, S, Na, K and Zn, resulted in the formation of highly aggressive condensate on the tube surface when the operating temperature dropped below 200 ° C. The result was a more than 80% reduction in the wall thickness of the tube at the bottom of its arc, leading to perforation of the economizer tube wall. Spilled heated water released a protective corrosion layer from the surface and exposed the active steel surface. The solution of the unfavourable corrosion mechanical process is to ensure the required technological parameters (operating temperature and pressure of the flowing medium), chemical composition of the flue gas while ensuring sufficient operational capability and material life of the pressure parts of the heat equipment.