With burning of municipal solid waste (MSW), the potential for corrosion and tube wastage is always present. This is mainly due to certain corrosive substances in the refuse and some of its other constituents. There are two approaches to corrosion control, either prevention by conservative design, or by utilization of corrosion resistant materials. This paper will describe both of these corrosion control methods, with specific emphasis on application and experience. Both mass-burn and refuse-derived-fuel (RDF) systems will be addressed.
MSW is one of the most difficult fuels to burn because of its heterogeneous and highly variable nature. This mixture of household, commercial, institutional and industrial wastes provides special challenges during the handling and burning process. Depending on the refuse components and their variation, MSW ranges from relatively easy to very difficult to burn. The main problem is encountered with commercial and industrial wastes and their constitution, or possibly some other aspects such as sizing, moisture fluctuation, high chlorine content, etc. Because of the refuse composition and characteristics, the corrosion potential is always present. Acid gasses, specifically HCI, and some metals such as lead, zinc and tin, are the major contributors to the corrosion process. As refuse boilers are designed for ever higher steam conditions (pressure and temperature), many boiler components, specifically the tubes, are increasingly susceptible to corrosion.
It is most important to understand these issues and to properly address them.