Experience of superheater tubes in municipal waste incineration plant

Two years after the start of operations at the Tokachi Association for Muni cipal Waste Disposal and Treatment Services municipal waste incineration pl ant (name: Kuririn Center), which generates 400 degreesC steam, an investig ation of the plant's superheater tubes was conducted. The investigation con sisted primarily of analyzing ash deposits, measuring tube wall thickness l oss and observing tube sections after removal. The concentration of Cl in t he deposited ash was found to increase as the temperature of the gas rose, and the amount of deposited ash tended to increase as the temperature of th e gas rose. Tube damage consisted primarily of a uniform loss in thickness. Intergranular corrosion and other local corrosion was not observed. The re sults of thickness-loss measurements showed that, after approximately two y ears in operation, tubes (SUS310) lost a maximum of 0.45 mm in thickness du e to high-temperature corrosion in locations where the steam temperature re ached 400 degreesC. Superheater tubes were also apparently damaged from the effects of a soot blower, resulting in an observed maximum loss of 0.9 mm thickness after approximately two years. Furthermore, the rate of thickness loss tended to increase after one year had passed.