ASSESSMENT OF REMAINING LIFE OF SUPERHEATER AUSTENITIC STEEL TUBES IN OIL SHALE PF BOILERS

Superheater surfaces in oil shale-fired steam boilers are subject to intensive corrosion,which causes thinning of tube wall and increased stresses. It leads to reduction of creep life of superheater tubes and results in the necessity of superheater repair every 3–4 years with replacement of up to 30–50 % of austenitic tubes. The ability to predict accurately the remaining life of superheater tubes allows to reduce the amount and cost of repair. The method of assessment of remaining life for superheater austenitic steel tubes operating in conditions of intensive high-temperature corrosion is presented in this paper. The method is based on measurements of tube wall thickness and kinetic diagram of corrosion resistance of a particular steel