CORROSION ANALYSIS OF AIR PRE-HEATER TUBES OF CFBC BOILER (SLPP) AND IMPROVEMENT IN OPERATION

This paper presents an approach for the optimization of air pre-heater design with inline & staggered tube arrangement. The tube failure of an air pre-heater in Gujarat Industries Power Company Limited (SLPP) is one of the main reasons for higher unit heat rate & is responsible for deterioration in boiler efficiency. The main problem of air pre-heater is the leakage of air to the flue gas side & thereby resulting in poor thermal performance. The higher ash content in Indian coal also adds to the problems associated with tubular air pre-heater. Air pre-heaters are designed to meet performance requirements with consideration of highly influencing parameters viz. heat transfer, leakage and pressure drop. In the present work the performance of tubular air pre-heater is minimized tube failure by using different material of steel or by reducing H2SO4 formation from the flue gas while power plant taking start-up. In the flue gas system of a boiler plant, gaseous acidic substances (such as SOX and HCl) included in high-temperature exhaust gas condense into dew, depending on the moisture content of the gas and the surface temperature of a steel material to which it comes into contact, and corrode the material