A study on damages in alloyed super heater tubes of thermal power station

19-23In this paper, an investigation on the damages in alloyed super heater and reheater tubes materials for natural circulation water wall tubes (NCWWTs) high-pressure drum boiler units TGME-COB-206 (Russia) of Ghorasal Thermal Power Station (GTPS), Bangladesh, have been carried out at different schedule maintenances. Extensive analyses of different chemical parameters of boiler water chemical regime (BWCR), and generated steam (live) quality at rated operating steam temperature and pressure, revealed carryover of SiO₂ 20 (±5) mgL-¹ in steam (live) during cold startup and abrupt increase in thermal load of boiler unit. The micro and macro structural examinations of super heater tube materials, scale composition; scale thickness and composition of super heater tubes materials have been monitored very carefully. Silica is found to be the major component for the super heater scaling which has strong affinity to the chromium containing steel reheater tubes materials