Failure analysis of an economizer tube in a steam generation systems

Document Type : Review

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Abstract

Corrosion in steam generation systems may lead to many problems in industrial units. The economizer and heating systems are the first parts in which corrosion happens. Due to use of boiler exhaust gases, an economizer is a key factor in increasing boiler thermal efficiency. Generally, corrosion in economizer equipment is due to O2, CO2 and NH3. In this work, the failure of a finned tube economizer is investigated by chemical analysis of the fin and tube samples, XRD and XRF analysis of corrosion product and the relation between the corrosion morphology and sediment composition. In addition, effect of tube thinning due to corrosion on mechanical strength is evaluated under operational conditions. The obtained results clearly showed that oxygen was the main cause of corrosion. Additionally, mechanical strength and resistance of the tube to internal pressure are higher than the minimum limit value despite tube thinning by corrosion.

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