Failures and fouling analysis in heat exchangers

Abstract

In this paper the analysis of failures and fouling in heat exchangers has been presented. The approach combines laboratory scale experiments with industrial observations to study the thermal and fouling characteristics of plate type heat exchangers. The process of heat transfer under real operation conditions is investigated. The paper presents examples of defects in connecting pipes, corrosion inside heat exchangers due to influence of heat transfer media. Materials for heat transfer plates of heat exchangers were analysed. Damages of heat exchangers due to wrong installation and exploitation conditions and corrosion have been investigated. The Vicker's indentation method has been employed in the experimental verifications of this analysis, because the resultant deformation/fracture geometry appears to confirm the main simplifying assumption of the analysis. Analyzing an interface between inner tube surface and fouling it was determined that fouling has hardness of 100 Vicker's points higher than that of the tube analyzed. Measurements of indentation stress-strain responses on defected tubes and heat transfer plates may be used to determine strength properties during evaluation reliability and durability of heat exchangers.