Avoid operating problems in air-cooled heat exchangers

Description/Abstract

Air-cooled heat exchangers (ACHEs) have become the norm in the chemical process industries for process cooling after process-to-process heat exchange has been maximized. To evaluate and optimize ACHE performance, it is important to understand what type of problems can exist on the tubeside and shellside and how to solve them. ACHEs consist of banks of finned tubes across which air flows, driven by fans located above or below the unit. Tubeside performance is exactly the same as for more common shell-and-tube heat exchangers. Consequently, identical correlations are used to determine heat transfer coefficients and pressure drops. However, airside performance is totally different since crossflow across finned tubes is used. Special correlations have been developed for airside heat transfer and pressure drop. The paper discusses the configuration of ACHEs, construction, tubeside operating problems, airside operating problems, and performance evaluation