Lifetime Estimation of Aluminum Plate Fin Heat Exchangers

Abstract

Aluminum Plate Fin Heat Exchangers (Al-PFHE) are often used in low temperature applications of chemical plants when huge heat transfer capacities are required. Typically the equipment is insulated or installed in insulated containments — so called “Cold Boxes”. Al-PFHE may either fail by corrosion or by mechanical overload due to trip scenarios or blockage / fouling. No failures due to mechanical overload should occur under the conditions of the ALPEMA [9] guideline (ALPEMA = Aluminum Plate-fin Heat Exchanger Manufacturer’s Association). However, ALPEMA doesn’t describe all operational situations in the exchanger block itself and the ALPEMA load conditions are not followed in all cases. The specific design of Al-PFHE does not allow standard inspection and maintenance procedures, which makes it difficult to evaluate the equipment condition and the expected remaining service life. Corrosion, blockage, fouling, and mechanical/thermal overload are the key degradation mechanisms that operators need to control to avoid premature failure of their aluminum plate fin heat exchangers. This paper describes how to incorporate finite element analysis and dynamic process simulation in the design and operation to evaluate the lifetime of Al-PFHE.