A RISK BASED COST MODEL OF A SHELL-AND-TUBE HEAT EXCHANGER SUBJECT TO FOULING

Fouling may be defined as the deposition of unwanted material on heat transfer equipment that reduces heat-transfer and increases the resistance to fluid flow. Once the thermal-hydraulic performance decreases to a minimum acceptable level, cleaning of the equipment has to be done to restore the performance. The decision regarding periodic off-line maintenance of the heat exchangers is generally based on a thermoeconomic performance of the process. In this paper, we discuss a maintenance model by incorporating the risk level and scatter parameter of the four random fouling growth models, namely linear, power law, falling rate and asymptotic models, which are integrated in the dimensionless cost model for a heat exchanger used in a crude oil preheat train.