Modeling and Prediction of Shell-Side Fouling in Shell-And-Tube Heat Exchangers

Abstract

Fouling is a challenging, longstanding and costly problem affecting a variety of heat transfer applications in industry. Mathematical models that aim at capturing and predicting fouling trends in shell-and-tube heat exchangers typically focus on fouling inside the tubes, while fouling on the shell-side has generally been neglected. However, fouling deposition on the shell-side may be significant in practice, impairing heat transfer, increasing pressure drops and modifying flow paths. In this paper, a new model formulation is presented that enables capturing fouling on the shell-side of shell-and-tube heat exchangers including the effect of occlusion of the shell-side clearances. It is demonstrated by means of an industrial case study in a crude oil refinery application. The model, implemented in an advanced simulation environment, is fitted to plant data. It is shown to capture the complex thermal and hydraulic 2 interactions between fouling growth inside and outside of the tubes, the effect of fouling on the occlusion of the shell-side construction clearances, and to unveil the impact on shell-side flow patterns, heat transfer coefficient, pressure drops and overall exchanger performance. The model is shown to predict the fouling behavior in a seamless dynamic simulation of both deposition and cleaning operations, with excellent results.