Detection of changes in fouling behavior by simultaneous monitoring of thermal and hydraulic performance of refinery heat exchangers

Abstract Monitoring of pre-heat trains in oil refineries is a crucial activity to assess the gradual decay in performance of heat transfer equipment due to fouling. It is also important to assist in operational decisions with respect to fouling mitigation options and cleaning strategies. In this paper, a novel graphical representation of time varying operational data is proposed to monitor crude oil fouling. This dynamic thermo-hydraulic plot, named the TH-λ plot, simultaneously captures both thermal and hydraulic performance and presents it in a way easily interpreted by field engineers. Its features and applications are demonstrated here for typical situations using data generated using an advanced dynamic simulation model for shell-and-tube heat exchanger undergoing fouling. The results show that consideration of thermal and hydraulic effects, together with process dynamics, is essential to adequately monitor performance, detect changes in fouling behaviour and properly interpret available data. They also show this is achievable using only measurements of inlet and outlet streams to heat exchangers.