Heat exchanger network retrofit under fouling effect

Abstract

The energy conservation by heat exchanger network (HEN) is important in process design according to an increase of energy costs and global environmental concerns. To minimize the energy consumption with positive net present value (NPV), the retrofitted HEN plays an important role in process energy systems. The HEN retrofit model is based on stage-wise superstructure by Yee and Grossmann (1990). In addition, fouling deposition on the surface area of heat exchangers causes extra energy consumption, production loss and maintenance costs. The new proposed model is retrofitting HEN with fouling effects. This method achieves HEN with the optimal trade-offs between energy savings, and investment over operating period. For cleaning schedule, retrofitted HEN shows better capability to recover heat and NPV higher than base-case considered from a lower number of cleaning requirement. In this study, the proposed model is combined between cleaning schedule strategy and HEN retrofitting with fouling effect to achieve profitable HEN.