Evaluation of HEN controllability

Abstract

In the last three decades the importance of resolve a robust, rigorous and operable heat exchanger networks (HEN) is boosted due to the change in the concepts of effective cost of a HEN several methodologies are applied to solve the operability aspects of a HEN including flexibility and controllability of a HEN in this work a systematic approach is introduced to solve the controllability issue for HENs. The work framework consist of two major steps where in the first step a disturbance propagation model for a HEN is constructed adopting Yang et.al disturbance model[1][2][3]. The second step is to install a bypass to reject the disturbance then pair the manipulated and controlled variables in a HEN using NS-RGA (None Square Relative Gain Array) and SVD (Singular Value decomposition), by adopting controllability index developed by Westphalen et al.[4]to measure the HEN controllability and finally a cost tradeoff between the bypass installation and utility installation to control the same disturbance is evaluated to check for the more cost effective method to eliminate and reject the disturbance in hand.