On the operability of heat exchanger networks

• Main Author: Hattingh, Caleb
• Other Authors: Swartz, Chris
• Format: Dissertation
• Language: English
• Published: University of Cape Town 2014
• Online Access: http://hdl.handle.net/11427/5320

Bibliography: leaves 127-132. === The dynamic operability of processes refers to the degree to which plants may be satisfactorily controlled. This report presents a study of the operability of heat exchanger networks (HENs).The integration of heat exchange systems such as HENs typically results in significant steady-state cost savings which is the motivation for their implementation. However, such integration may lead to problems in the dynamic operation of the system if the operability of HENs is not considered. Operability analysis techniques are presented that provide a quantitative measure of the operability of HENs that is related to the minimum integral setpoint error of a closed-loop HEN under a step disturbance. The different operability analysis techniques are specified by ,u sing different controller types which are optimally tuned in an optimization framework. The different controllers include PI (proportionalintegral) control, MPC (model predictive control), optimal linear control (via Qparametrization) and an optimal open-loop control strategy that represents the best possible closed-loop performance.