Effect of Delta Temperature Minimum Contribution in Obtaining an Operable and Flexible Heat Exchanger Network

Abstract

This paper presents the control structure decision making for heat exchanger networks (HENs) to obtain operable and flexible network. Delta temperature minimum (ΔTmin) contribution is considered in this study. Several studies have been done to determine the effect of ΔTmin-contribution on the annual cost. Usually, HENs designed without consider controllability analysis and control structure decision making. In control structure decision making analysis are done to already designed HEN. Design and controllability analysis for HEN are done seperately. Therefore, there are still lacks of studies on how the ΔTmin-contribution effects the controllability and control structure desion making. Optimal ΔTmin selection is important decision to make in the early stage to avoid inflexible and inoperable heat exchanger networks. The question that needs to be answerd here is how to determine the optimal value of ΔTmin that will have better operating conditions that satisfy process design (HEN), controllability and as well as economy. In this study, this problem will be formulated as a mathematical programming (optimizattion with constraints) and solved by decomposing it into four hierarchiacal stages: (i) target selection, (ii) HEN design analysis, (iii) controllability analysis, and (iv) optimal selection and verification. A case study plant was selected as a case study. Small value of ΔTmin was first implemented and will gradually be increased to see the effect on the operability and flexibility of a case study.