Synthesis of Heat Exchanger Networks for Controllability

Heat exchanger networks are widely employed in the chemical processing industries to recover energy, resulting in reduced operating costs. Several methodologies can be found in the literature for the design of heat exchanger networks. Typical criteria are maximum energy recovery and minimum heat transfer area. However, the heat integration of process streams can lead to process structures that are difficult to control. In this work, a heat exchanger network controllability index was proposed as a measure of heat exchanger network controllability. This controllability index can be easily calculated, making it very appropriate for use at the conceptual design stage of a chemical process. A case study is presented where the controllability index is used to compare the controllability of different networks, and also to identify the trade-offs between controllability and heat integration. As a conclusion, the use of the proposed index enables process engineers to consider controllability aspects on the early stages of the design of heat exchanger networks