Heat Transfer Blocks Diagram: A Novel Tool for Targeting and Design of Heat Exchanger Networks Inside Heat Integrated Water Allocation Networks

摘要

Sustainability is essential for process industries, as energy and resources are getting scarcer and scarcer. For the past decade, heat integrated water allocation networks (HIWANs) have drawn more and more attention, owing to the efficient utilization of water and energy. In this article, a systematic procedure for the synthesis of heat exchanger networks (HENs) in HIWANs has been proposed. A graphical tool, named heat transfer blocks diagram, is developed to improve the conceptual understanding for the implications of HEN structures in HIWANs. The minimum hot/cold utility consumption can be obtained by analyzing heat surpluses and heat deficits between cold stream and hot stream heat transfer blocks, while heat transfer matching blocks are introduced to deal with the heat exchange matches. Not only simplex series or parallel structures but also hybrid structures can be obtained via this graphical tool. Besides, a heuristic of step by step maximizing the heat load of heat exchangers is presented to guide the heat transfer matching blocks to the lower investment cost direction. Cost-effective HENs have been identified by the proposed systematic procedures. Two examples are illustrated to demonstrate the operability and availability of the systematic procedures.