Indexed by:期刊论文

Date of Publication:2020-10-01

Journal:ENERGY

Volume:208

ISSN No.:0360-5442

Key Words:Heat exchanger networks; Controllability; Optimization; Control structure

Abstract:Controllability issue of heat exchanger networks (HENS) has drawn an increasing attention in recent years. Currently, the study of controllability of HENs is still towards a certain network structure, which is still not able to integrate controllability within HEN synthesis. To overcome this challenge, a new two-stage optimization framework is proposed in this work to implement the HEN design with economy and controllability automatically incorporated. In the first stage, an iterative procedure is developed to incorporate the optimization of network and control structure. Two controllability rules, referring to network structure design and control loops selection, are introduced to ensure the initial network structure is endowed with good controllability property, and the disturbance propagation and control (DP&C) model is re-formulated based on superstructure presentation to perform the automatic evaluation of controllability. Afterwards, the decision variable optimization stage is executed to further optimize the results by taking the locations and fractions of bypasses as decision variables. Finally, two cases are studied and the results show that the controllability are improved by 10.6% and 30.0%, respectively, with a less increment of total cost. Based on the results, the inconsistent effect of bypass fraction on cost and controllability has been also discussed. (C) 2020 Elsevier Ltd. All rights reserved.