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Optimal Operation of Heat Exchanger Networks
Journal
IFAC-PapersOnLine
Date Issued
2022-01-01
Author(s)
Karthika, M.
Jogwar, Sujit S.
Abstract
Heat exchanger networks (HENs) constitute the backbone of any process industry. They serve as one of the key elements for energy savings and provide for economic viability in a long run. While the structural design considers minimising utility or heat transfer area or total annualised cost, operability aspects are usually neglected or given minimum consideration. Typically, bypasses are employed across certain heat exchangers in a HEN to improve flexibility and controllability of the system. These extra degrees of freedom can also be used to optimise the operation. In this paper, a strategy of optimal operation based on a novel concept of energy flow redistribution is proposed. It is shown that the energetic effect of a disturbance can be optimally distributed across the HEN to minimize its impact on the overall utility consumption. This optimal redistribution is computed by allowing duties of individual heat exchangers to vary within their allowable limits and implemented through the manipulation of the corresponding bypass fraction using a feedback control system. The approach is illustrated for an example HEN with 3 hot and 3 colds streams. The proposed approach allows for significant reduction in utility consumption in the presence of disturbances.
Subjects