An alternative procedure to retrofit an industrial plant. A case study

In this work, an alternative procedure to retrofit an industrial plant is proposed, based on a new heat exchanger network (HEN) synthesis and evolution algorithm. The idea is to consider the retrofitting as a grassroots design, but with match constrains accounted for during the synthesis. First, a lower bound for the HEN total annual cost (TAC) is determined and a new HEN is synthesized. A comparison between this HEN and the actual one is performed to search for structural similarities, forming the set of match constrains. Then, a new HEN keeping those similarities is proposed. The comparison among the three HENs indicate the recommended structural modifications. A Case Study is considered. Results show a reduction on the TAC, indicating the actual HEN is poorly integrated and a retrofit can be performed without many changes on the structure. The automatic HEN synthesis and evolution are performed using the software AtHENS.