Chamorro-Romero L., Radgen P., 2020, Optimal Integration of Organic Rankine Cycles with Heat Exchanger Networks Using Intermediate Heat Transfer Fluids, Chemical Engineering Transactions, 81, 991-996.
In recent years, different methodologies and mathematical models have been proposed for the optimal integration of Organic Rankine Cycles (ORC) into Heat Exchanger Networks (HEN) for the recovery of low-grade heat. Most of these works have been focused on the optimization of the ORC configuration or its operational parameters and assume a direct heat exchange between the working fluid and the process streams. However, in many industrial applications a direct heat exchange between the working fluids and the process streams is undesirable due to logistics, controllability or safety reasons and an intermediate heat recovery loop (HRL) using heat transfer fluids (HTFs) is preferred. This work proposes a novel stage-wise superstructure for the optimal integration of ORCs into HENs through the use of intermediate HTFs. These HRLs can be located between the ORC and the hot or cold streams. In this work the objective function will be the net power generated by the ORC from the waste heat. A case study from the literature is presented to demonstrate the methodology and the results are compared with the case of the direct heat exchange between working fluid and process streams. The novelty of the formulation lies on the integration of the ORC into the background process using HTFs while simultaneously performing the synthesis of the HEN and the optimization of the operating parameters of the HRLs.
