Optimization of heat exchanger network via pinch technology: a case study of a dairy facility in Italy

Process integration via pinch technology is widely regarded as an effective approach to boost industrial sustainability and competitiveness by reducing process-related energy and material consumption and environmental impacts. So far, such approach has been mainly applied to energy-intensive processes. As a result, industrial sectors like the food industry still offer wide margins for energy efficiency improvement via pinch analysis. As well known, food manufacturing requires many process operations, such as pasteurization, sterilization, and drying, which involve the heat transfer between products and heating/cooling media. Therefore, the design and optimization of heat exchanger network is crucial to minimize external heating and cooling requirements and improve the recovery of waste heat streams. In this paper, a flexible open-source model is proposed for the design or retrofit of industrial heat exchanger networks (HENs) via pinch-analysis. The model is used to investigate a real dairy process for cream production with the aim to identify the energy saving opportunities and assess the potential techno-economic and environmental benefits. The study found out that the design of the heat exchangers network under conditions of maximum energy recovery results in a significant reduction of 95.8 kW in the thermal power exchanged with external utilities. This improvement provides a reduction in the thermal power of hot and cold utilities by 48.5% and 44.9% respectively compared to the reference case.