Heat exchanger network retrofit supported by extended Grid Diagram and heat path development

Heat exchanger network (HEN) retrofit has been an important task in process design. Many approaches have been presented. However, this important activity can still benefit from an enhanced visualisation and decision-making tool. This paper proposes an extended type of Grid Diagram properly visualising the HEN arrangements and key parameters such as heat capacity flowrates (CPs), temperatures and temperature differences. It is capable of accounting for thermodynamics and loads simultaneously. For solving a retrofit design, the SRTGD is supporting the analysis. It can show whether the proposed design is feasible in thermodynamic terms. The SRTGD provides a support for screening feasible and infeasible retrofit options. The possible trends are identified and the limits for the heat recovery increase after a new HEN path are specified. A case study has been used to demonstrate the retrofit procedure enhancement.