Design and Synthesis of Heat Exchanger Networks with Variable Stream Properties

Abstract

In recent years, demands for highly efficient processes have grown substantially due to environmental concerns, increase in global demand for high-quality products and search for more cost-effective ways to maintain operational goals. For more than 30 years, research in the field of process optimization has brought us closer to achieving rigorous mathematical models that can best describe an efficient, reliable heat exchange network for a process in order to reduce utility and resource costs while improving returns on investments. In this work, mathematical HEN models were designed to consider flexibility of operational conditions, such as temperature and flow rate, to reach an optimized process. This was done by proposing a novel approach to modeling that will investigate the effects of stream property profiles when considered as a variable function of temperature. The minimum total annual cost in two case studies has changed in the range of -0.9% to 7.2% compared to base cases (where properties are assumed constant). It was also observed that investment costs are mostly affected by heat exchanger design variables (heat transfer coefficient, viscosity and thermal conductivity) while utility costs are mostly affected by variable