Exergoeconomic optimization of a double effect evaporation process of coffee extract

Abstract

The exergoeconomic optimization performed on different industrial processes is used to reduce investment costs, operational costs and the exergy destruction rate in order to increase at the same time the rentability and sustainability of a factory. This study focuses on exergoeconomic optimization of a double effect evaporation process of coffee extract in a factory located in Ecuador. The specific product cost was minimized, and the exergetic efficiency was maximized by a parametric study with an iterative methodology and the integration of a sub-optimized steam recompression system. The parametric study showed that the exergetic efficiency could be increased by 5% and the exergy destruction cost cost rate reduced by $1143/h by changing the concentration of the feed extract, the pressure of the 1st effect and the outlet pressure in the expansion valve to 26 w/w%, 35 kPa and 300 kPa, respectively. However, by integrating the mono-objective optimized steam recompression system in the process, the exergy destruction cost rate could be reduced up to 73%, the exergetic efficiency could be increased by 13% and the specific product cost could be reduced by $225/t.