Design comparative analysis of convection-enhanced evaporation systems

Abstract

This study presents a detailed mathematical model for cross-flow and parallel-flow configurations of convection-enhanced evaporation (CEE) systems and uses the model to perform a design configuration comparison. Convection-enhanced evaporation is a brine management technology that relies on evaporating saline liquid films from packed wetted surfaces by forced air convection induced by means of a fan, natural wind, or a combination of both (hybrid approach). The systems were modeled numerically using the finite difference method to predict the evaporation rate and the spatial profiles of process variables, based on operating and inlet conditions. Comparison between the model and previously published experimental data showed a good agreement. Three design aspects were explored in this study. The first design aspect investigated the liquid–air flow configuration; cross-flow configuration was found to improve the evaporation performance by up to 6% at high liquid temperatures. The second design aspect was related to the alignment and wetting of the surfaces, where vertical double-sided wetted surfaces reduced the footprint area of the system by up to 77% at low liquid temperatures. Finally, a novel hybrid wind–fan operation to reduce energy consumption was described, achieving an energy savings of 18%.