Assessment of Water Droplet Evaporation Path in a Full Separation MED Desalination System

Abstract

An innovative concept of full separation multi effect distillation (FSMED) desalination system has been proposed in the present study. A full separation tank (FST) is integrated to a conventional multi effect distillation (MED) water treatment system to enhance the water productivity and thermal efficiency. The concentrated brine from the MED is atomized into tiny droplets and fully evaporated in the FST due to the effective convective heat transfer between water droplets and hot air-steam flow. A simplified non-equilibrium vaporization model is developed to describe the movement and evaporation behavior of a single water droplet in FST. Simulations are conducted to investigate the effect of the radiation heat transfer and droplet gravity on the droplet evaporation and movement behavior. The relationship of the water droplet size and falling distance with the hot air-steam temperature, and initial injection/spray parameters is investigated and presented. Results from the study provide important guidance to the design of such a water treatment system.