Enhancement of MSF Using Microbubbles

Abstract

Abstract Multi Stage Flash (MSF) distillation plants are widely used in saline water desalination. In order to enhance MSF, it is important to increase an evaporation rate in the flashing stage. A spray flash method, in which superheated water jets are injected through nozzles into a depressurized environment to increase the gas/liquid interface area, is a promising technique to make the increase of evaporation rate, which leads directly to the reduction of energy consumption and cost of the MSF plant. In this paper, the introduction of microbubbles into the spray jet as the nucleation sites to increase the evaporation rate of the spray flash is proposed. The spray flash behaviours with/without microbubbles at outside/inside of the nozzle-inside were observed by means of a high speed camera to investigate the mechanism of enhancement of spray flash due to microbubbles. Moreover, the number densities of droplets and bubble volume increase were obtained from visualized images in order to discuss quantitatively on the effects of introduction of microbubbles.