Experimental investigation and analysis of a new single-stage vacuum spray flash desalinator utilising a gas-liquid ejector

Abstract

Abstract The aim of this research is to investigate the performance and the dynamic thermo-fluid behaviour of a new vacuum spray flash desalinator. This is the key component of the open water cycle in the discharge thermal energy combined desalination (DTECD) system utilising a gas-liquid ejector (eductor). A down-flow eductor using saline water as a motive fluid is proposed for this new single-stage vacuum desalinator. The effects of the temperature and the salinity of motive fluid on the performance of eductor are investigated. The exergy efficiency of the system and its components are evaluated. Experimental results indicate that the performance of the proposed desalinator aligns well with the evaporation model. The proposed eductor is also reliable and easy to operate for generating a vacuum as required close to 6 kPa. This pressure is lower than the corresponding saturation pressures of the operating temperature range between 55 °C and 75 °C. The results show that lower vacuum pressure is obtained when the temperature of the motive fluid is lower (about 30 °C or less). The eductor was operated using 3% and 3.5% by weight of saline water and the results show that the salinity of the motive fluid does not significantly affect the performance of the system. Thus, utilising seawater can be an alternative and cheap option for operating the eductor.