Electrohydrodynamic (EHD) desalination of sea water

• Main Author: Chen, Yuanhong
• Format: Others
• Language: en
• Published: McGill University 1992
• Subjects: Saline water conversion.; Electrohydrodynamics.
• Online Access: http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60676

The distillation of sea water is of importance for the future demands for potable water and other uses in the world. A novel technique, based on electrohydrodynamic (EHD) principles, was used in this realm to desalinate artificial sea water of 3.3% (w/V) concentration. A single point corona electrode was operated at a potential of 5.3 kV (maximum output current 0.3 mA), and was installed one cm over the surface of sea water. The flux of air ions was about 3.0 $ times$ 10$ sp{12}$ cm$ sp{-2}$ s$ sp{-1}$ which produced an average electric wind of 1.72 m s$ sp{-1}$ at the sea water surface. Space charge from a corona electrode generated forces in the media to enhance the evaporation rate by about a factor of three compared with a control freely evaporating sea water. Water vapour was condensed and the condensate's purity was evaluated by chemical and physical analyses. Electrical conductivity and pH of the EHD distillate were found to be 14 $ mu$S cm$ sp{-1}$ and 5.5, respectively. In the absence of Joule heating, the energy required for EHD-distillation was comparable to the latent heat of vaporization of 2.3 $ times$ 10$ sp3$ kJ kg$ sp{-1}$ for water. The steady-state temperature of EHD solution was below that of the corresponding unventilated freely evaporating sea water. Electric wind caused by the ionic drag is considered to be the principal driving force for the enhancement.