Desalination of Seawater by Liquid Columns and Decompression Boiling (Recovery of Condensation Latent Heat)
- 1 Graduate School of Engineering, Mie University, Tsu-shi, Japan
Abstract
In this study, the concept of a new seawater desalination method and equipment using liquid columns of seawater and desalinated fresh water, decompression boiling and evaporation, condensation, and recovery of condensation latent heat are proposed. The equipment consists of seawater and freshwater columns approximately 10 m high with top spaces. The pressure of the top space, the evaporation and condensation area, of the seawater column, for example, is reduced approximately 30 mmHg (abs.) using the seawater column, after which it is heated from the general seawater temperature of 25°C to 30°C to boil and evaporate the seawater. The vapor is cooled by the seawater at approximately 25°C in a heat exchanger, and then, it is condensed and sent to the fresh water column. At this time, the condensation latent heat is recovered to preheat the newly flowing seawater. The evaporation or condensation rate, namely, the production rate of freshwater, by the new desalination equipment is also estimated by the results of the existing quadruplex effect vacuum evaporator used in the salt production industry. This new desalination method and its associated equipment also can be used to purify polluted water and waste water.
- Hashimoto, H. (2004) Vacuum- and Pressurized-Salt Production Methods. Vol. 38, Encyclopedia Salt, Tobacco & Salt Museum, The Salt Science Research Foundation, Japan. http://www.geocities.jp/t_hashimotoodawara/salt6/salt6-04-09.html
- Al-Kharabsheh, S. and Goswami, D.Y. (2003) Analysis of an Innovative Water Desalination System Sing Low-Grade Solar Heat. Desalination, 156, 323-332. https://doi.org/10.1016/S0011-9164(03)00363-1
- Gude, V.G. and Nirmalakhandan, N. (2009) Desalination at Low Temperatures and Low Pressure. Desalination, 244, 239-247. https://doi.org/10.1016/j.desal.2008.06.005
- Shalabh, C.M. and Goswami, D.Y. (2009) Theoretical Analysis of a Single-Stage and Two-Stage Solar Driven Flash Desalination System Based on Passive Vacuum Generation. Desalination, 249, 635-646.
- Shakouchi, T. (2014; 2011) Boiling Type Seawater Desalination Apparatus, and Method. Japanese Patent, No. 5398046B2.
- Naikai Salt Industries Co., Ltd. (2008) Technical Data.
- Water Reuse Promotion Center, Japan (2004) Desalination Technology Handbook.
- The Salt Industry Center of Japan (2006) Data Book for Seawater Science and Salt Production.