Theory Research on Desalination of Brackish Water Using Gas Hydrate Method

In allusion to some methods on desalination of brackish water such as distillation, electrodialysis method and reverse osmosis, this paper introduced the mechanism, advantages and disadvantages of these methods. It is convinced that these methods have higher energy consumption. Temperature is much lower annually in alpine region of China, it provides a good condition for hydrate formation. It also provides the possibility for the desalinating process of brackish water using hydrate methods in alpine region. This paper proposed a new method of desalinating brackish water. Based on the model of van der Waals-Plafteeuw, we calculated the phase equilibrium conditions of methane, ethane and propane hydrate in NaCl solution combined parameter equation which was used to calculate the Langmuir constant presented by DU Ya and GUO Tian-min and Pitzer equation used to water activity in the system of electrolyte solution. The result shows that it is possible to desalinate brackish water using environment cold quantity. It also shows that propane is more suitable for brackish water desalination among methane, ethane and propane. It is very significantly important to seek energy-saving and environment-friendly methods for the process of desalinating brackish water with energy shortage increasingly intensifying and with awareness of human being enthancing on energy conservation and emission reduction.