RO PRETREATMENT USING HYDRATE BASED ICE DESALINATION PROCESS

Abstract

There are a variety of methods for seawater desalination, and seawater desalination method through ice-freezing also exists. This study discusses freezing desalination as a new method to combine direct contact freezing and indirect contact freezing. It is the first method as well to generate ices by utilizing CO2 Hydrate itself as refrigerant. This study explores HBID (Hydrate Based Ice Desalination)process.In HBID process, hydrate dissociation energy is used for cooling down water temperature and finally making ice. There are three factors freezing energy of HBID system. Joule-Thomson Effect, endothermic energy of carbon dioxide emission and endothermic energy of hydrate dissociation. The endothermic energy of hydrate dissociation is most dominant proposition as the major freezing energy of HBID system among the three factors.TheHBID process rejection efficiency increased as the NaClconcentration of feed water increased. However, when the NaCl concentration of feed water decreased the produced water quantitydecreased. In case of 10, 20 and 50ppm humic acid solution treatment, the rejection is above 70%. .HBID process is not significantly influenced by impurities such as the concentration of ion or organic matters,It has huge advantage to be utilized as the preconditioning process of membrane separation when treating high salinity waste water such as RO brineand Shale gas drawback water. In the case of cation analysis every cation rejection is higer than 50%.It also have more than 50% of performance in treatment efficiency of B3+ with the highest difficulties in treatment so they can be easily utilized in the front side of RO. Therefore, the development of HBID technology can be utilized alone in the process of seawater desalination or waste water treatment to contribute to generating pure water and decreasing the volume of waste water such as RO brine.