The effect of operating gas pressure on CO2 gas hydrate-induced quick-freezing

Abstract

Desalination using freezing has recently attracted attentions for less heat of fusion for water (333 kJ/kg) than evaporation (2,500 kJ/kg). CO2 gas hydrate-induced quick-freezing is a lately developed freezing method using the dissociation energy of CO2 gas hydrate at ventilation. CO2 gas hydrate is an ice-like form with CO2 guest molecule under pressurized condition. The object of this study is to investigate the effect of operating gas pressure on CO2 gas hydrate-induced quick-freezing. Internal temperature shift during the process was monitored to evaluate energy transfer. It was found that two major energies were involved in the process: decarbonation of CO2 gas and dissociation of gas hydrate. DSC (Differential scanning calorimetry) study showed the heat of dissociation (500.13 J/g) was the dominant driving force caused quick-freezing than decarbonation (34.48 J/g). With increasing operating gas pressure, more gas was captured in the solution and caused more drop of temperature.