Effect of Additives on Hydrate Formation

Gas hydrates are crystalline ice-like solid materials that contain small molecular gas species. Their natural abundance has attracted worldwide attention as future clean energy resources, and a variety of industrial applications such as gas storage, separation, and transportation have been proposed. Of particular interest is the additives including hydrate promoters and inhibitors, since they seriously affect the hydrate thermodynamics and kinetics. Hydrate additives can alter the thermodynamic conditions of hydrate formation as well as the nucleation and growth kinetics of hydrates. Therefore, the development of hydrate additives and a comprehensive understanding of their role in hydrate formation and inhibition processes would bring the practical applications significantly closer. In this talk, our investigation of the effect of additives on hydrate formation will be presented. We developed a quartz crystal microbalance system for the quick screening of thermodynamic hydrate promoters. A continuous method using the hydrate memory effect proposed here can measure the hydrate phase equilibria approximately 30 times faster than the conventional method. Another topic is the proposal of amino acids as environmentally friendly hydrate inhibitors. Amino acids were found to have a great potential as both thermodynamic and kinetics hydrate inhibitors. Their inhibition mechanisms were investigated by correlating the inhibition performances with physical and chemical properties.