Effect of solid surface properties on <scp>CO₂</scp> hydrate propagation and capillary mechanism

Abstract The surface effect of certain material such as silicon wafer, quartz or mica on the formation of CO 2 hydrate is studied by in situ visual observation of CO 2 gas reacting with a water droplet in a restricted space. The results obtained show that the growing process of CO 2 hydrate in a restricted space can be divided into two consecutive stages, hydrate covering at gas–liquid interface and hydrate spreading on solid surface. It is indicated that hydrate spreads on solid surface by continuous formation at the advancing frontier, suggesting that water for hydrate formation might be delivered through both lateral and vertical transmitting path, and lateral driving force for water migration might play a dominant role. Qualitative and quantitative analyses show that solid surface properties play a significant role on hydrate spreading process, probably affecting both the interfacial interaction of hydrates with solid surface and water moving process near solid surfaces.