Formation of CO2 hydrate in the presence of montmorillonite

Since direct disposal of CO2 in the ocean is a highly potential sequestrati on option, the process of oceanic disposal of CO2 has attracted much attent ion as an effective technology that can declerate global-warming. When CO2 is discharged in deep sea region subject to high pressure and low temperatu re, CO2 hydrate can be formed easily. For the design pur pose of the CO2 di sposal process, the formation rate of the CO2 hydrate is required. Furtherm ore, it is well known that natural gas is often found at off-shore, buried under oceanic sediments. It should be necessary, therefore, to understand t he interaction between the gas hydrate and the solid materials in the deep sea bed. The purpose of this paper is to investigate experimentaly the effe ct of day materials in deep sea bed on rate of formation of CO2 hydrate. Si nce montmorillonites are the main components of the clay materials, the aut hors used two kinds of montmorillonites, Na- and Ca-montmorillonite. The Na -montmorillonite is hydrophillic, while the Ca-montmorillonite is hydrophob ic. The rate of formation of the hydrate was determined from measurements o f rate of consumption of CO2. During the process of formation of hydrate, b oth temperature and pressure in the reactor deviate from the initially sett ed values. The authors, therefore, studied the relation between the rate of formation of hydrate at an initial stage and the content of the montmorill onite. It was found that the initial rate of formation of hydrate drops as the content of Na-montmorillonite increases. On the other hand, the effect of the Ca-montmorillonite was not so significant.