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NÇ gw=molar ¯ux of CO2 di€using into water-rich liquid phase NÇ gh=molar ¯ux of CO2 through hydrate ®lm Mh=e€ective molar mass of hydrate given by Mg+nMw Kfg, kfw=kf in CO2-rich liquid phase and that in water-rich liquid phase, respectively Kf=reaction rate constant for hydrate formation

Kdg, kdw=kd in CO2-rich liquid phase and that in water-rich liquid phase, respectively Kd=reaction rate constant for hydrate decomposition *Address correspondence to: Fax: +81-4, e-mail: : CLATHRATE HYDRATE FORMATION

G,1=fugacity of CO2 in bulk of water-rich liquid phase All rights reservedĪg=activity of CO2 dissolved in water-rich liquid phaseĪh=speci®c hydrate/liquid interfacial areaĬg=mass concentration of CO2 in water-rich liquid phaseĬgs=solubility of CO2 in water expressed in mass concentrationĬgs(h)=cgs in equilibrium with hydrate (used only when distinction from cgs(0) is necessary)Ĭgs(0)=cgs in metastable absence of hydrate (used only when distinction from cgs(h) is necessary)Ĭg,d=cg at z = d (hydrate/water-rich-liquid interface)Ĭg,1=cg in bulk of water-rich liquid phaseĬÄg=molar concentration of CO2 in liquid phaseĬÄg,1=cÄg in bulk of water-rich liquid phaseĬ~*g =overall molar concentration of CO2 (excluding guest CO2 molecules in hydrate) in multi- or singlephase space equal to cÄg and cÄ $g when cÄh=0ĬÄ $g=overall molar concentration of CO2 (including guest CO2 molecules in hydrate) in multi- or singlephase space equal to c~*g and cÄg when cÄh=0ĬÄh=molar concentration of hydrate regarded as compound with molar mass MhĬÄL=molar density of liquid phase (=cÄg+cÄw)ĬÄw=molar concentration of water in liquid phaseĬ~*w =overall molar concentration of water (excluding host water molecules in hydrate) in multi- or singlephase space equal to cÄw when cÄh=0ĭgh=mass di€usivity for CO2 in hydrate phaseĭgw=mass di€usivity for CO2 in water-rich liquid phaseĭh=e€ective di€usivity for hydrate particles in liquid phaseĭwg=mass di€usivity for water in CO2-rich liquid phase Revealed suggests the necessity of more careful consulting of pertinent experimental observations toĮstablish our physical view about hydrate ®lms, which should serve as the base of any further work on The state of the art of hydrate-®lm modeling thus Reality or mathematical formulation is pointed out.

Each model is critically examined, and if any, its weakness in physical This paper reviews those rival models one by one and illustrates how they are discrepant. On the formation and metabolic self-preservation of a hydrate ®lm at the interface and also the mass Eight di€erent models have been proposed so far To mitigate the emission of CO2 into the atmosphere. Liquid water is one of the key processes in the course of direct CO2 disposal into deep seasÐan option All rights reservedĭepartment of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 2238522, JapanĪbstractÐThe clathrate hydrate formation at the interface between lique®ed carbon dioxide (CO2) and