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hydrate equilibrium data for gas mixture of carbon dioxide and nitrogen in the presence of an emulsion of cyclopentane in water.. Journal of Chemical and Engineering Data, American Chemical Society, 2014, 59 (3) ABSTRACTCarbon dioxide and nitrogen gas separation is achieved through clathrate hydrate formation in the presence of cyclopentane. A phase diagram is presented in which the mole fraction of CO 2 in the gas phase is plotted against the mole fraction of CO 2 in the carbon dioxide + nitrogen + cyclopentane mixed hydrate phase, both defined with respect to total amount of CO 2 and N 2 in the respective phase. The curve is plotted for temperatures ranging from 283.5 K to 287.5 K and pressures from 0.76 MPa to 2.23 MPa. The results show that the carbon dioxide selectivity is moderately enhanced when cyclopentane is present in the mixed hydrate phase. Carbon dioxide could be enriched in the hydrate phase by attaining a mole fraction of up to 0.937 when the corresponding mole fraction in the gas mixture amounts to 0.507. When compared to the three phase hydrate-aqueous liquid-vapour equilibrium in the ternary system 2 {water +carbon dioxide + nitrogen}, the equilibrium pressure of the mixed hydrate is reduced by 0.95 up to 0.97. The gas storage capacity approaches 40 m 3 gas.m -3 of hydrate. This value turns out to be roughly constant and independent of the gas composition and the operating conditions.

Re´sume´-Ame´lioration de la se´lectivite´du captage du CO 2 dans les semi-clathrates hydrates en utilisant les ammoniums quaternaires comme promoteurs thermodynamiques -La re´duction des e´missions de CO 2 est tre`s probablement l'un des enjeux importants de ce sie`cle. La capture puis le stockage ge´ologique de ce gaz, a`partir de sources industrielles ponctuelles et massives, est une voie d'importance. L'une des voies technologiques consiste a`utiliser les clathrates hydrates, ou semi-clathrates hydrates, qui ne´cessitent de pressuriser le gaz en amont du proce´de´. Sous pression, l'eau et les gaz forment un solide qui encapsule pre´fe´rentiellement le CO 2 , puis le gaz peut-eˆtre ensuite re´cupe´re´sous pression apre`s la dissociation du solide. L'abaissement de la pression ope´ratoire est un objectif en soi afin de faire baisser les couˆts ope´ratoires. Cet abaissement peut eˆtre obtenu par l'utilisation de promoteurs thermodynamiques, dont les sels d'ammonium quaternaires constituent une famille inte´ressante puisqu'ils forment des solides naturellement anti-agglome´rants, et plus facilement manipulables. Dans ce travail, nous pre´sentons de nouveaux re´sultats expe´rimentaux sur les e´quilibres des semi-clathrates de (CO 2 , N 2 ) en pre´sence de Tetra-n-Butyl Ammonium Bromide (TBAB). Nous donnons des mesures expe´rimentales de pression et tempe´rature en fonction de la concentration en TBAB. La pression ope´ratoire peut eˆtre abaisse´e jusqu'a`la pression atmosphe´rique. Nous donnons aussi une information supple´mentaire portant sur la composition de l'hydrate. Nous observons que la se´lectivite´du CO 2 dans les semi-clathrates hydrates est bien meilleure que pour les clathrates hydrates traditionnels, sans promoteur thermodynamique.Abstract -Enhanced Selectivity of the Separation of CO 2 from N 2 during Crystallization of SemiClathrates from Quaternary Ammonium Solutions -CO 2 mitigation is crucial environmental problem and a societal challenge for this century. CO 2 capture and sequestration is a route to solve a part of the problem, especially for the industries in which the gases to be treated are well localized. CO 2 capture by using hydrate is a process in which the cost of the separation is due to compression of gases to reach the gas hydrate formation conditions. Under pressure, the water and gas form a solid that encapsulates preferentially CO 2 . The gas hydrate formation requires high pressures and low

In electroless nickel–phosphorus plating (ENPP), growth of the plated layer under high pressure was found to be faster than under ambient pressure. To quantitatively elucidate the effect of high pressure on the mechanism of the ENPP reaction, we propose a kinetic model that takes into account both mass transfer and reaction of the chemical species present in the plating solution. We solved the mass balance equations between the chemical species to calculate the transient changes in the thickness of the plated layer as well as the concentrations of the chemical species in the plating solution. By fitting the calculated results to the experimentally acquired results based on the nonlinear least square method, we determined such parameters as the film mass transfer coefficient, the adsorption constants, and the reaction rate constants of the chemical species in the model. As a result, we found that the film mass transfer coefficient under high pressure was greater than that under ambient pressure and revealed the dependence of the coefficient on pressure. The transient changes in the concentrations of the chemical species in the plating solution that we calculated based on the kinetic model employing our estimated parameters closely modeled the experimental results with the determination coefficients being mostly over 99%.