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This work presents experimental data and a model for the initial kinetics of CO 2 into 3-(methylamino)propylamine (MAPA) solutions. MAPA has been tested as an activator for tertiary amines with encouraging results. The measurements were performed in a string of discs contactor and, since no initial kinetics data is available in literature, additional measurements were carried out and in a wetted wall column. The obtained overall mass transfer coefficients from both apparatuses are in reasonable agreement. To obtain values for the observed kinetic constant, obs k , the experimental results were interpreted using a two-film mass-transfer model and invoking the pseudo first order assumption. Needed experimental values for density, viscosity and Henry's law coefficient for CO 2 were measured and are given. The results indicate that MAPA is almost twice as fast as PZ, 8 times faster than AEEA, and 15 times faster than MEA, when comparing unloaded 1M solutions at 25ºC. The observed kinetic constant was modelled using the direct mechanism. The final expression for obs k can be applied for any concentration and temperature within the experimental data range, and, together with the presented physical data, comprises a complete model for calculating absorption fluxes.

The kinetics and morphology of ethane hydrate formation were studied in a batch type reactor at a temperature of ca. 270-280 K, over a pressure range of 8.83-16.67 bar. The results of the experiments revealed that the formation kinetics were dependant on pressure, temperature, degree of supercooling, and stirring rate. Regardless of the saturation state, the primary nucleation always took place in the bulk of the water and the phase transition was always initiated at the surface of the vortex (gas-water interface). The rate of hydrate formation was observed to increase with an increase in pressure. The effect of stirring rate on nucleation and growth was emphasized in great detail. The experiments were performed at various stirring rates of 110-190 rpm. Higher rates of formation of gas hydrate were recorded at faster stirring rates. The appearance of nuclei and their subsequent growth at the interface, for different stirring rates, was explained by the proposed conceptual model of mass transfer resistances. The patterns of gas consumption rates, with changing rpm, have been visualized as due to a critical level of gas molecules in the immediate vicinity of the growing hydrate particle. Nucleation and decomposition gave a cyclic hysteresis-like phenomena. It was also observed that a change in pressure had a much greater effect on the rate of decomposition than it did on the formation rate. Morphological studies revealed that the ethane hydrate resembles thread or is cotton-like in appearance. The rate of gas consumption during nucleation, with different rpm and pressures, and the percentage decomposition at different pressures, were explained precisely for ethane hydrate.

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