| Summary: | 碩士 === 中原大學 === 化學工程研究所 === 100 === The reaction kinetics for the absorption of CO2 into aqueous solutions of Diethylenetriamine (DETA) and into mixed aqueous solutions of DETA and Piperazine (PZ) were investigated by a wetted wall column at 30, 35 and 40°C. The systems studied were: DETA (5, 10, 15, 20, 25, and 30 wt%) + H2O and DETA (26 wt%) + PZ (4 wt%) + H2O, DETA (22 wt%) + PZ (8 wt%) + H2O, DETA (18 wt%) + PZ (12 wt%) + H2O. The physical properties such as density, viscosity, Henry’s constant and diffusivity of the studied systems were also measured. Due to the reactivity of CO2 to the amine system, an N2O analogy was used to estimate the solubility and diffusivity of CO2 in the aqueous amine solutions.
From the kinetics measurements, the absorption rates of CO2 in the aqueous blended DETA/PZ solutions were found to be significantly faster than in conventional amine systems. The reaction rate constants were calculated by applying a hybrid model which combines a pseudo-first-order model with a zwitterion mechanism. This model was found to satisfactorily represent the absorption of CO2 in both the aqueous DETA and aqueous blended DETA/PZ systems. It can be concluded that the results of this study can be used in the design of absorption processes which employ aqueous solutions of DETA or DETA/PZ as absorbents.
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