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The mass transfer performance of the absorption of CO 2 in an aqueous solution of monoethanolamine was evaluated experimentally in a lab-scale absorber packed with high efficiency DX structured packing and compared with that of methyldiethanolamine (MDEA) as well as that of a newly developed tertiary amino alcohol, 4-diethylamino-2-butanol (DEAB). The absorption experiments were conducted at atmospheric pressure, using a feed gas mixture containing 14.9% CO 2 and 85.1% nitrogen in an absorption column containing DX structured packing. The absorption performance was presented in terms of the CO 2 removal efficiency, absorber height requirement, effective interfacial area for mass transfer, and overall mass-transfer coefficient (K G a v ). In particular, the effects of parameters such as inert gas flow rate and liquid flow rate were compared for both DEAB and MDEA. The results show that the DEAB has a much higher removal efficiency for CO 2 along the height of the column than MDEA. Also, the K G a v of DEAB was much higher than that for MDEA. For all the solvents, the K G a v increased as the liquid flow rate was increased. An empirical correlation for the mass transfer coefficient for the CO 2 -DEAB system has been developed as a function of the process parameters. In terms of comparison, the results show that the DEAB system provided an excellent overall mass transfer coefficient, which is higher than that of the MDEA system but less than that of MEA.

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In this work, the solubility and diffusivity of nitrous oxide (N 2 O) in aqueous 4-(diethylamino)-2-butanol (DEAB) solutions were measured. Solubility was measured in a stirred cell reactor over the temperature range of 298À343 K and concentration range of 0.68À3.77 M. On the other hand, diffusivity was measured in a laminar jet absorber over the temperature range of 298À318 K and concentration range of 1.0À2.5 M. An attempt was made to correlate the solubility data with well-known models (semiempirical model, RedlichÀKister equation, and polynomial model). It was observed that only the polynomial model correlated the solubility of N 2 O in aqueous DEAB solution satisfactorily with an AAD of 0.1%. Similarly, an attempt was made to correlate the diffusivity data with well-known models (semiempirical model and modified StokesÀEinstein model). The semiempirical model provided better predicted N 2 O diffusivity data compared with the experimental data with an AAD of 3.4%. These data can then be used to determine the physical solubility and physical diffusivity of carbon dioxide (CO 2 ) in aqueous DEAB solutions using the "N 2 O analogy".