| Abstract The removal of carbon dioxide (CO2) using an absorption with chemical reaction technique is essential for many industrial operations where the primary purpose is either to enhance the quality of the gas products or to help reduce the emissions of greenhouse gases generated from fossil fuels. The efficiency of the CO2 absorption process is greatly dependent upon a number of factors, including the extent of gas-liquid contact provided by column internals. During the past decade structured packings, one category of column internal devices, are gaining popularity in a wide range of applications, including gas treating, owing to their favorable performance. However, knowledge of the mass-transfer characteristics and fluid dynamic behavior of these packings is very limited. Therefore, the objective of the present study is to develop a better understanding of the mass-transfer and dynamic behavior of structured packings for CO2 absorption processes with chemical reaction.; This thesis provides comprehensive experimental data on the CO2 absorption performance of structured packings. Over 100 runs of absorption experiments were carried out in a pilot-scale absorption unit where the columns were fitted with four types of stainless-steel structured packings: Gempak 4A, Mellapak 500Y Mellapak 500X, and Optiflow. Aqueous solutions of sodium hydroxide (NaOH) and monoethanolamine (MEA) were used as the absorption solvents. The performance of the packings is presented as CO2 concentration profiles and evaluated in terms of the volumetric overall mass-transfer coefficient (KGae) over ranges of operating and design parameters, i.e. 39--77 kmol/m2-h gas load, 3.8--30.0 m 3/m2-h liquid load, 1.0--5.2 kmol/m3 absorbent concentration, 19--50°C liquid feed temperature, 255--1528 points/m2 initial liquid distribution quality, and 0--90° packing rotation. The experimental results show that the CO2 absorption performance of the test packings varies significantly, not only with operating conditions but also with design parameters. The direct effect of each parameter on the absorption performance was determined.; This thesis also proposes a mechanistic concept or model that can predict the mass-transfer performance and provide an insight into the dynamic behavior within the structured packings used for CO2 absorption. The mechanistic concept was built upon the kinetics and thermodynamics of the absorption system, as well as the liquid irrigation features of the packing elements and the packing geometry. A computer program (Fortran 90) was written to simulate CO2 absorption into aqueous solutions of NaOH and MEA in a column packed with Gempak 4A, Mellapak 500Y and Mellapak 500X. (Abstract shortened by UMI.)... |
