Effect of axial dispersion on interphase mass transfer in packed absorption columns
"A steady state approach was followed in this investigation to determine the effects of liquid and gas flow rates, packing size and packing height on the interphase mass transfer coefficient and gas phase axial mixing Peclet numbers. Experiments were performed on the absorption of carbon dioxide from a mixture of carbon dioxide and nitrogen in a packed column. Absorption was performed using 1/4, 3/8 and l/2 inch Raschig rings, with a packing height of 3 feet and also using 3/8 inch Raschig rings with a packing height of 5 feet. The liquid and gas flow ranges used were 2865 to 5680 lb./hr.sq.ft. and 5.0 to 7.4 lb./hr.sq.ft respectively. Three mathematical models, viz. (i) plug flow in both the gas and liquid phases, (ii) axial mixing in gas phase and plug flow in liquid phase, and (iii) axial mixing in both gas and liquid phases, were used. It is found that axial mixing in the gas phase increases with increases in liquid flow rate, packing size and packing height. The behavior of apparent and true mass transfer coefficients indicates a decrease in axial mixing with increases in gas flow rates. However, axial mixing is found to be small under the experimental conditions used in this investigation. The gas phase Peclet numbers obtained in this investigation are about fifty times greater than reported by workers using a transient technique under the same conditions. Correlations for the apparent and true over-all liquid phase mass transfer coefficients are also presented"--Abstract, page ii.
Missouri University of Science and Technology
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