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Chemical Engineering – Absorption tower design.
Problem detail
A gaseous mixture containing CO2 and ethanol, with a molar composition of 92 % CO2 and 8 % ethanol, is evolved from a fermentation process. The ethanol must be recovered by means of a countercurrent absorption process using water as the solvent. The gas mixture will enter the tower at a rate of 4000 m3 h- at 25 °C and 1.1 atm, while the solvent (water) will be supplied at a flowrate of 6500 kg h-1 and also at 25 °C. The required recovery of ethanol is 97.0 %, while the pressure drop for the gas stream should not exceed 250 Pa m-1 of packed height. Assume negligible CO2 is absorbed into the water and the column is isothermal.