Question

Separations Question

It is desired to recover atleast 95% of ethanol from a mixture of ethanol and carbon dioxide (containing 98 % CO2 and 2 % ethanol) by scrubbing the vapor mixture with pure water. Assume equilibrium relation Y = 0.57 X. The gas stream enters the absorption column at 180 kmol/hour (V’) at 120 kPa (P) and 27 °C (T). The carrier gas may be considered insoluble in the solvent and the solvent may be considered nonvolatile. Assume dilute species with constant flow rates and isothermal and isobaric trays/stages.

(a) Calculate minimum water flow rate (L’min) to perform the operation.

(b) If the actual liquid rate is 1.5 times the minimum value, solve for the actual number of trays using graphical methods/EXCEL/MATLAB/MATHCAD etc. Calculate and show the concentrations after each stage.

(c) If the actual liquid rate is 1.5 times the minimum value, solve for the actual number of trays using the Kremser relationship.

Answer 1