Distillation Column By Jesse Reeves
Outline Where we are, where we want to be. How to get there. What we used and what we got. The trouble. The model.
What we have 12 tray bubble-cap distillation column Isoproply alcohol water separation
What we want Same distillation column Ethanol water separation
How to get there Operate column at total reflux Determine stage efficiency Model the column in Aspen Compare Aspen model to real IPA separation results Apply the Aspen model to an Ethanol separation
Theory to get there Equilibrium curveStripping operating line Rectifying operating lineMurphree-vapor efficiency
Theory in a graph
The Column
The Data Calibration StageStateMethodMass%IPAErrory* Mass% AveErrorEmv eqError 2LiquidPycnometer LiquidPycnometer LiquidPycnometer LiquidPycnometer LiquidPycnometer LiquidPycnometer LiquidPycnometer LiquidPycnometer LiquidRI LiquidRI LiquidRI
The Trouble
The IPA separation
The ETOH separation
The model The IPA Aspen model -4.7% at the top +8.4% at the bottom The three important stages 7, 9, and 10 Murphree- vapor efficiencies were %, %, % Overall column efficiency 8.3% Stage efficiency did not matter
The Aspen model for ETOH Max flow rate: 2.13 GPM Steam flow rate: 1.67 kg/min Condenser heat duty: kJ/min Feed composition: 2.5 wt% ETOH Distillate composition: 40 wt% ETOH ETOH recovery: 99.4%
Recomendations Replace the automatic control valve for the steam flow to the reboiler. Replace the leaky manual steam valve. Refine the ETOH model with steady state data.
Special thanks to team-J Jaron Stanley: Team Leader James Gardner: Operator Jesse Reeves: Team player
References Seader, J. D., Henley, Ernest J., Separation Process Principles, John Wiley & Sons, Inc. pp. 44, 301, (1998). Distillation Column Manual, unpublished printed notes, Univ. of Utah, Salt Lake City, Utah 1997.
Questions ?