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October, 2006
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The Effect of Reflux Ratio on Tray Distillation Efficiency

JoVE 10432

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA

Tray and packed columns are both commonly used for distillation, absorption, and stripping separation operations.1,2 The goal of this experiment is to distill a mixture of alcohols (methanol, isopropanol) and water in a sieve tray column and examine how closely simple theories of distillation based on equilibrium assumptions are followed. Sieve trays provide maximum interfacial area between the liquid and vapor. A P&ID schematic of the sieve tray (each tray contains holes in a support plate) distillation system can be found in Appendix A. In this demonstration, the Tray Distillation Unit (TDU) is started in total reflux mode. After a steady reflux drum level is attained, a switch to finite reflux mode is made by adjusting the bottoms, distillate and reflux flow rate controllers as necessary to maintain steady levels in the reflux drum and the reboiler, and to maintain a target reflux ratio RD = L/D. Once steady state is achieved (takes at least 90 min), liquid samples will be taken from the reflux drum, reboiler and on each tray and analyzed in a gas chromatograph. A typical protocol is to investigat

 Chemical Engineering

Gas Absorber

JoVE 10436

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA

Gas absorbers are used to remove contaminants from gas streams. Multiple designs are used to accomplish this objective1. A packed bed column uses gas and liquid streams running counter to each other in a column packed with loose packing materials, such as ceramics, metals, and plastics, or structured packing1. The packed bed uses surface area created by the packing to create a maximum amount of efficient contact between the two phases1. The systems are low maintenance and can handle corrosive materials with high mass transfer rates1. Spray columns are another type of absorber, which uses constant direct contact between the two phases, with gas moving up and liquid being sprayed down into the gas flow1. This system only has one stage and poor mass transfer rates, but is very effective for solutes with high liquid solubility1. The goal of this experiment is to determine how variables including gas flow rate, water flow rate, and carbon dioxide concentration affect the overall mass transfer coefficient in a gas absorber. Understand

 Chemical Engineering

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