The main purpose of this experiment is to determine the Murphree’s efficiency for a bubble cap tray and a sieve tray in a distillation column and how the vapor flow rate affects the Murphree’s efficiency. The understanding of efficiencies is essential in the design and assessment of distillation columns, because efficiency determines the degree of separation in mixtures. Distillation columns can be used to separate binary mixtures or mixtures of several components. The mixtures are separated by taking advantage of the different volatilities and boiling points of the individual components. As heat is added to the distillation tower, the more volatile component, and consequently the component with the lower boiling point will be boiled off faster than the less volatile components. The volatile vapor then travels up the tower through the column trays and comes into contact with the less volatile liquid at each tray. Since the vapor that travels up the tower does not only contain one component but a mixture of all the components, the less volatile component will condense back into liquid and create a higher concentrated vapor. The distillate stream is at the top of the tower and contains the desired product of separation.
A distillation column is used to separate a binary mixture of ethanol and water. Ethanol is a more volatile component and thus it will boil off faster than water. The distillation column is operated at total reflux, which is an operating condition where