Flash Separations: Example Problems

Try to solve these problems before watching the solutions in the screencasts.

Example Problem 1

A 50/50 binary liquid mixture of benzene(1) and toluene(2) is flashed to 1.4-bar pressure, and 25% of the liquid vaporizes: \[P_1^{sat}\,=\,2.0 bar\] What is the composition of the resulting vapor?

Example Problem 2

A liquid that is 60% component 1 and 40% component 2 is flashed to 1210 kPa. The outlet temperature is 150ºC. The saturation pressures in kPa are: \[P_1^{sat}\,=\,exp\left(15-\frac{3010}{T+250}\right)\;\;\;\;\;P_2^{sat}\,=\,exp\left(14-\frac{2700}{T+205}\right)\;\;\;\;T \,is\, in ^oC\]

Calculate the fraction of effulent that is liquid and the compositions of the liquid and vapor phases. Assume the liquid is ideal.

For an additional example problem, see this screencast.

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