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Composition of Streams Connected to a Flash Vaporization Unit

A feed stream to a flash vaporization (FV) unit contains water (30%, mole) and acetone. The feed flow rate is 1000 mole/min. The mixture is sent to a continuous flash vaporization unit at atmospheric pressure where 50% of the solution leaves the unit as vapor. The liquid stream from the flash vaporization unit is sent to a second FV unit. The liquid stream leaving the second unit contains 10% (mole) acetone.

a) Determine the composition of streams leaving the first FV unit.
b) Determine the amount of liquid and vapor leaving the first FV unit.
c) Determine the amount of streams leaving the second FV unit.
d) What is the composition of the vapor stream leaving the second FV unit?
e) Calculate the total recovery of acetone from this process.

Please see the attached files for more information on flash vaporization.


Solution Preview

Assumption: 50% of the solution leaves the unit as vapor - assuming molar percentage.

Moles of water entered in first FV unit = 30% (mole) = 300 moles/min
Moles of acetone entered in first FV unit = 70% (mole) = 700 moles/min

As Acetone is converted into vapor, 50% (mole) of the solution is converted into vapor, i.e., 500 moles/min of acetone converted into vapor.

Therefore, ...

Solution Summary

This solution helps with a problem regarding the composition of streams.