One thousand kilograms per hour of a mixture containing equal parts by mass of ethanol and water is distilled. Product streams leave the top and the bottom of the distillation column. The flowrate of the bottom stream is measured and found to be 673 kg/h, and the overhead stream is analyzed and found to contain 96 wt% ethanol. Find the flowrates of all components in all streams.

With both of the mass fractions known, we can write:

Foverhead,water = Foverhead,total * xoverhead,water = 327*0.04 = 13.08

Foverhead,ethanol = Foverhead,total * xoverhead,ethanol = 327*0.96 = 313.92

Let's put both of these values into our table:

Streams\mass flow rate Total Ethanol Water
Feed 1000 500 500
Overhead 327 313.92 13.08
Bottoms 673


There is nothing else that we can get from the problem statement at this point. We should write some mass balances in order to solve out the rest of the problem. Go ahead and try to fill in the rest of the table at this point.


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