One thousand kilograms per hour of a mixture of benzene (B) and toluene(T) that contains 50% benzene by mass are separated by distillation into two fractions. The mass flow rate of benzene in the top stream is 450 kg B/h, and that  of toluene in the bottom stream is 475 kg T/h.  The operation is at steady state.  Write balances on benzene and toluene to calculate the unknown component flow rates in the output streams.

The flowrate of benzene in the feed is 1000 * 0.50 = 500 kg/h.

Streams\mass flow rate Total Benzene Toluene
Feed 1000 500
Overhead
450
Bottoms
475

We are now to the point when we actually need to write our mass balance on this process. For a review, you should go back to look at the information on writing equations from the main pages. In essence, for any component (the total, bezene, or toluene)

Ffeed=Foverhead + Fbottoms

What can we fill in next?




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