A vapour mixture containing 15% ethane, 20% propane, 60% isobutane and the rest n-butane is subjected to partial condensation so that 75% of the vapour is condensed. If the condenser temperature is 300 k determine the pressure.
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Help with separation problem chemical engineering?
D7. We are separating a mixture of ethane, propane, n-butane and n-pentane in a distillation column
operating at 5.0 atm. The column has a total condenser and a partial reboiler. The feed flow rate is
1000.0 kmol/h. The feed is a saturated liquid. Feed is 8.0 mol% ethane, 33.0 mol% propane, 49.0
mol% n-butane and 10.0 mol% n-pentane. A 98.0% recovery of propane is desired in the
distillate. A 99.2% recovery of n-butane is desired in the bottoms. Use the optimum feed stage.
Use DePriester chart. Assume relative volatility is constant at value calculated at the bubble point
temperature of the feed.
a. Find Nmin
from the Fenske equation.
b. Find (L/D)min
from the Underwood equation.
c. Use L/D = 1.2 (L/D)min and estimate N and NFeed
from Gilliland correlation.