Call it 14 equilibrium stages plus a partial reboiler

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Unformatted text preview: the partial reboiler as an equilibrium stage. Exercise 7.29 (continued) Exercise 7.30 Subject: Recovery by distillation with open steam of solvent A from water in two feeds. Given: Two saturated liquid feeds, each containing 50 kmol/h of A. Feed 1 contains 40 mol% A and Feed 2 contains 60 mol% A. Unit consists of a column and a total condenser. Open steam is used in lieu of a partial reboiler. Relative volatility = 3.0 for A with respect to water. Distillate is to contain 95 mol% A with a 95% recovery. Assumptions: Constant molar overflow. Open steam enters bottom stage as saturated vapor. Both feeds enter at optimal locations. Find: For an overall plate efficiency of 70% and an R = L/D = 1.33 times minimum, determine the number of actual plates. Compute the bottoms composition. Determine analytically the location of all three operatiing lines. Analysis: The total flow rate of Feed 1 = 50/0.4 = 125 kmol/h. The total feed rate of Feed 2 = 50/0.6 = 83.3 kmol/h. The total feed rate of A = 50 + 50 = 100 kmol/h. For...
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This note was uploaded on 09/08/2008 for the course CHE 244 taught by Professor Selebi during the Spring '06 term at Lehigh University .

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