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A mixture of T and U is separated in a trayed distillation column. Two streams are fed to a tray column with a total condenser
A mixture of T and U is separated in a trayed distillation column. Two streams are fed to a tray column with a total condenser and partial reboiler operating at 1.2atm. Feed 1 is a mixture of 40 mol%T and 60mol%U while feed 2 is a mixture of 75mol%T and 25mol%U. The feeds are to be separated by distillation into a liquid distillate of 95mol%T and a liquid bottoms of 95mol% U. Molar flow rates for feeds 1 and 2 are 90kmol/h and 210kmol/h respectively. Feed 2 is a mixture of saturated liquid and vapor: q=0.65 and feed 1 is a superheated vapor: q=0.5. T and U form an ideal solution, such that relative volatility can be taken constant at T,U=2.8. The external reflux ratio (L0/D) is 1.6 and the reflux stream is a saturated liquid. The boilup is saturated vapor. a. Plot the y-x equilibrium curve after computing the value of y for x between 0 and 1 at an interval of 0.1. Connect the points by a smooth curve. b. Calculate the molar flow rates of distillate and bottoms. Also, determine molar flow rates of the internal liquid and vapor streams within the three (rectifying, middle and stripping) sections of the column and compute the boil-up ratio. c. Construct a McCabe-Thiele plot and determine the optimal tray (counting from the top of the column) at which each feed stream must be introduced. Also, determine the total number of equilibrium stages required to achieve this separation. Report in terms of "fractional" stages. d. A team member working on the design of this distillation column suggests that the reflux ratio must be reduced to 0.4 based on an operating cost analysis they performed. Check if the separation would still be possible if the team member's recommendation is followed and provide a justification for your response
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