Exercise 05 Solution ENG

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Assignment #5: Results Binary distillation Assuming F = 100 [kmol/h]: D = 28.57 [kmol/h], B = 71.43 [kmol/h]. To calculate the relative volatility of benzene with respect to toluene at the thermal conditions of the top of the column, of the bottom of the column and of the feed stream, the following three temperatures are determined:  dew-point temperature of the distillate product: Td,D = 355.74 [K];  bubble-point temperature of the bottom product: Tb,B = 381.92 [K];  bubble-point temperature of the feed stream: Tb,F = 371.61 [K]. The corresponding relative volatilities are: αD = 2.5770; αB = 2.3613; αF = 2.4397. The average relative volatility is α = 2.4577. The minimum reflux ratio is Rmin = 2.0519. When using the graphical/analytical Mc Cabe-Thiele method, it turns out that: NS = 7.13  NS = 8; xF- = 0.273793; NINF = 5.83. So that the number of ideal stages, N, is equal to 14. When using the Fenske -Gilliland method, the minimum number of ideal stages is determined according to Fenske total-reflux equation (Nmin = 6.81). The Gilliland graphical correlation can then be used to determine the number of ideal stages, N, or alternatively:  the Eduljee equation: ϕ(N) = 0.4773  N = 13.94  N = 14;  the Molokanov equation: ϕ(N) = 0.4888  N = 14.27  N = 15.