Question

A multi-component mixture consisting of 25 mol% ethanol, 15 mol% isopropanol, 35 mol% n-propanol, 10 mole% isobutanol and 15 mol% n-butanol is to be distilled. Antoine parameters for the components are given in Table Q.2 a) Define the bubble point of a multi-component mixture in words and by an equation b) First consider just the ternary mixture of the ethanol, isopropanol and n-propanol fractions. Show that the bubble point of this ternary mixture is 86.8 °C at latm. The best sequence of distillation columns required to separate the full five component mixture can be determined by optimisation using a simulation tool, or by heuristics. c) Define what is meant by heuristics. What are the main heuristics that are generally considered for distillation column sequencing? Explain the rationale behind each briefly 15) d) Determine the best possible column sequence based on heuristics for the separation of the mixture given above. Assume that the equilibrium data can be approximated as constant relative volatilities with n-propanol as the reference component ethanol, ?-209, isopropanol, ?-1.82, n-propanol, ?-| .00, isobutanol, ?-0677 n-butanol,? = 0.428 Briefly explain your answer e) Consider how thermally coupled or multi-effect distillation columns can be used to reduce the energy consumption for the separation outlined above Table Q.2. Antoine parameters for multi-component mixture (equation below) Componen Normal boiling ethanol isopropanol n-propanol isobutanol n-butanol nt ( 78 82 97 108 118 8.11220 1592.864 226.184 8.87829 2010.330 252.636 8.37895 1788.020 227.438 8.53516 1950.940 237.147 7.83800 1558.190 196.881 Antoine's equation for component i (where the vapour pressure is expressed in mmHg and the temperature is expressed in °C)

SEPARATION PROCESSES

Answer 1

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