Question

Hexane is a non-polar solvent with a boiling point of 68 °C, and is therefore the solvent of choice for oil extraction. The recovery system removes most of the hexane vapors from the air entering various pieces of equipment in the hexane solvent extraction plant, before discharging that air to the atmosphere. A gas stream contains 18 mole % hexane and the remainder is air leaving the solvent recovery unit at 150 °C and 1 atm and flow into condenser, where temperature is reduced and some of the hexane is liquefied. The hexane mole fraction in the gas stream leaving the condenser is 0.05. Liquid hexane collected is about 1.50 liter/min. As a new engineer in the plant: (a) Draw and label the process flowchart completely. (2.5 Marks) (b) Formulate and estimate the volumetric flow rate of the gas entering the condenser (up/min). m3.me 83-8 mol (min; 72-3 moi/min,2-92 M10 Marks) (c) If the feed temperature is increased to 200 °C, does your answer in part (b) changes and why? (3 Marks)

Answer 1

P Herane 0.05 Condensen Hexame 18% 1.50 liten min lig. Her. +50 0.655 kg/L density of Hexane - mass of Herone Condensed : 1.50x 0.655= 0.9825 kg Kino/min =o.ollu kad 0.9825 86 hexane Balance. apply 0.05 p + x 0.18 F 0 0.0114 0.187 -0.05 p : Balance. opply overall F= p+x F-P 0.0114 m 0.08345 kunl/min 83.45 mol/min 83.45 * 8.314 x 1273 +150) 2.897 1 X 1.013 Xior mm Vi nar If because ۱۱اليا we increase feed teup. to 200°c than vol flow increase at const pressure as we increase tamperature, volume increases. 8,897 x 473 3:24 m/min. 423 .