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It is desired to distill a mixture of ethane, propane, butane and pentane in a column of 5atm of total pressure. The feed is 1000kmol/h and is in the form of saturated liquid, its composition is 8%mol of ethane, 33%mol of propane, 49%mol of butane and 10%mol of pentane. It is desired to obtain a recovery of 98%mol of propane in the distillate and 99.2%mol of butane in the bottoms. Use the optimal feeding stage. Use the Depriester monogram; suppose that the relative volatility is constant and that its value is calculated at the temperature of the feeding bubble point. Calculate: -Number of minimum stages with Fenske -Calculate the minimum reflux with Underwood -Use L/D=1.2 Minimum reflux and estimate N and N feeding