Solve Example 9-2 with a spreadsheet using Eq. (9-18) over the following ranges of methanol mole fraction: 1.0 to \(0.9,0.9\) to \(0.7,0.7\) to \(0.5,0.5\) to 0.3 , and 0.3 to 0.1 . *Answers are in Example 9-2.

Example 9-2

A constant-mole batch distillation is being done to replace methanol with water as solvent for a nonvolatile solute currently dissolved in 10.0 kmol of pure methanol. After the distillation, the nonvolatile solute will be in a 90% water solution. The system has a still pot and a condenser and operates with no reflux. Pressure = 1.0 atm. Find kmol of steam added, the kmol of methanol evaporated, kmol of distillate, and the mole fraction of methanol in the distillate. If the heating rate is constant at 100 kW, how many hours does the constant mole batch distillation require?

Equation 9-18

 

S/W= In XW,initial -1 (XW,initial -xfin) Xfin