1. CHEN 4460 – Process Synthesis, Simulation and CHEN 4460 – Process Synthesis, Simulation and Optimization Dr. Mario Richard Eden Department of Chemical Engineering Auburn University Lab Lecture No. 5 – Midterm Exam Solution October 25, 2005 Review of Midterm Exam

2. Problem I (10 points) Binary mixtures of acetone and chloroform at 101.325 kPa x-y diagram Binary azeotrope at Acetone molefraction: x acetone = 0.35

3. Problem I (10 points) Binary mixtures of acetone and chloroform at 101.325 kPa T-x-y diagram Boiling Points: Pure Chloroform T b = 61.2  C Pure Acetone T b = 56.2  C Azeotrope T b = 64.5  C

4. Problem I (10 points) T-x-y diagram –Feed A: 90 mol% chloroform  10% acetone –Feed A: 25 mol% chloroform  75% acetone Feed A Feed B Feed A: Min x acetone = 0 @ 56.2  C Max x acetone = 0.35 @ 64.5  C Feed B: Min x acetone = 0.35 @ 64.5  C Max x acetone = 1.00 @ 56.2  C

5. Problem II (5 points) Vinylchloride Production –Direct chlorination of ethylene –Stoichiometric feed below, i.e. molar F E /F C = 1 –Ratio is increased to F E /F C = 5 and complete recovery of unreacted ethylene is assumed. F E, recycle = 4 * F E, stoichiometric = 4 * 44,900 lb/hr F E, recycle = 179,600 lb/hr  6,400 lbmol/hr

6. Problem III (20 points) Feed –30 kgmol/h A, T b = 50  C –30 kgmol/h B, T b = 70  C –140 kgmol/h C, T b = 65  C Binary azeotropes –A-C: x A = 0.50 @ 45  C –B-C: x B = 0.50 @ 60  C x A = 0.15 x B = 0.15 x C = 0.70

7. Problem III (20 points) A BC 70ºC 60ºC 45ºC 65ºC 50ºC Feed Spec. II Spec. I Spec. III Specifications I and II are achievable, but specification III is infeasible as it is on the other side of the distillation boundary

8. Problem IV (15 points) Multicomponent Separation –Sharp splits and cost is given as total cost SeparatorSplitCost $/yr 1A / BCD254,000 2AB / CD530,000 3ABC / D94,000 4B / CD460,000 5BC / D64,000 6A / BC247,000 7AB / C500,00 8C / D32,000 9B / C420,000 10A / C190,000 First Split Second Split Third Split

9. Problem IV (15 points)

10. SequenceTotal Cost $/yr 1-4-8746,000 1-5-9738,000 2-8-10752,000 3-6-9761,000 3-7-10784,000 1 st 2 nd Worst

11. Problem V (5 points) Hydrogen (H), Benzene (B) and Toluene (T) Due to presence of hydrogen in the vapor, condensation will be VERY expensive. Therefore best choice is Sequence A