Solutions%20to%20Homework#3

Solutions%20to%20Homework#3 - Solutions to Homework#3...

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Solutions to Homework#3 Chemical Engineering 2800 (Summer 2008) Fundamentals of Process Engineering University of Utah Dr.Mataz Alcoutlabi Problem 1 10.9, p. 300 In the anaerobic fermentation of grain, the yeast Saccharomyces cerevisiae digests glucose from plants to form the products ethanol and prepenoic acid by the following overall reaction: Reaction 1: 2 5 2 6 12 6 2 2 CO OH H C O H C + Reaction 2: O H H O H C O H C 2 2 3 2 6 12 6 2 2 + In an open, flow reactor 3500 kg of a 12% glucose/water solution flow in. During fermentation, 120 kg of carbon dioxide are produced together with 90 kg of unreacted glucose. What are the weight percents of ethyl alcohol and propenic acid that exit in the broth? Assume that none of the glucose is assimilated into the bacteria. Solution C 120 kgCO 2 3500 kg F w g =0.12 w w =0.88 Glucose/Water P 90 kg glucose ? kg EtOH ? kg propenoic acid ? kg water Reaction 1: 2 5 2 6 12 6 2 2 CO OH H C O H C + Reaction 2: O H H O H C O H C 2 2 3 2 6 12 6 2 2 + Assume no glucose incorporated in bacteria Basis: 3500 kg glucose Data: MW w =18.016 MW e = 46.07 MW c = 44 MW g = 180.16 MW p = 72.06 Approach: element balances on C, H, O g = glucose e = EtOH w = water p = prepanoic acid c = CO 2 Inlet moles (kg/mol) Outlet moles (kgmol) n gi n go n eo n wi n wo n po n co knowns are n gi, n go, n wi and n co We have 3 unknowns: n wo , n eo and n po
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This note was uploaded on 09/07/2009 for the course CHEN 2800 taught by Professor Process during the Summer '08 term at Utah.

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Solutions%20to%20Homework#3 - Solutions to Homework#3...

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