nco RQ= nco₂ no₂ or no₂
Oxygen consumed by a living organism in aerobic reactions is used in the organism's mass addition and/or for the production of chemicals and carbon dioxide. Since we may not know the molecular compositions of all species in such a reaction, it is common to define a ratio of moles of CO2 produced per mole of O2 consumed as the respiratory quotient, RQ, given by:
Since it is usually impossible to predict RQ values, they must be determined from operational data. Mammalian cells are used in a bioreactor to convert glucose to glutamic acid by the reaction:
C6H12O6 + a NH3 + b O2 → pC5H9NO4 + qCO2 + r H2O
The feed to the bioreactor consists of 1.00 × 10^2 mol C6H12O6/day, 1.20 × 10^2 mol NH3/day, and 1.10 × 10^2 mol O2/day. System data show that RQ = 0.45 mol of CO2 produced/mol of O2 consumed.
(a) Determine the five stoichiometric coefficients and the limiting reagent. Answer: a=1.11; b=1.01; p=1.11p; q=0.45; r=2.67; limiting reagent: C6H12O6
(b) Assuming the limiting reagent is completely consumed, calculate the molar and mass flow rates of all species leaving the reactor and the fractional conversions of non-limiting reactants. Answer: NH3: 153 g/day, 0.925; O2: 288 g/day, 0.918; C5H9NO4: 16300 g; CO2: 1980 g/day; H2O: 4810 g/day
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