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23-Chem-A4 Chemical Reactor Engineering: May 2016

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  1. Question 1 Ideal-Gas Batch Reaction $2A\rightarrow B+2C$ — Instantaneous Rates of Change at Constant $V$ and Constant $P$
  2. Question 2 Consecutive Reactions in a CSTR — Extracting Rate Constants and Orders from Residence-Time Data
  3. Question 3 Reversible Reaction $A\rightleftharpoons B$ in a PFR — Temperature of Minimum Residence Time
  4. Question 4 Reversible Gas-Phase Dimerization $2A\rightleftharpoons B$ in a Tubular Reactor — Reactor Length
  5. Question 5 Gas-Phase Trimerization $3A\rightarrow B$ in a CSTR — Fractional Conversion

Start with Question 1 →

National Exams / EGBC — May 2016 — 04-Chem-A4 Chemical Reactor Engineering. Three-hour open-book exam; one textbook of the candidate’s choice (Fogler or Levenspiel), unit-conversion / mathematical tables (CRC Handbook) and a non-communicating programmable calculator are permitted. Five questions are printed and any four constitute a complete paper (each worth 25 marks; Q1 is 12.5 + 12.5); all five are solved below for completeness. No credit is given for re-deriving standard rate expressions, so the batch / CSTR / PFR design equations are quoted and applied, and significant formulae are cited by origin as the rubric requests. Property look-ups not printed on the paper (the gas constant, molar volumes) are stated explicitly in each Given block as permitted open-book references.

Reference texts: H. S. Fogler, Elements of Chemical Reaction Engineering (4th/5th ed., Prentice Hall) — the stoichiometric table with expansion factor $\varepsilon$ for variable-volume gas reactions, batch / CSTR / PFR mole balances, parallel- and series-reaction analysis, and the Arrhenius relation; O. Levenspiel, Chemical Reaction Engineering (3rd ed., Wiley) — variable-density gas kinetics and reactor sizing; supporting property data from Perry’s Chemical Engineers’ Handbook (9th ed.). The gas constant is taken as $R = 0.082057\ \text{L}\cdot\text{atm}\cdot\text{mol}^{-1}\cdot\text{K}^{-1} = 8.314\ \text{J}\cdot\text{mol}^{-1}\cdot\text{K}^{-1}$.