23-Chem-A2 Unit Operations and Separation Processes, May 2017: worked solutions

Paper format. National Exams — 16-CHEM-A2 Unit Operations and Separation Processes, May 2017. 3 hours, open book (one text). Six problems — Part A Unit Operations (A1–A3) and Part B Separation Processes (B1–B3), each worth 25 marks; the rubric asks for at least two problems from each part (only the first two per part are marked). All six are worked below for completeness as a study resource.

Reference texts. McCabe, Smith & Harriott, Unit Operations of Chemical Engineering (7th ed.); Geankoplis, Transport Processes and Separation Process Principles (4th ed.); Coulson & Richardson, Chemical Engineering Vol. 2 (particle technology, filtration, crystallization, drying, absorption); Perry's Chemical Engineers' Handbook (9th ed.); Badger & Banchero, Introduction to Chemical Engineering.

Notes on chart / table reads. A1 uses the ISO nozzle discharge-coefficient chart ($C_n$ vs $Re$, $\beta$); B1's isotherm concentrations are printed as “g/cm³” but are read as g/L (= kg/m³) so the feed concentration (0.25 kg/m³) sits on the same scale as the data — a units slip in the source; B3's equilibrium $Y$ column carries an implied ×10⁻⁴ multiplier (the printed integers 0–202 cannot be literal mol/mol, and the inlet gas $Y_1=0.0177$ coincides exactly with the $X=10$ entry of 177, which fixes the scale). Engineering choices are flagged in Check callouts.

23-Chem-A2 Unit Operations and Separation Processes: May 2017

Part A — Unit Operations