NivaarExam PrepOfficial exam papers ↗

23-Chem-A2 Unit Operations and Separation Processes: December 2015

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

  1. Question 1 Voidage of a Segregated Two-Size Fluidized Bed
  2. Question 2 Optimum Cycle Time of a Constant-Rate / Constant-Pressure Filter
  3. Question 3 Time to Fill a Buffer Tank — Laminar vs. Turbulent Limits
  4. Question 4 Natural-Convection Heat Transfer to a Long Square Duct
  5. Question 5 Steam Consumption and Area of a Single-Effect Evaporator
  6. Question 6 Sizing a Tubular (Water-to-Water) Heat Exchanger

Start with Question 1 →

Paper format. National Exams — 04-CHEM-A2 Mechanical and Thermal Operations, December 2015. 3 hours, open book (one text). Six problems (Section A Mechanical Operations: A1–A3; Section B Thermal Operations: B1–B3), each 25 marks; candidates attempt at least two from each section. All six are worked below for completeness.

Reference texts. Coulson & Richardson, Chemical Engineering Vol. 1 (fluid flow, heat transfer) and Vol. 2 (particle technology, filtration, evaporation); McCabe, Smith & Harriott, Unit Operations of Chemical Engineering (7th ed.); Incropera & DeWitt, Fundamentals of Heat and Mass Transfer (8th ed.); Perry's Chemical Engineers' Handbook (9th ed.).

Note on the figureThe only figure in the paper is the LMTD correction-factor chart on page 5 (used in B3). It is read at the plotted parameters $P=0.25$, $R=2.0$; the value obtained ($F\approx0.94$) is confirmed analytically from the closed-form 1-outer-pass / 2-tube-pass expression.