23-Chem-A2 Unit Operations and Separation Processes, May 2015: worked solutions

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

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

Note on the charts and tables. Page 3 (Fanning friction-factor chart), page 5 (LMTD correction-factor plot) and page 6 (Table B.2, saturated water by pressure) were read from the printed figure. The smooth-pipe friction factor is computed from the Colebrook equation, which the chart plots; the B3 condenser is isothermal on the steam side, so the correction factor is exactly $F=1$; and the B2 saturation temperatures are read from the supplied Table B.2.

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