23-Chem-A3 Heat and Mass Transfer: May 2014

National Exams — May 2014 — 04-Chem-A3 Mass Transfer Operations. Three-hour, open-book exam; any non-communicating calculator permitted. Format: seven questions in three parts — answer one of Q1–Q2 (Part A), one of Q3–Q4 (Part B) and two of Q5–Q7 (Part C); four questions of equal value constitute a complete paper. All seven are solved below for completeness. Property data (diffusivities, vapour pressures, psychrometric enthalpies) are stated in each Given block; the psychrometric appendix supplied with the exam furnishes the saturated-air data used in Q6.

Reference texts: Geankoplis, Transport Processes and Separation Process Principles (4th ed., Prentice Hall) — molecular diffusion, convective mass transfer, absorption and humidification; Treybal, Mass-Transfer Operations (3rd ed., McGraw-Hill) — gas absorption, wetted-wall and cooling-tower design; Welty, Wicks, Wilson & Rorrer, Fundamentals of Momentum, Heat and Mass Transfer — boundary-layer and falling-sphere correlations; supporting property/psychrometric data from Perry's Chemical Engineers' Handbook (9th ed.).