23-Chem-A3 Heat and Mass Transfer: May 2013

National Exams — May 2013 — 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 constitute a complete paper (Parts A/B carry 20% each, Part C 30% each). All seven are solved below for completeness. Property data are stated in each Given block. Two chart appendices (SI humidity–temperature charts) accompany Q6.

Reference texts: Geankoplis, Transport Processes and Separation Process Principles (4th ed., Prentice Hall) — molecular diffusion, mass-transfer coefficients, absorption, humidification; Welty, Wicks, Wilson & Rorrer, Fundamentals of Momentum, Heat and Mass Transfer (5th/6th ed., Wiley) — transient diffusion, boundary-layer mass transfer; Treybal, Mass-Transfer Operations (3rd ed., McGraw-Hill) — packed-tower and cooling-tower design; supporting data from Perry's Chemical Engineers' Handbook (9th ed.) and Incropera & DeWitt, Fundamentals of Heat and Mass Transfer.