Low-Cost Experiments in Mass Transfer: Part 4. Measuring Axial Dispersion in a Bubble Column


  • M.H.I. Baird McMaster University
  • I. Nirdosh Lakehead University


Axial dispersion affects continuous mass transfer processes because it causes deviations from ideal plug flow. In this experiment involving an 8.9-cm diameter bubble column, axial dispersion is observed when an acid tracer is added at the top of the column, which initially contains a weakly alkaline solution; the fast acid-base reaction is controlled by mixing that is made visible by a colored indicator. Values of the axial dispersion coefficient can be calculated from the measured mixing times.

Author Biographies

M.H.I. Baird, McMaster University

Malcolm Baird received his PhD in chemical engineering from Cambridge University in 1960. After some industrial experience and a post-doctoral fellowship at the University of Edinburgh, he joined the McMaster University faculty in 1967. His research interests are liquid-liquid extraction, oscillatory fluid flows, and hydrodynamic modeling of metallurgical processes.

I. Nirdosh, Lakehead University

lnder Nirdosh received his BSc and MSc in chemical engineering from Panjab University (India) and his PhD from Birmingham University (United Kingdom). He joined Lakehead University in 1981, and his research interests are in the fields of mineral processing and electrochemical engineering.