In his 1961 review of the first edition of BSL's Transport Phenomena, John Butt described the book as “one of the most important texts to appear in the field of chemical engineering in many years”. Clearly his assessment is still true 50 years later! Luckily BSL was written at a time when the digital computer was in its infancy and the authors had no choice but to focus on problems that were amenable to mathematical, rather than numerical, analysis. This choice demanded the student combine intuition, dimensional analysis, and fairly elementary mathematical techniques to develop qualitative understanding of the basic physics of a problem. It emphasized thinking more than computation. But students who studied the book well, and especially those who mastered it, were well equipped to tackle an enormous variety of basic research problems in engineering science, and also many practical problems encountered in the chemical industry. Great progress has been made since then in ever more complex problems such as, simulation of multi-phase and turbulent reacting flows, flow of complex fluids, convection and diffusion in porous media, and the role of molecular structure in the transport phenomena of macromolecules. This progress has enabled the field of transport phenomena to expand its relevance into the biological, materials, environmental, and energy sciences, and continues to make it a central component of chemical engineering education alongside thermodynamics and chemical kinetics.

Problems in the chemical industry frequently involve simultaneous transport of heat, mass, and momentum. The most important problems are often those in which a system behaves qualitatively different than expected, rather than just quantitatively different; for example, the catalyst lifetime is a few weeks instead of ten years, a reactor shuts down whenever it rains, or the product formed is completely different than expected. Fundamental knowledge of transport phenomena combined with other basic areas of engineering science is critical to solving such problems.

In this talk I will describe some interesting transport problems that I have encountered during my 25 years in the chemical industry.