Chemical Reaction Engineering, the Environment, Pollution Prevention and Sustainable Development

Abstract

This presentation attempts to illustrate the links between chemistry, the environment, multiphase reaction engineering, pollution prevention and sustainable development. The choice of process chemistry impacts not only the atom efficiency but also the degree of environmental damage caused by the manufacture of the choisen product. The execution of this chemistry requires multi-phase reaction engineering and, depending on the contacting scheme used, leads to different degrees of product yield, energy efficiency and formation of unwanted products. As a consequence, the number and type of separation units used and the recycling burden created is a function of the reactor choice and operating conditions. Clearly, understanding the principles of multiphase reaction engineering and their application are very important for proper execution of truly environmentally benign processes.Advances in understanding the phase contacting and mixing in reactors with moving and stagnant catalysts, and proper use of appropriate CFD codes are reviewed. Two powerful techniques for evaluation of holdup distribution (Computer Tomography - CT) and assessment of velocity profiles and mixing (Computer Aided Radioactive Particle Tracking - CARPT) are introduced. The data gathered is used for validation of CFD multiphase codes and for the establishment of appropriate engineering models for a variety of multiphase reactors such as risers, bubble columns, stirred tanks, etc.