Fluid Mechanics for Chemical Engineering

Chapter 13

Physical Description of a Particulate Medium Dispersed Within a Fluid

13.1. Introduction

Part III of this book deals with the processes of mechanical separation. The implementation of a mechanical separation process is conceivable only if the materials to be separated can be clearly identified in space, so that mechanical forces exerted by one material upon the other can act to separate the two constituents. Mechanical separation methods, therefore, pertain to two- or three-phase media. Depending on the case, the terms solid/liquid or solid/gas separation will be used. Liquid/liquid separation, e.g. refers to the separation of two non-miscible liquids, such as oil and water.

Particles play a key role in many processes. In chemical engineering, catalytic reactors utilize catalysts, which are particles on the surface of which reactions occur. Major processing industries (plastic materials, ceramics, cement, paper, inks, etc.) operate based on their corresponding particulate materials. The same applies for the food processing industries also (powders, grains, beverage clarification, etc.). Lastly, in environmental studies, we may mention water treatment, gas scrubbing, incineration, and soil treatment processes, or indeed the problems of sedimentation in rivers, ports, and on beaches, all of which involve directly particulate media.

The different chapters of this third part present the mechanical principles used in different separation processes. This is discussed in the ...