Handbook of Industrial Drying, Fourth Edition

Book Preface

I am pleased to present this fourth enhanced edition of the Handbook of Industrial Drying, which is a reflection on the continuing industrial and academic interest in this interdisciplinary field of thermal dehydration and closely allied operations such as filtration and crystallization. As by far the most commonly encountered and also the most energyintensive unit operation in almost all industrial sectors, this is not surprising. The awareness of drying as an important unit operation has already led to significant enhancement in energy efficiency in most industrial drying technologies. The biennial International Drying Symposium series (IDS) as well as the only premier journal devoted exclusively to drying technologies, Drying Technology—An International Journal (Taylor & Francis Group), have provided a strong impetus to drying R&D around the globe over the past four decades. Their impact on energy savings in industrial drying is truly immeasurably high. With escalating concerns over global warming due to combustion of fossil fuels, the interest in innovation in this field will increase further in the coming decade.

As noted in my earlier prefaces, drying is an applied field where we try to combine basic sciences with engineering applications. Design and scale-up are key issues faced by those associated with selection, design, and operation of dryers. The focus of this book is on industrial applications. Despite the thousands of publications on all aspects of drying science, engineering, and technology, we still suffer from lack of a generalized theory or ability to model all types of dryers. Empirical information and know-how remain the hallmarks of dryer design and scale-up. The tremendous diversity of dryers found in practice is a direct result of the multitude of physical characteristics of the wet materials to be dried and of the diverse specifications of the dried product. Even the production requirements affect the selection of dryer type. This book covers most of the commonly encountered dryers as well as the less common innovative dryers that have potential in coming years. There is
yet no truly disruptive drying technology, but numerous incremental advances do lead to significant improvements in the technology.