Extrusion Processing Technology

Extrusion is the operation of forming and shaping a molten or dough-like material by forcing it through a restriction, or die. It is applied and used in many batch and continuous processes. However, extrusion processing technology relies more on continuous process operations which use screw extruders to handle many process functions such as the transport and compression of particulate components, melting of polymers, mixing of viscous media, heat processing of polymeric and biopolymeric materials, product texturization and shaping, defibering and chemical impregnation of fibrous materials, reactive extrusion, and fractionation of solid-liquid systems. Extrusion processing technology is highly complex, and in-depth descriptions and discussions are required in order to provide a complete understanding and analysis of this area: this book aims to provide readers with these analyses and discussions.

Extrusion Processing Technology: Food and Non-Food Biomaterials provides an overview of extrusion processing technology and its established and emerging industrial applications. Potency of process intensification and sustainable processing is also discussed and illustrated. The book aims to span the gap between the principles of extrusion science and the practical knowledge of operational engineers and technicians. The authors bring their research and industrial experience in extrusion processing technology to provide a comprehensive, technical yet readable volume that will appeal to readers from both academic and practical backgrounds.

This book is primarily aimed at scientists and engineers engaged in industry, research, and teaching activities related to the extrusion processing of foods (especially cereals, snacks, textured and fibrated proteins, functional ingredients, and instant powders), feeds (especially aquafeeds and petfoods), bioplastics and plastics, biosourced chemicals, paper pulp, and biofuels. It will also be of interest to students of food science, food engineering, and chemical engineering.

Also available

Formulation Engineering of Foods
Edited by J.E. Norton, P.J. Fryer and I.T. Norton ISBN 978-0-470-67290-7

Food and Industrial Bioproducts and Bioprocessing
Edited by N.T. Dunford ISBN 978-0-8138-2105-4

Handbook of Food Process Design
Edited by J. Ahmed and M.S. Rahman ISBN 978-1-4443-3011-3

Autorentext

About the authors

Professor Jean-Marie Bouvier is Scientific Advisor at Clextral, Firminy, France. Professor Osvaldo H. Campanella is a Professor of Agricultural and Biological Engineering at the Whistler Carbohydrate Research Center, Purdue University, Indiana, USA.

Inhalt
Foreword ix

Acknowledgements xi

1 Generic Extrusion Processes 1

1.1 A history of extrusion processing technology 1

1.1.1 The introduction of screw extruders 1

1.1.2 The generic extrusion process concept 2

1.1.3 Extrusion technology in the polymer-processing industry 3

1.1.4 Extrusion technology in the food- and feed-processing industry 4

1.1.5 Extrusion technology in the paper-milling industry 8

1.2 Factors driving the development of extrusion processing technology 9

1.2.1 Process productivity 9

1.2.2 Product innovation and functionality 9

1.2.3 Environmentally friendly processing 10

1.3 The industrial and economic importance of extrusion processing technology 10

1.3.1 In the polymer and plastics industry 10

1.3.2 In the food and feed industry 10

1.3.3 In the paper milling industry 11

1.4 Contents and structure of the book 11

References 12

2 Extrusion Equipment 13

2.1 Extruders 13

2.1.1 The kinematics of extruders 13

2.1.2 The screw-barrel assembly 15

2.1.3 The die assembly 20

2.1.4 The central operating cabinet 28

2.2 Extruder screw-barrel configurations 28

2.2.1 Single screw extruders 29

2.2.2 Intermeshing co-rotating twin screw extruders 31

2.2.3 Screw-barrel configuration and wear 33

2.3 Ancillary equipment 39

2.3.1 Upstream ancillary equipment 40

2.3.2 On-line ancillary equipment 44

2.3.3 Downstream ancillary equipment 46

References 51

3 Extrusion Engineering 53

3.1 Thermomechanical processing in screw extruders 53

3.1.1 Process configuration of single screw extruders 53

3.1.2 Process configuration of intermeshing co-rotating twin screw extruders 55

3.1.3 Processing specificities 56

3.2 Thermomechanical flow in screw extruders 58

3.2.1 Modeling approaches 58

3.2.2 Solids conveying section 67

3.2.3 Melt conveying section 72

3.2.4 Single screw extrusion versus twin screw extrusion 110

3.3 Thermomechanical extrusion processing: use of numerical methods 115

3.3.1 Single screw extrusion 115

3.3.2 Twin screw extrusion 118

3.3.3 Commercial software 120

References 122

4 The Generic Extrusion Process I: Thermomechanical Plasticating of Polymers and Polymer Melt Forming 125

4.1 The bio-based polymers and bio-based plastics 126

4.1.1 Definitions 126

4.1.2 Macromolecular characteristics of bio-based polymers 129

4.2 Melting mechanism of polymer materials in screw extruders 138

4.2.1 Melting mechanism in single screw extruders: qualitative description 139

4.2.2 Engineering analysis of polymer melting in single screw extruders 140

4.2.3 Melting mechanism in intermeshing co-rotating twin screw extruders 143

4.2.4 Polymer melting: single screw extrusion versus twin screw extrusion 146

4.3 Physical transitions of bio-based polymers 147

4.3.1 Physical transitions of polymeric materials: generalities 147

4.3.2 Glass and melting transitions: basics 149

4.3.3 Glass and melting transitions of bio-based polymers 151

4.4 Flow properties of bio-based polymer melts 157

4.4.1 Flow behavior: basics 157

4.4.2 Measurement of flow properties of polymer melts 159

4.4.3 Rheological characteristics of bio-based polymer melts 161

4.5 Case studies: emerging applications 162

4.5.1 Melting of polyamide-11 in a single screw extruder: exercise 162

4.5.2 Extrusion processing of biodegradable starch-based loose-fill packaging foams 163

4.5.3 Extrusion compounding of flax fiber-reinforced thermoplastics 165

References 168

5 The Generic Extrusion Process II: Thermomechanical Micromixing and Reactive Extrusion 173

5.1 Reactive extrusion: qualitative description 174 5.1.1 Bulk polym...