1st Edition

Agro-Product Processing Technology Principles and Practice

By B K Bala Copyright 2020
    420 Pages 23 Color & 184 B/W Illustrations
    by CRC Press

    420 Pages 23 Color & 184 B/W Illustrations
    by CRC Press

    Global food security is a challenging issue. Meeting the food and nutritional requirements of the world has become an issue for national policymakers and is of public concern. There is a need to enhance agricultural production, as well as, to reduce postharvest loss, improve the quality of processed products, and add value to products to make more quality food available. Agro-product processing technology plays a major role to reduce post-harvest losses, improve the quality of processed products, and add value to the products. It also generates employment and ultimately contributes to food security.

    Features:

    • Covers a wide spectrum of agro-product processing technology
    • Explains the principles and practices of agro-product processing technology with many worked examples to quickly teach the basic principles through examples
    • Contains examples from different operations on current problems to show the wide applications of the principles of agro-product technology
    • Includes process control and emerging technologies in agro-product processing such as energy and exergy analysis, neural network modeling, and CFD modeling

    This book deals with physical and thermal properties, cleaning and sorting, drying and storage, parboiling and milling, by-product utilization, heating and cooling, refrigerated cooling, and cold storage. The most unique feature of this book is the machine vision for grading fruits, process control and materials handling, and emerging technologies such as neural network, finite element, CFD, and genetic algorithm.

    Contents

    Foreword ..........................................................................................................................................xv

    Preface............................................................................................................................................xvii

    Author .............................................................................................................................................xix

    Chapter 1 Introduction ..................................................................................................................1

    1.1 Introduction .........................................................................................................1

    1.2 Impotence of Postharvest Technology .................................................................2

    1.3 Importance of Postharvest Losses .......................................................................2

    1.4 Postharvest Technology .......................................................................................3

    References ....................................................................................................................5

    Chapter 2 Physical, Thermal, and Chemical Properties of Food and Biological Materials .........7

    2.1 Introduction .........................................................................................................7

    2.2 Physical Properties ..............................................................................................7

    2.2.1 Physical Dimensions ................................................................................7

    2.2.2 1000-Grain Weight ..................................................................................7

    2.2.3 Bulk Density ............................................................................................8

    2.2.4 Shrinkage .................................................................................................8

    2.2.5 Friction ....................................................................................................9

    2.2.5.1 Angle of Internal Friction and Angle of Repose ......................9

    2.2.5.2 Coefficient of Friction ............................................................. 10

    2.3 Thermal Properties ............................................................................................ 11

    2.3.1 Specific Heat .......................................................................................... 11

    2.3.2 Thermal Conductivity ........................................................................... 13

    2.3.2.1 Theory ..................................................................................... 13

    2.3.2.2 Apparatus and Measurement .................................................. 14

    2.3.3 Latent Heat of Vaporization .................................................................. 15

    2.3.3.1 Determination of Latent Heat of Vaporization ....................... 16

    2.3.4 Heat Transfer Coefficient of Product Bed ............................................. 18

    2.3.4.1 Dimensional Analysis ............................................................. 19

    2.3.4.2 Comparison of Theory and Experiment ................................. 19

    2.3.4.3 Theory .....................................................................................20

    2.3.4.4 Determination of Volumetric Heat Transfer Coefficient ........22

    2.4 Chemical Properties ..........................................................................................24

    2.4.1 Starch .....................................................................................................24

    2.4.2 Protein ...................................................................................................24

    2.4.3 Fat ..........................................................................................................24

    2.4.4 Vitamin ..................................................................................................24

    Key to Symbols ..........................................................................................................24

    Exercises .....................................................................................................................26

    References ..................................................................................................................27

    Chapter 3 Cleaning, Grading, and Sorting .................................................................................29

    3.1 Grade Factor ....................................................................................................29

    3.2 Washing ...........................................................................................................30

    3.3 Sorting Fruits and Vegetables ..........................................................................30

    3.4 Sorting Grain ...................................................................................................30

    3.5 Spiral Separator ............................................................................................... 32

    3.6 Indent Cylinder Separator ............................................................................... 33

    3.7 Color Separator ................................................................................................ 33

    3.8 Centrifugal Separation ....................................................................................34

    3.8.1 Stokes’ Equation .................................................................................34

    3.9 The Centrifuge................................................................................................. 35

    3.10 The Cream Separator ....................................................................................... 35

    3.11 Cyclone Separator ............................................................................................36

    3.12 Machine Vision................................................................................................ 39

    3.12.1 Image Acquisition ............................................................................. 39

    3.12.1.1 Computer Vision System .................................................. 39

    3.12.1.2 Ultrasound and Infrared ...................................................40

    3.12.1.3 Tomographic Imaging ......................................................40

    3.12.2 Preprocessing ....................................................................................40

    3.12.3 Segmentation ..................................................................................... 41

    3.12.4 Feature Extraction ............................................................................. 42

    3.12.4.1 Color Features .................................................................. 42

    3.12.4.2 Morphological Features.................................................... 43

    3.12.4.3 Texture Features ............................................................... 43

    3.12.5 Classification .....................................................................................44

    Bibliography ............................................................................................................... 45

    Chapter 4 Psychrometry .............................................................................................................. 47

    4.1 Introduction ..................................................................................................... 47

    4.2 Psychrometric Terms ....................................................................................... 47

    4.2.1 Humidity Ratio ..................................................................................48

    4.2.2 Relative Humidity .............................................................................48

    4.2.3 Specific Volume ................................................................................49

    4.2.4 Vapor Pressure ..................................................................................49

    4.2.5 Dry-Bulb Temperature ......................................................................49

    4.2.6 Dew Point Temperature.....................................................................49

    4.2.7 Wet-Bulb Temperature ......................................................................49

    4.2.8 Enthalpy ............................................................................................50

    4.2.9 Adiabatic Wet-Bulb Temperature ...................................................... 51

    4.2.10 Psychrometric Wet-Bulb Temperature .............................................. 52

    4.3 Construction of Psychrometric Chart ..............................................................54

    4.4 Use of Psychrometric Chart ............................................................................54

    4.4.1 Sensible Heating and Cooling ........................................................... 55

    4.4.2 Heating with Humidification ............................................................. 55

    4.4.3 Cooling with Humidification ............................................................56

    4.4.4 Cooling with Dehumidification.........................................................56

    4.4.5 Drying ............................................................................................... 57

    4.4.6 Mixing of Airstreams ....................................................................... 59

    4.4.7 Heat Addition with Air Mixing .......................................................... 61

    4.4.8 Drying with Recirculation .................................................................. 62

    Key to Symbols ..........................................................................................................66

    Exercises .....................................................................................................................68

    Bibliography ...............................................................................................................68

    Chapter 5 Drying of Agro Products ............................................................................................69

    5.1 Principles of Drying ..........................................................................................69

    5.2 Importance of Drying ........................................................................................69

    5.3 Moisture Content ............................................................................................... 70

    5.3.1 Moisture Content Representation .......................................................... 70

    5.3.2 Determination of Moisture Content ...................................................... 72

    5.3.2.1 Direct Methods ....................................................................... 73

    5.3.2.2 Indirect Methods ..................................................................... 75

    5.4 Equilibrium Moisture Content .......................................................................... 76

    5.4.1 Determination of Static Equilibrium Moisture Content ........................77

    5.4.2 Static Equilibrium Moisture Content Models .......................................77

    5.5 Mechanism of Drying........................................................................................82

    5.6 Thin-Layer Drying ............................................................................................84

    5.6.1 Thin-Layer Drying Equations ...............................................................84

    5.6.1.1 Empirical Drying Equations ...................................................84

    5.6.1.2 Theoretical Drying Equations ................................................84

    5.6.1.3 Semi-Theoretical Drying Equations .......................................85

    5.6.2 Drying Rate ...........................................................................................87

    5.6.3 Drying Parameters .................................................................................87

    5.6.4 Drying Rate Constant and Diffusion Coefficient ..................................88

    5.6.4.1 Drying Rate Constant .............................................................88

    5.6.5 Half Response Time .............................................................................. 91

    5.7 Deep-Bed Drying ..............................................................................................92

    5.7.1 Logarithmic Model ................................................................................92

    5.7.2 Partial Differential Equation Model ......................................................98

    5.7.2.1 Method of Solution ............................................................... 102

    5.7.2.2 Comparisons of Simulated and Observed Results ................ 103

    5.8 Fluidized Bed Drying Model .......................................................................... 103

    5.8.1 Heat Balance Equation ........................................................................ 104

    5.8.2 Drying Rate Equation .......................................................................... 104

    5.8.3 Mass Balance Equation ....................................................................... 105

    5.9 Agro-Product Drying Systems ........................................................................ 106

    5.9.1 Solar Drying Systems .......................................................................... 106

    5.9.1.1 Solar Dryers .......................................................................... 106

    5.9.2 Batch Drying Systems ......................................................................... 110

    5.9.2.1 Flatbed Dryer ........................................................................ 111

    5.9.3 Continuous Flow Drying Systems ....................................................... 113

    5.9.3.1 Cross-Flow Dryer ................................................................. 113

    5.9.3.2 Cross-Flow Batch Dryer ....................................................... 113

    5.9.3.3 Concurrent Flow Dryer ......................................................... 114

    5.9.3.4 Counterflow Dryer ................................................................ 114

    5.9.3.5 Mixed-Flow Dryer ................................................................ 116

    5.10 Safe Temperature for Drying Grain .............................................................. 117

    5.11 Selection of Dryers ........................................................................................ 117

    Key to Symbols ........................................................................................................ 118

    Exercises ................................................................................................................... 119

    Bibliography ............................................................................................................. 120

    Chapter 6 Parboiling of Rice .................................................................................................... 123

    6.1 Introduction ................................................................................................... 123

    6.2 Principles of Parboiling .................................................................................124

    6.3 Soaking ..........................................................................................................124

    6.3.1 Kinetics of Soaking ........................................................................... 126

    6.3.2 Finite Element Modeling of Soaking of Water by Paddy .................. 132

    6.3.3 Half Response Time .......................................................................... 137

    6.3.4 Kinetics of Water Diffusion and Starch Gelatinization .................... 137

    6.4 Steaming ........................................................................................................ 140

    6.5 Drying ............................................................................................................ 140

    6.6 Effect of Parboiling on Milling, Nutritional, and Cooking Qualities

    of Rice ........................................................................................................... 141

    6.7 Parboiling Methods ....................................................................................... 142

    6.7.1 Traditional Methods .......................................................................... 142

    6.7.1.1 Single Stage Parboiling ...................................................... 142

    6.7.1.2 Double Stage Parboiling ..................................................... 142

    6.7.2 Modern Methods ............................................................................... 142

    6.7.2.1 CFTRI (Central Food Technological Research

    Industries) Method ............................................................. 143

    6.7.2.2 Jadavpur University Method .............................................. 143

    6.7.2.3 Malek Process .................................................................... 143

    6.7.2.4 Schule Process .................................................................... 143

    6.7.2.5 Crystal Rice Process .......................................................... 144

    6.7.2.6 Rice Conversion Process .................................................... 144

    6.7.2.7 Avorio Process .................................................................... 144

    6.7.3 Estimation of Heat Required for Parboiling ...................................... 144

    6.7.3.1 Soaking Operation.............................................................. 144

    6.7.3.2 Steaming Operation............................................................ 144

    6.7.3.3 Drying Operation ............................................................... 145

    Exercises ................................................................................................................... 159

    Bibliography ............................................................................................................. 160

    Chapter 7 Milling of Rice and Wheat ....................................................................................... 163

    7.1 Introduction ................................................................................................... 163

    7.2 Rice Milling .................................................................................................. 163

    7.3 Traditional Methods ...................................................................................... 163

    7.3.1 Home Pounding ................................................................................. 163

    7.3.2 Huller Mills ....................................................................................... 164

    7.3.3 Sheller Mills ...................................................................................... 164

    7.3.4 Rubber Roll Sheller Mills .................................................................. 164

    7.4 The Modern Rice Milling Process ................................................................ 165

    7.5 Modern Rice Milling Machinery .................................................................... 167

    7.5.1 Paddy Cleaner ...................................................................................... 167

    7.5.2 Stoner ................................................................................................... 167

    7.5.3 Rubber Roll Sheller ............................................................................. 167

    7.5.4 Paddy Separator ................................................................................... 169

    7.5.5 Whitening or Polishing........................................................................ 171

    7.5.5.1 Cone-Type Polisher ............................................................... 171

    7.5.5.2 Horizontal Abrasive-Type Polisher ....................................... 172

    7.5.5.3 Friction-Type Polisher ........................................................... 172

    7.5.6 Bran and Polished Rice Separator ....................................................... 173

    7.5.7 Rice Grader ......................................................................................... 173

    7.5.8 Rice Mixing ......................................................................................... 174

    7.6 Wheat Milling ................................................................................................. 174

    7.6.1 Conditioning/Hydrothermal Treatment ............................................... 174

    7.6.2 Milling ................................................................................................. 174

    7.6.3 Storage of Finished Products ............................................................... 175

    7.7 Size Characteristics ......................................................................................... 175

    7.7.1 Sieve ..................................................................................................... 175

    7.7.2 Fineness Modulus ................................................................................ 176

    7.7.3 Energy Requirements .......................................................................... 177

    Bibliography ............................................................................................................. 179

    Chapter 8 By-Product Utilization ............................................................................................. 181

    8.1 Introduction ..................................................................................................... 181

    8.2 Fuels and Combustion ..................................................................................... 181

    8.2.1 Furnaces .............................................................................................. 182

    8.3 Pyrolysis and Gasification ............................................................................... 183

    8.3.1 Pyrolysis (Destructive Distillation) and Gasification .......................... 183

    8.3.2 Types of Gasifiers ................................................................................ 184

    8.3.2.1 Countercurrent Moving Bed Gasifiers .................................. 185

    8.3.2.2 Concurrent Moving Bed Gasifiers ........................................ 185

    8.3.2.3 Crosscurrent Moving Bed Gasifiers ..................................... 185

    8.3.2.4 Fluidized Bed Gasifiers ........................................................ 185

    8.3.3 Gasification Process ............................................................................ 185

    8.3.3.1 Oxidation .............................................................................. 186

    8.3.3.2 Reduction .............................................................................. 186

    8.3.3.3 Drying ................................................................................... 186

    8.3.4 Gasifier Units ....................................................................................... 186

    8.4 Liquefaction ..................................................................................................... 187

    8.5 Hydrolysis Followed by Fermentation ............................................................. 189

    8.6 Biochar Production and Utilization ................................................................. 190

    8.6.1 Biochar Carbonizer ............................................................................. 190

    8.6.2 Types of Carbonizers ........................................................................... 191

    8.6.2.1 Application............................................................................ 192

    8.7 Rice Husk Pelletizing and Briquetting ............................................................ 192

    8.7.1 Need for Briquetting ............................................................................ 193

    8.7.2 Principle and Technology .................................................................... 193

    8.7.3 Types of Briquetting Machines ....................................................... 193

    8.7.3.1 High- and Medium-Pressure Compaction .......................194

    8.7.3.2 Screw Press ...................................................................... 194

    8.7.3.3 Piston Press ...................................................................... 195

    8.7.3.4 Low-Pressure Compaction ............................................... 195

    8.7.3.5 Hand-Molded Briquettes .................................................. 195

    8.7.4 Applications ..................................................................................... 195

    8.7.5 Limitations....................................................................................... 196

    8.7.6 Future Prospective ........................................................................... 196

    8.8 Biogas Digesters ............................................................................................ 196

    8.8.1 Anaerobic Digestion Process ........................................................... 197

    8.8.2 Indian-Type Biogas Digester ........................................................... 197

    8.8.3 The Chinese Biogas Digester .......................................................... 198

    8.8.4 Digester Sizing ................................................................................ 199

    8.9 Composting ....................................................................................................202

    8.9.1 Process of Composting ....................................................................203

    8.9.2 Mixing of Materials in the Compost ...............................................203

    8.9.3 Starting a Composter .......................................................................204

    8.9.4 Operating a Compost .......................................................................204

    8.9.5 Simple Thermophile Composting Procedure ..................................204

    8.9.6 Types of Composters .......................................................................205

    8.10 Utilization of Rice Bran – Stabilizer Design and Oil Extraction ..................207

    8.11 Bran – Stabilizer Design ...............................................................................207

    8.12 Oil Extraction ................................................................................................207

    8.12.1 Batch Extraction Method .................................................................208

    Bibliography .............................................................................................................208

    Chapter 9 Storage of Agro Products .........................................................................................209

    9.1 Principles of Storage ......................................................................................209

    9.2 Interactions of Physical, Chemical, and Biological Variables in the

    Deterioration of Stored Grains ...................................................................... 211

    9.3 Computer Simulation Modeling for Stored Grain Pest Management ........... 212

    9.4 Grain Storage Systems .................................................................................. 213

    9.4.1 Traditional Storage Systems ............................................................ 213

    9.4.2 Modern Storage Systems ................................................................. 214

    9.4.2.1 Bagged Storage System .................................................... 214

    9.4.2.2 Silo Storage System ......................................................... 215

    9.4.2.3 Airtight Grain Storage ..................................................... 216

    9.4.2.4 Aerated Storage System ................................................... 218

    9.4.2.5 Low-Temperature Storage System (Grain Chilling

    by Refrigeration) .............................................................. 221

    9.4.2.6 Controlled Atmosphere Storage Systems ........................224

    9.4.2.7 Damp Grain Storage System with Chemicals .................226

    9.5 Design of Grain Storages...............................................................................228

    9.5.1 Structural Requirements ..................................................................228

    9.5.2 Janssen’s Equation ...........................................................................229

    9.5.3 Rankine’s Equation.......................................................................... 232

    9.5.4 Airy’s Equation ................................................................................ 233

    9.5.5 Construction Materials ....................................................................236

    Key to Symbols ........................................................................................................240

    Exercises ................................................................................................................... 241

    Bibliography ............................................................................................................. 241

    Chapter 10 Heating and Cooling of Agro Products ....................................................................245

    10.1 Introduction ....................................................................................................245

    10.2 Heat Conduction ............................................................................................246

    10.2.1 The Differential Equation of Heat Conduction in Cartesian

    and Cylindrical Coordinate Systems ...............................................246

    10.2.1.1 The Differential Equation of

    Heat Conduction in Cartesian Coordinate System ..........246

    10.2.1.2 The Differential Equation of

    Heat Conduction in Cylindrical Coordinate System .......248

    10.2.2 The Composite Wall ........................................................................249

    10.2.3 Cylinder and Sphere ......................................................................... 251

    10.3 Convection ..................................................................................................... 252

    10.3.1 Forced Convection ........................................................................... 252

    10.3.2 Natural or Free Convection .............................................................. 255

    10.3.3 Heat Exchangers ..............................................................................256

    10.4 Radiation ........................................................................................................ 261

    10.4.1 Radiation Intensity and Shape Factor ..............................................263

    10.4.2 Radiation Exchange between Black Surfaces ..................................264

    10.4.3 Heat Exchange by Radiation between Gray Surfaces......................265

    10.5 Cooling ........................................................................................................... 267

    10.5.1 Cooling Rate .................................................................................... 267

    10.6 Freezing .........................................................................................................269

    10.6.1 Freezing Point Depression ...............................................................269

    10.7 Heating ........................................................................................................... 271

    10.7.1 Boiling-Point Elevation .................................................................... 272

    Key to Symbols ....................................................................................................... 275

    Exercises ................................................................................................................. 276

    Bibliography ............................................................................................................277

    Chapter 11 Refrigeration and Cold Storage ................................................................................ 279

    11.1 Introduction .................................................................................................... 279

    11.2 Vapor Compression Refrigeration Cycle .......................................................280

    11.3 Pressure–Enthalpy (p-h) Chart ......................................................................280

    11.3.1 Unit of Refrigeration ........................................................................ 281

    11.4 Refrigerants .................................................................................................... 281

    11.4.1 Desirable Characteristics of Refrigerants ........................................ 281

    11.5 Construction of Psychrometric Chart ............................................................287

    11.6 Moisture Control and Storage of Vegetables Crops ....................................... 291

    11.6.1 Potatoes ............................................................................................ 291

    11.6.1.1 Adequate Volume ............................................................. 291

    11.6.1.2 Adequate Strength ........................................................... 291

    11.6.1.3 Storage Environment .......................................................292

    11.6.1.4 Suberization Period ..........................................................292

    11.6.1.5 Short-Term Storage ..........................................................292

    11.6.1.6 Long-Term Storage ..........................................................292

    11.7 Cooling Requirement .....................................................................................293

    Exercises ...................................................................................................................297

    Bibliography .............................................................................................................298

    Chapter 12 Separation .................................................................................................................299

    12.1 Introduction ....................................................................................................299

    12.2 Contact Equilibrium Process .........................................................................299

    12.2.1 Absorption........................................................................................299

    12.2.2 Extraction .........................................................................................300

    12.2.2.1 Rate of Extraction ............................................................300

    12.2.2.2 Leaching .......................................................................... 301

    12.2.3 Distillation .......................................................................................303

    12.2.3.1 Vapor-Liquid Equilibrium ...............................................303

    12.2.3.2 Flash Vaporization ...........................................................305

    12.2.3.3 Batch Distillation .............................................................306

    12.2.3.4 Fractionation ....................................................................307

    12.2.3.5 Steam Distillation ............................................................ 311

    12.3 Mechanical Separation Process ..................................................................... 312

    12.3.1 Filtration ........................................................................................... 312

    12.3.2 Sedimentation .................................................................................. 314

    12.3.2.1 Sedimentation for Low Concentration Suspensions .......... 314

    12.3.2.2 Sedimentation for High Concentration Suspensions ......... 315

    12.3.3 Centrifugation .................................................................................. 316

    12.3.3.1 Rate Separation ................................................................ 316

    12.3.3.2 Liquid-Liquid Separation ................................................ 317

    12.3.3.3 Particle Gas Separation ................................................... 318

    Exercises ................................................................................................................... 319

    Bibliography ............................................................................................................. 319

    Chapter 13 Materials Handling and Conveying ......................................................................... 321

    13.1 Introduction .................................................................................................... 321

    13.2 Principles of Materials Handling ................................................................... 322

    13.3 Classification of Materials Handling Equipment ........................................... 322

    13.4 Belt Conveyors ............................................................................................... 323

    13.4.1 The Capacity of the Conveyor Belt Needed..................................... 325

    13.4.2 Belt Width ........................................................................................ 325

    13.4.3 Belt Speed ........................................................................................ 326

    13.4.4 Belt Tension ...................................................................................... 326

    13.4.5 Selection of Belt Carcass ................................................................. 327

    13.4.6 Selection of Driving and Other Pulleys ........................................... 327

    13.4.7 Motor Power ..................................................................................... 327

    13.4.8 Selection of Idlers ............................................................................ 328

    13.5 Chain Conveyors ............................................................................................ 329

    13.5.1 Trolley Chain Conveyor ................................................................... 329

    13.5.2 Scraper Chain Conveyor .................................................................. 330

    13.5.3 Apron Chain Conveyor .................................................................... 330

    13.6 Screw Conveyors ......................................................................................... 331

    13.6.1 Power Requirement for Screw Conveyors ..................................... 332

    13.7 Bucket Conveyors ........................................................................................ 333

    13.8 Pneumatic Conveyors .................................................................................. 334

    13.9 Hydraulic Conveyors ................................................................................... 337

    13.10 Gravity Conveyors ....................................................................................... 338

    13.11 Cranes.......................................................................................................... 338

    13.12 Lift and Carrying Trucks and Cart ............................................................. 338

    13.13 Robotic Handling System ........................................................................... 338

    Exercises ...................................................................................................................348

    Bibliography .............................................................................................................349

    Chapter 14 Process Dynamics and Control ................................................................................ 351

    14.1 Introduction ................................................................................................. 351

    14.2 Feedback Control Systems .......................................................................... 351

    14.3 Block Diagrams ........................................................................................... 351

    14.4 Dynamic Behavior of First- and Second-Order Systems ............................ 352

    14.4.1 First-Order System ........................................................................ 352

    14.4.2 Step Input ....................................................................................... 353

    14.4.3 Ramp Input .................................................................................... 354

    14.4.4 Sinusoidal Input ............................................................................. 354

    14.4.5 Second-Order System .................................................................... 355

    14.5 The Laplace Transform ............................................................................... 356

    14.6 Transfer Function ........................................................................................ 358

    14.6.1 Routh–Hurwitz Stability Criterion ................................................ 359

    14.7 Transient Response...................................................................................... 361

    14.7.1 Performance of Second-Order System .......................................... 361

    14.7.2 Performance Indices ...................................................................... 362

    14.8 Frequency Response .................................................................................... 362

    14.8.1 Bode Plot ....................................................................................... 363

    14.8.1.1 First-Order Process K

    (τs+1) ............................................... 363

    14.8.1.2 Integrating Process G(s) Ks

    = ........................................364

    14.8.1.3 Second-Order Process G(s) K

    2s2 2 s 1 =   + □  + ........................364

    14.8.1.4 Process Zero s +1 ........................................................365

    14.8.1.5 Time Delay e−j-  ...........................................................366

    14.8.1.6 Bode Stability Criterion ................................................ 367

    14.8.1.7 Gain Margin and Phase Margin ................................... 367

    14.8.2 Nyquist Criterion ...........................................................................368

    14.8.2.1 Gain Margin and Phase Margin ...................................369

    14.9 Frequency Response of Controllers ............................................................369

    14.9.1 Proportional Controller .................................................................369

    14.9.2 Proportional–Integral Controller ...................................................369

    14.9.3 Ideal Proportional–Derivative Controller...................................... 370

    14.9.4 Proportional–Derivative Controller with Filter ............................. 370

    14.9.5 Parallel PID Controller .................................................................. 370

    14.9.6 Series PID Controller .................................................................... 371

    14.9.7 Series PID Controller with a Derivative Filter .............................. 371

    Exercises ................................................................................................................... 373

    Bibliography ............................................................................................................. 374

    Chapter 15 Emerging Technologies ............................................................................................ 375

    15.1 Introduction .................................................................................................... 375

    15.2 Neural Network Modeling ............................................................................. 375

    15.2.1 Structure of ANN Model of a Dryer ................................................ 376

    15.2.2 Training of ANN Model .................................................................. 377

    15.3 Energy and Exergy Analysis of Drying Process ........................................... 378

    15.3.1 Drying Efficiency ............................................................................. 378

    15.3.2 Exergy Analysis through the Analysis of Second Law

    of Thermodynamics ......................................................................... 378

    15.3.3 Exergy Calculation for Dryer ........................................................... 379

    15.4 Finite Element Modeling of Single Kernel ....................................................380

    15.5 Computational Fluid Dynamics (CFD) Modeling ......................................... 385

    15.5.1 CFD Model Formulation ................................................................. 385

    15.5.1.1 Continuity Equation ........................................................386

    15.5.1.2 Momentum Conservation Equations ............................... 386

    15.5.1.3 Energy Conservation Equation ........................................ 386

    15.5.1.4 User-Defined Function .....................................................386

    15.5.2 CFD Analysis ................................................................................... 387

    15.5.2.1 Preprocessing ................................................................... 387

    15.5.2.2 Processing ........................................................................ 388

    15.5.2.3 Post-processing ................................................................ 388

    15.6 Optimal Design Using Genetic Algorithm ....................................................390

    15.6.1 Optimal Design of Agro-Product Processing Systems ....................390

    15.6.2 Genetic Algorithm ...........................................................................390

    15.6.2.1 Basic Principles of Genetic Algorithm ............................ 391

    15.6.2.2 Fitness Function ............................................................... 391

    15.6.2.3 Genetic Algorithm Procedure for Optimal

    Drying Parameters ........................................................... 391

    Key to Symbols ........................................................................................................ 393

    Bibliography ............................................................................................................. 394

    Index ..............................................................................................................................................397

    Biography

    Professor B. K. Bala is the dean of the Faculty of Engineering,

    Bangabandhu Sheikh Mujibur Rahman Science and Technology

    University, Gopalganj, Bangladesh, and was a professor in the

    Department of Farm Power and Machinery, Bangladesh Agricultural

    University, Mymensingh, Bangladesh, where he was engaged in teaching

    and research for over 42 years starting from 1970. He has supervised

    more than a dozen PhD students in the areas of drying and storage

    of agro products, modeling of food security, modeling of integrated

    energy systems and energy policy, renewable energy, modeling of climate

    change impacts, and emerging technologies such as neural network,

    exergy, genetic algorithm, and computational fluid dynamics.

    Professor Bala received a B.Sc. (Eng.) degree from Bangladesh

    University of Engineering and Technology, Dhaka, Bangladesh, in

    1969 and an M.Eng. degree from the Asian Institute of Technology, Bangkok, Thailand, in 1975.

    Professor Bala also received a Ph.D. degree from the University of Newcastle upon Tyne, UK, in

    1983 and worked on modeling and simulation of heat and mass transfer during industrial deep-bed

    drying of malt and provided the foundation and basis for energy conservation and online control of

    industrial deep bed drying of malt. He also worked on solar drying as an EC postdoctoral fellow at

    the University of Newcastle upon Tyne, UK, from 1992 to 1993. He was on a DAAD study visit at

    the Institute of Agricultural Engineering in the Tropics and Subtropics, University of Hohenheim,

    Germany, for research on solar drying in 1995. Professor Bala also served as a research fellow at the

    Institute of Agricultural and Food Policy Research, Universiti Putra Malaysia from 2012 to 2014.

    Professor Bala has published 207 scientific papers mostly in high-impact factor journals, and

    he is also the author of nine textbooks. He is the author of Drying and Storage of Cereal Grains

    published by Wiley-Blackwell in 2017, and he is the co-author of System Dynamics Modeling and

    Simulation published by Springer in 2017.