Drying Phenomena

Ibrahim Dincer is a full professor of Mechanical Engineering in the Faculty of Engineering and Applied Science at UOIT. He is Vice President for Strategy in International Association for Hydrogen Energy (IAHE) and Vice-President for World Society of Sustainable Energy Technologies (WSSET). Renowned for his pioneering works in the area of sustainable energy technologies he has authored and co-authored numerous books and book chapters, more than 1000 refereed journal and conference papers, and many technical reports. He has chaired many national and international conferences, symposia, workshops and technical meetings. He has delivered more than 350 keynote and invited lectures. He is an active member of various international scientific organizations and societies, and serves as editor-in-chief, associate editor, regional editor, and editorial board member on various prestigious international journals. He is a recipient of several research, teaching and service awards, including the Premier's research excellence award in Ontario, Canada in 2004. He has made innovative contributions to the understanding and development of sustainable energy technologies, including drying systems and applications, and his group has developed various novel technologies/methods/models/etc. He has recently been identified as one of the 2014's Most Influential Scientific Minds in Engineering. This honour, presented by Thomson Reuters, is given to researchers who rank among the top 1% most cited for their subject field and year of publication, earning the mark of exceptional impact. Calin Zamfirescu is a senior researcher in Dr. Dincer's group at UOIT where he has been working since 2007. His research falls in the field of clean energy technology and process engineering. He was a tenure-track assistant professor of mechanical engineering for four years at Technical University of Civil Engineering of Bucharest, Romania, where he received his PhD in 1999. He was awarded with six research fellowships during five years at the Universities of Delft (in the Netherlands), Duke (in North Carolina, USA) and Henri Poincare (in Nancy, France). He has co-authored some books and more that 50 peer-reviewed papers in well-recognized journals.

• Preface xiNomenclature xv1 Fundamental Aspects 11.1 Introduction 11.2 Fundamental Properties and Quantities 21.3 Ideal Gas and Real Gas 131.4 The Laws of Thermodynamics 191.5 Thermodynamic Analysis Through Energy and Exergy 241.5.1 Exergy 241.5.2 Balance Equations 271.6 Psychometrics 361.7 Heat Transfer 451.7.1 General Aspects 451.7.2 Heat Transfer Modes 481.7.3 Transient Heat Transfer 541.8 Mass Transfer 581.9 Concluding Remarks 631.10 Study Problems 63References 652 Basics of Drying 672.1 Introduction 672.2 Drying Phases 682.3 Basic Heat and Moisture Transfer Analysis 692.4 Moist Material 762.5 Types of Moisture Diffusion 812.6 Shrinkage 822.7 Modeling of Packed-Bed Drying 862.8 Diffusion in Porous Media with Low Moisture Content 882.9 Modeling of Heterogeneous Diffusion in Moist Solids 902.10 Conclusions 972.11 Study Problems 97References 983 Drying Processes and Systems 993.1 Introduction 993.2 Drying Systems Classification 1003.3 Main Types of Drying Devices and Systems 1053.3.1 Batch Tray Dryers 1053.3.2 Batch Through-Circulation Dryers 1063.3.3 Continuous Tunnel Dryers 1083.3.4 Rotary Dryers 1103.3.5 Agitated Dryers 1143.3.6 Direct-Heat Vibrating-Conveyor Dryers 1163.3.7 Gravity Dryers 1173.3.8 Dispersion Dryers 1193.3.9 Fluidized Bed Dryers 1283.3.10 Drum Dryers 1303.3.11 Solar Drying Systems 1323.4 Processes in Drying Systems 1373.4.1 Natural Drying 1373.4.2 Forced Drying 1453.5 Conclusions 1513.6 Study Problems 151References 1524 Energy and Exergy Analyses of Drying Processes and Systems 1534.1 Introduction 1534.2 Balance Equations for a Drying Process 1544.3 Performance Assessment of Drying Systems 1594.3.1 Energy and Exergy Efficiencies 1594.3.2 Other Assessment Parameters 1614.4 Case Study 1: Analysis of Continuous-Flow Direct Combustion Dryers 1624.5 Analysis of Heat Pump Dryers 1694.6 Analysis of Fluidized Bed Dryers 1784.6.1 Hydrodynamics of Fluidized Beds 1794.6.2 Balance Equations 1814.6.3 Efficiency Formulations 1834.7 Conclusions 1874.8 Study Problems 187References 1885 Heat and Moisture Transfer 1895.1 Introduction 1895.2 Transient Moisture Transfer During Drying of Regularly Shaped Materials 1905.2.1 Transient Diffusion in Infinite Slab 1915.2.2 Drying Time of an Infinite Slab Material 2005.2.3 Transient Diffusion in an Infinite Cylinder 2025.2.4 Transient Diffusion in Spherical-Shape Material 2055.2.5 Compact Analytical Solution or Time-Dependent Diffusion in Basic Shapes 2085.3 Shape Factors for Drying Time 2095.3.1 Infinite Rectangular Rod of Size 2L × 2β1L 2105.3.2 Rectangular Rod of Size 2L × 2β1L×2β2L 2105.3.3 Long Cylinder of Diameter 2L and Length 2β1L 2125.3.4 Short Cylinder of Diameter 2β1L and Length 2L 2135.3.5 Infinite Elliptical Cylinder of Minor Axis 2L and Major Axis 2β1L 2135.3.6 Ellipsoid Having the Axes 2L, 2β1L, and 2β2L 2135.4 Moisture Transfer Coefficient and Diffusivity Estimation from Drying Curve 2165.5 Simultaneous Heat and Moisture Transfer 2195.6 Models for Heat and Moisture Transfer in Drying 2255.6.1 Theoretical Models 2265.6.2 Semitheoretical and Empirical Models for Drying 2315.7 Conclusions 2325.8 Study Problems 233References 2346 Numerical Heat and Moisture Transfer 2376.1 Introduction 2376.2 Numerical Methods for PDEs 2396.2.1 The Finite Difference Method 2406.2.2 Weighted Residuals Methods: Finite Element, Finite Volume, Boundary Element 2466.3 One-Dimensional Problems 2496.3.1 Decoupled Equations with Nonuniform Initial Conditions and Variable Boundary Conditions 2496.3.2 Partially Coupled Equations 2536.3.3 Fully Coupled Equations 2566.4 Two-Dimensional Problems 2616.4.1 Cartesian Coordinates 2616.4.2 Cylindrical Coordinates with Axial Symmetry 2716.4.3 Polar Coordinates 2766.4.4 Spherical Coordinates 2806.5 Three-Dimensional Problems 2846.6 Influence of the External Flow Field on Heat and Moisture Transfer 2886.7 Conclusions 2916.8 Study Problems 291References 2927 Drying Parameters and Correlations 2957.1 Introduction 2957.2 Drying Parameters 2967.2.1 Moisture Transfer Parameters 2967.2.2 Drying Time Parameters 2997.3 Drying Correlations 3017.3.1 Moisture Diffusivity Correlation with Temperature and Moisture Content 3017.3.2 Correlation for the Shrinkage Ratio 3047.3.3 Biot Number–Reynolds Number Correlations 3057.3.4 Sherwood Number–Reynolds Number Correlations 3077.3.5 Biot Number–Dincer Number Correlation 3107.3.6 Regression Correlations for μ1 Eigenvalues versus Lag Factor 3127.3.7 Biot Number–Drying Coefficient Correlation 3137.3.8 Moisture Diffusivity–Drying Coefficient Correlation 3157.3.9 Biot Number–Lag Factor Correlation 3167.3.10 Graphical Determination of Moisture Transfer Parameters in Drying 3177.3.11 Moisture Transfer Coefficient 3187.4 Conclusions 3207.5 Study Problems 320References 3218 Exergoeconomic and Exergoenvironmental Analyses of Drying Processes and Systems 3238.1 Introduction 3238.2 The Economic Value of Exergy 3268.3 EXCEM Method 3298.4 SPECO Method 3378.5 Exergoenvironmental Analysis 3408.6 Conclusions 3458.7 Study Problems 345References 3469 Optimization of Drying Processes and Systems 3499.1 Introduction 3499.2 Objective Functions for Drying Systems Optimization 3519.2.1 Technical Objective Functions 3519.2.2 Environmental Objective Functions 3599.2.3 Economic Objective Functions 3629.3 Single-Objective Optimization 3639.3.1 Trade-off Problems in Drying Systems 3639.3.2 Mathematical Formulation and Optimization Methods 3669.3.3 Parametric Single-Objective Optimization 3719.4 Multiobjective Optimization 3759.5 Conclusions 3799.6 Study Problems 379References 38010 Sustainability and Environmental Impact Assessment of Drying Systems 38110.1 Introduction 38110.2 Sustainability 38310.2.1 Sustainability Assessment Indicators 38310.2.2 Exergy-Based Sustainability Assessment 39110.3 Environmental Impact 39710.3.1 Reference Environment Models 39910.3.2 Anthropogenic Impact on the Environment 40110.3.3 Exergy Destruction and Environmental Impact of Drying Systems 41110.4 Case Study: Exergo-Sustainability Assessment of a Heat Pump Dryer 41910.4.1 Reference Dryer Description 41910.4.2 Exergo-Sustainability Assessment for the Reference Drying System 42110.4.3 Improved Dryer Description 42510.4.4 Exergo-Sustainability Assessment for the Improved Drying System 42810.4.5 Concluding Remarks 43010.5 Conclusions 43010.6 Study Problems 430References 43111 Novel Drying Systems and Applications 43311.1 Introduction 43311.2 Drying with Superheated Steam 43611.3 Chemical Heat Pump Dryers 43811.4 Advances on Spray Drying Systems 44111.4.1 Spray Drying of CuCl2(aq) 44111.4.2 Spray Drying of Nanoparticles 44511.4.3 Microencapsulation through Spray Drying 44611.5 Membrane Air Drying for Enhanced Evaporative Cooling 44811.6 Ultrasound-Assisted Drying 44911.7 Conclusions 45111.8 Study Problems 451References 452Appendix A: Conversion Factors 455Appendix B: Thermophysical Properties of Water 457Appendix C: Thermophysical Properties of Some Foods and Solid Materials 461Appendix D: Psychometric Properties of Humid Air 463Index 469