PRINCIPLES AND MODERN APPLICATIONS OF MASS TRANSFER OPERATIONS

Transcription

1 PRINCIPLES AND MODERN APPLICATIONS OF MASS TRANSFER OPERATIONS Jaime Benitez iwiley- INTERSCIENCE A JOHN WILEY & SONS, INC., PUBLICATION

2 Preface Nomenclature xiii xv 1. FUNDAMENTALS OF MASS TRANSFER Introduction Molecular Mass Transfer Concentrations Velocities and Fluxes The Maxwell-Stefan Relations Fick's First Law for Binary Mixtures The Diffusion Coefficient Diffusion Coefficients for Binary Ideal Gas Mixtures Diffusion Coefficients for Liquids Effective Diffusivities in Multicomponent Mixtures Steady-State Molecular Diffusion in Fluids Molar Flux and the Equation of Continuity Steady-State Molecular Diffusion in Gases Steady-State Molecular Diffusion in Liquids Analogies Among Molecular Momentum, Heat, and Mass Transfer 49 Problems 51 References 64 VII

3 viii Contents 2. CONVECTIVE MASS TRANSFER Introduction Mass-Transfer Coefficients Diffusion of A Through Stagnant B Equimolar Counterdiffusion Dimensional Analysis The Buckingham Method Mass- and Heat-Transfer Analogies Convective Mass-Transfer Correlations Mass-Transfer Coefficients for Flat Plates Mass-Transfer Coefficients for Single Sphere Mass-Transfer Coefficients for Single Cylinder Turbulent Flow in Circular Pipes Mass Transfer in Packed and Fluidized Beds Mass Transfer in Hollow-Fiber Membranes Estimation of Multicomponent Mass-Transfer Coefficients 103 Problems 106 References INTERPHASE MASS TRANSFER Introduction Equilibrium Diffusion Between Phases Two-Resistance Theory Overall Mass-Transfer Coefficients Local Mass-Transfer Coefficients: General Case Material Balances Countercurrent Flow Cocurrent Flow Batch Processes Equilibrium-Stage Operations 158 Problems 164

4 ix References EQUIPMENT FOR GAS-LIQUID MASS-TRANSFER OPERATIONS Introduction 179 Gas-Liquid Operations: Liquid Dispersed Types of Packing Liquid Distribution Liquid Holdup Pressure Drop Mass-Transfer Coefficients Gas-Liquid Operations: Gas Dispersed Problems References Sparged Vessels (Bubble Columns) 203 Tray Towers 209 Tray Diameter 212 Tray Gas-Pressure Drop Weeping and Entrainment Tray Efficiency ABSORPTION AND STRIPPING Introduction Countercurrent Multistage Equipment Graphical Determination of Number of Ideal Trays Tray Efficiency and Real Trays by Graphical Methods Dilute Mixtures Countercurrent Continuous Contact Equipment Dilute Solutions; Henry's Law Thermal Effects During Absorption and Stripping Adiabatic Operation of a Tray Absorber 261

5 5.4.1 Adiabatic Operation of a Packed-Bed Absorber 261 Problems 276 References DISTILLATION Introduction Single-Stage Operation: Flash Vaporization Batch Distillation Continuous Rectification: Binary Mixtures McCabe-Thiele Metod for Trayed Towers Rectifying Section Stripping Section Feed Stage Number of Equilibrium Stages and Feed-Stage Location Limiting Conditions Optimum Reflux Ratio Large Number of Stages Use of Open Steam Tray Efficiencies Binary Distillation in Packed Towers Introduction to Multicomponent Distillation Fenske-Underwood-Gilliland Method Total Reflux: Fenske Equation Minimum Reflux: Underwood Equations Gilliland Correlation for Number of Stages Rigorous Calculation Procedures for Multicomponent Distillation Equilibrium Stage Model Nonequilibrium, Rate-based Model 353 Problems 368-

6 References LIQUID-LIQUID EXTRACTION Introduction Liquid Equilibria Stagewise Liquid-Liquid Extraction Single-Stage Extraction Multistage Crosscurrent Extraction Countercurrent Extraction Cascades Insoluble Liquids Continuous Countercurrent Extraction with Reflux Equipment for Liquid-Liquid Extraction Mixer-Settler Cascades Multicompartment Columns 423 Problems 427 References 435 Appendix A: Binary Diffusion Coefficients 436 Appendix B: Lennard-Jones Constants 439 Appendix C: Maxwell-Stefan Equations By Orthogonal Collocation. 441 Appendix D: Packed-Column Design Program 449 Appendix E: Sieve-Tray Design Program 453 Appendix F: McCabe-Thiele Method By MATHCAD 460 Appendix G: Liquid Extraction Calculations 479 Appendix H: Frequently Used Constants And Unit Conversions 486 Index 489