mcca_fm.qxd 8/3/00 8:42 AM Page xvii P R E FA C E This sixth edition of the text on the unit operations of chemical engineering has been extensively revised and updated, with much new material and considerable condensation of some sections. Its basic structure and general level of treatment, however, remain unchanged. It is an introductory text, written for undergraduate students in their junior or senior years who have completed the usual courses in mathematics, physics, chemistry, and an introduction to chemical engineering. An elementary knowledge of material and energy balances and of thermodynamic principles is assumed. Separate chapters are devoted to each of the principal unit operations, grouped into four sections: fluid mechanics, heat transfer, mass transfer and equilibrium stages, and operations involving particulate solids. One-semester or one-quarter courses may be based on any of these sections or combinations of them. The order of the first 16 chapters has not been changed; later ones, dealing with mass transfer and operations involving solids, have been rearranged in a more logical order. Nearly all equations have been written for SI units, and the Newton’s law conversion factor gc has been eliminated except in the few instances where it must be included. Symbols for dimensionless groups have been changed to Re for NRe, for example, Pr for NPr, and so forth. Many new examples and problems have been added, some reflecting the importance of biochemical engineering processes. Material on handling, mixing, and grinding particulate solids has been greatly condensed and dealt with in a single chapter. The number of appendixes is reduced from 22 to 19. Derivations of the differential equations for continuity and momentum balances, leading to the Navier-Stokes equation, have been added, as well as the differential forms of Fourier’s law and Fick’s law, emphasizing the analogies among momentum, heat, and mass transfer. The chapter on adsorption has been expanded to include new material on chromatography and ion exchange, and renamed “Fixedbed Separations.” Other new material has been added on viscoelastic fluids, laminar flow in annuli, drag coefficients, affinity laws for pumps, high-efficiency agitators and motionless mixers, plate-type heat exchangers, boiling by submerged tube bundles, cooling towers, aqueous phase extraction, cross-flow filtration, and many other topics. Many of the problems at the ends of the chapters are new or revised. Most are expressed in SI units. Nearly all the problems can be solved with the aid of a pocket calculator; for a few, a computer solution is preferable. McGraw-Hill and the authors thank Dr. N. T. Obot for his many suggestions regarding fluid mechanics and heat transfer, and Professor Charles H. Gooding of Clemson University for his detailed and helpful review of the manuscript. Julian C. Smith Peter Harriott xvii iii mcca_fm.qxd 8/3/00 8:42 AM Page vii CONTENTS Preface SECTION I 1 xvii Introduction Definitions and Principles 3 Unit Operations Unit Systems 4 4 Physical Quantities / SI Units / CGS Units / Gas Constant / FPS Engineering Units / Conversion of Units / Units and Equations Dimensional Analysis Basic Concepts 16 20 Equations of State of Gases Symbols Problems References SECTION II 2 3 24 25 27 Fluid Mechanics Fluid Statics and Its Applications 31 Hydrostatic Equilibrium 32 Applications of Fluid Statics Symbols Problems References 34 Fluid Flow Phenomena 44 Laminar Flow, Shear Rate, and Shear Stress Rheological Properties of Fluids Turbulence Boundary Layers Symbols Problems References 45 41 42 43 46 51 59 63 64 65 vii mcca_fm.qxd viii 8/3/00 8:42 AM Page viii CONTENTS 4 5 6 7 8 Basic Equations of Fluid Flow 67 Mass Balance in a Flowing Fluid; Continuity Differential Momentum Balance; Equations of Motion Macroscopic Momentum Balances Mechanical Energy Equation Symbols Problems References 67 Incompressible Flow in Pipes and Channels 94 Shear Stress and Skin Friction in Pipes Laminar Flow in Pipes and Channels Turbulent Flow in Pipes and Channels Friction from Changes in Velocity or Direction Symbols Problems References 94 72 77 82 90 92 93 97 104 117 123 124 127 Flow of Compressible Fluids 128 Definitions and Basic Equations Processes of Compressible Flow Isentropic Flow through Nozzles Adiabatic Friction Flow Isothermal Friction Flow Symbols Problems References 128 Flow Past Immersed Bodies 150 Drag and Drag Coefficients Flow through Beds of Solids Motion of Particles through Fluids Fluidization Symbols Problems References 150 Transportation and Metering of Fluids 187 Pipe, Fittings, and Valves Pumps 187 133 134 140 145 147 148 149 157 162 171 182 183 185 194 mcca_fm.qxd 8/3/00 8:42 AM Page ix CONTENTS ix Positive-Displacement Pumps / Centrifugal Pumps Fans, Blowers, and Compressors 209 Fans / Blowers and Compressors / Comparison of Devices for Moving Fluids Measurement of Flowing Fluids 219 Full-Bore Meters / Insertion Meters 9 SECTION III 10 11 Symbols Problems References 234 Agitation and Mixing of Liquids 238 Agitated Vessels Blending and Mixing Suspension of Solid Particles Dispersion Operations Agitator Selection and Scaleup Symbols Problems References 239 236 237 259 265 270 278 281 282 284 Heat Transfer and Its Applications Heat Transfer by Conduction 291 Basic Law of Conduction Steady-State Conduction Unsteady-State Conduction Symbols 291 Problems References 312 Principles of Heat Flow in Fluids 315 Typical Heat-Exchange Equipment Energy Balances Heat Flux and Heat-Transfer Coefficients 315 293 300 311 314 319 321 Overall Heat-Transfer Coefficient / Individual Heat-Transfer Coefficients Symbols Problems References 333 334 335 mcca_fm.qxd x 8/3/00 8:42 AM Page x CONTENTS 12 Heat Transfer to Fluids Without Phase Change 336 Boundary Layers Heat Transfer by Forced Convection in Laminar Flow Heat Transfer by Forced Convection in Turbulent Flow 336 339 346 Transfer by Turbulent Eddies and Analogy Between Transfer of Momentum and Heat Heat Transfer in Transition Region Between Laminar and Turbulent Flow Heat Transfer to Liquid Metals Heating and Cooling of Fluids in Forced Convection Outside Tubes Natural Convection Symbols Problems References 13 14 15 358 360 362 365 371 373 375 Heat Transfer to Fluids with Phase Change 377 Heat Transfer from Condensing Vapors Heat Transfer to Boiling Liquids Symbols Problems References 377 Radiation Heat Transfer 406 Emission of Radiation Absorption of Radiation by Opaque Solids Radiation Between Surfaces 407 Radiation to Semitransparent Materials Combined Heat Transfer by Conduction-Convection and Radiation Symbols Problems References 423 Heat-Exchange Equipment 431 Shell-and-Tube Heat Exchangers Plate-Type Exchangers Extended-Surface Equipment Scraped-Surface Exchangers 432 389 401 403 404 410 413 425 427 428 430 446 449 455 mcca_fm.qxd 8/3/00 8:42 AM Page xi CONTENTS 16 xi Condensers and Vaporizers Heat Transfer in Agitated Vessels Heat Transfer in Packed Beds Symbols Problems References 456 Evaporation 473 Types of Evaporators 475 Performance of Tubular Evaporators 479 459 463 467 469 471 Evaporator Capacity / Evaporator Economy Vapor Recompression Symbols Problems References SECTION IV 17 498 500 500 502 Mass Transfer and Its Applications Principles of Diffusion and Mass Transfer Between Phases Theory of Diffusion Prediction of Diffusivities Mass-Transfer Theories 511 512 518 523 Film Theory / Boundary Layer Theory / Penetration Theory / Two-Film Theory Mass-Transfer Coefficients 530 Experimental Measurements / Coefficients for Mass Transfer through Known Areas 18 Symbols Problems References 540 Gas Absorption 546 Packings and Packed Tower Design Principles of Absorption Absorption from Rich Gases Mass-Transfer Correlations 546 542 544 557 574 580 Absorption in Plate Columns Absorption with Chemical Reaction 588 mcca_fm.qxd xii 8/3/00 8:42 AM Page xii CONTENTS 19 Symbols Problems References 590 Humidification Operations 596 Definitions Humidity Chart Wet-Bulb Temperature Cooling Towers 596 592 594 600 604 608 Theory of Counterflow Cooling Towers 20 Symbols Problems References 618 Equilibrium-Stage Operations 622 Equipment for Stage Contacts Principles of Stage Processes 622 619 621 625 Equilibrium-Stage Calculations for Multicomponent Systems 21 Symbols Problems References 639 Distillation 641 Flash Distillation Continuous Distillation with Reflux 641 639 640 645 Material Balances in Plate Columns / Number of Ideal Plates; McCabe–Thiele Method Enthalpy Balances Design of Sieve-Plate Columns Plate Efficiencies 672 681 689 Theory of Plate Efficiency 22 Distillation in Packed Columns Batch Distillation Symbols Problems References 699 Introduction to Multicomponent Distillation 713 Phase Equilibria in Multicomponent Distillation Flash Distillation of Multicomponent Mixtures 713 700 704 706 711 717 mcca_fm.qxd 8/3/00 8:42 AM Page xiii CONTENTS 23 xiii Fractionation of Multicomponent Mixtures Azeotropic and Extractive Distillation Symbols Problems References 718 Leaching and Extraction 739 Leaching 739 734 735 736 738 Leaching Equipment / Principles of Continuous Countercurrent Leaching Liquid Extraction 747 Extraction Equipment / Principles of Extraction Special Extraction Techniques 766 Supercritical Fluid Extraction 24 Symbols Problems References 768 Drying of Solids 773 Principles of Drying 775 769 772 Phase Equilibria Cross-Circulation Drying Through-Circulation Drying 782 790 Drying of Suspended Particles Freeze-Drying Drying Equipment 793 794 Dryers for Solids and Pastes / Dryers for Solutions and Slurries / Selection of Drying Equipment 25 Symbols Problems References 807 Fixed-Bed Separations 812 Adsorption Adsorption Equipment 812 809 810 813 Equilibria; Adsorption Isotherms / Principles of Adsorption / Basic Equations for Adsorption / Solutions to Mass-Transfer Equations / Adsorber Design / Continuous Operation Ion Exchange Equilibria / Mass-Transfer Rates / Operation of Ion Exchangers 839 mcca_fm.qxd xiv 8/3/00 8:42 AM Page xiv CONTENTS 26 Chromatography Symbols Problems References 845 Membrane Separation Processes 857 Separation of Gases Separation of Liquids 857 852 854 855 878 Dialysis / Membranes for Liquid-Liquid Extraction / Pervaporation / Reverse Osmosis 27 Symbols Problems References 896 Crystallization 902 Crystal Geometry Equilibria and Yields Nucleation Crystal Growth Crystallization Equipment Crystallizer Design: Crystal Size Distribution 903 898 900 904 911 918 921 927 MSMPR Crystallizer Crystallization from Melts Symbols Problems References SECTION V 28 936 937 939 941 Operations Involving Particulate Solids Properties and Handling of Particulate Solids 945 Characterization of Solid Particles Properties of Masses of Particles 945 951 Storage and Conveying of Solids Mixing of Solids 955 Mixers for Noncohesive Solids / Mixers for Cohesive Solids Size Reduction Computer Simulation of Milling Operations / Equipment for Size Reduction 965 mcca_fm.qxd 8/3/00 8:42 AM Page xv CONTENTS 29 xv Ultrafine Grinders Symbols Problems References 977 Mechanical Separations 986 Screening 986 981 983 984 Screening Equipment Filtration; General Considerations 991 Cake Filters 993 Centrifugal Filters / Filter Media / Filter Aids / Principles of Cake Filtration Clarifying Filters 1018 Liquid Clarification / Gas Cleaning / Principles of Clarification Crossflow Filtration; Membrane Filters 1021 Type of Membranes / Permeate Flux for Ultrafiltration / Concentration Polarization / Microfiltration Gravity Sedimentation Processes Centrifugal Sedimentation Processes Symbols Problems References Appendix 1 Conversion Factors and Constants of Nature Appendix 2 Dimensionless Groups Appendix 3 Dimensions, Capacities, and Weights of Standard Steel Pipe Appendix 4 Condenser and Heat-Exchanger Tube Data 1035 Appendix 5 Appendix 6 Appendix 7 Appendix 8 Appendix 9 Appendix 10 Appendix 11 1070 Tyler Standard Screen Scale Properties of Liquid Water Properties of Saturated Steam and Water Viscosities of Gases Viscosities of Liquids Thermal Conductivities of Metals Thermal Conductivities of Various Solids and Insulating Materials Appendix 12 Thermal Conductivities of Gases and Vapors Appendix 13 Thermal Conductivities of Liquids Other Than Water Appendix 14 Specific Heats of Gases 1045 1056 1058 1061 1063 1066 1068 1069 1071 1072 1074 1076 1079 1080 1082 1083 1084 mcca_fm.qxd xvi 8/3/00 8:42 AM Page xvi CONTENTS Appendix 15 Appendix 16 Appendix 17 Appendix 18 Specific Heats of Liquids Prandtl Numbers for Gases at 1 atm and 100°C Prandtl Numbers for Liquids Diffusivities and Schmidt Numbers for Gases in Air at 0°C and 1 atm Appendix 19 Collision Integral and Lennard-Jones Force Constants 1085 Index 1091 1086 1087 1088 1089 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 58 59 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 379 380 381 382 383 384 385 386 387 388
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