Separation Process Principles

About the Authors iii Preface to the Fourth Edition v

General Nomenclature xiii

Dimensions and Units xvii

1. Separation Processes 1

1.0∗ Instructional Objectives 1

1.1∗ Industrial Chemical Processes 1

1.2∗ Basic Separation Techniques 3

1.3⚬ Separations by Phase Creation 4

1.4⚬ Separations by Phase Addition 6

1.5⚬ Separations by Barrier 7

1.6⚬ Separations by an External Field or Gradient 7

1.7∗ Brief Comparison of Common Separation Operations 8

1.8∗ Separation Processes, Product Purity, Component Recovery, and Separation Sequences 9

Summary, References, Study Questions, Exercises

2. Thermodynamics of Separation Operations 16

2.0∗ Instructional Objectives 16

2.1∗ Phase Equilibria 16

2.2∗ Ideal-Gas, Ideal-Liquid-Solution Model 20

2.3⚬ Graphical Representation of Thermodynamic Properties 21

2.4⚬ Nonideal Thermodynamic Property Models 23

2.5⚬ P-v-T Equation-of-State (EOS) Models 23

2.6⚬ Highly Nonideal Liquid Solutions 27

2.7⚬ Gibbs Excess Free-Energy (gE) Models 29

2.8⚬ Predictive Models 34

2.9⚬ Electrolyte Solution Models 36

2.10⚬ Polymer Solution Models 36

2.11∗ K-Value Methods in Process Simulators 36

2.12∗ Exergy and Second-Law Analysis 37

Nomenclature, Summary, References, Study Questions, Exercises

3. Mass Transfer and Diffusion 46

3.0∗ Instructional Objectives 46

3.1∗ Steady-State, Ordinary Molecular Diffusion 47

3.2∗ Diffusion Coefficients (Diffusivities) 51

3.3∗ Steady-State and Unsteady-State Mass Transfer Through Stationary Media 58

3.4∗ Mass Transfer in Laminar Flow 60

3.5∗ Mass Transfer in Turbulent Flow 68

3.6∗ Models for Mass Transfer in Fluids with a Fluid–Fluid Interface 73

3.7∗ Two-Film Theory and Overall Mass-Transfer Coefficients 76

Nomenclature, Summary, References, Study Questions, Exercises

4. Single Equilibrium Stages and Flash Calculations 87

4.0∗ Instructional Objectives 87

4.1∗ Gibbs’ Phase Rule and Degrees of Freedom 88

4.2∗ Binary Vapor–Liquid Systems at Equilibrium 89

4.3∗ Equilibrium Two-Phase Flash Calculations 93

4.4∗ Ternary Liquid–Liquid Systems at Equilibrium 97

4.5⚬ Multicomponent Liquid–Liquid Systems 101

4.6∗ Liquid–Solid Systems 102

4.7∗ Gas–Liquid Systems 104

4.8∗ Gas–Solid Systems 105

4.9⦁ Three-Phase Equilibrium Systems 107

Nomenclature, Summary, References, Study Questions, Exercises

5. Multistage Cascades and Hybrid Systems 118

5.0∗ Instructional Objectives 118

5.1∗ Cascade Configurations 118

5.2∗ Single-Section Liquid–Liquid Extraction Cascades 119

5.3∗ Two-Section Distillation Cascades 121

5.4⚬ Membrane Cascades 123

5.5⚬ Hybrid Systems 125

5.6∗ Degrees of Freedom and Specifications for Cascades 125

Nomenclature, Summary, References, Study Questions, Exercises

6. Absorption and Stripping 137

6.0∗ Instructional Objectives 137

6.1⚬ Equipment for Vapor–Liquid Separations 138

6.2⚬ General Design Considerations 143

6.3∗ Graphical Method for Trayed Towers 144

6.4∗ Kremser Group Method for Multicomponent Absorption and Stripping 148

6.5∗ Stage Efficiency and Column Height for Trayed Columns 154

6.6∗ Flooding, Column Diameter, and Tray Layout for Trayed Columns 161

6.7∗ Rate-Based Method for Packed Columns 164

6.8∗ Packed-Column Liquid Holdup, Diameter, Flooding, Pressure Drop, and Mass-Transfer Efficiency 169

6.9⦁ Reactive (Chemical) Absorption 180

Nomenclature, Summary, References, Study Questions, Exercises

7. Distillation of Binary Mixtures 191

7.0∗ Instructional Objectives 191

7.1⚬ Equipment and Design Considerations 193

7.2∗ McCabe–Thiele Graphical Method for Trayed Towers 193

7.3⚬ Extensions of the McCabe–Thiele Method 203

7.4∗ Estimation of Tray Efficiency for Distillation 208

7.5∗ Column and Reflux-Drum Diameters 215

7.6∗ Rate-Based Method for Packed Distillation Columns 216

Nomenclature, Summary, References, Study Questions, Exercises

8. Liquid–Liquid Extraction with Ternary Systems 231

8.0∗ Instructional Objectives 231

8.1⚬ Equipment for Solvent Extraction 233

8.2⚬ General Design Considerations 239

8.3∗ Hunter–Nash Graphical Equilibrium-Stage Method 243

8.4⚬ Theory and Scale-Up of Extractor Performance 252

Nomenclature, Summary, References, Study Questions, Exercises

9. Approximate Methods for Multicomponent Distillation 267

9.0∗ Instructional Objectives 267

9.1∗ Fenske–Underwood–Gilliland (FUG) Method 267

9.2∗ Using the Shortcut (FUG) Method with Process Simulators 279

Nomenclature, Summary, References, Study Questions, Exercises

10. Equilibrium-Based Methods for Multicomponent Absorption, Stripping, Distillation, and Extraction 284

10.0∗ Instructional Objectives 284

10.1∗ Simple Model for a Vapor–Liquid Equilibrium Stage 284

10.2⦁ Evolution of Methods for Solving the Mesh Equations 286

10.3∗ Strategies for Applying Process-Simulator Methods 287

10.4∗ Main Mathematical Procedures 291

10.5∗ Bubble-Point (BP) and Sum-Rates (SR) Methods 294

10.6∗ Simultaneous-Correction Method 297

10.7∗ Inside-Out Method 304

10.8⦁ Rigorous Methods for Liquid–Liquid Extraction 309

Nomenclature, Summary, References, Study Questions, Exercises

11. Enhanced Distillation and Supercritical Extraction 320

11.0∗ Instructional Objectives 320

11.1∗ Use of Triangular Graphs 321

11.2∗ Extractive Distillation 332

11.3⦁ Salt Distillation 335

11.4⦁ Pressure-Swing Distillation 337

11.5⦁ Homogeneous Azeotropic Distillation 339

11.6∗ Heterogeneous Azeotropic Distillation 343

11.7⦁ Reactive Distillation 352

11.8⦁ Supercritical-Fluid Extraction 357

Nomenclature, Summary, References, Study Questions, Exercises

12. Rate-Based Models for Vapor–Liquid Separation Operations 368

12.0⦁ Instructional Objectives 368

12.1⦁ Rate-Based Model 370

12.2⦁ Thermodynamic Properties and Transport-Rate Expressions 372

12.3⦁ Methods for Estimating Transport Coefficients and Interfacial Area 375

12.4⦁ Vapor and Liquid Flow Patterns 375

12.5⦁ Method of Calculation 376

Nomenclature, Summary, References, Study Questions, Exercises

13. Batch Distillation 385

13.0∗ Instructional Objectives 385

13.1∗ Differential Distillation 385

13.2∗ Binary Batch Rectification 388

13.3⦁ Batch Stripping and Complex Batch Distillation 390

13.4⦁ Effect of Liquid Holdup 391

13.5∗ Stage-by-Stage Methods for Batch Rectification 391

13.6∗ Intermediate-Cut Strategy 400

13.7⦁ Optimal Control by Variation of Reflux Ratio 401

Nomenclature, Summary, References, Study Questions, Exercises ∗Suitable for an UG course ⚬Optional ⦁Advanced

14. Membrane Separations 408

14.0∗ Instructional Objectives 408

14.1⚬ Membrane Materials 410

14.2⚬ Membrane Modules 414

14.3∗ Mass Transfer in Membranes 416

14.4∗ Dialysis 430

14.5⚬ Electrodialysis 432

14.6∗ Reverse Osmosis 434

14.7∗ Gas Permeation 438

14.8⚬ Pervaporation 441

Nomenclature, Summary, References, Study Questions, Exercises

15. Adsorption, Ion Exchange, and Chromatography 451

15.0∗ Instructional Objectives 451

15.1∗ Sorbents 453

15.2∗ Equilibrium Considerations 461

15.3∗ Kinetic and Transport Rate Considerations 470

15.4⚬ Equipment for Sorption Operations 475

15.5∗ Slurry and Fixed-Bed Adsorption Systems 479

15.6∗ Continuous, Countercurrent Adsorption Systems 494

15.7⚬ Ion-Exchange Cycle 502

15.8∗ Chromatographic Separations 503

Nomenclature, Summary, References, Study Questions, Exercises

Answers to Selected Exercises 519

Index 521