Page 13 - Chemical engineering design

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Separation Columns (Distillation, Absorption and Extraction)
11
493
11.1 Introduction CONTENTS 493
11.2 Continuous distillation: process description 494
11.2.1 Reflux considerations 495
11.2.2 Feed-point location 496
11.2.3 Selection of column pressure 496
11.3 Continuous distillation: basic principles 497
11.3.1 Stage equations 497
11.3.2 Dew points and bubble points 498
11.3.3 Equilibrium flash calculations 499
11.4 Design variables in distillation 501
11.5 Design methods for binary systems 503
11.5.1 Basic equations 503
11.5.2 McCabe-Thiele method 505
11.5.3 Low product concentrations 507
11.5.4 The Smoker equations 512
11.6 Multicomponent distillation: general considerations 515
11.6.1 Key components 516
11.6.2 Number and sequencing of columns 517
11.7 Multicomponent distillation: short-cut methods for stage and reflux requirements 517
11.7.1 Pseudo-binary systems 518
11.7.2 Smith-Brinkley method 522
11.7.3 Empirical correlations 523
11.7.4 Distribution of non-key components (graphical method) 526
11.8 Multicomponent systems: rigorous solution procedures (computer methods) 542
11.8.1 Lewis-Matheson method 543
11.8.2 Thiele-Geddes method 544
11.8.3 Relaxation methods 545
11.8.4 Linear algebra methods 545
11.9 Other distillation systems 546
11.9.1 Batch distillation 546
11.9.2 Steam distillation 546
11.9.3 Reactive distillation 547
11.10 Plate efficiency 547
11.10.1 Prediction of plate efficiency 548
11.10.2 O’Connell’s correlation 550
11.10.3 Van Winkle’s correlation 552
11.10.4 AIChE method 553
11.10.5 Entrainment 556
11.11 Approximate column sizing 557
11.12 Plate contactors 557
11.12.1 Selection of plate type 560
11.12.2 Plate construction 561
11.13 Plate hydraulic design 565
11.13.1 Plate-design procedure 567
11.13.2 Plate areas 567
11.13.3 Diameter 567
11.13.4 Liquid-flow arrangement 569
11.13.5 Entrainment 570
11.13.6 Weep point 571
11.13.7 Weir liquid crest 572
11.13.8 Weir dimensions 572
11.13.9 Perforated area 572
11.13.10 Hole size 573
11.13.11 Hole pitch 574
11.13.12 Hydraulic gradient 574
11.13.13 Liquid throw 575
11.13.14 Plate pressure drop 575
11.13.15 Downcomer design [back-up] 577
11.14 Packed columns 587
11.14.1 Types of packing 589