Separation Process Engineering

by Wankat, Phillip C.

• ISBN13: 9780130847898
• ISBN10: 0130847895
• Edition: 2nd
• Format: Hardcover
• Copyright: 2006-08-11
• Publisher: Prentice Hall

Summary

The Comprehensive Introduction to Standard and Advanced Separation for Every Chemical EngineerSeparation Process Engineering, Second Editionhelps readers thoroughly master both standard equilibrium staged separations and the latest new processes. The author explains key separation process with exceptional clarity, realistic examples, and end-of-chapter simulation exercises using Aspen Plus.The book starts by reviewing core concepts, such as equilibrium and unit operations; then introduces a step-by-step process for solving separation problems. Next, it introduces each leading processes, including advanced processes such as membrane separation, adsorption, and chromatography. For each process, the author presents essential principles, techniques, and equations, as well as detailed examples.Separation Process Engineeringis the new, thoroughly updated edition of the author's previous book,Equilibrium Staged Separations. Enhancements include improved organization, extensive new coverage, and more than 75% new homework problems, all tested in the author's Purdue University classes.Coverage includes Detailed problems with real data, organized in a common format for easier understanding Modular simulation exercises that support courses taught with simulators without creating confusion in courses that do not use them Extensive new coverage of membrane separations, including gas permeation, reverse osmosis, ultrafiltration, pervaporation, and key applications A detailed introduction to adsorption, chromatography and ion exchange: everything students need to understand advanced work in these areas Discussions of standard equilibrium stage processes, including flash distillation, continuous column distillation, batch distillation, absorption, stripping, and extraction

Author Biography

Phillip C. Wankat is Clifton L. Lovell Distinguished Professor of Chemical Engineering at Purdue University, and Director of Undergraduate Degree Programs in Purdue's Department of Engineering Education.

Table of Contents

Preface	xv
Acknowledgments	xvii
About the Author	xix
Nomenclature	xxi
Chapter 1 Introduction to Separation Process Engineering	1	(11)
1.1. Importance of Separations	1	(1)
1.2. Concept of Equilibrium	2	(2)
1.3. Mass Transfer	4	(1)
1.4. Problem-Solving Methods	5	(2)
1.5. Prerequisite Material	7	(1)
1.6. Other Resources on Separation Process Engineering	8	(1)
1.7. Summary— Objectives	9	(1)
References	9	(1)
Homework	10	(2)
Chapter 2 Flash Distillation	12	(53)
2.1. Basic Method of Flash Distillation	12	(2)
2.2. Form and Sources of Equilibrium Data	14	(2)
2.3. Graphical Representation of Binary VLE	16	(5)
2.4. Binary Flash Distillation	21	(8)
2.4.1. Sequential Solution Procedure	21	(6)
Example 2-1. Flash separator for ethanol and water	24	(3)
2.4.2. Simultaneous Solution Procedure	27	(2)
2.5. Multicomponent VLE	29	(5)
2.6. Multicomponent Flash Distillation	34	(6)
Example 2-2. Multicomponent flash distillation	37	(3)
2.7. Simultaneous Multicomponent Convergence	40	(5)
Example 2-3. Simultaneous convergence for flash distillation	43	(2)
2.8. Size Calculation	45	(4)
Example 2-4. Calculation of drum size	47	(2)
2.9. Utilizing Existing Flash Drums	49	(1)
2.10. Summary— Objectives	50	(1)
References	51	(1)
Homework	52	(7)
Appendix Computer Simulation of Flash Distillation	59	(6)
Chapter 3 Introduction to Column Distillation	65	(21)
3.1. Developing a Distillation Cascade	65	(7)
3.2. Distillation Equipment	72	(2)
3.3. Specifications	74	(2)
3.4. External Column Balances	76	(5)
Example 3-1. External balances for binary distillation	79	(2)
3.5. Summary— Objectives	81	(1)
References	81	(1)
Homework	81	(5)
Chapter 4 Column Distillation: Internal Stage-by-Stage Balances	86	(75)
4.1. Internal Balances	86	(4)
4.2. Binary Stage-by-Stage Solution Methods	90	(7)
Example 4-1. Stage-by-stage calculations by the Lewis method	94	(3)
4.3. Introduction to the McCabe-Thiele Method	97	(4)
4.4. Feed Line	101	(8)
Example 4-2. Feed line calculations	106	(3)
4.5. Complete McCabe-Thiele Method	109	(3)
Example 4-3. McCabe-Thiele method	109	(3)
4.6. Profiles for Binary Distillation	112	(2)
4.7. Open Steam Heating	114	(4)
Example 4-4. McCabe-Thiele analysis of open steam heating	114	(4)
4.8. General McCabe-Thiele Analysis Procedure	118	(7)
Example 4-5. Distillation with two feeds	120	(5)
4.9. Other Distillation Column Situations	125	(5)
4.9.1. Partial Condensers	125	(1)
4.9.2. Total Reboilers	126	(1)
4.9.3. Side Streams or Withdrawal Lines	126	(2)
4.9.4. Intermediate Reboilers and Intermediate Condensers	128	(1)
4.9.5. Stripping and Enriching Columns	129	(1)
4.10. Limiting Operating Conditions	130	(3)
4.11. Efficiencies	133	(2)
4.12. Simulation Problems	135	(1)
4.13. New Uses for Old Columns	136	(2)
4.14. Subcooled Reflux and Superheated Boilup	138	(2)
4.15. Comparisons between Analytical and Graphical Methods	140	(2)
4.16. Summary— Objectives	142	(1)
References	143	(1)
Homework	144	(13)
Appendix Computer Simulations for Binary Distillation	157	(4)
Chapter 5 Introduction to Multicomponent Distillation	161	(15)
5.1. Calculational Difficulties	161	(6)
Example 5-1. External mass balances using fractional recoveries	164	(3)
5.2. Profiles for Multicomponent Distillation	167	(5)
5.3. Summary—Objectives	172	(1)
References	172	(1)
Homework	172	(4)
Chapter 6 Exact Calculation Procedures for Multicomponent Distillation	176	(29)
6.1. Introduction to Matrix Solution for Multicomponent Distillation	176	(2)
6.2. Component Mass Balances in Matrix Form	178	(3)
6.3. Initial Guess for Flow Rates	181	(1)
6.4. Bubble-Point Calculations	181	(3)
Example 6-1. Bubble-point temperature	183	(1)
6.5. theta-Method of Convergence	184	(7)
Example 6-2. Matrix calculation and theta-convergence	186	(5)
6.6. Energy Balances in Matrix Form	191	(3)
6.7. Summary—Objectives	194	(1)
References	195	(1)
Homework	195	(5)
Appendix Computer Simulations for Multicomponent Column Distillation	200	(5)
Chapter 7 Approximate Shortcut Methods for Multicomponent Distillation	205	(20)
7.1. Total Reflux: Fenske Equation	205	(5)
Example 7-1. Fenske equation	209	(1)
7.2. Minimum Reflux: Underwood Equations	210	(5)
Example 7-2. Underwood equations	214	(1)
7.3. Gilliland Correlation for Number of Stages at Finite Reflux Ratio	215	(4)
Example 7-3. Gilliland correlation	217	(2)
7.4. Summary—Objectives	219	(1)
References	219	(1)
Homework	220	(5)
Chapter 8 Introduction to Complex Distillation Methods	225	(51)
8.1. Breaking Azeotropes with Other Separators	225	(2)
8.2. Binary Heterogeneous Azeotropic Distillation Processes	227	(7)
8.2.1. Binary Heterogeneous Azeotropes	227	(3)
8.2.2. Drying Organic Compounds That Are Partially Miscible with Water	230	(10)
Example 8-1. Drying benzene by distillation	232	(2)
8.3. Steam Distillation	234	(4)
Example 8-2. Steam distillation.	235	(3)
8.4. Two-Pressure Distillation Processes	238	(2)
8.5. Complex Ternary Distillation Systems	240	(6)
8.5.1. Distillation Curves	240	(3)
8.5.2. Residue Curves	243	(3)
8.6. Extractive Distillation	246	(5)
8.7. Azeotropic Distillation with Added Solvent	251	(3)
8.8. Distillation with Chemical Reaction	254	(4)
8.9. Summary— Objectives	258	(1)
References	259	(1)
Homework	260	(10)
Appendix Simulation of Complex Distillation Systems	270	(6)
Chapter 9 Batch Distillation	276	(25)
9.1. Binary Batch Distillation: Rayleigh Equation	278	(1)
9.2. Simple Binary Batch Distillation	279	(4)
Example 9-1. Simple Rayleigh distillation	281	(2)
9.3. Constant-Level Batch Distillation	283	(1)
9.4. Batch Steam Distillation	284	(1)
9.5. Multistage Batch Distillation	285	(6)
9.5.1. Constant Reflux Ratio	286	(4)
Example 9-2. Multistage batch distillation	286	(4)
9.5.2. Variable Reflux Ratio	290	(1)
9.6. Operating Time	291	(1)
9.7. Summary—Objectives	292	(1)
References	292	(1)
Homework	293	(8)
Chapter 10 Staged and Packed Column Design	301	(53)
10.1. Staged Column Equipment Description	301	(8)
10.1.1. Trays, Downcomers, and Weirs	304	(2)
10.1.2. Inlets and Outlets	306	(3)
10.2. Tray Efficiencies	309	(5)
Example 10-1. Overall efficiency estimation	312	(2)
10.3. Column Diameter Calculations	314	(6)
Example 10-2. Diameter calculation for tray column	318	(2)
10.4. Sieve Tray Layout and Tray Hydraulics	320	(7)
Example 10-3. Tray layout and hydraulics	324	(3)
10.5. Valve Tray Design	327	(2)
10.6. Introduction to Packed Column Design	329	(1)
10.7. Packed Column Internals	329	(2)
10.8. Height of Packing: HETP Method	331	(2)
10.9. Packed Column Flooding and Diameter Calculation	333	(8)
Example 10-4. Packed column diameter calculation	338	(3)
10.10. Economic Trade-Offs	341	(4)
10.11. Summary— Objectives	345	(1)
References	345	(3)
Homework	348	(6)
Chapter 11 Economics and Energy Conservation in Distillation	354	(31)
11.1. Distillation Costs	354	(5)
11.2. Operating Effects on Costs	359	(7)
Example 11-1. Cost estimate for distillation	364	(2)
11.3. Changes in Plant Operating Rates	366	(1)
11.4. Energy Conservation in Distillation	366	(4)
11.5. Synthesis of Column Sequences for Almost Ideal Multicomponent Distillation	370	(6)
Example 11-2. Sequencing columns with heuristics	374	(2)
11.6. Synthesis of Distillation Systems for Nonideal Ternary Systems	376	(4)
Example 11-3. Process development for separation of complex ternary mixture	378	(2)
11.7. Summary— Objectives	380	(1)
References	380	(2)
Homework	382	(3)
Chapter 12 Absorption and Stripping	385	(39)
12.1. Absorption and Stripping Equilibria	387	(2)
12.2. Operating Lines for Absorption	389	(5)
Example 12-1. Graphical absorption analysis	392	(2)
12.3. Stripping Analysis	394	(2)
12.4. Column Diameter	396	(1)
12.5. Analytical Solution: Kremser Equation	397	(6)
Example 12-2. Stripping analysis with Kremser equation	402	(1)
12.6. Dilute Multisolute Absorbers and Strippers	403	(3)
12.7. Matrix Solution for Concentrated Absorbers and Strippers	406	(4)
12.8. Irreversible Absorption	410	(1)
12.9. Summary— Objectives	411	(1)
References	412	(1)
Homework	413	(8)
Appendix Computer Simulations for Absorption and Stripping	421	(3)
Chapter 13 Immiscible Extraction, Washing, Leaching, and Supercritical Extraction	424	(44)
13.1. Extraction Processes and Equipment	424	(4)
13.2. Countercurrent Extraction	428	(7)
13.2.1. McCabe-Thiele Method for Dilute Systems	428	(6)
Example 13-1. Dilute countercurrent immiscible extraction	432	(2)
13.2.2. Kremser Method for Dilute Systems	434	(1)
13.3. Dilute Fractional Extraction	435	(4)
13.4. Single-Stage and Cross-Flow Extraction	439	(4)
Example 13-2. Single-stage and cross-flow extraction of a protein	440	(3)
13.5. Concentrated Immiscible Extraction	443	(1)
13.6. Batch Extraction	444	(1)
13.7. Generalized McCabe-Thiele and Kremser Procedures	445	(3)
13.8. Washing	448	(4)
Example 13-3. Washing	451	(1)
13.9. Leaching	452	(2)
13.10. Supercritical Fluid Extraction	454	(3)
13.11. Application to Other Separations	457	(1)
13.12. Summary—Objectives	457	(1)
References	457	(2)
Homework	459	(9)
Chapter 14 Extraction of Partially Miscible Systems	468	(33)
14.1. Extraction Equilibria	468	(3)
14.2. Mixing Calculations and the Lever-Arm Rule	471	(3)
14.3. Single-Stage and Cross-Flow Systems	474	(3)
Example 14-1. Single-stage extraction	474	(3)
14.4. Countercurrent Extraction Cascades	477	(8)
14.4.1. External Mass Balances	477	(2)
14.4.2. Difference Points and Stage-by-Stage Calculations	479	(4)
14.4.3. Complete Extraction Problem	483	(30)
Example 14-2. Countercurrent extraction	483	(2)
14.5. Relationship between McCabe-Thiele and Triangular Diagrams	485	(1)
14.6. Minimum Solvent Rate	486	(2)
14.7. Extraction Computer Simulations	488	(1)
14.8. Leaching with Variable Flow Rates	489	(3)
Example 14-3. Leaching calculations	490	(2)
14.9. Summary—Objectives	492	(1)
References	492	(1)
Homework	493	(6)
Appendix Computer Simulation of Extraction	499	(2)
Chapter 15 Mass Transfer Analysis	501	(34)
15.1. Basics of Mass Transfer	501	(3)
15.2. HTU-NTU Analysis of Packed Distillation Columns	504	(7)
Example 15-1. Distillation in a packed column	508	(3)
15.3. Relationship of HETP and HTU	511	(2)
15.4. Mass Transfer Correlations for Packed Towers	513	(8)
15.4.1. Detailed Correlations for Random Packings	513	(7)
Example 15-2. Estimation of HG and HL	515	(5)
15.4.2. Simple Correlations	520	(1)
15.5. HTU-NTU Analysis of Absorbers and Strippers	521	(5)
Example 15-3. Absorption of SO2	525	(1)
15.6. HIL-NTU Analysis of Co-current Absorbers	526	(2)
15.7. Mass Transfer on a Tray	528	(3)
Example 15-4. Estimation of stage efficiency	530	(1)
15.8. Summary— Objectives	531	(1)
References	531	(1)
Homework	532	(3)
Chapter 16 Introduction to Membrane Separation Processes	535	(74)
16.1. Membrane Separation Equipment	537	(4)
16.2. Membrane Concepts	541	(3)
16.3. Gas Permeation	544	(14)
16.3.1. Gas Permeation of Binary Mixtures	544	(3)
16.3.2. Binary Permeation in Perfectly Mixed Systems	547	(8)
Example 16-1. Well-mixed gas permeation—sequential, analytical solution	549	(1)
Example 16-2. Well-mixed gas permeation—simultaneous analytical and graphical solutions	550	(5)
16.3.3. Multicomponent Permeation in Perfectly Mixed Systems	555	(3)
Example 16-3. Multicomponent, perfectly mixed gas permeation	556	(2)
16.4. Reverse Osmosis	558	(15)
16.4.1. Analysis of Osmosis and Reverse Osmosis	558	(6)
Example 16-4. RO without concentration polarization	562	(2)
16.4.2. Determination of Membrane Properties from Experiments	564	(2)
Example 16-5. Determination of RO membrane properties	564	(2)
16.4.3. Determination of Concentration Polarization	566	(7)
Example 16-6. RO with concentration polarization	567	(2)
Example 16-7. Prediction of RO performance with concentration polarization	569	(4)
16.4.4. RO with Concentrated Solutions	573	(1)
16.5. Ultrafiltration	573	(6)
Example 16-8. UF with gel formation	577	(2)
16.6. Pervaporation	579	(9)
Example 16-9. Pervaporation: feasibility calculation	586	(2)
Example 16-10. Pervaporation: development of feasible design	588	(1)
16.7. Bulk Flow Pattern Effects	588	(7)
Example 16-11. Flow pattern effects in gas permeation	589	(1)
16.7.1. Binary Cross-Flow Permeation	590	(2)
16.7.2. Binary Co-current Permeation	592	(2)
16.7.3. Binary Countercurrent Flow	594	(1)
16.8. Summary— Objectives	595	(1)
References	596	(1)
Homework	597	(6)
Appendix Spreadsheets for Flow Pattern Calculations for Gas Permeation	603	(6)
16.A.1. Cross-Flow	603	(2)
16.A.2. Co-current Flow	605	(1)
16.A.3. Countercurrent Flow	606	(3)
Chapter 17 Introduction to Adsorption, Chromatography, and Ion Exchange	609	(104)
17.1. Sorbents and Sorption Equilibrium	610	(11)
17.1.1. Definitions	610	(2)
17.1.2. Sorbent Types	612	(3)
17.1.3. Adsorption Equilibrium Behavior	615	(6)
Example 17-1. Adsorption equilibrium	620	(1)
17.2. Solute Movement Analysis for Linear Systems: Basics and Applications to Chromatography	621	(10)
17.2.1. Movement of Solute in a Column	623	(2)
17.2.2. Solute Movement Theory for Linear Isotherms	625	(1)
17.2.3. Application of Linear Solute Movement Theory to Purge Cycles and Elution Chromatography	626	(5)
Example 17-2. Linear solute movement analysis of elution chromatography	628	(3)
17.3. Solute Movement Analysis for Linear Systems: Thermal and Pressure Swing Adsorption and Simulated Moving Beds	631	(23)
17.3.1. Temperature Swing Adsorption	631	(10)
Example 17-3. Thermal regeneration with linear isotherm	635	(6)
17.3.2. Pressure Swing Adsorption	641	(8)
Example 17-4. PSA system	644	(5)
17.3.3. Simulated Moving Beds	649	(5)
Example 17-5. SMB system	652	(2)
17.4. Nonlinear Solute Movement Analysis	654	(9)
17.4.1. Diffuse Waves	655	(3)
Example 17-6. Diffuse wave	656	(2)
17.4.2. Shock Waves	658	(5)
Example 17-7. Self-sharpening shock wave	659	(4)
17.5. Ion Exchange	663	(9)
17.5.1. Ion Exchange Equilibrium	666	(1)
17.5.2. Movement of Ions	667	(5)
Example 17-8. Ion movement for divalent-monovalent exchange	668	(4)
17.6. Mass and Energy Transfer	672	(6)
17.6.1. Mass Transfer and Diffusion	672	(2)
17.6.2. Column Mass Balances	674	(1)
17.6.3. Lumped Parameter Mass Transfer	675	(2)
17.6.4. Energy Balances and Heat Transfer	677	(1)
17.6.5. Derivation of Solute Movement Theory	677	(1)
17.6.6. Detailed Simulators	678	(1)
17.7. Mass Transfer Solutions for Linear Systems	678	(9)
17.7.1. Lapidus and Amundson Solution for Local Equilibrium with Dispersion	679	(1)
17.7.2. Superposition in Linear Systems	680	(3)
Example 17-9. Lapidus and Amundson solution for elution	681	(2)
17.7.3. Linear Chromatography	683	(4)
Example 17-10. Determination of linear isotherm parameters, N, and resolution for linear chromatography	686	(1)
17.8. LUB Approach for Nonlinear Systems	687	(5)
Example 17-11. LUB approach	690	(2)
17.9. Checklist for Practical Design and Operation	692	(1)
17.10. Summary—Objectives	693	(1)
References	693	(3)
Homework	696	(12)
Appendix Introduction to the Aspen Chromatography Simulator	708	(5)
Appendix A. Aspen Plus Troubleshooting Guide for Separations	713	(2)
Answers to Selected Problems	715	(6)
Index	721

Excerpts

In the twenty-first century, separations remain as important, if not more important than in the previous century. The development of new industries such as biotechnology and nanotechnology and the increased importance of removing traces of compounds have brought new separations to the fore. Chemical engineers must understand and design new separation processes such as membrane separations, adsorption, and chromatography in addition to the standard equilibrium staged separations including distillation, absorption, and extraction. Since membrane separations, adsorption, chromatography, and ion exchange are now included, I have changed the title of this second edition from Equilibrium Staged Separationsto Separation Process Engineeringto reflect this broader coverage. To satisfy this demand for new separations, I have added two new chapters to the book. The new Chapter 16 on membrane separations includes gas permeation, reverse osmosis, ultrafiltration, and pervaporation. Examples of the use of these membrane separation methods are purification of hydrogen and carbon dioxide, water purification, pharmaceutical processing, and purification of ethanol, respectively. The new Chapter 17 is an extensive introduction to adsorption, chromatography and ion exchange. These separations are commonly used for fine chemical and pharmaceutical processing. Adsorption and ion exchange are also commonly used for water treatment. Although neither membrane nor sorption separations are typically operated as equilibrium-staged separations, there are surprisingly many connections to equilibrium-staged processes. The second edition is unavoidably longer than the first. I have tried to avoid excessive length by removing some of the original material and combining some chapters. The material on equilibrium (the old Chapter 2) is now dispersed throughout the text so that it is presented in a just-in-time format. The original Chapters 5 and 6 on the McCabe-Thiele method for analyzing binary distillation have been combined into the single new Chapter 4. The McCabe-Thiele method retains its use as a visualization tool and troubleshooting guide, but it is no longer used for detailed design in the USA. The three chapters on multicomponent distillation (the new Chapters 5 through 7) have been retained, but in simplified form. The Chapter on complex distillation (the new Chapter 8) has been increased in scope to reflect the strides that have been made in understanding extractive and azeotropic distillation. The coverage on batch distillation (the new Chapter 9) has also been increased. The two original chapters on column design have been combined into the new Chapter 10. The economics information (from the old Chapter 14) has been condensed since it is generally taught in design classes. However, the material on energy conservation and sequencing of distillation columns from this chapter has been expanded to include some of the advances in complex distillation in the new Chapter 11. The old Chapters 16 and 17 have been combined into the single new Chapter 13 using the McCabe-Thiele method and Kremser equation for immiscible extraction, washing, leaching, and supercritical extraction. The section on humidification has been removed from Chapter 19 (the new Chapter 15) since it seemed out of place. All of the chapters have a host of new homework problems. Since these problems were created as I continued to teach this material at Purdue University, a Solution Manual is available. A number of simulation problems have been added, and the answers are provided in the Solution Manual. Since process simulators are now used extensively in commercial practice, I have included process simulation examples and homework problems throughout the text. I now teach the required three-credit, junior-level separations course at Purdue as two lectures and a two-hour computer lab every week. The computer lab includes a lab test to assess the ability of the students to use the simulator. Although I use Aspen Plus as the simulator, any process simulator can be used. New Chapters 2, 6, 8, 12, and 14 include appendices that present instructions for operation of Aspen Plus. The appendix to Chapter 16 includes Excel spreadsheets with Visual Basic programs for cross-flow, co-current and counter-current gas permeation. I chose to use spreadsheets instead of a higher level mathematical program since spreadsheets are universally available. The appendix to Chapter 17 includes brief instructions for operation of the commercial Aspen Chromatography simulatormore detailed instruction sheets may be requested from the author by sending an e-mail [e-mail]. The material in the second edition has been extensively tested in the required juniorlevel course on separations at Purdue University. Although I teach the material at the junior level, Chapters 1 through 14 could be taught to sophomores, and all of the material is suitable for seniors. The second edition is too long to cover in one semester, but complete coverage, including computer simulations, is probably feasible in two semesters. Many schools, including Purdue, allocate a single, three-credit semester course for this material. Because there is too much material, topics will have to be selected in this case. Several course outlines for a single semester course are included in the Solution Manual.