Copyright © 2008, 1997, 1984, 1973, 1963, 1950, 1941, 1934 by The McGraw-Hill Companies, Inc All rights reserved Manufactured in the United States of America Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher 0-07-154222-1 The material in this eBook also appears in the print version of this title: 0-07-151138-5 All trademarks are trademarks of their respective owners Rather than put a trademark symbol after every occurrence of a trademarked name, we use names in an editorial fashion only, and to the benefit of the trademark owner, with no intention of infringement of the trademark Where such designations appear in this book, they have been printed with initial caps McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs For more information, please contact George Hoare, Special Sales, at george_hoare@mcgraw-hill.com or (212) 904-4069 TERMS OF USE This is a copyrighted work and The McGraw-Hill Companies, Inc (“McGraw-Hill”) and its licensors reserve all rights in and to the work Use of this work is subject to these terms Except as permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of the work, you may not decompile, disassemble, reverse engineer, reproduce, modify, create derivative works based upon, transmit, distribute, disseminate, sell, publish or sublicense the work or any part of it without McGraw-Hill’s prior consent You may use the work for your own noncommercial and personal use; any other use of the work is strictly prohibited Your right to use the work may be terminated if you fail to comply with these terms THE WORK IS PROVIDED “AS IS.” McGRAW-HILL AND ITS LICENSORS MAKE NO GUARANTEES OR WARRANTIES AS TO THE ACCURACY, ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING THE WORK, INCLUDING ANY INFORMATION THAT CAN BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE, AND EXPRESSLY DISCLAIM ANY WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE McGraw-Hill and its licensors not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or error free Neither McGraw-Hill nor its licensors shall be liable to you or anyone else for any inaccuracy, error or omission, regardless of cause, in the work or for any damages resulting therefrom McGraw-Hill has no responsibility for the content of any information accessed through the work Under no circumstances shall McGraw-Hill and/or its licensors be liable for any indirect, incidental, special, punitive, consequential or similar damages that result from the use of or inability to use the work, even if any of them has been advised of the possibility of such damages This limitation of liability shall apply to any claim or cause whatsoever whether such claim or cause arises in contract, tort or otherwise DOI: 10.1036/0071511385 This page intentionally left blank Section 15 Liquid-Liquid Extraction and Other Liquid-Liquid Operations and Equipment* Timothy C Frank, Ph.D Research Scientist and Sr Technical Leader, The Dow Chemical Company; Member, American Institute of Chemical Engineers (Section Editor, Introduction and Overview, Thermodynamic Basis for Liquid-Liquid Extraction, Solvent Screening Methods, Liquid-Liquid Dispersion Fundamentals, Process Fundamentals and Basic Calculation Methods, Dual-Solvent Fractional Extraction, Extractor Selection, Packed Columns, Agitated Extraction Columns, Mixer-Settler Equipment, Centrifugal Extractors, Process Control Considerations, Liquid-Liquid Phase Separation Equipment, Emerging Developments) Lise Dahuron, Ph.D Sr Research Specialist, The Dow Chemical Company (Liquid Density, Viscosity, and Interfacial Tension; Liquid-Liquid Dispersion Fundamentals; Liquid-Liquid Phase Separation Equipment; Membrane-Based Processes) Bruce S Holden, M.S Process Research Leader, The Dow Chemical Company; Member, American Institute of Chemical Engineers [Process Fundamentals and Basic Calculation Methods, Calculation Procedures, Computer-Aided Calculations (Simulations), Single-Solvent Fractional Extraction with Extract Reflux, Liquid-Liquid Phase Separation Equipment] William D Prince, M.S Process Engineering Associate, The Dow Chemical Company; Member, American Institute of Chemical Engineers (Extractor Selection, Agitated Extraction Columns, Mixer-Settler Equipment) A Frank Seibert, Ph.D., P.E Technical Manager, Separations Research Program, The University of Texas at Austin; Member, American Institute of Chemical Engineers (LiquidLiquid Dispersion Fundamentals, Process Fundamentals and Basic Calculation Methods, Hydrodynamics of Column Extractors, Static Extraction Columns, Process Control Considerations, Membrane-Based Processes) Loren C Wilson, B.S Sr Research Specialist, The Dow Chemical Company (Liquid Density, Viscosity, and Interfacial Tension; Phase Diagrams; Liquid-Liquid Equilibrium Experimental Methods; Data Correlation Equations; Table of Selected Partition Ratio Data) INTRODUCTION AND OVERVIEW Historical Perspective Uses for Liquid-Liquid Extraction Definitions 15-6 15-7 15-10 Desirable Solvent Properties Commercial Process Schemes Standard Extraction Fractional Extraction 15-11 15-13 15-13 15-13 *Certain portions of this section are drawn from the work of Lanny A Robbins and Roger W Cusack, authors of Sec 15 in the 7th edition The input from numerous expert reviewers also is gratefully acknowledged 15-1 Copyright © 2008, 1997, 1984, 1973, 1963, 1950, 1941, 1934 by The McGraw-Hill Companies, Inc Click here for terms of use 15-2 LIQUID-LIQUID EXTRACTION AND OTHER LIQUID-LIQUID OPERATIONS AND EQUIPMENT Dissociative Extraction pH-Swing Extraction Reaction-Enhanced Extraction Extractive Reaction Temperature-Swing Extraction Reversed Micellar Extraction Aqueous Two-Phase Extraction Hybrid Extraction Processes Liquid-Solid Extraction (Leaching) Liquid-Liquid Partitioning of Fine Solids Supercritical Fluid Extraction Key Considerations in the Design of an Extraction Operation Laboratory Practices 15-15 15-16 15-16 15-16 15-17 15-18 15-18 15-18 15-19 15-19 15-19 15-20 15-21 THERMODYNAMIC BASIS FOR LIQUID-LIQUID EXTRACTION Activity Coefficients and the Partition Ratio 15-22 Extraction Factor 15-22 Separation Factor 15-23 Minimum and Maximum Solvent-to-Feed Ratios 15-23 Temperature Effect 15-23 Salting-out and Salting-in Effects for Nonionic Solutes 15-24 Effect of pH for Ionizable Organic Solutes 15-24 Phase Diagrams 15-25 Liquid-Liquid Equilibrium Experimental Methods 15-27 Data Correlation Equations 15-27 Tie Line Correlations 15-27 Thermodynamic Models 15-28 Data Quality 15-28 Table of Selected Partition Ratio Data 15-32 Phase Equilibrium Data Sources 15-32 Recommended Model Systems 15-32 SOLVENT SCREENING METHODS Use of Activity Coefficients and Related Data Robbins’ Chart of Solute-Solvent Interactions Activity Coefficient Prediction Methods Methods Used to Assess Liquid-Liquid Miscibility Computer-Aided Molecular Design High-Throughput Experimental Methods 15-32 15-32 15-33 15-34 15-38 15-39 LIQUID DENSITY, VISCOSITY, AND INTERFACIAL TENSION Density and Viscosity 15-39 Interfacial Tension 15-39 LIQUID-LIQUID DISPERSION FUNDAMENTALS Holdup, Sauter Mean Diameter, and Interfacial Area Factors Affecting Which Phase Is Dispersed Size of Dispersed Drops Stability of Liquid-Liquid Dispersions Effect of Solid-Surface Wettability Marangoni Instabilities 15-41 15-41 15-42 15-43 15-43 15-43 PROCESS FUNDAMENTALS AND BASIC CALCULATION METHODS Theoretical (Equilibrium) Stage Calculations McCabe-Thiele Type of Graphical Method Kremser-Souders-Brown Theoretical Stage Equation Stage Efficiency Rate-Based Calculations Solute Diffusion and Mass-Transfer Coefficients Mass-Transfer Rate and Overall Mass-Transfer Coefficients Mass-Transfer Units Extraction Factor and General Performance Trends Potential for Solute Purification Using Standard Extraction 15-44 15-45 15-45 15-46 15-47 15-47 15-47 15-48 15-49 15-50 CALCULATION PROCEDURES Shortcut Calculations Example 1: Shortcut Calculation, Case A 15-51 15-52 Example 2: Shortcut Calculation, Case B Example 3: Number of Transfer Units Computer-Aided Calculations (Simulations) Example 4: Extraction of Phenol from Wastewater Fractional Extraction Calculations Dual-Solvent Fractional Extraction Single-Solvent Fractional Extraction with Extract Reflux Example 5: Simplified Sulfolane Process—Extraction of Toluene from n-Heptane LIQUID-LIQUID EXTRACTION EQUIPMENT Extractor Selection Hydrodynamics of Column Extractors Flooding Phenomena Accounting for Axial Mixing Liquid Distributors and Dispersers Static Extraction Columns Common Features and Design Concepts Spray Columns Packed Columns Sieve Tray Columns Baffle Tray Columns Agitated Extraction Columns Rotating-Impeller Columns Reciprocating-Plate Columns Rotating-Disk Contactor Pulsed-Liquid Columns Raining-Bucket Contactor (a Horizontal Column) Mixer-Settler Equipment Mass-Transfer Models Miniplant Tests Liquid-Liquid Mixer Design Scale-up Criteria Specialized Mixer-Settler Equipment Suspended-Fiber Contactor Centrifugal Extractors Single-Stage Centrifugal Extractors Centrifugal Extractors Designed for Multistage Performance 15-52 15-53 15-53 15-54 15-55 15-55 15-56 15-56 15-58 15-59 15-59 15-60 15-63 15-63 15-63 15-69 15-70 15-74 15-78 15-79 15-79 15-83 15-84 15-85 15-85 15-86 15-86 15-87 15-87 15-88 15-89 15-90 15-91 15-91 15-92 PROCESS CONTROL CONSIDERATIONS Steady-State Process Control Sieve Tray Column Interface Control Controlled-Cycling Mode of Operation 15-93 15-94 15-94 LIQUID-LIQUID PHASE SEPARATION EQUIPMENT Overall Process Considerations Feed Characteristics Gravity Decanters (Settlers) Design Considerations Vented Decanters Decanters with Coalescing Internals Sizing Methods Other Types of Separators Coalescers Centrifuges Hydrocyclones Ultrafiltration Membranes Electrotreaters 15-96 15-96 15-97 15-97 15-98 15-99 15-99 15-101 15-101 15-101 15-101 15-102 15-102 EMERGING DEVELOPMENTS Membrane-Based Processes Polymer Membranes Liquid Membranes Electrically Enhanced Extraction Phase Transition Extraction and Tunable Solvents Ionic Liquids 15-103 15-103 15-104 15-104 15-105 15-105 LIQUID-LIQUID EXTRACTION AND OTHER LIQUID-LIQUID OPERATIONS AND EQUIPMENT 15-3 Nomenclature A given symbol may represent more than one property The appropriate meaning should be apparent from the context The equations given in Sec 15 reflect the use of the SI or cgs system of units and not ft-lb-s units, unless otherwise noted in the text The gravitational conversion factor gc needed to use ft-lb-s units is not included in the equations Symbol a ap aw bij A A Acol Adow Ai,j/RT Ao C CAi C* CD Co Ct d dC di dm dp d32 Dcol Deq Dh Di Di Dsm Dt D DAB E E′ E Definition Interfacial area per unit volume Specific packing surface area (area per unit volume) Specific wall surface area (area per unit volume) NRTL model regression parameter (see Table 15-10) Envelope-style downcomer area Area between settled layers in a decanter Column cross-sectional area Area for flow through a downcorner (or upcomer) van Laar binary interaction parameter Cross-sectional area of a single hole Concentration (mass or mol per unit volume) SI units m2/m3 U.S Customary System units ft2/ft3 EC m /m ft /ft Ei m2/m3 ft2/ft3 Es K K Ew m 2 Symbol fda ft m ft fha m2 m2 ft2 ft2 F F F′ Dimensionless m kgրm3 or kgmolրm3 or gmolրL Concentration of component kgրm3 or A at the interface kgmolրm3 or gmolրL Concentration at equilibrium kgրm3 or kgmolրm3 or gmolրL Drag coefficient Dimensionless Initial concentration kgրm3 or kgmolրm3 or gmolրL Concentration at time t kgրm3 or kgmolրm3 or gmolրL Drop diameter m Critical packing dimension m Diameter of an individual drop m Characteristic diameter of m media in a packed bed Orifice or nozzle diameter m Sauter mean drop diameter m Sauter mean drop diameter m Column diameter m Equivalent diameter giving m the same area Equivalent hydraulic diameter m Distribution ratio for a given chemical species including all its forms (unspecified units) Impeller diameter or m characteristic mixer diameter Static mixer diameter m Tank diameter m Molecular diffusion coefficient m2/s (diffusivity) Mutual diffusion coefficient m2/s for components A and B Mass or mass flow rate of kg or kg/s extract phase Solvent mass or mass flow rate (in the extract phase) Axial mixing coefficient m2/s (eddy diffusivity) Dimensionless FR in2 lb/ft3 or lbmolրft3 g Gij h lb/ft3 or lbmolրft3 h h lb/ft3 or lbmolրft3 hiE H Dimensionless lb/ft3 or lbmolրft3 lb/ft3 or lbmolրft3 H ∆H HDU He in in in in HETS Hor in in in in or ft in Hr I k in k km in or ft ko in or ft ft cm2/s kc ks ks cm /s kd lb or lb/h kt cm2/s K K′s Definition Extraction factor for case C [Eq (15-98)] Extraction factor for component i Stripping section extraction factor Washing section extraction factor Fractional downcomer area in Eq (15-160) Fractional hole area in Eq (15-159) Mass or mass flow rate of feed phase Force Feed mass or mass flow rate (feed solvent only) Solute reduction factor (ratio of inlet to outlet concentrations) Gravitational acceleration NRTL model parameter Height of coalesced layer at a sieve tray Head loss due to frictional flow Height of dispersion band in batch decanter Excess enthalpy of mixing Dimensionless group defined by Eq (15-123) Dimension of envelope-style downcomer (Fig 15-39) Steady-state dispersion band height in a continuously fed decanter Height of a dispersion unit Height of a transfer unit due to resistance in extract phase Height equivalent to a theoretical stage Height of an overall mass-tranfer unit based on raffinate phase Height of a transfer unit due to resistance in raffinate phase Ionic strength in Eq (15-26) Individual mass-transfer coefficient Mass-transfer coefficient (unspecified units) Membrane-side mass-transfer coefficient Overall mass-transfer coefficient Continuous-phase mass-transfer coefficient Dispersed-phase mass-transfer coefficient Setschenow constant Shell-side mass-transfer coefficient Tube-side mass-transfer coefficient Partition ratio (unspecified units) Stripping section partition ratio (in Bancroft coordinates) SI units U.S Customary System units Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless kg or kg/s lb or lb/h N kg or kg/s lbf lb or lb/h Dimensionless Dimensionless 9.807 m/s Dimensionless m 32.17 ft/s2 Dimensionless in m m in in Jրgmol Dimensionless Btuրlbmol or calրgmol Dimensionless m in or ft m in m m in in m in m in m in m/s or cm/s ft/h m/s or cm/s ft/h m/s or cm/s ft/h m/s or cm/s ft/h m/s or cm/s ft/h Lրgmol m/s or cm/s Lրgmol ft/h m/s or cm/s ft/h Mass ratio/ mass ratio Mass ratio/ mass ratio 15-4 LIQUID-LIQUID EXTRACTION AND OTHER LIQUID-LIQUID OPERATIONS AND EQUIPMENT Nomenclature (Continued) U.S Customary System units Symbol Definition SI units K′ w Washing section partition ratio (in Bancroft coordinates) Partition ratio, mass ratio basis (Bancroft coordinates) Partition ratio, mass fraction basis Partition ratio, mole fraction basis Partition ratio (volumetric concentration basis) Mass ratio/ mass ratio Mass ratio/ mass ratio Mass fraction/ mass fraction Mole fraction/ mole fraction Ratio of kg/m3 or kgmolրm3 or gmolրL m Mass ratio/ mass ratio Mass ratio/ mass ratio Mass fraction/ mass fraction Mole fraction/ mole fraction Ratio of lb/ft3 or lbmolրft3 Re in or ft S′ m in or ft S′ s Mass ratio/ mass ratio Mass ratio/ mass ratio K′ K″ Ko vol K L Lfp m m′ mdc mer mvol M MW N NA Nholes Nor Ns Nw P P P Pe Pi,extract Pi,feed Po ∆Pdow ∆Po q Q R R RA Downcomer (or upcomer) length Length of flow path in Eq (15-161) Local slope of equilibrium line (unspecified concentration units) Local slope of equilibrium line (in Bancroft coordinates) Local slope of equilibrium line for dispersed-phase concentration plotted versus continuous-phase concentration Local slope of equilibrium line for extract-phase concentration plotted versus raffinate-phase concentration Local slope of equilibrium line (volumetric concentration basis) Mass or mass flow rate Molecular weight Number of theoretical stages Flux of component A (mass or mol/area/unit time) Number of holes Number of overall mass-transfer units based on the raffinate phase Number of theoretical stages in stripping section Number of theoretical stages in washing section Pressure Dimensionless group defined by Eq (15-122) Power Péclet number Vb/E, where V is liquid velocity, E is axial mixing coefficient, and b is a characteristic equipment dimension Purity of solute i in extract (in wt %) Purity of solute i in feed (in wt %) Power number Pր(ρmω3D5) i Pressure drop for flow through a downcomer (or upcomer) Orifice pressure drop MOSCED induction parameter Volumetric flow rate Universal gas constant Mass or mass flow rate of raffinate phase Rate of mass-transfer (moles per unit time) Symbol ReStokes S S S′ w Si,j Stip tb T ut ut∞ Ratio of kg/m3 or kgmolրm3 or gmolրL kg or kg/s kgրkgmol or gրgmol Dimensionless (kg or kgmol)/ (m2⋅s) Dimensionless Dimensionless Ratio of lb/ft3 or lbmolրft3 units lb or lb/h lbրlbmol Dimensionless (lb or lbmol)ր (ft2⋅s) Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless bar or Pa Dimensionless atm or lbf /in2 Dimensionless W or kW Dimensionless HP or ft⋅lbf /h Dimensionless v V V Vcf Vcflow Vdf Vdrop Vic Vo,max Vs Vso Vsm W W′ s wt % wt % W′ w wt % wt % We Dimensionless bar or Pa Dimensionless atm or lbf /in2 bar or Pa Dimensionless atm or lbf /in2 Dimensionless m3/s 8.31 J⋅Kր kgmol kg or kg/s ft3/min 1.99 Btu⋅°Rր lbmol lb or lb/h kgmolրs lbmolրh x X X″ X′ B f X Definition Reynolds number: for pipe flow, Vdρրµ; for an impeller, ρmωD2րµm; for drops, Vsodp ρc ր i µc; for flow in a packed-bed coalescer, Vdmρc րµ; for flow through an orifice, Vodoρd րµd ρc ∆ρgd3ր18µ2 p c Mass or mass flow rate of solvent phase Dimension of envelope-style downcomer (Fig 15-39) Solvent mass or mass flow rate (extraction solvent only) Mass flow rate of extraction solvent within stripping section Mass flow rate of extraction solvent within washing section Separation power for separating component i from component j [defined by Eq (15-105)] Impeller tip speed Batch mixing time Temperature (absolute) Stokes’ law terminal or settling velocity of a drop Unhindered settling velocity of a single drop Molar volume Liquid velocity (or volumetric flow per unit area) Volume Continuous-phase flooding velocity Cross-flow velocity of continuous phase at sieve tray Dispersed-phase flooding velocity Average velocity of a dispersed drop Interstitial velocity of continuous phase Maximum velocity through an orifice or nozzle Slip velocity Slip velocity at low dispersed-phase flow rate Static mixer superficial liquid velocity (entrance velocity) Mass or mass flow rate of wash solvent phase Mass flow rate of wash solvent within stripping section Mass flow rate of wash solvent within washing section Weber number: for an impeller, ρcω2Di3 րσ; for flow through an orifice or nozzle, V2doρd րσ; for a static mixer, o V2 Dsmρc րσ sm Mole fraction solute in feed or raffinate Concentration of solute in feed or raffinate (unspecified units) Mass fraction solute in feed or raffinate Mass solute/mass feed solvent in feed or raffinate Pseudoconcentration of solute in feed for case B [Eq (15-95)] SI units U.S Customary System units Dimensionless Dimensionless Dimensionless kg or kg/s Dimensionless lb or lb/h m ft kg or kg/s lb or lb/h kg/s lb/h kg/s lb/h Dimensionless Dimensionless m/s s or h K m/s or cm/s ft/s or h °R ft/s or ft/min m/s or cm/s ft/s or ft/min m րkgmol or cm3րgmol m/s ft3րlbmol m3 m/s ft3 or gal ft/s or ft/min m/s ft/s or ft/min m/s ft/s or ft/min m/s ft/s or ft/min m/s ft/s or ft/min m/s ft/s or ft/min m/s m/s ft/s or ft/min ft/s or ft/min m/s ft/s or ft/min kg or kg/s lb or lb/h kg/s lb/h ft/s or ft/min kg/s lb/h Dimensionless Dimensionless Mole fraction Mole fraction Mass fractions Mass fractions Mass ratios Mass ratios Mass ratios Mass ratios LIQUID-LIQUID EXTRACTION AND OTHER LIQUID-LIQUID OPERATIONS AND EQUIPMENT 15-5 Nomenclature (Concluded) Symbol Definition XfC Pseudoconcentration of solute in feed for case C [Eq (15-97)] Concentration of solute i in extract Concentration of solute i in feed Concentration of component i in the phase richest in j Mole fraction solute in solvent or extract Concentration of solute in the solvent or extract (unspecified units) Mass fraction solute in solvent or extract Mass solute/mass extraction solvent in solvent or extract Pseudoconcentration of solute in solvent for case B [Eq (15-96)] Dimension or direction of mass transfer Sieve tray spacing Point representing feed composition on a tie line Number of electronic charges on an ion Total height of extractor Xi,extract Xi,feed Xij y Y Y″ Y′ YsB z z z zi Zt SI units Mass ratios U.S Customary System units α αi,j αi,j β β γi,j γ∞ γC i γI i γR i ε ε δ δd δh δp MOSCED hydrogen-bond acidity parameter Solvatochromic hydrogen-bond acidity parameter Separation factor for solute i with respect to solute j NRTL model parameter MOSCED hydrogen-bond basicity parameter Solvatochromic hydrogen-bond basicity parameter Activity coefficient of i dissolved in j Activity coefficient at infinite dilution Activity coefficient, combinatorial part of UNIFAC Activity coefficient of component i in phase I Activity coefficient, residual part of UNIFAC Void fraction Fractional open area of a perforated plate Solvatochromic polarizability parameter Hansen nonpolar (dispersion) solubility parameter Hansen solubility parameter for hydrogen bonding Hansen polar solubility parameter δi ⎯ δ ζ Mass fraction Mass fraction Mass fraction Mass fraction Mass fraction Mass fraction Mole fraction Mole fraction λ λm µ µI i Mass fraction Mass fraction µm Mass ratio Mass ratio Mass ratio Mass ratio µw ξ1 ξ batch m in or ft m in or ft ξm ξmd Dimensionless Dimensionless ξo π m ft θ θi ξcontinuous ∆π ρ ρm (J/cm3)1/2 (cal/cm3)1/2 1/2 1/2 (J/cm ) (cal/cm ) Dimensionless Dimensionless Dimensionless (J/cm3)1/2 Dimensionless (cal/cm3)1/2 (J/cm3)1/2 (cal/cm3)1/2 Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless σ τ τi,j φ φd Dimensionless Dimensionless Dimensionless φd,feed φo ϕ Φ χ ω Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless (J/cm3)1/2 (cal/cm3)1/2 (J/cm3)1/2 (cal/cm3)1/2 (J/cm3)1/2 (cal/cm3)1/2 (J/cm3)1/2 (cal/cm3)1/2 Definition SI units U.S Customary System units Greek Symbols Mass ratios Greek Symbols α Symbol Solubility parameter for component i Solubility parameter for mixture Tortuosity factor defined by Eq (15-147) Residence time for total liquid Fraction of solute i extracted from feed MOSCED dispersion parameter Membrane thickness Liquid viscosity Chemical potential of component i in phase I Mixture mean viscosity defined in Eq (15-180) Reference viscosity (of water) MOSCED asymmetry factor Efficiency of a batch experiment [Eq (15-175)] Efficiency of a continuous process [Eq (15-176)] Murphree stage efficiency Murphree stage efficiency based on dispersed phase Overall stage efficiency Solvatochromic polarity parameter Osmotic pressure gradient Liquid density Mixture mean density defined in Eq (15-178) Interfacial tension MOSCED polarity parameter NRTL model parameter Volume fraction Volume fraction of dispersed phase (holdup) Volume fraction of dispersed phase in feed Initial dispersed-phase holdup in feed to a decanter Volume fraction of voids in a packed bed Factor governing use of Eqs (15-148) and (15-149) Parameter in Eq (15-41) indicating which phase is likely to be dispersed Impeller speed (J/cm3)1/2 (cal/cm3)1/2 (J/cm3)1/2 Dimensionless (cal/cm3)1/2 Dimensionless s Dimensionless s or Dimensionless (J/cm3)1/2 mm Pa⋅s J/gmol (cal/cm3)1/2 in cP Btu/lbmol Pa⋅s cP Pa⋅s Dimensionless Dimensionless cP Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless (J/cm3)1/2 Dimensionless (cal/cm3)1/2 bar or Pa kg/m3 kg/m3 atm or lbf /in2 lb/ft3 lb/ft3 N/m (J/cm3)1/2 Dimensionless Dimensionless Dimensionless dyn/cm (cal/cm3)1/2 Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Dimensionless Rotations/s Rotations/min Additional Subscripts c d e f i j H L max o r s Continuous phase Dispersed phase Extract phase Feed phase or flooding condition (when combined with d or c) Component i Component j Heavy liquid Light liquid Maximum value Minimum value Orifice or nozzle Raffinate phase Solvent GENERAL REFERENCES: Wankat, Separation Process Engineering, 2d ed (Prentice-Hall, 2006); Seader and Henley, Separation Process Principles, 2d ed (Wiley, 2006); Seibert, “Extraction and Leaching,” Chap 14 in Chemical Process Equipment: Selection and Design, 2d ed., Couper et al., eds (Elsevier, 2005); Aguilar and Cortina, Solvent Extraction and Liquid Membranes: Fundamentals and Applications in New Materials (Dekker, 2005); Glatz and Parker, “Enriching Liquid-Liquid Extraction,” Chem Eng Magazine, 111(11), pp 44–48 (2004); Solvent Extraction Principles and Practice, 2d ed., Rydberg et al., eds (Dekker, 2004); Ion Exchange and Solvent Extraction, vol 17, Marcus and SenGupta, eds (Dekker, 2004), and earlier volumes in the series; Leng and Calabrese, “Immiscible LiquidLiquid Systems,” Chap 12 in Handbook of Industrial Mixing: Science and Practice, Paul, Atiemo-Obeng, and Kresta, eds (Wiley, 2004); Cheremisinoff, Industrial Solvents Handbook, 2d ed (Dekker, 2003); Van Brunt and Kanel, “Extraction with Reaction,” Chap in Reactive Separation Processes, Kulprathipanja, ed (Taylor & Francis, 2002); Mueller et al., “Liquid-Liquid Extraction” in Ullmann’s Encyclopedia of Industrial Chemistry, 6th ed (VCH, 2002); Benitez, Principles and Modern Applications of Mass Transfer Operations (Wiley, 2002); Wypych, Handbook of Solvents (Chemtec, 2001); Flick, Industrial Solvents Handbook, 5th ed (Noyes, 1998); Robbins, “Liquid-Liquid Extraction,” Sec 1.9 in Handbook of Separation Techniques for Chemical Engineers, 3d ed., Schweitzer, ed (McGraw-Hill, 1997); Lo, “Commercial Liquid-Liquid Extraction Equipment,” Sec 1.10 in Handbook of Separation Techniques for Chemical Engineers, 3d ed., Schweitzer, ed (McGrawHill, 1997); Humphrey and Keller, “Extraction,” Chap in Separation Process Technology (McGraw-Hill, 1997), pp 113–151; Cusack and Glatz, “Apply LiquidLiquid Extraction to Today’s Problems,” Chem Eng Magazine, 103(7), pp 94–103 (1996); Liquid-Liquid Extraction Equipment, Godfrey and Slater, eds (Wiley, 1994); Zaslavsky, Aqueous Two-Phase Partitioning (Dekker, 1994); Strigle, “LiquidLiquid Extraction,” Chap 11 in Packed Tower Design and Applications, 2d ed (Gulf, 1994); Schügerl, Solvent Extraction in Biotechnology (Springer-Verlag, 1994); Schügerl, “Liquid-Liquid Extraction (Small Molecules),” Chap 21 in Biotechnology, 2d ed., vol 3, Stephanopoulos, ed (VCH, 1993); Kelley and Hatton, “Protein Purification by Liquid-Liquid Extraction,” Chap 22 in Biotechnology, 2d ed., vol 3, Stephanopoulos, ed (VCH, 1993); Lo and Baird, “Extraction, Liquid-Liquid,” in Kirk-Othmer Encyclopedia of Chemical Technology, 4th ed., vol 10, Kroschwitz and Howe-Grant, eds (Wiley, 1993), pp 125–180; Science and Practice of Liquid-Liquid Extraction, vol 1, Phase Equilibria; Mass Transfer and Interfacial Phenomena; Extractor Hydrodynamics, Selection, and Design, and vol 2, Process Chemistry and Extraction Operations in the Hydrometallurgical, Nuclear, Pharmaceutical, and Food Industries, Thornton, ed (Oxford, 1992); Cusack, Fremeaux, and Glatz, “A Fresh Look at Liquid-Liquid Extraction,” pt 1, “Extraction Systems,” Chem Eng Magazine, 98(2), pp 66–67 (1991); Cusack and Fremeauz, pt 2, “Inside the Extractor,” Chem Eng Magazine, 98(3), pp 132–138 (1991); Cusack and Karr, pt 3, “Extractor Design and Specification,” Chem Eng Magazine, 98(4), pp 112–120 (1991); Methods in Enzymology, vol 182, Guide to Protein Purification, Deutscher, ed (Academic, 1990); Wankat, Equilibrium Staged Separations (Prentice Hall, 1988); Blumberg, Liquid-Liquid Extraction (Academic, 1988); Skelland and Tedder, “Extraction—Organic Chemicals Processing,” Chap in Handbook of Separation Process Technology, Rousseau, ed (Wiley, 1987); Chapman, “Extraction—Metals Processing,” Chap in Handbook of Separation Process Technology, Rousseau, ed (Wiley, 1987); Novak, Matous, and Pick, Liquid-Liquid Equilibria, Studies in Modern Thermodynamics Series, vol (Elsevier, 1987); Bailes et al., “Extraction, Liquid-Liquid” in Encyclopedia of Chemical Processing and Design, vol 21, McKetta and Cunningham, eds (Dekker, 1984), pp 19–166; Handbook of Solvent Extraction, Lo, Baird, and Hanson, eds (Wiley, 1983; Krieger, 1991); Sorenson and Arlt, Liquid-Liquid Equilibrium Data Collection, DECHEMA, Binary Systems, vol V, pt 1, 1979, Ternary Systems, vol V, pt 2, 1980, Ternary and Quaternary Systems, vol 5, pt 3, 1980, Macedo and Rasmussen, Suppl 1, vol V, pt 4, 1987; Wisniak and Tamir, Liquid-Liquid Equilibrium and Extraction, a Literature Source Book, vols I and II (Elsevier, 1980–1981), Suppl (1985); Treybal, Mass Transfer Operations, 3d ed (McGraw-Hill, 1980); King, Separation Processes, 2d ed (McGraw-Hill, 1980); Laddha and Degaleesan, Transport Phenomena in Liquid Extraction (McGraw-Hill, 1978); Brian, Staged Cascades in Chemical Processing (Prentice-Hall, 1972); Pratt, Countercurrent Separation Processes (Elsevier, 1967); Treybal, “Liquid Extractor Performance,” Chem Eng Prog., 62(9), pp 67–75 (1966); Treybal, Liquid Extraction, 2d ed (McGraw-Hill, 1963); Alders, Liquid-Liquid Extraction, 2d ed (Elsevier, 1959) INTRODUCTION AND OVERVIEW Liquid-liquid extraction is a process for separating the components of a liquid (the feed) by contact with a second liquid phase (the solvent) The process takes advantage of differences in the chemical properties of the feed components, such as differences in polarity and hydrophobic/hydrophilic character, to separate them Stated more precisely, the transfer of components from one phase to the other is driven by a deviation from thermodynamic equilibrium, and the equilibrium state depends on the nature of the interactions between the feed components and the solvent phase The potential for separating the feed components is determined by differences in these interactions A liquid-liquid extraction process produces a solvent-rich stream called the extract that contains a portion of the feed and an extractedfeed stream called the raffinate A commercial process almost always includes two or more auxiliary operations in addition to the extraction operation itself These extra operations are needed to treat the extract and raffinate streams for the purposes of isolating a desired product, recovering the solvent for recycle to the extractor, and purging unwanted components from the process A typical process includes two or more distillation operations in addition to extraction Liquid-liquid extraction is used to recover desired components from a crude liquid mixture or to remove unwanted contaminants In developing a process, the project team must decide what solvent or solvent mixture to use, how to recover solvent from the extract, and how to remove solvent residues from the raffinate The team must also decide what temperature or range of temperatures should be used for the extraction, what process scheme to employ among many possibilities, and what type of equipment to use for liquid-liquid contacting and phase separation The variety of commercial equipment options is large and includes stirred tanks and decanters, specialized mixer-settlers, a wide variety of agitated and nonagitated extraction columns or towers, and various types of centrifuges Because of the availability of hundreds of commercial solvents and extractants, as well as a wide variety of established process schemes and equipment options, liquid-liquid extraction is a versatile technology with a wide range of commercial applications It is utilized in the 15-6 processing of numerous commodity and specialty chemicals including metals and nuclear fuel (hydrometallurgy), petrochemicals, coal and wood-derived chemicals, and complex organics such as pharmaceuticals and agricultural chemicals Liquid-liquid extraction also is an important operation in industrial wastewater treatment, food processing, and the recovery of biomolecules from fermentation broth HISTORICAL PERSPECTIVE The art of solvent extraction has been practiced in one form or another since ancient times It appears that prior to the 19th century solvent extraction was primarily used to isolate desired components such as perfumes and dyes from plant solids and other natural sources [Aftalion, A History of the International Chemical Industry (Univ Penn Press, 1991); and Taylor, A History of Industrial Chemistry (Abelard-Schuman, 1957)] However, several early applications involving liquid-liquid contacting are described by Blass, Liebel, and Haeberl [“Solvent Extraction—A Historical Review,” International Solvent Extraction Conf (ISEC) ‘96 Proceedings (Univ of Melbourne, 1996)], including the removal of pigment from oil by using water as the solvent The modern practice of liquid-liquid extraction has its roots in the middle to late 19th century when extraction became an important laboratory technique The partition ratio concept describing how a solute partitions between two liquid phases at equilibrium was introduced by Berthelot and Jungfleisch [Ann Chim Phys., 4, p 26 (1872)] and further defined by Nernst [Z Phys Chemie, 8, p 110 (1891)] At about the same time, Gibbs published his theory of phase equilibrium (1876 and 1878) These and other advances were accompanied by a growing chemical industry An early countercurrent extraction process utilizing ethyl acetate solvent was patented by Goering in 1883 as a method for recovering acetic acid from “pyroligneous acid” produced by pyrolysis of wood [Othmer, p xiv in Handbook of Solvent Extraction (Wiley, 1983; Krieger, 1991)], and Pfleiderer patented a stirred extraction column in 1898 [Blass, Liebl, and Haeberl, ISEC ’96 Proceedings (Univ of Melbourne, 1996)] INTRODUCTION AND OVERVIEW With the emergence of the chemical engineering profession in the 1890s and early 20th century, additional attention was given to process fundamentals and development of a more quantitative basis for process design Many of the advances made in the study of distillation and absorption were readily adapted to liquid-liquid extraction, owing to its similarity as another diffusion-based operation Examples include application of mass-transfer coefficients [Lewis, Ind Eng Chem., 8(9), pp 825–833 (1916); and Lewis and Whitman, Ind Eng Chem., 16(12), pp 1215–1220 (1924)], the use of graphical stagewise design methods [McCabe and Thiele, Ind Eng Chem., 17(6), pp 605–611 (1925); Evans, Ind Eng Chem., 26(8), pp 860–864 (1934); and Thiele, Ind Eng Chem., 27(4), pp 392–396 (1935)], the use of theoretical-stage calculations [Kremser, National Petroleum News, 22(21), pp 43–49 (1930); and Souders and Brown, Ind Eng Chem 24(5), pp 519–522 (1932)], and the transfer unit concept introduced in the late 1930s by Colburn and others [Colburn, Ind Eng Chem., 33(4), pp 459–467 (1941)] Additional background is given by Hampe, Hartland, and Slater [Chap in Liquid-Liquid Extraction Equipment, Godfrey and Slater, eds (Wiley, 1994)] The number of commercial applications continued to grow, and by the 1930s liquid-liquid extraction had replaced various chemical treatment methods for refining mineral oil and coal tar products [Varteressian and Fenske, Ind Eng Chem., 28(8), pp 928–933 (1936)] It was also used to recover acetic acid from waste liquors generated in the production of cellulose acetate, and in various nitration and sulfonation processes [Hunter and Nash, The Industrial Chemist, 9(102–104), pp 245–248, 263–266, 313–316 (1933)] The article by Hunter and Nash also describes early mixer-settler equipment, mixing jets, and various extraction columns including the spray column, baffle tray column, sieve tray column, and a packed column filled with Raschig rings or coke breeze, the material left behind when coke is burned Much of the liquid-liquid extraction technology in practice today was first introduced to industry during a period of vigorous innovation and growth of the chemical industry as a whole from about 1920 to 1970 The advances of this period include development of fractional extraction schemes including work described by Cornish et al., [Ind Eng Chem., 26(4), pp 397–406 (1934)] and by Thiele [Ind Eng Chem., 27(4), pp 392–396 (1935)] A well-known commercial example involving the use of extract reflux is the Udex process for separating aromatic compounds from hydrocarbon mixtures using diethylene glycol, a process developed jointly by The Dow Chemical Company and Universal Oil Products in the 1940s This period also saw the introduction of many new equipment designs including specialized mixer-settler equipment, mechanically agitated extraction columns, and centrifugal extractors as well as a great increase in the availability of different types of industrial solvents A variety of alcohols, ketones, esters, and chlorinated hydrocarbons became available in large quantities beginning in the 1930s, as petroleum refiners and chemical companies found ways to manufacture them inexpensively using the byproducts of petroleum refining operations or natural gas Later, a number of specialty solvents were introduced including sulfolane (tetrahydrothiophene-1,1-dioxane) and NMP (N-methyl-2-pyrrolidinone) for improved extraction of aromatics from hydrocarbons Specialized extractants also were developed including numerous organophosphorous extractants used to recover or purify metals dissolved in aqueous solutions The ready availability of numerous solvents and extractants, combined with the tremendous growth of the chemical industry, drove the development and implementation of many new industrial applications Handbooks of chemical process technology provide a glimpse of some of these [Riegel’s Handbook of Industrial Chemistry, 10th ed., Kent, ed (Springer, 2003); Chemical Processing Handbook, McKetta, ed (Dekker, 1993); and Austin, Shreve’s Chemical Process Industries, 5th ed (McGraw-Hill, 1984)], but many remain proprietary and are not widely known The better-known examples include the separation of aromatics from aliphatics, as mentioned above, extraction of phenolic compounds from coal tars and liquors, recovery of ε-caprolactam for production of polyamide-6 (nylon-6), recovery of hydrogen peroxide from oxidized anthraquinone solution, plus many processes involving the washing of crude organic streams with alkaline or acidic 15-7 solutions and water, and the detoxification of industrial wastewater prior to biotreatment using steam-strippable organic solvents The pharmaceutical and specialty chemicals industry also began using liquid-liquid extraction in the production of new synthetic drug compounds and other complex organics In these processes, often involving multiple batch reaction steps, liquid-liquid extraction generally is used for recovery of intermediates or crude products prior to final isolation of a pure product by crystallization In the inorganic chemical industry, extraction processes were developed for purification of phosphoric acid, purification of copper by removal of arsenic impurities, and recovery of uranium from phosphate-rock leach solutions, among other applications Extraction processes also were developed for bioprocessing applications, including the recovery of citric acid from broth using trialkylamine extractants, the use of amyl acetate to recover antibiotics from fermentation broth, and the use of water-soluble polymers in aqueous two-phase extraction for purification of proteins The use of supercritical or near-supercritical fluids for extraction, a subject area normally set apart from discussions of liquid-liquid extraction, has received a great deal of attention in the R&D community since the 1970s Some processes were developed many years before then; e.g., the propane deasphalting process used to refine lubricating oils uses propane at near-supercritical conditions, and this technology dates back to the 1930s [McHugh and Krukonis, Supercritical Fluid Processing, 2d ed (Butterworth-Heinemann, 1993)] In more recent years the use of supercritical fluids has found a number of commercial applications displacing earlier liquid-liquid extraction methods, particularly for recovery of high-value products meant for human consumption including decaffeinated coffee, flavor components from citrus oils, and vitamins from natural sources Significant progress continues to be made toward improving extraction technology, including the introduction of new methods to estimate solvent properties and screen candidate solvents and solvent blends, new methods for overall process conceptualization and optimization, and new methods for equipment design Progress also is being made by applying the technology developed for a particular application in one industry to improve another application in another industry For example, much can be learned by comparing equipment and practices used in organic chemical production with those used in the inorganic chemical industry (and vice versa), or by comparing practices used in commodity chemical processing with those used in the specialty chemicals industry And new concepts offering potential for significant improvements continue to be described in the literature (See “Emerging Developments.”) USES FOR LIQUID-LIQUID EXTRACTION For many separation applications, the use of liquid-liquid extraction is an alternative to the various distillation schemes described in Sec 13, “Distillation.” In many of these cases, a distillation process is more economical largely because the extraction process requires extra operations to process the extract and raffinate streams, and these operations usually involve the use of distillation anyway However, in certain cases the use of liquid-liquid extraction is more cost-effective than using distillation alone because it can be implemented with smaller equipment and/or lower energy consumption In these cases, differences in chemical or molecular interactions between feed components and the solvent provide a more effective means of accomplishing the desired separation compared to differences in component volatilities For example, liquid-liquid extraction may be preferred when the relative volatility of key components is less than 1.3 or so, such that an unusually tall distillation tower is required or the design involves high reflux ratios and high energy consumption In certain cases, the distillation option may involve addition of a solvent (extractive distillation) or an entrainer (azeotropic distillation) to enhance the relative volatility Even in these cases, a liquid-liquid extraction process may offer advantages in terms of higher selectivity or lower solvent usage and lower energy consumption, depending upon the application Extraction may be preferred when the distillation option requires operation at pressures less than about 70 mbar (about 50 mmHg) and an unusually large-diameter distillation tower is required, or when most of the 25-38 TABLE 25-13 Special Stainless Steels Mechanical properties† Composition, %* Alloy UNS Cr 13.5–16 Ni Mo C Mn Si Other 24–27 1.0–1.5 0.08 2.0 1.0 1.90–2.35 Ti, 0.1– 0.5 V, 0.001–0.01 B, × C–1.0 Cb 3.0–4.0 Cu 0.90–1.35 Al 0.75–1.5 Al, 0.15–45 Cb 2.5–4.5 Cu 0.75–1.5 Al, 0.15– 0.45 Cb 3.0–5.0 Cu, 0.4 Al 0.75–1.5 Al 0.08–0.18 N 0.15–0.40 N 0.07–0.13 N A-286 S66286 20Cb-3 PH13-8Mo PH14-8Mo N08020 S13800 S14800 19–21 12.25–13.25 13.75–15.0 32–38 7.5–8.5 7.75–8.75 2.0–3.0 2.0–2.5 2.0–3.0 0.07 0.05 0.05 2.0 0.2 1.0 1.0 0.1 1.0 15-5PH PH15-7Mo S15500 S15700 14.0–15.5 14.0–16.0 3.5–5.5 6.5–7.75 2.0–3.0 0.07 0.09 1.0 1.0 1.0 1.0 17-4PH 17-7PH Nitronic 60 21-6-9 AM350 AM355 Stab 26-1 S17400 S17700 S21800 S21900 S35000 S35500 S44626 15.5–17.5 16.0–18.0 16.0–18.0 18.0–21.0 16.0–17.0 15.0–16.0 25.0–27.0 3.0–5.0 6.5–7.75 8.0–9.0 5.0–7.0 4.0–5.0 4.0–5.0 0.5 2.5–3.25 2.5–3.25 0.75–1.50 0.07 0.09 0.10 0.08 0.07–0.11 0.10–0.15 0.06 1.0 1.0 7.0–9.0 8.0–10.0 0.5–1.25 0.5–1.25 0.75 1.0 1.0 3.5–4.5 1.0 0.5 0.5 0.75 29-4 29-4-2 S44700 S44800 28.0–30.0 28.0–30.0 0.15 2.0–2.5 3.5–4.2 3.5–4.2 0.010 0.010 0.3 0.3 0.2 0.2 Custom 450 Custom 455 S45000 S45500 14.0–16.0 11.0–12.5 5.0–7.0 7.5–9.5 0.5–1.0 0.5 0.05 0.05 1.0 0.5 1.0 0.5 254 SMO AL6XN 27-7Mo S31254 N08367 S31277 19.5–20.5 20.0–22.0 20.5–23.0 17.5–18.5 23.5–25.5 26.0–28.0 6.0–6.5 6.0–7.0 6.5–8.0 0.02 0.03 0.02 1.0 2.0 3.0 0.8 1.0 0.5 *Single values are maximum values unless otherwise noted †Typical room-temperature properties ‡To convert MPa to lbf/in2, multiply by 145.04 × (C + Ni)– 1.0 Ti, 0.15 Cu 0.02 N, 0.15 Cu 0.02 N, × C Cb 1.25–1.75 Cu 1.5–2.5 Cu, 0.8– 1.4 Ti 0.18–0.22 N 0.18–0.25 N 0.3–0.4 N 0.5–1.5 Cu Yield strength, kip/ in2 (MPa)‡ 100 (690) Tensile strength, kip/ in2 (MPa)‡ Elongation, % Hardness, HB 140 (970) 20 53 (365) 120 (827) 55–210 (380–1450) 98 (676) 160 (1100) 125–230 (860–1540) 33 17 2–25 185 300 200–450 145 (1000) 55–210 (380–1450) 160 (1100) 130–220 (900–1520) 15 2–35 320 200–450 145 (1000) 40 (276) 60 (410) 68 (470) 60–173 (410–1200) 182 (1250) 50 (345) 160 (1100) 130 (710) 103 (710) 112 (770) 145–206 (1000–1420) 216 (1490) 70 (480) 15 10 62 44 13.5–40 19 30 320 185 210 220 200–400 402–477 165 70 (480) 85 (590) 90 (620) 95 (650) 25 25 210 230 117–184 (800–1270) 115–220 (790–1500) 144–196 (990–1350) 140–230 (970–1600) 14 10–14 270–400 290–460 45 (310) 45 (310) 95 (655) 95 (655) 35 30 223 241 52 (260) 112 (770) 40 168 PROPERTIES OF MATERIALS TABLE 25-14 25-39 Standard Cast Heat-Resistant Stainless Steels Mechanical properties at 1600°F Short term ACI Equivalent AISI HC HD HE HF HH HH-30 HI HK HL HN HP HT HU HW-50 HX Composition, %* 302B 309 310 330 Cr Ni C Mn 26–30 26–30 26–30 18–23 24–28 24–28 26–30 24–28 28–32 19–23 24–28 13–17 17–21 10–14 15–19 4–7 8–11 9–12 11–14 11–14 14–18 18–22 18–22 23–27 33–37 33–37 37–41 58–62 64–68 0.5 0.5 0.2–0.5 0.2–0.4 0.2–0.5 0.2–0.5 0.2–0.5 0.2–0.6 0.2–0.6 0.2–0.5 0.35–0.75 0.35–0.75 0.35–0.75 0.35–0.75 0.35–0.75 1.0 1.5 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Stress to rupture in 1000 h Other 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.5 2.5 2.5 2.5 2.5 0.2 N 0.2 N Elongation, % kip/in2 MPa† 23 (159) Si J92605 J93005 J93403 J92603 J93503 J93513 J94003 J94224 N08604 J94213 N08705 N08002 N08004 N08006 N06006 446 327 UNS Tensile strength, kip/in2 (MPa)† 18 1.3 7.0 9.0 48‡ 21 (145) 18.5 (128) 21.5 (148) 26 (179) 23 (159) 30 (207) 20 (138) 26 (179) 19 (131) 20 (138) 19 (131) 20.5 (141) 16 30 18 12 16 4.4 3.8 3.8 4.8 6.0 30 26 26 33 41 37 27 26 20 7.4 7.5 5.8 5.2 4.5 4.0 51 52 40 36 31 28 48 *Single values are maximum values; S and P are 0.04 maximum; Mo is 0.5 maximum †To convert MPa to lbf/in2, multiply by 145.04 ‡At 1400°F (760°C) TABLE 25-15 Standard Cast Corrosion-Resistant Stainless Steels Mechanical propertiesb ACI CA-15 CA-15M CA-6NM CA-40 CB-30 CC-50 CE-30 CB-7Cu–1 CB-7Cu–2 CF-3 CF-8 CF-3M CF-8M CF-10M CG-12 CG-3M CF-8C CF-16F CH-20 CK-20 CN-7M CD-4MCu a Equivalent AISI 410 420 431 446 312 17-4PH 15–5PH 304L 304 316L 316 316H 317 317L 347 303 309 310 Alloy20 2205 UNS J91150 J91151 J91540 J91153 J91803 J92615 J93423 J92180 J92110 J92500 J92600 J92800 J92900 J92901 J93001 J92999 J92710 J92701 J93402 J94202 J95150 J92205 J93372 Cr 11.5–14 11.5–14 11.5–14 11.5–14 18.21 26–30 26–30 14.0–15.5 17–21 18–21 17–21 18–21 18–21 18–21 18–21 18–21 18–21 22–26 23–27 19–22 21.0–23.5 25–26.5 Ni Mo C Mn Si 1.0 1.0 3.5–4.5 1.0 2.0 4.0 8–11 0.5 0.15–1.0 0.4–1.0 0.5 0.15 0.15 0.06 0.20–0.40 0.30 0.50 0.30 0.07 0.07 0.03 0.08 0.03 0.08 0.12 0.08 0.03 0.08 0.16 0.20 0.20 0.07 0.03 0.04 1.0 1.0 1.0 1.0 1.0 1.0 1.5 1.5 1.5 1.0 1.5 1.5 1.5 2.0 0.7 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.0 1.0 2.0 2.0 1.5 2.0 1.5 1.5 1.5 2.0 2.0 2.0 2.0 1.5 1.0 1.0 4.2–5.5 8–12 8–11 9–13 9–12 9–12 9–13 9–13 9–12 9–12 12–15 19–22 27.5–30.5 4.5–6.5 4.75–6.0 2.0–3.0 2.0–3.0 2.0–3.0 3.0–4.0 3.0–4.0 1.50 2.0–3.0 7.5–3.5 1.75–2.25 Single values are maximum values P and S values are 0.04 maximum Typical room-temperature properties for solution-annealed material unless otherwise noted To convert MPa to lbf/in2, multiply by 145.04 d For material air-cooled from 1800°F and tempered at 600°F e For material air-cooled from 1750°F and tempered at 1100 to 1150°F f For material annealed at 1450°F, furnace-cooled to 1000°F, then air-cooled g Air-cooled from 1900°F h 1.0 maximum b c Other Yield strength, kip/in2 (MPa)c Tensile strength, kip/in2 (MPa)c 150 (1034)d 150 (1034)d 100 (690)e 165 (1138)d 60 (414) f 65 (448)g 63 (434) 165 (1138) Composition, %a 200 (1379)d 200 (1379)d 120 (827)e 220 (1517)d 95 (655) f 97 (669)g 97 (669) 7d 7d 4e 1d 15 f 18g 18 390d 390d 269e 470d 195 f 210g 190 418 77 (531) 77 (531) 80 (552) 80 (552) 80 (552) 83 (572) 80 (552) 77 (531) 77 (531) 88 (607) 76 (524) 69 (476) 90 (621) 108 (745) 60 55 55 50 50 45 50 39 52 38 37 48 20 25 140 140 150 160 160 170 150 149 150 190 144 130 250 253 Elongation, % Hardness, HB 2.5–3.5 Cu (8 × C) Cbh 3–4 Cu 0.1–0.3 N 2.75–3.25 Cu 36 (248) 37 (255) 38 (262) 42 (290) 42 (290) 44 (303) 40 (275) 38 (262) 40 (276) 50 (345) 38 (262) 32 (221) 60 (414) 82 (565) 25-40 TABLE 25-16 Nickel and Cobalt Alloys Mechanical properties† Composition, %* Alloy UNS Ni or Co Cr Fe 200 201 400 K-500 N02200 N02201 N04400 N05500 99 99 63–70 63–70 600 625 825 B-3 C-276 C-22 C-2000 MAT21 686 G-3 G-35 N06600 N06625 N08825 N10665 N10276 N06022 N06200 N06210 N06686 N06985 N06035 72 Bal 38–46 65 Bal Bal Bal Bal Bal Bal Bal 14–17 20–23 19.5–23.5 1.0–3.0 14.5–16.5 20.0–22.5 22.0–24.0 18.0–20.0 19.0–23.0 21.0–23.5 32.3–34.3 6–10 Bal 1.0–3.0 4–7 2–6 1.0 5.0 18.0–21.0 2.0 600 601 625 706 N06600 N06601 N06625 N09706 72 58–63 Bal 39–44 14–17 21–25 20–23 14.5–17.5 6–10 Bal Bal 718 N07718 50–55 17–21 Bal X-750 N07750 70 14–17 5–9 30–35 30–35 30–34 32–37 Bal 35–39 Bal 44.5 Bal 18.2–21 19–23 19–23 19–22 25–29 20.5–23 223–27 20–24 20–24 26–30 20–22.5 Bal Bal Bal Bal 17–20 Bal 3 3.5 Bal Bal Bal 19–21 20–24 3 Mo C Other Condition Yield strength, kip/in2 (MPa)‡ Tensile strength, kip/ in2 (MPa)‡ Elongation, % Hardness, HB 15–30 (103–207) 10–25 (69–172) 25–50 (172–345) 85–120 (586–827) 55–80 (379–552) 50–60 (345–414) 70–90 (483–621) 130–165 (896–1138) 55–40 60–40 60–35 35–20 90–120 75–102 110–149 250–315 30–50 (207–345) 60–95 (414–655) 35–65 (241–448) 76 (524) 52 (358) 52 (358) 52 (358) 52 (358) 52 (358) 52 (358) 52 (358) 80–100 (552–690) 120–150 (827–1034) 85–105 (586–724) 139 (958) 115 (793) 115 (793) 115 (793) 115 (793) 115 (793) 115 (793) 115 (793) 55–35 60–30 50–30 53 61 61 61 61 61 61 61 120–170 145–220 120–180 210 194 194 194 194 194 194 194 30–50 (207–345) 30–60 (207–414) 60–95 (414–655) 161 (1110) 80–100 (552–690) 80–115 (552–793) 120–150 (827–1034) 193 (1331) 55–35 70–40 60–30 20 120–170 110–150 145–220 371 171 (1180) 196 (1351) 17 382 115–142 (793–979) 162–193 (1117–1331) 30–15 300–390 30–60 (207–414) 20–50 (138–345) 79.5 (548) 75–100 (517–690) 65–95 (448–655) 129 (889) 60–30 50–30 29.5 120–184 100–184 56 (386) 110 (758) 45 178 45 (310) 35 (240) 35 (240) 50 (345) 110 (760) 95 (655) 90 (670) 110 (760) 40 30 40 30 187 170 170 192 69 (475) 69 (475) 146 (1005) 142 (985) 50 55 200 200 Corrosion Alloys 0.4 0.4 1.0–2.5 2.0 0.15 0.02 0.3 0.25 8–10 2.5–3.5 27–32 15–17 12.5–14.5 15.0–17.0 18.0–20.0 15.0–17.0 6.0–8.0 7.6–9.0 0.15 0.10 0.05 0.010 0.010 0.015 0.010 0.015 0.010 0.015 0.05 28–34 Cu 2.3–3.15 Al 0.35–0.85 Ti, 30 Cu 3.15–4.15 (Cb + Ta) 1.5–3.0 Cu, 0.6–1.2 Ti Ni + Mo = 94.0–98.0 3.0–4.5 W 2.5–3.5 W 1.3–1.9 Cu 1.5–2.2 Ta 3.0–4.4 W, 0.02–0.25 Ti Cb + Ta 0.5 Annealed Annealed Annealed Age-hardened Annealed Annealed Annealed Annealed Annealed Annealed Annealed Annealed Annealed Annealed Annealed Annealed High-Temperature Alloys 800 N08800 800H N08810 801 N08801 803 S35045 X N06002 HR-120 N08120 230 N06230 617 N06617 HR-160 N12160 N155R30155 25 R30605 188R30188 8–10 2.8–3.3 0.15 0.10 0.10 0.06 1.0–1.7 Al 3.15–4.15 (Cb + Ta) 0.08 4.75–5.5 (Cb + Ta) 0.08 8–10 2.5 1.0–3.0 8.0–10.0 1.0 2.5–3.5 0.65–1.15 Ti, 0.2–0.8 Al 0.7–1.2 (Cb + Ta) 2.25–2.75 Ti, 0.4–1.0 Al 0.10 0.15–0.6 Al, 0.15–0.6 Ti 0.05–0.10 0.15–0.6 Al, 0.15–0.6 Ti 0.10 0.75–1.5 Ti 0.06–0.10 0.15–0.6 Ai 0.15–0.6 Ti 0.05–0.15 0.2–1.0 W 0.02–0.1 0.05–0.15 13.15 W, 0.005–0.05 La 0.05–0.15 10–15 Co, 0.8–1.5 Al 0.15 27–33 Co, 2.4–3.0 Si 0.08–0.16 19–21 Ni, 0.75–1.25 Cb 2.0–3.0 W 0.38–0.48 9–11 Ni, 14–16 W 0.05–0.45 20–24 Ni, 13–16 W 0.03–0.15 La *Single values are maximum unless otherwise noted †Typical room-temperature properties ‡To convert MPa to lbf/in2, multiply by 145.04 §Single values are minima Those alloys with N UNS numbers are nickel and R numbers are cobalt alloys Annealed Annealed Annealed Solution-treated and aged Special heat treatment Special heat treatment Annealed Solution-treated Stabilized Annealed Annealed Annealed Annealed Annealed Annealed Annealed Annealed Annealed PROPERTIES OF MATERIALS TABLE 25-17 25-41 Aluminum Alloys Mechanical properties† AA designation Other Condition‡ Yield strength, kip/in2 (MPa) 99.6 Al 99.0 Al 0 T4 H14 0 0 T6 T6 T6 (28) (34) 47 (324) 21 (145) 13 (90) 21 (145) 17 (117) 17 (117) 40 (276) 31 (214) 73 (503) Composition, %* UNS Wrought 1060 1100 2024 3003 5052 5083 5086 5154 6061 6063 7075 A91060 A91100 A92024 A93003 A95052 A95083 A95086 A95154 A96061 A96063 A97075 Cast 242.0 295.0 336.0 B443.0 514.0 520.0 A02420 A02950 A03360 A24430 A05140 A05200 Cr Cu 0.05–0.2 0.1 3.8–4.9 0.05–0.2 0.15–0.35 0.1 0.05–0.25 0.1 0.05–0.25 0.1 0.05–0.35 0.1 0.04–0.35 0.15–0.4 0.1 0.1 0.18–0.28 1.2–2.0 0.25 3.5–4.5 4.0–5.0 0.5–1.5 0.15 0.15 0.25 Mg 1.2–1.8 2.2–2.8 4.0–4.9 3.5–4.5 3.1–3.9 0.8–1.2 0.45–0.9 2.1–2.9 1.2–1.8 0.03 0.7–1.3 0.05 3.5–4.5 9.5–10.6 Mn Si 0.3–0.9 0.5 1.0–1.5 0.6 0.1 0.4–1.0 0.4 0.2–0.7 0.4 0.1 0.25 0.15 0.4–0.8 0.1 0.2–0.6 0.3 0.40 0.35 0.35 0.35 0.35 0.35 0.15 0.7 0.7–1.5 11–13 4.5–6.0 0.35 0.25 5.1–6.1 Zn 1.7–2.3 Ni 2.0–3.0 Ni S-T571 S-T4 P-T551 S-F S-F S-T4 22 (152) Tensile strength, kip/in2 (MPa) Elongation in in, % Hardness, HB 10 (69) 13 (90) 68 (469) 22 (152) 2.8 (193) 43 45 19 16 30 19 23 120 40 47 38 (262) 35 (241) 45 (310) 35 (241) 63 (572) 30 27 17 18 11 58 95 73 150 29 (200) 29 (200) 31 (214) 17 (117) 22 (152) 42 (290) 6 12 *Single values are maximum values †Typical room-temperature properties ‡S = sand-cast; P = permanent-mold-cast; other = temper designations SOURCE: Aluminum Association To convert MPa to lbf/in , multiply by 145.04 other configurations are commercially available PVDF has a use range from −40 to 302oF (150oC) PVDF has a high tensile strength, flex modulus, and heat deflection temperature It is easily welded, resists permeation, and offers a high-purity smooth polymer surface This is the polymer of choice for high-purity applications such as semiconductor, bioprocessing, and pharmaceutical industries Ethylene chlorotrifluoroethylene (Halar) (ECTFE) has excellent chemical resistance to most chemicals including caustic ECTFE can be used from −105oF (−76oC) to 302oF (150oC) To obtain good extrusion characteristics, this polymer is usually compounded with a small amount of extrusion aid Ethylene trifluoroethylene (Tefzel) (ETFE) has good mechanical properties from cryogenic levels to 350oF (177oC) It has an upper continuous working temperature limit of 300oF (149oC) Polyethylene (PE) is one of the lowest-cost polymers There are various types of polyethylene denoted by their molecular weight This ranges from low-density polyethylene (LDPE) through ultrahighmolecular-weight (UHMW) polyethylene Physical properties, processability, and other characteristics of the polyethylene vary greatly with the molecular weight Polypropylene (PP) is a crystalline polymer suitable for low-stress applications up to 225oF (105oC) For piping applications this polymer is not recommended above 212oF (100oC) Polypropylene is shielded, pigmented, or stabilized to protect it from uv light Polypropylene is often a combination of polyethylene and polypropylene which enhances the ductility of the polymer Polyvinyl chloride (PVC) has excellent resistance to weak acids and alkaline materials PVC is commonly utilized for applications that not require high-temperature resistance or a high-purity resin Chlorinated PVC (CPVC or PVC-C) represents more than 80 percent of all the PVC used in North America PVC contains 56.8 percent chlorine by weight in contrast to about 67 percent for CPVC Both PVC and CPVC are compounded with ingredients such as heat stabilizers, lubricants, fillers, plasticizers, pigments, and processing aids The actual amount of polymer may range from 93 to 98 percent The remaining to percent is filler, pigment, stabilizer, lubricant, and plasticizer Other commercial thermoplastics include acrylonitrile butadiene styrene (ABS), cellulose acetate butyrate (CAB), polycarbonate (PC), nylon (PA), and acetals These resins are frequently used in consumer applications Thermosets* There are several generic types of thermosetting resins used for the manufacture of fiberglass-reinforced plastic (FRP composites) equipment Unlike thermoplastic polymers, thermosetting polymers are hardened by an irreversible crosslinking cure and are almost exclusively used with fiber reinforcement such as glass or carbon fibers in structural applications It is important to note that because thermoset resins are used with fiber reinforcements, the properties of the resultant laminate are dependent upon the resin and the type, amount, and orientation of reinforcement fibers To reduce the number of generally used constructions, ASTM and ASME RTP-1 define several standard corrosion-resistant laminate constructions suitable for most equipment In addition to new construction, thermoset composites are providing practical solutions to the engineer faced with the challenges of restoring structural integrity, increasing load-bearing capabilities, and/or enhancing the strength and stiffness of aging structures See Table 25-19 for typical thermoset fiber reinforced laminate properties The advantages of composites are inherent in their construction A variety of resin/fiber systems can yield possible solutions for many types of situations Depending on the product and application, FRP products for civil and mechanical applications can deliver the following benefits: Part design (orientation of the fibers) can be optimized for specific loads Reduced structure dead load can increase load ratings Reduced maintenance costs due to resistance from salts and other corrosive agents Engineered system packaging reduces field installation time Faster installation due to lower weight Enhanced durability and fatigue characteristics—FRP does not rust nor is it chloride susceptible Myriad FRP products are available for either the repair or the outright replacement of existing structures In addition to chemicalprocess pipes and tanks, FRP composite products include structural shapes, bridge systems, grating, handrail ladders, etc *Note: Thermosets are also used in non-fiber-reinforced applications such as gel coats and cast polymer 25-42 TABLE 25-18 Typical Thermoplastic Properties PP Units Density Melting point (crystalline) PVC Homopolymer g/cm3 0.91 0.88–0.91 1.38 °C 160–175 150–175 — °F 320–347 302–347 — CPVC Copolymer PVDF ECTFE ETFE FEP TFE PFA 1.76–1.79 1.68 1.70 2.12–2.17 2.2–2.3 2.12–2.17 141–160 220–245 270 275 327 310 285–320 460 518 527 621 590 4.5–7.0 3.5–6.0 6.6–7.8 6.5 2.7–3.1 2.0–2.7 4.0–4.5 Homopolymer Copolymer 1.5 1.75–1.79 — 160–170 — 320–340 Physical Properties Break strength; ASTM D 638 Modulus flex @ 73°F; ASTM D 790 Yield strength; ASTM D 638 kpsi 4.5–6.0 4.0–5.3 6.0–7.5 — MPa 1135–1550 345–1035 — — kpsi 165–225 50–150 — — 165–325 90–180 180–260 200 80–95 190–235 120 kpsi 4.5–5.4 1.6–4.0 — — 5.0–8.0 2.9–5.5 — 7.1 — — — Thermal Properties HDT at 0.46 MPa (66 psi); ASTM D 648 Linear coefficient of expansion; ASTM D 696 Conductivity; ASTM C 177 °C 107–121 75–89 57 — 132–150 93–110 90 104 70 221 75 °F 225–250 167–192 135 — 270–300 200–230 194 220 158 250 166 in/(in⋅°C) × 10−5 10 7–9.5 4.4 3.9 7.2–14.4 14.0 8–11 10 12 W/(m⋅K) 0.1 0.16 — — 0.17–0.19 0.16 — — — — — Btu/(ft2⋅h⋅ °F/in) 0.7 1.1 — — 1.18–1.32 1.11 — — — — — TABLE 25-19 Typical Thermoset Fiber-Reinforced Laminate Properties Property → ASTM test method Thermal Heat Thermal Impact Specific coeff of distor- conductiGlass Tensile Tensile Flexural Flexural Compress strength, heat, expansion, tion, vity’ Dielectric Water Mold fiber, Specific Density, strength, modulus, Elongation, strength, modulus, strength, ft⋅lb./in FlamBtu/ 10–6 in/ °F at 264 Btu/h, ft2/ strength, absorption, shrinkage, 3 6 % gravity lb/in 10 psi 10 psi % 10 psi 10 psi 10 psi of notch mability (lb⋅°F) (in⋅°F) psi °F/in V/mil % in 24 h in/in D 638 D 638 D 638 D 790 D 790 D 695 D 256 UL-94 D 696 D 648 C 177 D 149 D 570 D 955 Polyester preform, low profile D 790 D 792 24 1.74 0.063 11.5 1.70 2.5 28.5 1.32 20.0 20.8 * 0.30 14.0 400+ 1,3 400 0.000 (Compression) general-purpose 25 1.55 0.056 13.5 1.80 2.5 27.0 1.10 25.0 18.0 * 0.30 14.0 350+ 1.5 400 25 0.001 (Compression) high glass 40 1.70 0.061 21.5 2.25 2.5 38.5 1.50 32.0 23.0 * 0.30 14.0 400+ 1.5 400 0.0005 23.0 2.10 1.0 25.0 2.00 Carbon/epoxy fabric * N/A Polyester SMC LP, low profile 30 1.85 0.067 12.0 1.70