Cane Sugar Engineering

Peter Rein

Cane Sugar Engineering

Peter Rein

CANE SUGAR

ENGINERING

Verlas Dr. Albert Bartens KG - Berlin 2007

Numerical data, descriptions of methods, and other information pesented in this book have been carefullychecked for accuracy. Nevertheless authors and publishers do not assume any liability for misprints, faultystatements, or other kinds of errors. Persons intending to handle chemicals or to work according to infor-mation derived from this book are advised to consult the original sources as well as relevant regulations inorder to avoid possible hazards.

ISBNwww.canesugarengineering.com2007

© Verlag Dr. Albert KG 16, Berlin, Germany

www.Bartens.comTelefon: +49 (0) 30 8035678Telefax: +49 (0) 30 8032049E-Mail: [email protected] rights reserved (including those of translation into other languages). No part of this book may be repro-duced in any form - by photoprint, microfilm, or any other means - transmitted or translated into a machinelanguage without written permission from the publishers.Registered names, trademarks, etc., used in this book and not marked as such are not to beconsidered unprotected.

Composition: Verlag Dr. Albert Bartens KG, BerlinPrinting and binding: Elbe Druckerei WittenbergPrinted in Germany

About the Author

Professor Peter Rein wasborn in South Africa.In 1965 he was awarded a B.S.in Chemical Engineering at theUniversity of Cape Town lead-ing on to a M.S. in 1967 at thesame university. In 1973 he wasawarded a Ph.D. in ChemicalEngineering at the Universityof Natal.

He began his career as aResearch Officer with De BeersDiamond Division between1967 and 1969 after which hetransferred to research and pro-duction engineering with Ton-

Sugar until 1979. In that year he waspromoted to Consulting Technologist, which posi-tion he held until 1992, when he was further promot-ed to Technical Director until January, 2000. In Feb-ruary 2000 he accepted a Professorship at the Audu-bon Sugar Institute, LSU AgCenter at Baton Rouge,Louisiana, USA, becoming Head of that institute.Prof. Rein is registered as a Chartered Engineer(UK) and a Professional Engineer (South Africa).He is a member of the Institution of Chemical En-gineers, a Fellow of the South African Institution ofChemical Engineers and a Member of the AmericanInstitute of Chemical Engineers. His membershipof sugar organizations include: The South AfricanSugar Technologists' Association, the InternationalSociety of Sugar Cane Technologists, the Sugar In-dustry Technologists, and the American Societyof Sugar Cane Technologists.

Prof. Peter Rein has contributed to more than100 papers including patents and has made numer-ous contributions to books and invited lectures. He

has also been the recipientof many awards includingthe following:- Part of team awarded

South African Instituteof Mechanical Engi-neers Projects and Sys-tems Award 1985 forFelixton Sugar MillProject.

- Leader of team awardedSouth African Institu-tion of Chemical Engi-neers Innovation Award1993, for ContinuousPan Development.

South African Associated Scientific and Tech-nical Societies National Award for ContinuousVacuum Pan Crystallizers.

- Sugar Industry Technologists (New York) SugarCrystal Award 1997 for achievement in sugartechnology.First recipient of Sugar Processing Research In-stitute (New Orleans) Technology Award 1998for outstanding contribution to sugar processingand technology.

- Gold Medal of the South African Sugar CaneTechnologists Association, presented in August2000.Elected Honorary Life Member InternationalSociety of Sugar Cane Technologists, February2005.

Professor Peter Rein is well-known throughout thesugar world for his outstanding contributions, hisopenness, and his leadership skills. Prof. Peter Reinhas been one of the most renowned cane sugar tech-nologists in the last 40 years.

Preface

7

Although it is with some trepidation that I haveauthored a new book on sugarcane technology, itseems that it is an opportune time. Most practicalsugarcane technology texts are dated and develop-ments in technology in the last 25 years have beensubstantial. Undertaking the task of writing a bookwas the suggestion of the publisher Dr.

of Verlag Dr. Albert Bartens, who recog-nized the need and persuaded me to produce a bookof practical usefulness. Many of the previous topicshave received a new treatment here and new mate-rial is evident particularly in relation to cane qualityand payment, cane diffusion, clarifica-tion and filtration, syrup clarification, continuouspan boiling, molasses exhaustion, chemical controlof factories, boilers, steam generation and steam andwater balances.

The challenges have been to combine the newtechnology with the old, to be critically selective inthe material published and to produce a book coher-ent in form and content. It is important also to main-tain a balanced perspective between theoretical andempirical information. The practicing engineer mustuse both to be effective, because in most cases atheoretical background promotes a more productiveuse of empirical information. Where possible a con-sistent structure has been followed in each chapter,starting with objectives, followed by theoretical andfundamental issues, then design, equipment details,operation and control, in roughly that order.

While attempting to be comprehensive, the temp-tation to be totally inclusive has had to be resisted, inorder to meet the objectives of the book. The bookis designed to provide relevant and useful informa-tion for the practicing engineer and technologist, as

well as for those involved in design and optimiza-tion of processes and equipment. Further referencesare provided for those needing to delve deeper. Thebook covers most of the background material pre-sented in courses on Sugar Processing Engineeringand Sugar Factory Design in the Louisiana StateUniversity College of Engineering.

A valuable foundation for sugarcane technol-ogy has been laid by earlier authors, particularly

Honig, Spencer, Meade, Hugot and Chen.However, most of the information in this book hasbeen gleaned from the literature and from those withwhom I have worked over many years and fromwhom I have learned most of what 1 know. I identifywith the quote of Isaac Newton: "If I have seen fur-ther, it is by standing on the shoulders of giants".

I have been most fortunate in enlisting the aidof outstanding who authored roughlya quarter of the book. They are all experts in theirfields and add immeasurably to its value and useful-ness. I am grateful too to those who have undertakento review the chapters, in particular Dr. Mike Ink-son, Ian Smith, Dave Muzzell, Dr. Luis Bento, Dr.Ed Richard, Jimmy Cargill, Dr. Regis Lima VerdeLeal and Dr. Dave Love. Their comments and advicehave been invaluable. John Dutton also contributedthorough diligent editing and assistance. I have beenfortunate to have associated during my career withthese and other technologists in the internationalsugar community.

In attempting to produce a relevant text, SI unitshave been adopted. This will not be strange in mostof the sugar-producing areas. However, the ISO setof notation has been adopted, and the symbols used

might appear unfamiliar to some readers. 1 believethat familiarity with them will prove that they are infact easy to use and less subject to confusion. Thereis a real need for standardization in this area. In thisrespect, the beet sugar industry has been more pro-active, and the system used here brings cane andbeet sugar technology closer together.

I am indebted to the Louisiana State UniversityAgricultural Center for their support. Dr.Bruhns proved to be far more than a publisher. His

constructive suggestions have added valueand identified errors. He also helped to keep me

on the straight and narrow when I strayed on thepaths of inconsistency. Even so, in a work like thisit is difficult to ensure that no errors are present. Itrust they are few and far between and I take totalresponsibility. I hope that readers will draw atten-tion to them so that they can be corrected in futureeditions.

Finally I wish to thank my wife for her un- support and the fact that she never begrudged

the long hours I spent on this task. I could not havewished for a better companion through my sugar ca-reer.

Peter ReinBaton RougeDecember 2006

Contributors

R. G. ATTARDProduction ChemistMackay Sugar Co-operativeAustralia(Chapter 11)

T. L.Formerly Consulting EngineerTongaat-Hulett SugarSouth Africa(Chapter 30)

N.Thermal Energy SystemsSouth Africa(Chapter 27)

D. M. MEADOWSExecutive Director - Technology ManagementTongaat-Hulett SugarSouth Africa(Chapters 24)

ConsultantBosch Projectsformerly Director Tongaat-Hulett SugarSouth Africa(Chapters 5 and 7)

A.B.Formerly Director andTechnical Director Illovo Sugar GroupSouth Africa(Chapter 20)

WRIGHTPrincipal ConsultantPGWAustralia(Chapters 11)

10

Index to advertisers

Echangeurs, 4630 Belgium

BetaTec Hopfenprodukte GmbH, 90482 Germany

BMA Braunschweigische AG, 38122 Braunschweig, Germany

Bosch Projects (Pty) Ltd, 4001 Durban, South Africa

Technologies Inc., Calgary, Canada

Chemviron Carbon, Belgium

Dedini S/A de Base, Piracicaba, Brazil

Dr. Wolfgang Kernchen GmbH, 30926 Seelze, Germany

Ferguson Perforating & Wire Co., 02905, USA

Fives Division 59666 Villeneuve d'Ascq Cedex, France

GEA GmbH, Germany

Industrieplanung GmbH, 57589 Germany

Industrieprojekt GmbH, Germany

Keller & Bohacek GmbH & Co. KG, 40472 Germany

Neltec Denmark 6541 Bevtoft, Denmark

pro/M/tec GmbH, 76275 Ettlingen, Germany

Putsch GmbH & Co. KG, 58095 Hagen, Germany

Siemens AG, 90475 Germany

Silver Weibull Sweden 28143 Sweden

Spray Engineering Devices Limited, 134 109 India

The Western States Machine Co, Ohio 45012-0327, USA

Thermal Energy Systems, Orpington, BR6 7LZ, United Kingdom

Thomas Broadbent & Sons Ltd., HDl 3EA, United Kingdom

Verlag Dr. Albert KG, 14129 Berlin, Germany

GmbH, 1051 Austria

200

147

front fly sheet

front fly sheet

466

536

218

57

452

back fly sheet

268

575

bookmark

back fly sheet

451

352

bookmark

535

422

267

450

618

453

738

736

Contents

About the author

Preface

Contributors

List of symbols

List of subscripts

Abbreviations

Terminology

1 SUGARCANE Structure of cane

Anatomy of the cane stalk Location of sucrose and impurities Definitions of components

1.2 Composition of cane1.2.1 Clean stalk1.2.2 Tops and leaves1.2.3 Typical composition of delivered cane 36

Composition of fiber1.2.5 Nonsucrose in cane1.2.6 Extraneous matter1.2.7 Effect of cane delays

Effect of cane variety1.2.9 Changes due to climatic conditions

and time of seasonReferences

2 CANE EVALUATION AND PAYMENT Evaluation of cane quality

Quality parameters

5

7

9

23

25

26

27

3132323434353535363738393941

4142

434343

2.1.22.1.32.1.42.1.52.1.62.22.2.12.2.2

2.2.3

2.32.3.12.3.22.3.32.3.42.3.52.42.4.12.4.22.4.32.4.4

2.4.5

33.1

3.1.13.1.23.1.33.1.43.1.53.1.6

Effect on recoverable sugar 43Effect on mill capacity 45Field soil and dirt 46Dextran 46Effect on mill costs 46

Cane payment systems 47Options for payment 47Cane payment recoverable

sugar formulae 47Distribution of proceeds between

growers and millers 48Cane sampling 49

Core sampling of cane 49Hatch sampling 50Grab samplingFirst expressed juice sampling 51Cane tracking 52

Methods of analysis 52Press method 52Wet disintegration method 53First expressed juice 53Accurate measurement of sucrose

by chromatography 54 Measurements 54

References 56

SUPPLY AND HANDLING OF SUGARCANE 59

Harvesting, transport and storage cane

Harvesting methods 59Transport systems 62Bundle handling 63Container systems 63Cane weighing 63Storage systems 63

12 Contents

Damage and deterioration of cane 633.2 Unloading cane 643.2.1 Tippers 64

Spillers 653.2.3 End-tipping trucks 653.2.4 Gantry cranes 663.3 Cane tables and cross carriers 66

Feeder tables 663.3.2 Spiller tables 663.4 Cane cleaning 673.4.1 Dry cleaning 673.4.2 Cane washing 693.4.3 Wash water handling

waste disposal 703.5 Cane conveying 71

Apron carriers3.5.2 Belt conveyors 723.5.3 Chain and slat conveyors 733.5.4 Magnets 743.5.5 Conveyor drives and automatic

controlReferences

4 CANE PREPARATION Objectives and measurement of

cane preparation Objectives Effect of cane preparation

on extraction4.1.3 Measurement of cane preparation4.2 Cane knives

Leveler knives4.2.2 Cane knifing arrangements4.2.3 Knife speeds and power requirements 844.2.4 Details of knives and rotors4.3 Shredders

Types of shredder4.3.2 Shredder feeding4.3.3 Factors affecting the preparation

achieved4.3.4 Shredder size and

throughput Hybrid shredders

4.3.6 Technical of heavy dutyshredder design

4.3.7 Power requirements for canepreparation

Prime mover requirements4.4 Operation and maintenance

References

55.15.1.15.1.25.25.2,15.2.25.2.35.2.45.2.5

5.2.6

5.2.75.2.85.2.95.2.10

MILLING 99Extraction by mills 99

Extraction 99Other measures of mill performance

7476

79

7979

80818383838485868687

89

9090

92

94969798

5.2.125.35.3.15.3.25.3.35.3.45.3.55.3.65.3.75.3.85.3.95.3.105.45.4.15.4.25.4.35.4.45.55.5.15.5.25.5.35.5.45.65.75.7.15.7.25.7.35.7.45.7.55.7.6

Theory of milling 101Basic volumetric model 101Assumptions for simple modelCane throughput formulae 102Feed ratio for maximum throughput 102Compaction ratio, compression

ratio and fiber fills 102Fiber with extracted juice

103Non-cylindrical rolls 103Floating rolls 103Friction and feed openingInfluence of roll diameter on

mill feeding 104Reabsorption, shearing in the

cane and slip 105Mill load and torque 106

Mills and mill components 107Conventional mills 107

108Mill rolls 109Roll grooving 112

groovesLotus rollsMill and loadingsMill bearings 115Mill pinions 116Trash plates and scrapers

Two-roll mills 117 development

STG-FCBBundaberg's high extraction millFives extraction unit

Mill drivesMill drive power requirementsPrime movers for millsMill gearing 122Mill couplings and tail bars 123

Cane preparation 124Mill settings 125

Mill roll settings 125Adjustment for top roll float 127Pressure feeder settings 127Underfeed settings 127Chute openings 127Trash plate settings 128

Contents 13

5.7.7 Practical optimization of mill settings 1295.8 Imbibition and related issues 1295.8.1 Imbibition 1295.8.2 Implications of cush with

extracted juice 1335.8.3 Maceration and maceration carriers 1335.8.4 Juice recycling 1345.8.5 Low-pressure extraction 1345.8.6 Mill drainage 1345.9 Mill feeding 1345.9.1 Roll surface preparation 1355.9.2 Chevrons 1355.9.3 Pusher feeders 1355.9.4 Donnelly chutes 1355.9.5 Pressure feeders 1375.9.6 Toothed pressure feeders 1385.10 Mill capacity 1385.10.1 Individual mill size and capacity 1395.10.2 Milling tandem capacity 1395.10.3 Number of mills 1405.10.4 Mill speed 1415.11 Mill control 1415.11.1 Throughput and other mill controls 141

Routine mill tests 142 Mill lift and hydraulic pressures 144 Mill operation 144

5.12 Sucrose losses along the milling train 1445.12.1 Physical losses 1445.12.2 Sucrose destruction losses 1445.12.3 Measurement and control of sucrose

destruction 1455.12.4 Cane payment implications 145

References 146

6 CANE DIFFUSION 1496.1 Theory 1496.1.1 Mechanism of extraction 149

Variables affecting extraction 150 Fiber packing density 150

6.1.4 Juice holdup 151 Juice percolation rates

6.1.6 Mass and energy balances 1536.1.7 Sizing 1546.2 Plant and equipment 1546.2.1 Types of diffuser 1546.2.2 Moving bed diffusers 1556.2.3 Cane feed arrangements 1566.2.4 Diffuser drive requirements 1576.2.5 Mechanical details 1586.2.6 Juice heating 159

6.2.7 Interstage juice application 1596.2.8 Instrumentation and control 1606.3 Recycle of mud 1606.4 Factors affecting diffuser work 1616.4.1 Cane preparation 1616.4.2 Cane residence time 1626.4.3 Imbibition rate 1626.4.4 Number of stages 1636.4.5 Percolation rate and flooding 1636.4.6 Temperature 1636.5 Dewatering of bagasse 1636.6 Control and operation of diffusers 165

Monitoring of efficiency ofextraction 165

6.6.2 Control of feed of cane and bedspeed

6.6.3 Control of percolation in diffusers 1666.6.4 control 1676.6.5 Corrosion control in diffusers 1676.6.6 Maintenance of diffusers 1686.6.7 Microbiology of extraction 1686.7 Comparison with milling 1696.7.1 Capital costs 1696.7.2 Maintenance and operating costs 1696.7.3 Effect on steam balance and

power requirements 1696.7.4 Effect on raw juice quality 1706.7.5 Juice screening and filtration 1716.7.6 Effect on overall recovery 1716.7.7 Effect on operations 1726.7.8 Expansion of mill and diffuser

capacity 1726.7.9 Maximum capacity of a single

extraction line 173References 173

7 AND BAGASSE CONVEYORS 175

7.1 175 Apron intercarriers 175 Belt-type intercarriers, low incline 176

scraper intercarriers 176 Belt-type intercarriers

chute conveyors7.2 Bagasse conveyors 1837.2.1 Bagasse belt 1837.2.2 Bagasse chain conveyors 1867.2.3 Bagasse feeding to boilers 1867.2.4 Bagasse sampling 1877.3 Magnets 187

References 188

14 Contents

8 RAW JUICE HANDLING

8.1 Juice screening Types of screen

8.1.2 cush return8.1.3 Screen cleaning8.1.4 Screening clarified juice8.2 Juice mass flow measurement8.2.1 Batch scales8.2.2 Other metering systems8.3 Juice sampling and analysis8.3.1 Sampling systems8.3.2 Suspended solids sampling8.3.3 Pol vs. sucrose analysis8.4 Juice pumping8.4.1 Pump duties8.4.2 Materials of construction8.4.3 Raw juice tank sizing8.4.4 Juice flow control

References

9 JUICE HEATING

Theoretical considerations9.1.1 Heat balance

Heat transfer rate9.1.3 Heat transfer coefficient in

tubular juice heaters Use of evaporator vapors

9.2 Tubular heater design Heat transfer coefficients

9.2.2 Liquid velocities9.2.3 Heater area calculations9.2.4 Tubular heater details9.2.5 Pressure drop calculations9.3 Plate heaters9.4 Direct contact heaters

Sizing of direct contact heaters9.4.2 Heater details9.4.3 Effect on thermal economy9.5 Scaling and cleaning

Scale characterization Formation of scale

9.5.3 Tube cleaning9.5.4 Vapor side fouling9.6 Juice flash tanks

Requirements of flashing9.6.2 Types of flash tank9.6.3 Sizing of tanks and nozzles9.6.4 Flow splitting to9.6.5 Temperature control9.7 Liquid-liquid heaters

189189189192192192193193194194194195195195195198198199200

9.8 Clarified juice heaters9.8.1 Objectives9.8.2 Sizing heaters

References

1010.110.1.110.1.210.1.3

10.1.4

10.1.5

10.1.6

10.1.710.1.8

201201201202

203204204205206206207209210211212212212212212213213213213213214214215215216

10.210.2.110.2.210.2.310.310.410.4.110.4.210.4.310.4.410.4.510.510.5.110.5.210.5.310.5.410.610.6.110.6.210.6.310.6.410.6.510.710.7.110.7.210.7.3

10.7.410.7.510.7.6

CLARIFICATIONChemical and physical processes

Objectives of juice clarificationAnalysis of raw juiceEffects of heating and

lime addition to juiceChemical reactions occurring

in simple juice clarificationVariants of defecation clarification

proceduresPractical procedures for defecation

clarificationOptimal pH of clarified juiceRole of phosphoric acid in juice

and additions of phosphateLime supply and handling

The quality of limeLime slaking and handlingMilk of lime and lime saccharate

pH controlTypes of

Description of clarifiersResidence timesFlash tanksBatch settling testsCapacities of clarifiers

Operation of the clarifier stationClarifier operationMud level control, mud consistencyPhosphoric acid and other additivesLiquidation

Flocculants and dosing systemsTypes of flocculantsPhysical reactions of flocculation

216216217218

219219219220

220

220

221

223224

224225225225226227228228232233233235236236236237237238238238

Flocculant preparation and addition 239 testing 239

Cationic flocculants 239 240

Preparation of sulfur dioxide 240Sulfur furnaces 240Use of anhydrous liquid

sulfur dioxide 241Sulfur and lime consumption 241Sulfitation apparatus 242Sulfitation procedures 242

Contents 15

10.7.7 Advantages and disadvantages ofsulfitation

10.7.8 Sulfitation of syrupReferences

Mud handling and bagacilloaddition

Mud quantities Handling of muds

11.1.3 Mud mixers Bagacillo quantities

Filter equipment details Plate and frame filter press

technologies Rotary drum vacuum filters Equipment details Conditioning of filter feed Screens and scrapers Capacity and sizing Level control and filter boot

agitation Filter cake washing Operational control

Filter cake analyses andmud solids retention

11.2.11 Cake handling Filtrate handling

Filtrate quantities Filtrate collection and pumping

separation11.3.4 Filter condensers11.3.5 Filtrate clarification

Microbiological losses Effect of temperature Purity changes and lactic acid

monitoringReferences

12 EVAPORATION12.1 Boiling heat transfer12.1.1 Range of temperatures and

pressures12.1.2 Boiling point elevation

Hydrostatic head12.1.4 Single vessel equations12.1.5 Definition of the heat transfer

coefficient12.2 Principles of multiple effect

evaporation

12.2.1 principles 273243 Vapor bleeding 273243 12.2.3 vs. countercurrent vs.244 mixed flow systems 274

12.2.4 Heat transfer rates 275245 12.2.5 Heat losses 277

12.2.6 Quantity of incondensable gases 278245 Multiple effect calculations -245 shortcut calculations 278248 12.4 Multiple effect calculations -249 rigorous evaporator calculations 280250 12.4.1 Derivation of equations 280251 12.4.2 Calculation by the rigorous method 281

12.4.3 Comparison of the shortcut and rigorous calculation methods 283

252 12.5 Factors affecting steam economy252 and capacity 283255 12.5.1 Influence of number of effects 283255 12.5.2 Effect of vapor bleeds 285256 12.5.3 Effect of exhaust steam and

last vessel absolute pressures 285Effect of clarified juice temperature 286Use of condensate flash 287Heating surface distribution 288

Evaporator equipment 288Types of evaporator 8Comparison of types of evaporator 291Pre-evaporators 293Vapor line sizing 294

Design of tubular evaporator vessels 294Calandria design 294Tube and tube plate dimensions and

specifications 296Downtakes 297Removal of condensate and

incondensable gases 297265 12.7.5 Liquid feed and offtake systems 298266 12.7.6 Plate evaporator details 299

12.8 Operation of evaporators 299269 12.8.1 Optimum operating conditions 299269 12.8.2 Automatic control of evaporators 300

12.8.3 Effect of steam superheat 300269 12.8.4 Testing for leaks 302271 12.8.5 Arrangement of vessels in series271 and parallel 302271 12.8.6 Syrup pumping 302

12.8.7 Causes of 302272 12.8.8 Sucrose losses in evaporators 303

12.8.9 Change 303273 12.9 Entrainment separation 304

257258260

260262262262263263264264265265

12.5.412.5.512.5.612.612.6.112.6.212.6.312.6.412.712.7.112.7.2

12.7.312.7.4

16 Contents

12.9.1 Types of separator 30412.9.2 Sizing and design 307

Condensate removal and flashing 30912.10.1 Piping systems 30912.10.2 Traps and 30912.10.3 Flash pots 310

Scaling and cleaning of evaporators12.11.1 Occurrence of scaling 310

Characterization of scale 312 Anti-sealants 312 Chemical cleaning

12.11.5 Mechanical cleaning 31412.11.6 Steam side cleaning 314

tarch and dextran removal12.12.1 Enzyme properties 31512.12.2 Optimal use of enzyme 315

References 316

1313.113.1.113.1.213.1.3

13.1.413.1.5

13.1.613.213.2.1

13.2.213.2.313.2.413.2.513.2.613.2.713.313.413.4.1

13.4.213.4.313.4.413.4.513.513.5.113.5.213.5.313.5.4

CONDENSERS AND VACUUM EQUIPMENTBasics 319

Absolute pressures requiredWater and vapor quantities 320Effect of condenser water

temperature 321Incondensable gas quantity 322Total quantity of cooling water used

in a factory 323Heat recovery 323

Condensers 324Condenser arrangements and

requirements 324Types of condenser 324Design of countercurrent condensers 325Materials of constructionBarometric sealAbsolute pressure controlIdentifying air leaks

Injection water pumpsSpray ponds and cooling towers

Design and specification ofcooling systems

Cooling towersSprays pondsEntrainment and drift lossesWater quality and treatment

Vacuum pumpsLiquid ring pumpsSizing of pumpsService water systemPump efficiency and testing

329329330330331331

331332333334334334335335336336

13.6 Ejector systems 33713.6.1 Steam jet ejectors 33713.6.2 Water jet ejectors 33813.7 After coolers 338

References 338

14 SYRUP CLARIFICATION 33914.1 Introduction 33914.2 Principles involved 34014.2.1 Effect of operating parameters 34014.2.2 Effect of added chemicals 34114.2.3 Aeration of syrup 34214.2.4 Clarification of B and C molasses 34214.2.5 Application of syrup clarification

in the raw sugar mill 34314.3 Benefits of syrup clarification 34514.3.1 Sugar quality 34514.3.2 Massecuite viscosity14.4 Equipment 34614.4.1 vessels 34614.4.2 Systems of aeration 34714.4.3 Scum handling 34814.4.4 In-line mixer 34814.5 Operation 34914.5.1 Control of addition of chemicals 34914.5.2 Laboratory testing and evaluation 34914.5.3 Scum layer control 35014.6 Enhancement of color removal 350

References 351

15 CRYSTALLIZATION 35315.1 Fundamentals of crystallization 353

olubility and supers aturation Crystal growth and nucleation 354

15.1.3 Effect of nonsucrose 356 Crystallization rates 356

15.1.5 Boiling point elevation 35715.1.6 Crystal size and shape 35915.1.7 Massecuite crystal content 36015.1.8 The crystallization process 36115.1.9 Objectives of pan house 36115.2 Sugar boiling schemes 36215.2.1 Description of boiling schemes used 36215.2.2 Comparison of boiling schemes 36515.2.3 Pan floor calculations and mass

balances 36515.2.4 Effect of the relationship between

and sucrose and between Brixand dissolved solids 368

15.2.5 Effect on sugar color 368

Contents 17

368

369369370370371371375376376378379379384

15.2.6 Effect of exhaustionand crystal yield

15.2.7 Factors affecting C massecuitequantity

15.2.8 Capacity and steam requirements Batch vacuum pans

15.3.1 Types pan15.3.2 Pan circulation15.3.3 Batch pan design15.3.4 Pan capacity

Evaporation rates15.3.6 and circulation steam15.3.7 separation

Continuous vacuum pans15.4.1 Types of continuous pan15.4.2 Design of continuous pans15.4.3 Comparison of batch and

continuous pan systems15.5 Pan control and operation15.5.1 Conduct of a batch boiling15.5.2 Seeding15.5.3 Meeting crystal size15.5.4 Vacuum testing15.5.5 Assessing the quality of pan boiling 39115.5.6 Boiling temperatures and pressures 39215.5.7 Effect of pan conditions and

operation on sugar quality15.5.8 Continuous pan operation15.6 Pan instrumentation and control

Measurement transducers15.6.2 Control valve sizing15.6.3 Batch pan control15.6.4 Automatic control of continuous pans 39715.7 Pan floor peripheral equipment15.7.1 Molasses conditioning15.7.215.7.3 Storage tanks15.7.4 Vacuum seed receivers15.7.5 Cutover systems15.7.6 Strike receivers

References

16 40316.1 Theoretical considerations 40316.1.1 Objectives and requirements of

cooling crystallization 403 Residence times and temperatures 404 Mixing/stirring 404

16.1.4 Rheological properties of 405

387389389390390390391392

393393394394395396397399399399399399399400400

1717.117.1.117.1.217.1.317.1.417.1.517.217.2.117.2.217.2.317.2.417.2.517.2.617.2.7

17.317.3.117.3.217.3.317.3.417.3.517.3.617.3.7

Pumping and handling massecuites 40816.2 Equipment 40916.2.1 Batch and continuous crystallizers 40916.2.2 Horizontal vs. vertical crystallizers 41016.2.3 41016.2.4 crystallizers 41116.2.5 Heat transfer coefficients 41416.2.6 Cooling system design 41416.2.7 Crystallizer drives 41516.2.8 Vacuum crystallizers 41616.2.9 Massecuite pumps 41616.3 Operation and control 41716.3.1 Operation of continuous crystallizers 41716.3.2 Massecuite flow characteristics 41816.3.3 Maillard reaction 42016.3.4 Cooling water circuits 420

References 421

CENTRIFUGAL SEPARATION 423Theory 423

and continuous centrifugals 423Centrifugal forces 424

separation theory 426Washing efficiency 426Crystal breakage 427

Batch centrifugals 427General description 427Batch cycle 428Comparison of different designs 428Centrifugal capacities 430Centrifugal drivesOperation of batch centrifugalsBasket inspection 434Feed mixers 434

Continuous centrifugals 434General description 434Comparison of different designs 435Centrifugal capacities 437Screens 438Operation of continuous centrifugals 440Continuous high grade centrifuges 441Comparison of batch and continuous

high grade centrifugals 44317.3.8 Melter and mingling centrifugals 44317.4 Massecuite reheating 444

Mother liquor supersaturation 44417.4.2 Reheater area requirements 44517.4.3 Types of reheater 44617.4.4 Pressure drop in tubular 44817.5 Remelters and minglers 448

18 Contents

17.5.1 Design of17.5.2 Details of magma minglers

References

448449452

18 MOLASSES EXHAUSTION 45518.1 Molasses exhaustibility 45518.1.1 Solubility of sugar in molasses 45518.1.2 Laboratory exhaustion trials 457

Target purity equationsmolasses exhaustion 457

Simplified methods for estimationof dry substance and ash 459

Effect of high dextran and starchcontents 460

18.1.6 reaction 46018.2 Quantity of C massecuite and

final molasses 46118.3 Optimum operation of C stations 461

Effect of factory operating conditionson molasses exhaustion 461

18.3.2 Recommended practice forachieving good molasses exhaustion 462

18.4 Molasses desugarization 463 separations 463

18.4.2 Ethanol precipitation 46418.4.3 Other chemical methods 464

References 465

19 DRYING AND STORAGE OF RAW SUGAR 467 Theory of drying 467

19.1.1 Context and objective 46719.1.2 Drying mechanisms 46719.1.3 Modeling 468

Practical interpretation 47019.2 Sugar driers 47119.2.1 Types of equipment 47119.2.2 Design and sizing 47619.2.3 Instrumentation and automation 47919.3 Handling and storage 479

Conveyors and hoppers 47919.3.2 Raw sugar warehousing 479

References 481

20 RAW SUGAR QUALITY 48320.1 Introduction 48320.2 Grades of raw sugar 48320.3 Effect of raw house operations

on sugar quality 484 Cane transport and harvesting 485

20.3.2 Sucrose extraction 485

20.3.320.3.420.3.520.3.620.3.720.420.4.120.4.220.4.3

20.520.5,120.5.220.620.6.120.6.220.6.320.6.420.6.520.6.620.6.720.6.820.6.9

2121.1

21.1.121.1.221.1.321.221.2.121.2.221.2.321.2.421.321.3.121.3.221.3.321.421.4.121.4.2

2222.122.222.2.122.2.2

Juice heatingClarificationEvaporationPan boilingCentrifugal operations

Specifications and standardsNon-centrifugal sugarsCentrifugal sugarsStandards for direct consumption

centrifugal sugarsPayment systems

Pol-based paymentQuality-based payment systems

Refining qualitiesPolarizationColorFilterabilityDextransStarchMoistureAshReducing sugarsOther parametersReferences

485485486486486486487487

487488488489491491491491492493494494495495496

499MOLASSES HANDLING AND STORAGEMolasses quantity, quality and

composition 499Calculation of quantities of molasses 499Typical analyses 500Physical properties 503

Molasses cooling 504Requirements 504Types of cooling system 504Heat transfer coefficients 505Temperature control 506

Pumping and piping systems 506Piping design for molasses handling 506Choice of molasses pump 507Mass flow measurement 508

Storage of molasses 509Degradation in storage 509Prevention of Maillard reaction 509References 510

SUGAR REFININGWhite sugar yield

and meltingRaw sugar handlingMingling

511512512513513

Contents 19

22.2.3 Affiliation of sugar 513 23.2.122.2.4 Design of melters22.3 Clarification processes 515 23.2.222.3.1 51522.3.2 Phosphatation22.3.3 Comparison of carbonatation

and phosphatation22.422.5 Filtration

Equations for filtration22.5.2 Laboratory filtration measurements22.5.3 Types of filters22.5.4 Filter area required22.5.5 Filter operation22.5.6 Cake handling and desweetening22.5.7 Deep bed filtration22.6 Evaporation and

Evaporator systems22.6.2 Crystallization schemes and yields

for white sugar22.6.3 White pan house operation22.6.4 Recovery house operations22.7 White sugar standards22.8 Steam requirements

ratios22.8.2 Reducing steam consumption by

operational and plant changes22.8.3 Pinch technology studies22.9 White-end refineries 53222.9.1 Advantages of back-end refineries 53222.9.2 Operation in season 532 2422.9.3 Off-crop refining 53322.10 Direct production of white sugar 533 24.122.10.1 Plantation white sugar 533 24.1.122.10.2 Options for white sugar production 24.1.2

mill 533 24.2References 534 24,2.1

24.2.223 COLOR AND DECOLORIZATION SYSTEMS 537 24.2.323.1 Colorants and color formation 24.2.4

in processing 537 24.2.523.1.1 Nature and origin of colorants 537 24.3

Measurement of color 539 24.3.123.1.3 Identification of 539 24.3.223.1.4 Color formation in the 24.3.3

raw sugar mill23.1.5 Color formation in the refinery 540 24.3.523.1.6 Color inclusion in sugar crystals 540 24.423.2 Choice of optimal refinery

decolorization scheme 541 24.4.2

518

520521521521522522523523524525526526

526528529530530531

531532

23.323.3.123.3.223.3.323.3.423.3.523.3.623.423.4.123.4.223.4.323.4.423.523.5.123.5.223.5.323.5.423.623.6.123.6.223.723.7.123.7.223.7.3

Comparison of decolorizationsystems 541

Combinations of clarificationand decolorization 542

Ion exchange decolorization 542Type of resin used 542Resin usage 542Ion exchange systems 543Color removal 544Regeneration of resin 544Treatment of effluent 545

Bone char 545Advantages and disadvantages 545Char systems used 545Regeneration 546Sweet water handling 546

Activated carbons 546Activated carbon systems 546Color removal 547Regeneration 547Energy consumption 547

Use of additives 547Oxidants 547Color 548

Decolorization of cane juice 548Chemical treatments 548Membranes 548Ion exchange 549References 549

WHITE SUGAR HANDLING ANDCONDITIONING

Drying, cooling and conditioning 551Conditioning 551Refined sugar drying and cooling 556

Refined sugar storage 557Types of bulk silo 557Bulk storage design and operation 560Ventilation 562Packed sugar storage 562Color formation 563

Sugar handling 563Conveying 563Hoppers, chutes and transfer points 565Screening or sieving 567Sugar dust explosions 569Dedusting 571

Bagging and packaging 572Weighers and feeders 572Packaging materials 572

20 Contents

24.4.3 Forming, filling and sealing 57324.4.4 Baling and palletizing 57424.4.5 Speciality products 574

References 576

25 CHEMICAL CONTROL OF FACTORIES 57725.1 Measurements and analyses 577

of commonly usedanalyses

Limitations and accuracies Determination of mass flow rates Cane

25.2 Factory sucrose balances Recovery calculations

25.2.2 Application of true sucroseanalytical data

25.2.3 Calculation of stock of sugar inprocess

25.2.4 Undetermined loss25.2.5 Mechanisms and causes of

undetermined losses25.3 Evaluation of factory performance25.3.1 Overall factory25.3.2 Extraction section25.3.3 Boiling house25.3.4 Other factory performance

measurements 58925.3.5 Time account 58925.4 Inversion losses 58925.4.1 Measurement of inversion losses 58925.4.2 Calculation of inversion losses from

equations 59025.4.3 Correction for effect of temperature

and dilution on pH 59025.4.4 59125.4.5 Tables for estimation of inversion 59125.5 Factory reporting 59325.5.1 Purpose 59325.5.2 Benchmarking and technical

auditing of factory figures 593 Format of reports 94

Appendix: Checklist forundetermined loss 596References 600

26 BAGASSE HANDLING, STORAGE ANDDRYING 601

26.1 Bagasse characteristics 60126.2 Bagasse storage and reclaim 60226.2.1 Bagasse conveying 602

577579581581582582

583

584584

585586586586587

26.3.226.3.326.3.4

26.426.4.126.4.226.4.326.4.426.4.526.4.626.526.5.126.5.226.5.326.5.4

26.2.2 Bagasse weighing 60226.2.3 Bagasse stores and reclaim

systems 60326.2.4 Bulk pile storage of bagasse 60526.2.5 Baling 60626.3 Bagasse drying 60626.3.1 Effect on boiler efficiency and

capacity 607Types of drier 607Operational issues 609Other alternatives for bagassedrying agacillo collectionBagacillo screensPneumatic louver separationPneumatic extractionPneumatic transportScrew conveyors 613Bagacillo cyclones 613

De-pithing of bagasse 614Fiber/pith splitPneumatic separation

615Fiber quality assessment 616References

27 STEAM GENERATION27.1 Introduction 61927.2 Combustion calculations 61927.2.1 Fuel characteristics 61927.2.2 Combustion air requirements 62227.3 Boiler efficiency 625

Measuring efficiency 62527.3.2 Quantifying losses 62527.4 Furnace design 628

Types of furnaces 62827.4.2 Bagasse feeding and metering 62927.4.3 Grate heat release rates 63027.4.4 Grate design for high efficiency

and low emissions27.4.5 Bagasse distributors and over

fire air design 63327.4.6 Furnace size 63327.5 Boiler design 63427.5.1 Design overview 63427.5.2 Heat transfer 63527.5.3 Boiler support structure 63827.5.4 Convection bank 64027.5.5 Superheater 64027.5.6 Circulation 641

Contents 21

27.5.7 Heat recovery 641 28.3.427.5.8 Erosion 64227.5.9 Fans 642 28.427.6 Controls and instrumentation 643 28.4.127.6.1 Steam demand profile 643 28.4.227.6.2 Control loops 644 28.4.327.6.3 Instrumentation 64627.6.4 Control technologies 647 28.4.427.7 Stack emissions and discards 28.5

disposal 648 28.5.1 Regulations and units of

measurement 648 28.5.227.7.2 emissions 648 28.5.327.7.3 Dust collectors 65021.1 A Choice of collector and

collector location27.7.5 Gaseous emissions27.7.6 Discards disposal27.8 Boiler operation and maintenance27.8.1 Manufacturer's manuals27.8.2 Start-up and shutdown27.8.3 Control systems27.8.4 Other operational concerns27.8.5 Upgrading boilers27.9 Boiler feed water systems27.9.1 Source of boiler feed water27.9.2 Required water quality27.9.3 Feed pump and feed control 29.2.5

valve sizing 65927.9.4 Deaeration 661 29.2.627.9.5 Feed water treatment 662 29.327.9.6 Boiler blowdown 66227.10 Feed water and steam reticulation 663 29.3.1

Pipework design 663 29.3.227.10.2 Pressure letdown systems 665 29.4

References 666 29.4.129.4.2

28 STEAM BALANCE 667 29.4.328.1 Steam available from bagasse 66728.1.1 of bagasse 667 29.4.5

Steam generated from bagasse 667 29.528.2 Sugar mill steam requirements 668 29.5.128.2.1 Prime mover energy requirements 668 29.5.228.2.2 Balance between high pressure and

exhaust steam requirements 669 29.5.328.2.3 Steam losses 669 29.5.428.3 Process steam usage 669 29.5.528.3.1 Evaporator configuration 67028.3.2 Pan requirement 67028.3.3 Juice heating requirements 670

652653655656656656656656657659659659

2929.129.1.129.1.229.1.329.229.2.129.2.229.2.3

29.2.4

Options for reducing processsteam usage 671

Overall steam balanceHigh pressure steam 671Exhaust steam usage 674Other factors affectingthe steam balance 675Power available for export 675

Vapor recompression 676Situations conducive torecompression 676Thermo-compression 676Mechanical vapor

recompression 678References 678

WATER AND CONDENSATE SYSTEMS 679Factory water balance 679

Water inputs and losses 679Evaporation losses 680Water balances 680

Boiler feed water 682Condensate recovery 682Condensate quality 682Monitoring sugar contaminationin condensate 683Softening 684Pressure-dependent qualityparameters 684Feed water storage 684

Factory process waterrequirements 684

Imbibition 684Process water usage 684

Service water requirements 685Raw water 685Treated water 685Service cooling systems 686Boiler ash and scrubber water 686Firewater supply 686

Treatment of effluent 686Surplus water handling systems 686Quantity of surplus water to

be treated 686Quality of surplus water stream 688Effluent treatment standards 688Biological treatment 689References 692

22 Contents

30 ELECTRICITY Generation of electricity

Factory requirements30.1.2 Selection of voltage30.1.3 Steam turbines

Steam usage30.2 Alternators30.2.1 Size30.2.2 Type30.2.3 Efficiency30.2.4 Control equipment30.2.5 Lubrication and cooling30.2.6 Electrical control30.2.7 Protection30.3 Operation of the power house

Alternator and turbine monitoring30.3.2 Load control30.3.3 Vibration monitoring30.3.4 Sale and purchase of power30.4 Electric motors30.4.1 Classes30.4.2 Insulation class30.4.3 Voltage supply30.4.4 Speed and slip30.4.5 Direct current (DC) motors30.4.6 Variable frequency drives30.5 Power distribution and usage30.5.1 Transformers30.5.2 Cable sizing30.5.3 Power factor correction30.6 Cogeneration

Back pressure and condensingturbines

30.6.2 Safety systems30.6.3 Control30.6.4 Power wheeling30.6.5 Gasification

References

BY-PRODUCT UTILIZATION Filter cake

Quantity and quality of filter cake31.1.2 Use in fields31.1.3 Composting

Extraction of value added proucts31.1.5 Animal feed31.2 Bagasse

in pulp and paper Bagasse board

31.2.3 Animal feeds

693693693694694698698698698699699699700700700700700701701702702702703703705705705705706709711

711711712712712713

714715715716716

31.2.431.2.531.2.631.2.731.331.3.131.3.231.431.531.5.131.5.231.5.331.5.431.631.6.131.6.231.6.331.6.431.6.531.6.631.6.7

3232.132.1.1

32.1.232.1.332.232.332.432.4.132.4.232.4.332.4.432.532.5.132.5.232.5.332.5.432.632.6.132.6.2

717717717717720721

Furfural manufactureIntegrated biomass processingCharcoal and activated carbonBoiler ash, smuts and fly ash

Cane leaves and topsCollection as additional fuelRecovery of value-added products

Sugar based by-productsMolasses

Fermentation productsAnimal feedUse as a fertilizerRecovery of products of value

productionEthanol yieldsFermentation systemsDistillationStorage and handlingStillage production and disposalCarbon dioxide recoveryEconomics of productionReferences

PHYSICAL PROPERTIESSteam and water

Equations representing steamand water propertiesTables for saturated steamProperties of superheated steam

Juice and syrupSugarcaneSugar

Crystal densityBulk densitiesSpecific heat and enthalpySolubility of sucrose

BagasseDensity of fiberBulk densityDry fiber bulk densityCoefficient of friction

LimeMilk of limeLimeReferencesTables, SI unitsConversion factors

Subject index

721721723724724724724725726726727728728728728729731733733735735737

739739

739739739744744744744744746746746746746747747747747747747748750

752

23

List of symbolsSymbol Quantity

bc

c , ,

c

§

hh

kkkkk

LV

G

k

mmn

nn

PPPP

Specific areaHydrogen ion activityBreadth or widthConcentrationConstant

Specific heat capacity atconstant pressure

DiameterMean crystal (grain) sizeFriction factor (Moody)FrequencyAcceleration due to gravity(= 9.807)Height, depthSpecific enthalpySpecific heat of evaporation

factor (milling)Reaction rateHeat transfer coefficientDischarge coefficientOverall crystal growthcoefficientMass transfer

LengthMassMass flow rateFlow behavior index(non-Newtonian power law)Rotational frequencyCycles/hourPressureBoiler pressurePitchCrystal growth dispersion

parameterRatio (mass)Solubility at saturationLiquid holdup to fiber ratioNonsucrose to water ratio

to ash ratioReducing sugar to ash ratioSucrose to water ratioRadius

Unit

K)mmmm

Hzy

m or mmkJ/kg

n

K)

kg/s or • • Pa)

mg or kg or tkg/s or t/h

v) or

kPa Pabar (g)mm

mm

g/g water0

ioo

m or mm

Symbol

t (

r

V

X ]

y

AACC

cc

F

cv

DEEE

FFFrGHHoH \\IIKKLMMN

Ne

Quantity

Fouling factorCelsius temperatureVapor saturation temperatureVelocityTerminal velocitySuperficial velocitySpecific volumeMass fractionMass fractionSupersaturation coefficient

AreaLight absorbanceCapacitance

Brown equationcoefficient

Fiber fill ratioCompaction ratioFilling ratioCoefficient of variationValve sizing coefficientDrag coefficientDiffusion coefficientEnergyExtractionPotential differenceActivation energyForce, weight

numberNo. of g forcesPump head or head lossGross calorific valueNet calorific valueElectric currentInversionConsistencyNo. of velocity headsLossRelative molecular massTorqueNumber of effects, rolls,tubes, etc.Newton number

number

Unit

•

°C

g

s

%V

m

Afraction

24 List of symbols / Subscripts

Symbol Quantity

P PurityP Power

Reactive powerPr numberQ Heat flow rateR Gas constantR RecoveryR Mill ratioR Growth rate

Linear growthRe Reynolds numberS EntropyS SlopeSC Solubility coefficientSt numberT Absolute temperature

VolumeV Volume flow rateW Water content

a Anglea, (3 Crystal shape factorsp Angle Shear rate

5 Thickness, thickness of layere Pipe roughnesss Porosity or void fraction

Efficiency Sphericity Thermal conductivity Dynamic viscosity Frictional coefficient

p Densitya Standard deviation9 Roller groove angleT TimeT Mean retention time Shear stress Volume fraction

(p Phase angle lag Angular velocity

A Pressure difference Boiling point elevation Log mean temperature

differenceAT Log mean temperature

difference

Unit

%

kVAr

kJ/(kmol - K)fraction or %

kg/s

K

kg/m3

o

mm

• K)

s, h or dayss or or hPa

Pa or°C

°C

K

Subscriptsapp Apparentb Bulk

Effectiveeq Equilibriumesc Escribedf Fittingsg Gravityh Hydraulich Hydrostatichoriz Horizontali Effect number or stage numberi Inlet, inputi Insidei Impure, technical1 Linearloss Lossm Meanmax Maximummin Minimumo Outlet, outputo Outsideo Oversizep Pure

rad radialred Reduced

Relativesat Saturatedstoictang Tangentialtot Totalu Undersizevert Vertical

A AshA Spray advanceAir Air

AmbientB BagasseC CaneCake Filter cakeC CondensateC Carbon (unburned fuel)CJ Clarified juiceCO Carbon monoxideCr CrystalD DiffusionD Drag

Subscripts 25

D Discharge (mill roll)DB bagasseDS Dry substance (Brix)E EvaporationEx ExhaustF FeedF FiberF FructoseFF Fiber fill

FiltrateFuel FuelFV Flash vaporFW Feed waterG GasG GlucoseHP High pressure

ImbibitionJ JuiceL LiquidMa Magma, massecuiteML Mother liquor

MolassesMS MonosaccharidesMSo Mud solids fiber)Mud mud to filtersN NormalNS NonsucroseP ParticlePW Press waterR ResultantR ReactionRDS Refractometric dissolved solids (Brix)

Raw juiceRS Reducing substancesS SucroseS SugarSeed SeedSo Solids

St SteamSTP At standard temperature and pressureSyr SyrupT TargetTW Tube wallTP Trash plateTRS Theoretical recoverable sugar

Undetermined lossUF UnderflowVVB Bleed vaporW WaterWB Wet bulb

0 At given conditions0 Beginning, zero0 Superficialf J First expressed juice

At infinity

26

Abbreviations

AC Alternating current ID Automatic voltage regulator IU

BHR Boiling house recovery LVBOD Biochemical oxygen demand MCRCAD Continuous ash discharge (stoker) MVCCS Commercial cane sugarCDR deposition rate NCVCFD Computational fluid dynamics NPSHCOD Chemical oxygen demand OFACRB Corrected reduced boiling house OR

recovery PICRE Corrected reduced extraction POCDAC Direct analysis of cane RDSDAF Dissolved air flotation RVDC Direct current SCADADOL Direct-on-line SCRDS Dry substance or dissolved solids (Brix) SEEM Extraneous matter SFERC Estimated recoverable crystal SNCRESP Electrostatic precipitator SJMGC Gas chromatography SRGCV Gross calorific value SRIGPS Global positioning system SRTHADP Hexose alkaline degradation products STPHP High pressure TDS

High performance ion chromatography TRSHPLC High performance liquid TSAS

chromatography VHPICUMSA International Commission for VSD

Uniform Methods of Sugar Analysis

Induced draftICUMSA UnitsLow voltageMaximum continuous ratingMedium voltageMechanical vapor recompressionNet calorific valueNet positive suction head

airOverall recoveryPreparation indexPol in open cellsRefractometric dissolved solidsRecoverable valueSupervisory control and data acquisitionSelective catalytic reductionExtractable sugarSafety factorSelective reductionFormula to estimate the recovery of sugarRecoverable sugar estimateSugar Research InstituteShort residence timeStandard temperature and pressureTotal dissolved solidsTheoretical recoverable sugarTotal sugars as sucroseVery high (sugar)Variable speed drive

Terminology

27

Affiliation: Treatment of raw sugar crystals to re-move the film of adhering molasses. This is achievedby mixing sugar with a concentrated syrup and thencentrifuging the magma with or without water wash-ing.

sugar: Sugar purified by

Agglomeration: Sticking together of two or morecrystals during the centrifuging and drying opera-tions.

Ash content: Solid residue determined after incineration in the presence of oxygen. In

analysis of sugar products, sulfuric acid is added tothe sample, and this residue as sulfated ash heatedto 525 °C is taken to be a measure of the inorganicconstituents. Sometimes determined indirectly bymeasurement of electrical conductivity of the prod-uct in solution (see Conductivity ash).

Bagacillo: Fine fraction of bagasse obtained byscreening or pneumatic separation, generally usedas a filter aid in filtration.

Bagasse: Cane residue leaving mills after extraction

Boiling house: That part of the sugar mill in whichthe processes of production of sugar from raw juiceare carried out. It is also referred to as the back-endor raw house.

Boiling point elevation: Difference between thetemperature of a boiling sugar solution and the tem-perature of boiling pure water, both measured at thesame pressure.

Brix: Measure of dissolved solids in sugar, juice,liquor or syrup using a refractometer, otherwise re-ferred to as refractometric dry solids. For solutionscontaining only sugar and water, Brix = % sugar bymass. Spindle Brix is determined using a hydrom-eter, but is now seldom used.

Brix-free water: Water forming part of the structure of the cane, and hence not part of the

juice expressed in milling. It cannot be separatedfrom natural fiber by mechanical means but is drivenoff at elevated temperatures.

Calandria: Tubular or plate heating element in avacuum pan or evaporator vessel.

Carbonatation: Process involving introduction ofcarbon dioxide gas into limed juice or syrup to re-move color and nonsugar solids.

Carbonatation gas: Gas rich in carbon dioxide foruse in Carbonatation.

Centrifugal: Centrifuge used to separate sugar frommother liquor.

Apparatus for the separation by sedimen-tation of suspended solids from a turbid sugar solu-tion.

Clarified juice: Juice from also referredto as clear juice.

Color: Attenuation index, determined by absorptionof light under defined conditions. Generally mea-sured using the ICUMSA method at 420 andreferred to as ICUMSA units or IU.

Conductivity ash: Estimate of ash content by mea-surement of the conductivity of the solution.

Conglomerate: Two or more crystals grown togeth-er during pan boiling.

Cooling crystallization: Crystallization by coolingof the

Crystal content: Proportion by mass of crystals inmassecuite, often expressed as a percentage, and re-ferred to total massecuite mass or to massecuite drysubstance (Brix).

28 Terminology

Crystallization: Nucleation and growth of crystals.

Crystallization scheme: Defines the number andarrangement of crystallization stages involved inproducing sugar.

Cush cush: The stream of wet bagasse or bagacilloseparated from raw juice by the juice screens.

Cut a pan: Discharge a portion of the massecuitefrom a pan, retaining a footing upon which to feedmore syrup or molasses for crystallization.

Dissolved solids: All solute material which is in so-lution, including sucrose, ash andother organic impurities.

Drop a pan: Discharge all of the massecuite from apan. Also referred to as striking a pan.

Dry substance: A measure of total solids obtainedfrom evaporating a solution or massecuite undervacuum to dryness. Also referred to as total solidsby drying or dry solids.

separator: Apparatus for removingjuice, syrup or massecuite entrained in the vapor.

Evaporator effect: One of a system of evaporatorsoperating in series as a multiple effect system (e.g.,first effect, second effect). Condensates and vaporsare labeled correspondingly (e.g., first condensateand vapor one: condensate and vapor from the firsteffect respectively).

Exhaustion: Applied to a massecuite, it representsthe g of sucrose present in crystalline form per 100g of sucrose.

Extraction: Proportion of sugar extracted from canein the extraction plant; equals mass of sugar in rawjuice as a percentage of mass of sugar in cane.

Extraneous matter: All cane leaves and tops, mud,soil, roots, rocks, stones and tramp iron deliveredwith the cane.

False grain: Undesirable small crystals, formedspontaneously by secondary nucleation when thesupersaturation during crystallization is too high.

Fiber: The dry fibrous insoluble structure of thecane plant. Generally taken to mean all insolublematerial in the cane delivered to a mill, and there-fore includes soil or other extraneous insolublematter in cane.

Filter cake: Material retained on the filter screensand discharged from the filters after filteringfier muds.

Filtrate: Liquid passed through the screens of thefilters.

Flocculant: Polyelectrolyte in solution added tojuice to assist clarification.

Footing: A charge of massecuite retained in or trans-ferred to a pan as the start of a massecuite boiling.

Imbibition: The process of adding imbibition waterto the extraction plant to increase extraction. Some-times incorrectly referred to as maceration (steep-ing cane in juice). Water added is called imbibitionwater.

Invert sugar: Mixture of approximately equal partsof glucose and fructose (monosaccharides) resultingfrom the hydrolysis of sucrose (inversion).

Liming: Process step in juice purification in whichlime is introduced into the sugar juice in the form ofmilk of lime or lime saccharate solution.

Liquid sugar: Refined sugar products in liquid form(e.g. liquid sucrose, liquid invert).

Liquor: A sugar syrup, a term generally used insugar refining.

Magma: Mixture of crystals and liquid (water,clarified juice, syrup or molasses) produced by min-gling.

Magma mixer: Mingler, where crystal and liquidare mixed together.

Massecuite: The mixture of crystals and motherliquor resulting from the crystallization process.Massecuites are classified according to purity as A,B, or C massecuites.

Terminology 29

Massecuite mixer: Apparatus from which masse- is distributed to the centrifugals.

Melter: Equipment in which dissolving of sugartakes place.

Melting: Another term for dissolving of sugar crys-tals.

Molasses: The mother liquor separated from thecrysta]s by centrifuging. A, or C molasses is de-rived from the corresponding C molas-ses is also referred to as final molasses.

Mother liquor: Liquid phase in the massecuite dur-ing crystallization; refers to syrup or liquor in whichthe crystals are growing.

Nonsucrose: Dissolved solids contained in any pro-cess stream other than sucrose.

Common term for ssolved solidsother than sugar contained in any process stream.

Nucleation: Generation and development of smallcrystals capable of growth.

Pan or vacuum pan: Vacuum evaporative crystal- used in the sugar industry to crystallize sugar

from liquor, syrup or molasses.

Phosphatation: using phosphoric acidand lime, in which certain nonsugar components areremoved by flotation.

Polarization (or The apparent sucrose contentexpressed as a mass percent measured by the opticalrotation of polarized light passing through a sugarsolution. This is accurate only for pure sucrose solu-tions.

Press water: Juice expressed from dewatering millsafter a

Purity: The true purity is the sucrose content asa percent of the dry substance or dissolved solidscontent. The solids consist of sugar plus nonsucrosecomponents such as invert, ash, and colorants. Ap-parent purity is expressed as polarization divided byrefractometer multiplied by 100.

Raw juice: Juice obtained from the cane extractionprocess. Also referred to as mixed juice mills)or draft juice (from

Raw sugar: Brown sugar produced in a raw sugarmill generally destined for further processing towhite sugar in a refinery.

Reducing sugars: Generally referred to in-terpreted as invert sugar, determined by measuringreducing substance content by laboratory analysis.

Refining: Purification of sugar through chemicaland physical methods, generally including some orall of clarification, filtration, decolorization and re-crystallization.

Refractometric dry solids (RDS): Measurement oftotal dissolved solids in a sugar liquor or syrup usinga refractometer. For solutions containing only sugarand water, % RDS Brix = % sugar by mass.

A syrup made from centrifuged low-gradesugar which is dissolved or remelted and returned tothe high grade boilings.

Runoff: General term for syrups or molasses pro-duced on centrifuging a massecuite.

Safety factor: Number to indicate keeping qualityof raw sugar, calculated from pol and moisture con-tent (= moisture g sugar) / (100 -

Saturation: A sugar solution at saturation will notdissolve any more crystals at the temperature of thesolution.

Seeding: (a) Introducing crystal fragments to inducenucleation, as a means of initiating thetion process; (b) introduction of fine crystals in theform of a slurry (similar to full seeding) to start crys-tallization. Sometimes referred to as graining.

Seed: Suspension of fine crystals in saturated solu-tion of alcohol, or the initial grain resulting fromseeding in a vacuum pan.

Solubility coefficient: Ratio of concentration ofsucrose in impure saturated solution to the concen-tration in a pure sucrose solution saturated at the

30 Terminology

same temperature (with concentration expressed assucrose/water ratio). Referred to as saturation coef-ficient in the beet sugar industry.

Strike: Massecuite as a completed boiling, all ofwhich is discharged from the pan.

Sucrose: Pure chemical compoundknown as white sugar, generally measured by polar-ization in pure solution or by GC or HPLC in impuresolution. The chemical term is

.

Sugar: Term for the sucrose and prod-ucts of the sugar industry, essentially composed ofsucrose.

Introduction of sulfur dioxide into juiceor liquor.

Supersaturation: The degree to which the sucrosecontent in solution is greater than the sucrose con-tent in a saturated solution.

Supersaturation coefficient: Calculated as thequotient formed by dividing the sugar/water ratio ofthe supersaturated solution by the sugar/water ratioof a saturated solution under the same conditions(temperature and purity or nonsucrose/water ratio).It shows whether the solution is (<1),saturated or supersaturated (>1).

Supersaturation, critical: Supersaturation at whichnucleation begins spontaneously.

Suspended solids: Insoluble solids in juice or otherliquid, removable by mechanical means.

Sweet water: Wash water or water containing asmall amount of sugar.

Syrup: The concentrated juice from the evaporators.

Target purity: Equilibrium purity of final molasses,derived from a formula taking into account the ef-fect of nonsucrose on its exhaustibility. Sometimesreferred to as expected molasses purity.

Trash: Cane tops, leaves, dead stalks of cane andany other vegetable matter delivered with the cane.