Crystallization (eBook)

Front Cover 1
Crystallization 4
Copyright Page 5
Table of Contents 12
PREFACE 6
CHAPTER 1. CRYSTALLOGRAPHY OF SUCROSE 20
1. Introduction 20
2. Characterization of a Crystal 22
3. History of and Introduction to Crystallography 22
4. Crystallography of Sucrose 29
5. Forms of Sucrose Crystals 46
6. Physical Properties and Internal Structure of Sucrose Crystals 51
7. Distribution of Impurities in Sucrose Crystals 63
8. Crystallographic Comments upon Cane Raw and Refined Sugars 66
9. Particle Sizes of Granulated and Raw Sugars 71
10. Determination of M.A. and C.V. 72
Bibliography 79
CHAPTER 2. THE SOLUBILITY OF SUCROSE IN IMPURE SOLUTIONS 86
1. Introduction 86
2. Solubility Determination 87
3. Three Component Sucrose Solutions 93
4. Multi-Component Sucrose Solutions 98
5. Sucrose Double Compound Formation 105
6. The Phase Rule and Phase Equilibrium Diagrams 107
7. Ternary Systems with Two Liquid Phase Solutes 127
Bibliography 129
CHAPTER 3. NUCLEATION IN SUPERSATURATED SUCROSE SOLUTIONS 132
1. Introduction 132
2. General. Nucleation and Growth 133
3. Nucleation Theory as Applied to Sugar Solutions 138
4. Experimental Methods and Results 151
CHAPTER 4. KINETICS OF CRYSTALLIZATION GROWTH OF CRYSTALS 168
1. Introduction 168
2. Methods 170
3. Rate of Growth in Pure Solutions 174
4. Impurities 193
5. Dissolution 201
Bibliography 203
CHAPTER 5. CHEMISTRY OF CRYSTALLIZATION 207
1. Introduction 207
2. Decomposition of Sucrose during the Crystallization Process 208
3. Decomposition of Reducing Sugars 213
4. Reactions of Organic Nonsugars 223
5. Phenomena Related with the Different Types of Inorganic Nonsugars 227
6. Nonsugars Affecting the Crystallization of Sugars 232
7. Phenomena Related with the Dissolution and Regrowth of Sucrose Crystals 237
8. Effect of Precipitated Nonsugars on the Purity of Centrifuged Sugar 241
Bibliography 242
CHAPTER 6. CONTROL METHODS AND EQUIPMENT IN SUGAR CRYSTALLIZATION 243
1. Introduction 243
2. Development of Control methods 243
3. Importance of Control Equipment 245
4. Basic Data and Definitions 246
5. Pan Control Equipment 253
6. Automatic Control Equipment 264
7. Summary 266
Bibliography 267
CHAPTER 7. APPLICATION OF THE CONDUCTIVITY METHOD TO CONTROL THE CRYSTALLIZATION PROCESS AND SEEDING TECHNIQUE 269
1. Introduction 269
2. The use of the Cuitometer as Operational Control Instrument 271
3. Graining of Low Grade Boilings in Raw Sugar Mills 296
Bibliography 322
CHAPTER 8. DETERMINATION OF HEAT TRANSMISSION AS AN INDIRECT METHOD FOR THE DETERMINATION OF THE VISCOSITY AND SUPERSATURATION OF TECHNICAL SUGAR SOLUTIONS 323
1. Introduction 323
2. Relation between Viscosity and Supersaturation 324
3 . The Measurement of Heat Transmission 326
4. Theory of the Electrical Instrument 329
5. Heat Transmission under Static Conditions 330
6. Heat Transmission under Dynamic Conditions 332
7. Relation between Viscosity and Velocity of Circulation 333
8. The Heat Transmission Recorder 335
Bibliography 336
CHAPTER 9. TECHNOLOGY OF SUGAR CRYSTALLIZATION 337
1. Introduction 337
2. The Technology of Crystallization of Granulated Sugars 342
3. The Aims of Sugar Crystallization 344
4. Desugaration of Boilings and Nonsugar Circulation 344
5. Development of the Technology of Sugar Crystallization 349
6. The Crystallization Installation Consists of a Number of Interrelated Equipment Units 356
7. Fundamentals in the Practice of Sugar Boiling 359
8. The Significance of Circulation on Supersaturation 364
9. Feeding of Pans 365
10. Crystallization of Final Product Boilings 367
11. Application of Conductivity Control for the Crystallization Process 371
12. The Conductivity of Technical Sugar Solutions at Saturation Point 372
13. Supersaturation in Technical Sugar Crystallization 376
14. Technical Control Instrument for Conductivity Control 380
15. The Evaporating Surface in Vacuum Pans 381
16. Technological Investigations on the Crystallization Process 384
BIBLIOGRAPHY 389
CHAPTER 10. EVAPORATION AND CIRCULATION IN THE CRYSTALLIZATION PROCESS 390
1. Introduction 390
2. Effective Driving Forces 391
3. Effective Resistances 393
4. The Effect of Temperature on Crystallization and Circulation 397
5. Measurements of Pan Circulation 399
6. Measurement of the Circulation Pattern 401
7. Circulation Patterns and their Interpretation 405
Bibliography 412
CHAPTER 11. NATURAL AND MECHANICAL CIRCULATION IN VACUUM PANS WITH PERFORMANCE DATA AND TESTS 413
1. Circulation in Vacuum Pans 413
2. The Rehabilitation of Mechanical Circulation 437
3. Equipment and Operating Conditions for Satisfactory Vacuum Pan Performance 448
4. Application of Mechanical Circulators in the Sugar Industry around the World 469
Bibliography 470
CHAPTER 12. CRYSTALLIZATION OF MASSECUITES BY COOLING 472
1. Introduction 472
2. Solubility of Sucrose in Pure and Impure Solutions 473
3. The Rate of Crystallization of Sucrose 479
4. History of the Crystallizer Station 484
5. Types of Crystallizers and cooling Systems 485
6. Construction Material and Shape of Cooling Elements 489
7. Heat Transfer Coefficients for Different Types of Massecuite 490
8. Speed of Rotation of Cooling Elements for Different Types of Massecuite 491
9. Crystallizer Drive and Power Consumption 492
10. Crystallizer Control and Control Instruments 493
11. Maintenance of Cooling Systems in Crystallizers 495
12. Time Needed for the Efficient Cooling of Different Types of Massecuite 496
13. Reduction in Total Massecuite Quantity by Rapid Cooling of First Boilings. Simplification of Boiling Scheme 497
14. Secondary Grain Formation in Crystallizers 501
15. Installation of Crystallizers. The Use of Massecuite Pumps 502
Bibliography 503
CHAPTER 13. CONDITIONING OF MASSECUITES IN CRYSTALLIZERS 504
1. Introduction 504
2. Supersaturation 505
3. Viscosity 509
4. Crystal Content and Size 517
5. Crystal Movement 519
6. Cooling 520
7. Reheating and Diluting 523
8. Conductivity Control 524
9. Molasses Exhaustibility 524
10..Summary and Conclusions 525
Bibliography 527
CHAPTER 14. MAXIMUM RECOVERY OF CRYSTALLIZED SUCROSE FROM LOW GRADE BOILINGS 529
1. Introduction 529
2. Phase Rule Considerations 532
3. Hydrated Sugar-Salt Compounds 542
4. Solubility of Sucrose in Solutions also Containing Nonsucrose Components 543
5. The Rate of Crystallisation of Sucrose from Impure Solutions 544
6. Some Practical Considerations 544
7. Exhaustibility of Final Molasses 547
Bibliography 573
AUTHOR INDEX 576
SUBJECT INDEX 581