Process-Spray (eBook)

Prof. Dr.-Ing. habil. Udo Fritsching is a Research Director at the Institute of Materials Science, University of Bremen, Germany.

Preface 6
Contents 8
Part I: Process-Spray Micro Scale: Elementary Processes at Phase Boundaries 11
Chapter 1: Investigation of Elementary Processes of Non-Newtonian Droplets Inside Spray Processes by Means of Direct Numerical... 12
1.1 Introduction 15
1.2 Mathematical Modeling 16
1.2.1 Governing Equations 16
1.2.2 Basics of VOF Method 18
1.3 Results and Discussion 19
1.3.1 Lamella Stabilization 19
1.3.1.1 Head-On Collisions 20
1.3.1.2 Off-Center Collisions 22
1.3.2 Collision of Shear-Thinning Droplets 25
1.3.2.1 Head-On Collisions 26
1.3.2.2 Off-Center Collisions 30
1.3.3 Collision of Non-isoviscous Droplets 34
1.3.3.1 Modeling of Non-isoviscous Flow 35
1.3.3.2 Coalescence Suppression Algorithm 36
1.3.3.3 Collision of Equal Sized Droplets 37
1.3.3.4 Collision of Unequal Sized Droplets 39
1.3.4 Collision of Viscoelastic Droplets 43
1.3.4.1 Numerical Methods for Viscoelastic Flows 45
1.3.4.2 Simulation of Head-On and Off-Center Collisions 46
1.3.5 Mechanistic Modeling of the Collision of Viscous Droplets 49
1.3.5.1 Model Extension 51
1.3.5.2 Validation 52
1.3.5.3 Hybrid Model 54
1.4 Summary and Outlook 57
References 58
Chapter 2: Interfacial Engineering for the Microencapsulation of Lipophilic Ingredients by Spray-Drying 61
2.1 Introduction 62
2.2 Materials and Methods 65
2.3 Results and Discussion 69
2.4 Process Windows for beta-Lactoglobulin-Stabilised Emulsions 69
2.5 Impact of Protein Hydrolysis on the Interfacial Properties of beta-Lactoglobulin 73
2.6 When Limiting the Degree of Hydrolysis Good Encapsulation Properties May Be Achieved. Peptides at the Interface Reduce Aut... 79
2.7 Controlled Fibril Formation for the Stabilisation of the Oil-Water Interface and Enhancement of the Functionality of Spray... 82
2.8 Bilayer Emulsions with Pectin as Poly-Anion Are Stable During Atomisation and Drying 84
2.8.1 Molecular Structure of Pectin 84
2.9 Conclusion 89
References 90
Chapter 3: Structure Formation within Spray-Dried Droplets Mathematical Modelling of Spray Polymerisation
3.1 Introduction 98
3.2 Modelling of Morphology Evolution Using Mesh-free Methods 100
3.3 The Smoothed Particle Hydrodynamics Method 101
3.4 Modelling Droplet Drying Using SPH 103
3.5 Modelling Morphology Evolution Within a Single Slurry Droplet by SPH 104
3.6 Representation of Primary Particles Within a Slurry 106
3.7 Surface Tension and Contact Angle 107
3.8 Simulation with a Constant Drying Rate (First Drying Period) 108
3.9 Model Extension to the Second Drying Period 112
3.10 Diffusion-Driven Drying of a Porous Structure and Coupling of SPH with a Grid-Based Method 117
3.11 A Mathematical Model of Spray Polymerisation and Reactive Spray Drying 119
3.12 Numerical Simulations of Spray Polymerisation 122
3.13 Conclusion and Outlook 129
References 130
Chapter 4: Acoustic Levitation: A Powerful Tool to Model Spray Processes 133
4.1 Introduction 135
4.2 Principles of the Acoustic Levitation 137
4.3 Material and Methods 138
4.3.1 Levitator Setup 138
4.3.2 Visualization Methods 140
4.3.3 Droplet Generation 140
4.3.4 Particle Removal 141
4.3.5 Raman Spectroscopy 142
4.3.6 Automatization 142
4.3.7 Substance Systems 143
4.4 Results and Discussion 144
4.4.1 Validation of the Simulated Fluid Dynamics Inside the Levitator 144
4.5 Reactive Systems 148
4.5.1 Polymerization of N-Vinyl-2-Pyrrolidone to Polyvinylpyrrolidone 148
4.5.1.1 Conversion Tracking by Raman Spectroscopy 148
4.5.1.2 Particle Morphology 153
4.5.2 Polymerization of Sodium Acrylate 155
4.5.3 Polymerization of Partially Neutralized Acrylic Acid 157
4.5.3.1 Process Properties 157
4.5.3.2 Particle Properties 161
4.6 Nonreactive System 164
4.6.1 Mannitol 164
4.6.1.1 Evaporation Process 164
4.6.1.2 Particle Morphology 167
4.7 Conclusions 171
4.8 Outlook 172
References 172
Chapter 5: Movement and Hydrodynamic Instabilities of Particle-Laden Liquid Jets in the Centrifugal Field Influenced by a Gas ... 176
5.1 Introduction 179
5.2 Physical-Mathematical Modeling 181
5.3 Time Steady Flow 183
5.4 Perturbation Analysis 189
5.5 Experiments 195
5.6 Experimental Results 198
5.7 Calculation Results and Comparison 201
5.8 Conclusion 206
5.9 Acknowledgment 207
References 207
Chapter 6: Experimental Investigation and Modeling of Coalescence and Agglomeration for Spray Drying of Solutions 210
6.1 Introduction 211
6.2 Material and Methods (Low Viscosity) 214
6.2.1 Experimental Setup 214
6.2.2 Liquid Properties 216
6.3 Results and Discussion (Low Viscosity) 217
6.3.1 Collision Maps of Low-Viscous Liquids 217
6.3.2 Satellite Droplet Formation with K30 Solutions 223
6.4 Material and Methods (High Viscosity) 226
6.4.1 Drop Generator for High-Viscous Liquids 226
6.4.2 Liquid Properties 227
6.5 Results and Discussion (High Viscosity) 228
6.5.1 Performance of the HiDrip Drop Generator 228
6.5.2 Collision Maps of High-Viscous Liquids 230
6.6 Methods and Materials (Different Viscosities) 232
6.7 Results and Discussion (Different Viscosities) 233
6.8 Conclusions 235
References 237
Chapter 7: Particle Formation from Gas-Enriched Polymeric Melts and Polymeric Solutions 239
7.1 Introduction 240
7.2 Material and Methods 241
7.2.1 Material 241
7.2.1.1 Carbon Dioxide 241
7.2.1.2 Water 241
7.2.1.3 Polyethyleneglycol (PEG 6000) 241
7.2.1.4 Polyvinylpyrrolidone (K30 and K90) 242
7.2.2 Methods 242
7.2.2.1 Spray Experiments 242
7.2.2.2 Lab Scale Plant 242
7.2.2.3 Pilot Scale Plant 243
7.2.2.4 Experiments in a High-Pressure View Cell 245
7.2.2.5 Thermography 246
7.3 Results and Discussion 246
7.3.1 Experiments Using a High-Pressure View Cell 246
7.3.1.1 Phase Behavior of Aqueous PVP K30 Solution and CO2 246
7.3.1.2 Phase Equilibrium 247
7.3.2 Spray Experiments (Saturated and Undersaturated Solutions) 247
7.3.2.1 Experiments with Flat Jet Nozzles 248
7.3.2.2 Experiments with Orifices and Capillaries 251
7.3.2.3 Experiments Using an Optically Transparent Capillary (Flow Observations) 255
7.3.3 Estimation of the Flow Regime of the Resulting Two Phase Flow in a Capillary 258
7.3.3.1 Deductions for the Continuously Working Process 260
7.3.4 Spray Experiments (with an Excess of CO2) 261
7.3.4.1 Experiments Using an Optically Transparent Capillary (Flow Observations) 261
7.3.4.2 Powder Generation of PEG 6000 262
7.3.4.3 Powder Generation of PVP (K30 and K90) 264
7.3.4.4 Thermography 264
7.4 Summary 267
References 268
Chapter 8: A Real-Time Process Analysis System for the Simultaneous Acquisition of Spray Characteristics 269
8.1 Introduction 269
8.2 Real-Time Process Analysis System 272
8.2.1 Goals 272
8.2.2 Architecture of the Real-Time Process Analysis System on the System Level 275
8.2.2.1 Choosing a Computing Platform for the Image-Processing Hardware 276
Evaluation Summary 279
8.3 Image-Processing Methods for Droplet and Particle Measurement 280
8.3.1 A Novel Connected Components Analysis Algorithm 281
8.3.1.1 Data Structures, Operations, and Parameters 281
8.3.1.2 Algorithmic Description 283
8.3.2 A Novel Connected Components Analysis Architecture 286
8.3.2.1 Global Merger Patterns 287
8.3.2.2 Coalescing Unit 289
8.3.2.3 Evaluation of the CCA Architecture 290
8.4 Filament Formation 291
8.5 Droplet Collisions 294
8.6 Shape of Non-spherical Particles 296
8.7 Analysis of Droplet Jets 298
8.8 Measuring the Interfacial Tension of a Pendant Droplet 300
8.9 Characterization of Dynamic Spray Processes 303
8.10 Conclusion 305
References 305
Part II: Process-Spray Meso Scale: Process Analysis, Modeling and Scaling 310
Chapter 9: Modeling and Simulation of Single Particle and Spray Drying of PVP- and Mannitol-Water in Hot Air 311
9.1 Introduction 312
9.2 Single Bi-component Droplet Drying 313
9.2.1 Mathematical Model 314
9.2.2 Results and Discussion 319
9.2.2.1 Particle Expansion 322
9.2.2.2 Design of Experiments 325
9.2.3 Conclusions 327
9.3 Spray Drying 327
9.3.1 Mathematical Model 328
9.3.2 Results and Discussion 332
9.3.3 Conclusions 338
9.4 Perspectives 338
References 339
Chapter 10: Droplet-Stream Freeze-Drying for the Production of Protein Formulations: From Simulation to Production 342
10.1 Introduction 345
10.2 Methods 346
10.2.1 Spray Solutions 346
10.2.2 Spray-Drying 346
10.2.3 Spray-Freeze-Drying 346
10.2.3.1 Droplet Generation 346
10.2.3.2 Stroboscopic and High-Speed Camera Recordings 347
10.2.3.3 Droplet Freezing 348
10.2.3.4 Droplet Drying 349
10.2.3.5 Acoustic Levitator 350
10.2.4 Particle Analysis 351
10.2.5 Numerical Simulations 351
10.2.5.1 Hybrid Simulations of Fluid Flow and Temperature Field 352
10.2.5.2 Thermal Lattice-Boltzmann Method 353
10.2.5.3 Lagrangian Model for Drying of Frozen Particles 356
10.3 Results and Achievements 359
10.3.1 Droplet Generation 359
10.3.2 Collisions and Coalescence in Fast Streams of Small Droplets 359
10.3.3 Droplet Freezing 362
10.3.3.1 Droplet Freezing in Stagnant Cold Air 362
10.3.3.2 Droplet Freezing in a Cold, N2 -GasVortex 362
10.3.3.3 Jet-Vortex-Freezer 364
10.3.4 Drying 364
10.3.5 Dosage Forms 365
10.3.6 Numerical Simulations 368
10.3.6.1 Isothermal Flow About Porous Particles 368
10.3.6.2 Test Cases for Thermal LBM 375
10.3.6.3 Validation of the Drying Model 379
References 380
Chapter 11: Correlations Between Suspension Formulation, Drying Parameters, Granule Structure, and Mechanical Properties of Sp... 383
11.1 Introduction 384
11.2 Material and Methods 386
11.3 Method Development for Internal Structure Preparation and Quantification 389
11.3.1 Model Granules for Characterization Tasks 389
11.3.2 Internal Structure Preparation and Visualization 390
11.3.3 Internal Structure Quantification on Micro- and Macrostructure Level 392
11.3.4 Evaluation of Binder Distribution 395
11.3.5 Alternative Structure Visualization Techniques: Opportunities and Threads 398
11.4 Variation of Internal Granule Structure Via Suspension Formulation and Process Parameters 400
11.4.1 Investigated Parameters: Experimental Design 400
11.4.2 Effect of Changed Suspension Formulation on Suspension Properties and Resulting Internal Granule Structures 402
11.4.2.1 Variation of Solid Content 402
11.4.2.2 Variation of Primary Particle Size 403
11.4.2.3 Variation of Suspension Temperature 408
11.4.2.4 Variation of Suspension pH Value 409
11.4.2.5 Variation of Additive Type 413
11.4.2.6 Variation of Additive Amount 419
11.4.2.7 Summary: Effect of Varied Suspension Formulation on Suspension Properties and Resulting Internal Granule Structures 420
11.4.3 Effect of Changed Process Parameters on Resulting Internal Granule Structures 423
11.4.3.1 Pretests Regarding Droplet Size Determination Using External Nozzle Test Stand 424
11.4.3.2 Effect of Nozzle Gas Mass Flow, Suspension Mass Flow, and Drying Temperature: Analysis Using Design of Experiments DoE 427
Suspension 1:3wt% Additive Component 428
Suspension 2: No Additive Component 431
11.4.3.3 Further Examples for Varied Process Parameters 433
Variation of Drying Kinetics 436
Variation of Atomizer Type 438
11.4.3.4 Summary 442
11.4.4 Single Droplet Drying Experiments Regarding Influencing Internal Structure Development Via Suspension Formulation and P... 442
11.5 Conclusion: Correlations Between Internal Structure Parameters and Mechanical Properties 444
References 447
Chapter 12: Statistical Extinction Method for the Inline Monitoring of Particle Processes 449
12.1 Introduction 450
12.2 Statistical Extinction Method 452
12.3 Advanced Statistical Extinction Method 455
12.4 Simulation Model for the Extinction of Light Beams 457
12.5 Particle Arrangement in a Light Beam 459
12.6 Influence of the Distribution of the Light Intensity 461
12.7 Influence of the Aperture of the Detector Optic 463
12.8 Influence of the Polydispersity of a Particle Collective 464
12.9 Optical Principles of the SE-Sensor 467
12.10 Optical Principle of the PSD-SE-Sensor 471
12.11 One-Piece vs. Two-Piece Sensor Concept for Process Plants 472
12.12 Sensor Designs of the SE-Sensor for the Investigation of Different Particle Processes 475
12.13 Sensor Design of the PSD-SE-Sensor for the Investigation of Particle Processes 475
12.14 Measurement Range and Measurement Uncertainty of the SE-Method 477
12.15 Validation of the SE-Method with Monodisperse Particles 479
12.16 Investigation of Polydisperse Spray Processes with the SE-Method 482
12.17 Investigation of Spray Processes with the PSD-SE-Sensor 485
12.18 Summary and Conclusions 488
References 490
Chapter 13: Numerical Simulation of Monodispersed Droplet Generation in Nozzles 492
13.1 Introduction 493
13.2 Mathematical Model 495
13.2.1 Level Set Method 496
13.2.2 Treatment of Surface Tension Effects 498
13.2.3 New Generation Mesh Deformation Technique 499
13.2.4 Discrete Projection Method (DPM) 501
13.3 Numerical Results 504
13.3.1 Rising Bubble 504
13.3.2 Simulation of Laminar Jet Breakup: Dripping 505
13.3.3 Simulation of Laminar Jet Breakup: Jetting 508
13.3.4 Simulation of Laminar Jets: Coiling 509
13.3.5 Oscillating Non-Newtonian Droplet Simulations 510
13.3.6 Simulation of Encapsulation Processes 512
References 514
Chapter 14: Spray Drying Tailored Mannitol Carrier Particles for Dry Powder Inhalation with Differently Shaped Active Pharmace... 516
14.1 Introduction 517
14.2 Material and Methods 519
14.2.1 Materials 519
14.2.2 Spray Drying of Mannitol 520
14.2.2.1 Droplet Size Experiments 520
14.2.2.2 Pilot Scale Spray Dryer 521
Early Experimental Setup 521
Improved Experimental Setup 521
14.2.2.3 Hot Stage Microscopy 522
14.2.2.4 Droplet Size Analysis 522
14.2.2.5 Design of Experiments 522
14.2.2.6 Particle Size 523
14.2.2.7 Particle Visualisation 523
14.2.2.8 Particle Morphology 524
Survey for Particle Shape and Surface Roughness 524
Particle Cross Sections 524
Surface Roughness by SEM Evaluation 525
Particle Shape by Image Analysis 525
14.2.2.9 Flowability 525
14.2.2.10 Brunauer-Emmett-Teller (BET) Surface Area 526
14.2.2.11 Breaking Strength 526
14.2.2.12 Mercury Intrusion Porosity (MIP) 526
14.2.2.13 X-Ray Powder Diffraction 527
14.2.3 Simulation of the Drying of Bi-component Droplets 527
14.2.4 Drug Preparation 527
14.2.4.1 Jet Mill Micronisation of Model Drugs 528
14.2.4.2 Spray Drying of Model Drugs 528
14.2.4.3 Particle Size 528
14.2.4.4 X-Ray Powder Diffraction 528
14.2.4.5 Visualisation 529
14.2.5 Preparation of Interactive Powder Blends 529
14.2.5.1 Blending of Mannitol and Drug 529
14.2.5.2 Drug Localisation by Confocal Raman Analysis 529
14.2.5.3 Blend Homogeneity 530
14.2.5.4 Drug Quantification 530
14.2.6 Aerodynamic Characterisation 531
14.2.6.1 Assessment of Fine Particles 531
14.2.6.2 Drug Quantification 532
14.3 Results and Discussion 532
14.3.1 Impact of Droplet Size on the Drying of Mannitol 532
14.3.2 Hot Stage Microscopy to Elucidate the Drying of Mannitol 533
14.3.3 Spray Drying of Mannitol: Pilot Scale 535
14.3.3.1 Design of Experiments: Power of the Model 536
14.3.3.2 Particle Size 536
14.3.3.3 Particle Morphology 539
Particle Shape 539
Surface Roughness 542
14.3.3.4 Flowability 544
14.3.3.5 BET Surface Area 545
14.3.3.6 Breaking Strength 545
14.3.3.7 Mercury Intrusion Porosimetry (MIP) 546
14.3.3.8 Crystallinity 547
14.3.4 Simulation of the Drying of Bi-component Droplets 547
14.3.5 Drug Quality and Carrier Selection 548
14.3.6 Aerodynamic Characterisation 551
14.3.6.1 Micronised SBS Quality 552
14.3.6.2 Spray Dried SBS Quality 553
Correlation of Particle Shape and FPF 553
Correlation of Surface Roughness and FPF 556
Correlation of Particle Size and FPF 558
Correlation of Flowability and FPF 559
14.3.6.3 Correlation of Spray Drying Parameters and DPI Performance 560
14.3.6.4 Transferability to Other Drugs: Blends with Budesonide 560
14.4 Conclusions 561
References 562
Chapter 15: Pulverisation of Emulsions with Supercritical CO2 566
15.1 Introduction 567
15.2 Materials 567
15.3 Thermodynamic Properties of the Investigated Liquids 568
15.3.1 Experimental Procedures 568
15.3.1.1 Solubility Measurements 568
15.3.1.2 Viscosity and Density Measurements 569
15.3.1.3 Interfacial Tension Measurements 571
15.3.2 Results 573
15.3.2.1 Solubility 573
15.3.2.2 Viscosity 578
15.3.2.3 Density 581
15.3.2.4 Interfacial Tension 584
15.3.3 Spray Behaviour and Powder Production 588
15.3.3.1 Experimental Procedure 588
15.3.4 Results 591
15.3.4.1 Disintegration of Pure and Gas-Saturated Liquid Sheets 591
15.3.4.2 Powder Characteristics 598
15.4 Conclusions 603
References 605
Chapter 16: Superheated Atomization 608
16.1 Introduction 610
16.2 Material and Methods 611
16.2.1 Test Facility and Nozzles 611
16.2.2 Measurement Devices 614
16.2.3 Sprayed Fluids 615
16.3 Results 619
16.3.1 Characteristics Inside the Nozzle 619
16.3.2 Spray Characteristics 625
16.4 Discussion 635
16.5 Conclusion 642
References 643
Chapter 17: Direct Numerical Simulations of Shear-Thinning Liquid Jets and Droplets 645
17.1 Introduction 646
17.2 Numerical Method 648
17.3 Viscosity Model and Material Properties 649
17.4 Investigation of a PVP Solution Liquid Jet 651
17.5 Investigation of Praestol Jets 656
17.6 Investigation of Droplet Oscillations 664
17.7 Conclusion 673
References 675
Chapter 18: IntegralProcess Modelling and Simulation for Solid-Particle-Forming Spray Processes 677
18.1 Introduction 679
18.2 Jet/Sheet Fragmentation Model 681
18.2.1 Volume of Fluid Method 681
18.2.2 Numerical Simulation of Liquid Sheet Fragmentation Process 682
18.2.2.1 Case Setup 682
18.2.2.2 Liquid Sheet Disintegration 686
18.2.2.3 Liquid Sheet Breakup Length 687
18.2.2.4 Primary Droplet Size and Velocity 688
18.3 Droplet Breakup Model 690
18.3.1 Empirical Models 692
18.3.2 Droplet-Deformation-Based Models 693
18.3.2.1 TAB Model 693
18.3.2.2 ETAB Model 694
18.3.3 Validation: Melt Atomization Process 695
18.3.3.1 Case Setup 696
18.3.3.2 Gas Flow Dynamics 700
18.3.3.3 Pressure-Swirl Atomization Process 701
18.3.3.4 Free-Fall Atomization Process 705
18.4 Heat Transfer and Solidification Model 706
18.5 Particle-Droplet Collision Model 709
18.5.1 Collision Number 709
18.5.2 Collision Efficiency 710
18.5.2.1 Case Setup 711
18.5.2.2 Gas Flow Dynamics 712
18.5.2.3 Collision Efficiency 712
18.6 Particle Penetration Model 715
18.6.1 Force Balance Approach 716
18.6.2 CFD Model Description 717
18.6.2.1 Volume of Fluid Method 717
18.6.2.2 Six-DoF Method 717
18.6.2.3 Dynamic Mesh Technique 718
18.6.3 Penetration Model Validation 719
18.6.4 CFD Penetration Model Results and Discussion 723
18.6.4.1 Case Setup 723
18.6.4.2 Collision Outcomes 724
18.6.4.3 Re-We Regime Maps for Particle Penetration 726
18.7 Multiscale Modelling Spray Processing of Composite Particles 730
18.7.1 Particle-Droplet Mixing Behaviour (Macro-scale) 732
18.7.2 Particle-Droplet Collision Behaviour (Mesoscale) 733
18.7.3 Particle Penetration Behaviour (Micro-scale) 737
18.7.3.1 Apparent Viscosity 737
18.7.3.2 Critical Penetration Velocity 738
18.7.3.3 Incorporation Efficiency and Sticking Efficiency 741
18.8 Summary and Conclusions 743
References 743
Part III: Process-Spray Macro Scale: Process Function, Particle and Powder Properties 747
Chapter 19: Hot Gas Atomization of Complex Liquids for Powder Production 748
19.1 Introduction 749
19.2 Material and Methods 752
19.3 Hot Gas Atomization Setup: Hot Gas Nozzle Characteristics and Implementation of Hot Gas Nozzle into the Spray Tower 754
19.4 Basic Flow and Temperature Field in the Spray Tower 758
19.5 Atomization Characteristics and Spray Propagation 765
19.6 Drying of PVP Solutions in Hot Gas Atomization Process 768
19.7 Impact on Droplet Clustering on Heat Transfer Within the Spray 770
19.7.1 Numerical Setup for Prediction of Spray Propagation with Large-Eddy Simulation 770
19.8 Results: Particle Clustering 773
19.9 Impact of Spray Chamber Design and Atomizer Gas Pressure on Cluster Sizes 779
19.10 Correlation of the Droplet-Gas Interaction 783
19.11 Summary and Conclusions 787
References 788
Chapter 20: Polymerization in Sprays: Atomization and Product Design of Reactive Polymer Solutions 792
20.1 Introduction 794
20.2 Material and Methods: Atomization of Polymer Solutions 798
20.3 Results of the Atomization of Polymer Solutions 803
20.4 Material and Methods: Rheokinetics 813
20.5 Results of the Rheokinetics 820
20.6 Pre-reaction Within the Nozzle 827
20.7 Conclusion 834
References 835
Chapter 21: Investigation on the Usage of Effervescent Atomization for Spraying and Spray Drying of Rheological Complex Food L... 839
21.1 Introduction 841
21.2 Material and Methods 841
21.2.1 Model Systems 841
21.2.2 Polyvinylpyrrolidone 841
21.2.3 Maltodextrin 845
21.2.4 Emulsions 847
21.2.5 Effervescent Atomizer 852
21.2.6 Conventional Atomizers 853
21.2.7 Two-Phase Flow Inside an Effervescent Atomizer 854
21.2.8 Test Rig 855
21.2.9 Modeling of Spray Drop Sizes 857
21.2.10 Abel Inversion 859
21.2.11 Spray Dryer 860
21.3 Results, Achievements, and Discussion/Conclusions 861
21.3.1 Flow Pattern Inside the Atomizer 861
21.3.2 Flow Pattern Inside the Nozzle Orifice 866
21.3.3 Spray Characteristics 866
21.3.3.1 Spray Structure 866
21.3.3.2 Spray Drop Sizes of Single-Phase Feeds 870
21.3.3.3 Spray Drop Sizes of Multiphase Feeds 880
21.3.3.4 Pulsation of Spray 883
21.3.3.5 Predicted Spray Drop Size 883
21.3.3.6 Local Spray Drop Sizes 885
21.3.4 Oil Drop Size 886
21.3.5 Spray Drying of PVP K30 Solutions 891
21.4 Conclusion 895
References 895
Chapter 22: Experimental Evaluation and Control of Interaction of Gas Environment and Rotary Atomized Spray for Production of ... 899
22.1 Introduction 901
22.1.1 Spraying of Liquid 902
22.1.2 Laminar Operating Rotary Atomizer 902
22.1.3 Similarity Trials 904
22.1.4 Objective 906
22.2 Breakup of Stretched Liquid Threads Influenced by Cross-Wind Flow: Similarity Trials 906
22.2.1 Theory 906
22.2.2 Material and Method 908
22.2.3 Experimental Results: Breakup Length 909
22.2.4 Experimental Results: Mean Drop Size 912
22.2.5 Experimental Results: Drop Size Distribution 916
22.3 Design of Gas-Distribution System 918
22.3.1 Flow Simulation Theory 919
22.3.2 Gas-Distribution Concept 919
22.3.3 Realization of the Gas Distributor´s Concept 920
22.4 Optimization of the LamRot Spraying Device 924
22.4.1 Direction of Thread Propagation 925
22.4.2 Avoiding Sedimentation 927
22.4.3 Assistance of Swirl Flow by the LamRot Design 927
22.5 Proving of the Gas-Distribution Concept 928
22.5.1 Spray Drying of PVP Solution 929
22.5.2 Spray Drying of Mannitol 931
22.6 Conclusion 933
References 934
Chapter 23: Processing of Functional Capsule Powder Particles Based on Multiple Emulsions Using a Prilling Process 937
23.1 Introduction 939
23.2 Materials and Methods 943
23.2.1 Materials 943
23.2.1.1 Watery Phases 943
23.2.1.2 Oil Phases 943
23.2.1.3 Surfactants 943
23.2.1.4 Thickener 944
23.2.1.5 Model Emulsion Systems and Their Compositions 944
23.2.1.6 Materials for Iron Release Experiment 944
23.2.2 Analytical Methods and Procedures and Selected Analytical Results 944
23.2.2.1 Shear Viscosity of Emulsions 946
23.2.2.2 Viscoelasticity of Emulsions 948
23.2.2.3 Extensional Viscosity of Emulsions 949
23.2.2.4 Surface Tension sigma 950
23.2.2.5 Interfacial Tension gamma (O/W and W/O/W Emulsions) 951
23.2.3 Processing Procedures and Conditions 953
23.2.3.1 Emulsion Preparation 953
SE Preparation Using Rotor-Stator System 953
DE Preparation Using Rotating Membrane 953
23.2.3.2 Spray Processing Experiments Using Air-Assisted Atomizer 954
Experimental Setup 954
Spray Processing of DE with Functional Tracer 955
Emulsion Prilling Experiments 956
23.2.3.3 Spraying of Emulsions Applying a Novel ROtary Pressure ATomizer (ROPAT) 956
23.2.3.4 Iron Release Experiment Setup and Procedure 957
23.3 Results, Achievements, and Discussion/Conclusions 958
23.3.1 Spray Processing: Structural Preservation Criterion (Process-Structure Relation) 958
23.3.1.1 Influence of Spray Process Parameters on Secondary Droplets (3AT Nozzles) 959
Impact of Gas/Liquid Ratio on SE Structure 960
Impact of GLR on DE Structure 961
Impact of Pure Liquid-Cap Nozzle Flow on Secondary Droplet Size of SE, DE 963
Two-Phase Flow Impact on Secondary Droplet Size of SE, DE in 3AT Nozzles 968
Impact of Spray Processing on Tertiary Emulsion Droplet/Spray Particle Size 971
Spraying of DE (W1/O/W2) and Release of Tracer into Continuous Phase 974
23.3.1.2 Rotary Pressure Atomization a Mechanically Gentle Alternative (ROPAT Nozzle) 976
23.4 Conclusions/Summary 977
Bibliography 979
Chapter 24: Analysis of Mechanisms for PVP-Active-Agent Formulation as in Supercritical Antisolvent Spray Process 982
24.1 Introduction 983
24.2 Materials and Methods 984
24.2.1 Material 984
24.2.2 Antisolvent 985
24.2.3 Solvents 985
24.2.4 Solutes 986
24.2.5 SAS Plant 987
24.2.6 Saturation Measurements 989
24.2.7 Elastic Light Scattering Setup 990
24.2.8 Combined Elastic and Inelastic Scattering Light Setup 993
24.2.9 Particle Analysis 995
24.2.10 Dissolution Measurements 997
24.3 Results and Discussion 998
24.3.1 Solute Solubility Measurements of Certain Solutes 999
24.3.2 Mixing Behavior of Certain Solvents 1001
24.3.3 Generation of Amorphous PVP Particles 1006
24.3.4 Influence of Pressure and Concentration 1007
24.3.5 Influence of the Solvent Composition 1008
24.4 Generation of Paracetamol Crystals from EtOH, AC, and EtOH/AC Mixture Solutions 1011
24.4.1 Ethanol Solutions 1011
24.4.2 Acetone Solutions 1013
24.4.3 Mixtures of Ethanol and Acetone 1016
24.4.4 Generation of Solid Dispersions 1019
24.4.5 PCM: PVP 1019
24.4.6 PVP and Paracetamol (EtOH/AC=70/30 as Solvent) 1020
24.4.7 Combined Elastic and Inelastic Scattered Light Measurements 1023
24.5 Conclusion 1025
References 1027