The Stickiness
3.2 Outcomes from using the simulation
Figure 6 shows the typical drying prediction obtained form the parallel flow model. Chiou et al. [5][6] have found that this simulation predicted the correct trends in terms of lactose crystallinity when lactose was spray dried in a Buchi B-290 spray dryer. Islam and Langrish [2] and Islam et al. [4] have found that the simulation also predicts the correct trends when spray drying lactose, sucrose and ascorbic acid, since the order of their glass-transition temperatures (a key part of the Gordon-Taylor equation) is 101oC for lactose, around 60-65oC for sucrose and -50oC for ascorbic acid. However, the simulation clearly does not allow for recirculation of particles, so its quantitative accuracy is likely to be modest.
1. Williams, M.L.; Landel, R.F.; Ferry, J.D. The temperature dependence of relaxation mechanisms in amorphous polymers and other glass-forming liquids. Journal of the American Chemical Society 1955, 77(14), 3701-3707.
2. Islam, Md.I.; Langrish, T.A.G. Comparing the crystallization of sucrose and lactose in spray dryers. Transactions I.Chem.E., Foods and Bioproducts Engineering 2009, 87(2), 87-95.
3. Migliardo, F.; Branca, C.; Magazu, S.; Migliardo, P.; Coppolino, S.;
Villari, A.; Micali, N. Quasielastic and inelastic neutron scattering study of vitamin c aqueous solutions. Physica A: Statistical Mechanics and Its Applications 2002, 304(1-2), 294-298.
4. Islam, Md.I.; Sherrell, R.; Langrish, T.A.G. An investigation of the relationship between glass-transition temperatures and the crystallinity of spray-dried powders. paper accepted for publication in Drying Technology (accepted for publication 25 September 2009).
5. Chiou, D.; Langrish, T.A.G. A comparison of crystallisation approaches in spray drying. Journal of Food Engineering 2008, 88(2), 177-185.
6. Chiou, D.; Langrish, T.A.G.; Braham, R. Partial crystallisation
behaviour during spray drying: simulations and experiments. Drying Technology 2008, 26(1), 27-38.
7. Langrish, T.A.G. Assessing the rate of solid-phase crystallization for lactose: the effect of the difference between material and glass-transition temperatures. Food Research International 2008, 41(6), 630-636.
8. Trivedi, P.; Axe, L. Ni and Zn sorption to amorphous versus crystalline iron oxides: macroscopic studies. Journal of Colloid and Interface Science 2001, 244(2), 221-229.
9. Blagden, N.; De Matas, M.; Gavan, P.T.; York, P. Crystal engineering of active pharmaceutical ingredients to improve solubility and
dissolution rates”, Advanced Drug Delivery Reviews 2007, 59(7), 617-630.
4.0 References
3.2 Outcomes from using the simulation
10. Pokharkar, V.B.; Mandpe, L.P.; Padamwar, M.N.; Ambike, A.A.;
Mahadik, K.R.; Paradkar, A. Development, characterization and stabilization of amorphous form of a low Tg drug. Powder Technology 2006, 167(1), 20-25.
11. Choi, W.S.; Kim, H.I.; Kwak, S.S.; Chung, H.Y.; Chung, H.Y.;
Yamamoto, K.; Oguchi, T.; Tozuka, Y.; Yonemochi, E.; Terada, K.
Amorphous ultrafine particle preparation for improvement of bioavailability of insoluble drugs: grinding characteristics of fine grinding mills. International Journal of Mineral Processing 2004, 74(SUPPL), 165-172.
12. Hancock, B.C.; Parks, M. What is the true solubility for amorphous pharmaceuticals? Pharmaceutical Research 2000, 17(4), 397-404.
13. Briggner, L.; Buckton, G.; Bystrom, K.; Darcy, P. The use of isothermal microcalorimetry in the study of changes in crystallinity induced during the processing of powders. International Journal of Pharmaceuticals 1994, 105(2), 125-135.
14. Buckton, G.; Darcy, P. The influence of additives on the
recrystallisation of amorphous spray dried lactose. International Journal of Pharmaceuticals 1995, 121(1), 81-87.
15. Hancock, B.C.; Zografi, G. Characteristics and significance of the amorphous state in pharmaceutical systems. International Journal of Pharmaceuticals 1997, 86(1), 1-12.
16. Lehto, V.-P.; Tenho, M.; Vaha-Heikkila, K.; Harjunen, P.; Paallysaho, M.; Valisaari, J.; Niemela, P.; Jarvinen, K. The comparison of seven different methods to quantify the amorphous content of spray dried lactose. Powder Technology 2006, 167(2), 85-93.
17. Fitzpatrick, J.J.; Barry, K.; Cerqueira, P.S.M.; Iqbal, T.; O’Neill, J.;
Roos, Y.H. Effect of composition and storage conditions on the flowability of dairy powders. International Dairy Journal 2007, 17(4), 383-392.
18. Truong, V.; Bhandari, B.R.; Howes, T. Optimization of co-current spray drying process of sugar-rich foods. Part I - Moisture and glass
transition temperature profile during drying. Journal of Food Engineering 2005, 71(1), 55-65.
19. Keey, R.B.; Pham, Q.T. Behaviour of spray dryers with nozzle
atomizers. Chemical Engineer (London), July/August, 1976, 311, 516-521.
20. Keey, R.B.; Suzuki, M. On the characteristic drying curve. Int. J. Heat Mass Transfer 1974, 17(12), 1455-1464.
21. Langrish, T.A.G.; Zbicinski, I. The Effects of Air Inlet Geometry and Spray Cone Angle on the Wall Deposition Rate in Spray Dryers.
Transaction of IChemE 1994, 72(A), 420-430.
22. Langrish, T.A.G.; Kockel, T.K. The implementation of a characteristic drying curve for milk powder using a Computational Fluid Dynamics simulation”, Chem. Engng. J. 2001, 84(1), 69-74.
23. Liou, J.K.; Bruin, S. An approximate method for the nonlinear diffusion problem with a power relation between the diffusion coefficient and concentration. 1. Computation of desorption times. 2. Computation of the concentration profile. Int. J. Heat Mass Transfer 1982, 25(8), 1209-1229.
24. Kieviet, F.G.1997. Modelling Quality in Spray Drying”, Ph.D. Thesis, T.U. Eindhoven, The Netherlands, pp. 121-156.
25. Adhikari, B.; Howes, T.; Bhandari, B.R.; Truong, V. Surface stickiness of drops of carbohydrate and organic acid solutions during convective drying: experiments and modelling. Drying Technology 2003, 21(5), 839-873.
26. Chen, X.D. Heat-mass transfer and structure formation during drying of single food droplets. Drying Technology 2004, 22(1&2), 179-190.
27. Seydel, P.; Sengespeick, A.; Blömer, J.; Bertling, J. Experiment and mathematical modeling of solid formation at spray drying. Chem. Eng.
Technol. 2004, 27(5), 505-510.
28. Chen, X.D.; Lin, S.X.Q. Air drying of milk droplets under constant and time-dependent conditions. AIChE Journal 2005, 51(6), 1790–1799.
29. Patel, K.C.; Chen, X.D. Prediction of spray-dried product quality using two simple drying kinetic models. Journal of Food Process Engineering 2005, 28(6), 567-594.
30. Bhandari, B.R.; Datta, N.; Howes, T. Problems associated with spray drying of sugar-rich foods. Drying Technology 1997, 15(2), 671-684.
31. Price, R.; Young, P.M. Visualization of the crystallization of lactose from the amorphous state. Journal of Pharmaceutical Sciences 2003, 93(1), 155-164.
32. Chan, H.-K.; Chew, N.Y.K. Novel alternative methods for the delivery of drugs for the treatment of asthma. Advanced Drug Delivery Reviews 2003, 55(7), 793-805.
33. King, N. The physical structure of dried milk. Dairy Science Abstracts 1965, 27(3), 91-104.
34. Bushill, J.H.; Wright, W.B.; Fuller, C.H.F.; Bell, A.V. The crystallization of lactose with particular reference to its occurrence in milk powder.
Journal of the Science of Food and Agriculture 1965, 16(10), 622-628.
35. Chiou, D.; Langrish, T.A.G. Crystallisation of amorphous components in spray-dried powders. Drying Technology 2007, 25(9), 1423-1431.
36. Roos, Y.H.; Karel, M. Differential Scanning Calorimetry study of phase transitions affecting the quality of dehydrated materials. Biotechnology Progress 1990, 6(2), 159-163.
37. Gordon, M.; Taylor, J.S. Ideal copolymers and the second-order transitions of synthetic rubbers. I Non-crystalline copolymers. Journal of Applied Chemistry 1952, 2(9), 493-500.
38. Jouppila, K.; Roos, Y.H. Water sorption and time-dependent phenomena of milk powders. Journal of Dairy Science 1994, 77(7), 1798-1808.
Contents Page
1.0 Introduction 78
2.0 Modelling description 83
2.1 Particle size distribution 84
2.2 Spray transport equation 85
Conservation of mass and species 86
Conservation of momentum 86
Conservation of energy 88
2.3 Evaluation of film properties 89
2.4 Turbulence models 90
2.5 Primary atomization 92
2.6 Secondary atomization 93
2.7 Binary collision model 96
Coalescence-Separation Model by Ashgriz & Poo 97
Bouncing Model by Estrade et al. 100
Coalescence-Separation Model by O’Rourke 100 Satellite Model by Munnannur and Reitz 102 Post-Collision Properties for Liquid Binary Drops 103
2.8 Particle-wall impact 104
Bouncing 105
Sliding 106
Splashing 106
Surface roughness 107
3.0 Conclusion 107
4.0 Acknowledgement 107
5.0 References 107