
Yang Fluidization, Solids Handling, and Processing
.pdf426 Fluidization, Solids Handling, and Processing
Qk |
Rate of feed or product withdrawal |
# particles/s |
|
rp |
Characteristic length of process zone |
|
m |
R |
Radius of capillary |
|
m |
S |
Saturation or spray rate |
|
- |
St, St* |
Stokes number and critical Stokes number, Eq. (20) |
|
- |
Sf |
Shape Factor in Eqs. (29) and (31) |
|
- |
t |
Time |
|
s |
Tbulk |
Bulk gas temperature |
|
°C |
Ts |
Surface temperature of liquid droplet or minimum |
|
°C |
|
sintering temperature of a solid |
|
|
TM |
Melting point of a solid |
|
°C |
T |
= (Tbulk - Ts) |
|
°C |
tv |
Time for complete evaporation of a liquid droplet |
|
s |
tcirc |
Time elapsed between successive passages of a |
|
s |
|
particle through the spray zone |
|
|
u |
Particle size measure (volume) for coalescing particles |
m3 |
|
U |
Superficial gas velocity |
|
m/s |
UB |
Rise velocity of a bubble |
|
m/s |
Ui |
Impact velocity |
|
m/s |
Umf |
Minimum fluidizing velocity |
|
m/s |
Uo |
Relative velocity of two approaching particles |
|
m/s |
v |
Particle size measure (volume) for coalescing particles |
m3 |
|
V |
Volumetric wear or breakage rate or volumetric flow |
|
|
|
of feed |
|
m3/s |
Var |
Variance |
|
|
w* |
Critical average granule size capable of rebound |
|
|
|
from a collision |
|
|
Xtotal |
Total mass of coating received by a particle in a |
|
kg |
|
batch coating operation |
|
|
xc |
Critical specimen size, Eq. (35) |
|
|
xk |
Amount of mass received by a particle in its kth |
|
kg |
|
passage through the spray zone |
|
|
Coating and Granulation |
427 |
|
y |
Liquid loading |
|
|
ybulk |
Mass fraction of solvent in the bulk |
- |
|
yd |
Mass fraction of solvent in the liquid droplet |
- |
|
ys |
Mass fraction of solvent in gas at the liquid surface |
- |
|
Y |
Yield number, Eq. (28) |
- |
|
Greek Letters |
|
|
|
α |
Thermal diffusivity |
m2/s |
|
β |
Constant in Eq. (34) |
- |
|
β() |
Coalescence kernel, Eq. (40) |
- |
|
Γ |
Shear rate |
s-1 |
|
γ |
Surface tension or interfacial energy |
N/m |
|
δ |
Dimensionless bubble spacing |
- |
|
δc |
Effective increase in crack length |
m |
|
εDimensionless separation of two particles = 2h/a
or powder void fraction, Eq. (26)
θContact angle between liquid and powder compact
λ |
Latent heat of vaporization |
J/kg |
μ |
Viscosity |
kg/m·s |
ρ |
Density |
kg/m3 |
σy |
True yield stress of material |
Pa |
σf |
Applied fracture stress |
Pa |
τ |
Coating run time |
s |
τ |
Yield strength of wet granule |
N/m2 |
o |
|
|
φFilling angle defined in Fig. 22
ϕProbability distribution function
Subscripts
ave |
Average value |
breakage |
Breakage |
c |
Crystal |
Coating and Granulation 429
REFERENCES
Adetayo, A. A., and Ennis, B. J., A Unifying Approach to Modeling Coalescence Mechanisms, in Review, AIChEJ (1996)
Adetayo, A. A., Litster, J. D., Pratsinis, S. E., and Ennis, B. J., “Population Balance Modelling of Drum Granulation of Materials with Wide Size Distributions,” Powder Tech, 82:37–49 (1995)
Aulton, M. E., and Banks, M., Proceedings of Powder Technology in Pharmacy Conference, Powder Advisory Centre, Basel, Switzerland (1979)
Capes, C. E., “A Note on Size Distributions in Granulation, Balling and Wet Pelletization,” Chem. Engineer, 45:CE78-80 (1967)
Cheng, X. X., “Studies of Uniformity of Particle Coating in Fluidized Beds,” Ph.D. Dissertation, West Virginia University, Morgantown, WV (1993)
Cheng, X. X., and Turton, R., “The Uniformity of Particle Coating Occurring in Fluidized Beds,” AIChE Symp. Ser., 301(90):142–151 (1994)
Choi, M., and Meisen, A., “Sulfur Coating of Urea in Shallow Spouted Beds,” paper presented at AIChE meeting, Miami, Fl (Nov, 1995)
Compo, P., Tardos, G. I., Mazzone, D., and Pfeffer, R., “Sintering Temperatures of Fluidizable Particles,” Particle Characterization - An International Journal, 1:171 (1984)
Compo, P., Pfeffer, R., and Tardos, G. I., “Minimum Sintering Temperatures and Defluidization Characteristics of Agglomerating Particles,” Powder Technology, 51(1):87–103 (1987)
Compo, P., Tardos, G., and Pfeffer, R., “Thermally Induced Agglomeration and Defluidization Characteristics of Fluidizable Particles,” Proceedings of the Second World Congress in Particle Technology, Kyoto, Japan (1990)
Ennis, B. J., “On the Mechanisms of Granulation,” Ph.D. Dissertation, The City University of New York (1990)
Ennis, B. J., Tardos, G. I., and Pfeffer, R. “A Microlevel-Based Classification of Granulation Regimes and Mechanisms,” Proceedings of the Second World Congress on Powder Technology, p. 409, Kyoto, Japan (1990a)
Ennis, B. J., Li, J., Tardos, G. I., and Pfeffer, R., ”The Influence of Viscosity on the Strength of an Axially Strained Pendular Liquid Bridge,” Chem. Eng. Sci., 45:3071–3088 (1990b)
Ennis, B. J., Tardos, G. I., and Pfeffer, R., “A Microlevel-Based Characterization of Granulation Phenomena,” Powder Technology, 65:257–272, (1991)
Ennis, B. J., and Sunshine, G., “On Wear as a Mechanism of Granule Attrition,” Tribology Int., 26:319–327 (1993)
430 Fluidization, Solids Handling, and Processing
Ennis, B. J., and Adetayo, A. A., “On the Unification of Granule Coalescence Mechanisms: A New Approach,” 1st Int. Part. Tech. Forum, pp. 271–277, Denver, USA (1994)
Evans, A. G., and Wilshaw, T. R., “Quasi-Static Solid Particle Damage in Brittle Solids - 1. Observations, Analysis and Implications,” Acta Metallurgica, 24:939–956 (1976)
Friedlander, S. K., and Wang, C. S., “The Self Preserving Particle Size Distribution for Coagulation by Brownian Motion,” J. Colloid Interface Sci., 22:126– 132 (1966)
Geldart, D., “Types of Gas Fluidization,” Powd. Technol., 7:285–292 (1973)
Gilligan, C. A., and Po, A .L. W., “Factors affecting Drug Release from a Pellet System Coated with an Aqueous Colloidal Dispersion,” Int. J. Pharmaceutics, 73:51–68 (1991)
Gluba, T., Heim, A., and Kochanski, B., “Application of the Theory of Moments in the Estimation of Powder Granulation of Different Wettabilities,”
Powder Hand. and Proc., 2:323–326 (1990)
Griffith, A. A., “The Phenomena of Rupture and Flow in Solids,” Phil. Trans. Royal. Soc., A221:163–198 (1920)
Hall, H. S., Coating of Granular Bioproducts, Granulation Technology for Bioproducts, (K. L. Kadam, ed.), Ch. 10, CRC Press, Boca Raton, Fl (1991)
Irwin, G. R., “Analysis of Stresses and Strains Near End Crack Traversing Plate,”
J. Applied Mechanics, 24:361–364 (1957)
Iveson, S., Litster, J. D., and Ennis, B. J., “Fundamental Studies of Granule Consolidation,” 21st Australasian Chem. Engng. Conf., CHEMECA (1994)
Jones, D. M., “Factors to Consider in Fluid-Bed Processing,” Pharm. Tech., 9:50–62 (1985)
Jozwiakowski, M. J., Jones, D. M., and Franz, R. M., “Characterization of a HotMelt Fluid Bed Coating Process for Fine Granules,” Pharm. Res., 7:1119– 1126 (1990)
Kanury, A. M., Introduction to Combustion Phenomena, Gordon and Breach Science Publishers, New York (1975)
Kapur, P. C., “Kinetics of Granulation by Non-Random Coalescence Mechanism,” Chem. Eng. Sci., 27:1863–1869 (1972)
Kapur, P. C., and Fuerstenau, D. W., “Kinetics of Green Pelletization,” Trans. AIME, 229:348–355 (1964)
Kristensen, H. G., Holm, P., and Schaefer, T., “Mechanical Properties of Moist Agglomerates in Relation to Granulation Mechanisms. Part I: Deformability of Moist Densified Agglomerates,” Powder Technology, 44:227–237 (1985)
Coating and Granulation 431
Kristensen, H. G., Holm, P., and Schaefer, T., “Mechanical Properties of Moist Agglomerates in Relation to Granulation Mechanisms. Part II: Effect of Particle Size Distribution,” Powder Technology, 44:239–247 (1985)
Kristensen, H. G., “Agglomeration of Powders,” Acta Pharm. Soc., 25:187–204 (1988)
Kucharski, J., and Kmiec, A., “Hydrodynamics, Heat and Mass Transfer During Coating of Tablets in a Spouted Bed,” Can. J. Chem. Eng., 61:435–439 (1983)
Landgrebe, J. D., and Pratsinis, S. E., “Gas Phase Manufacture of Particulates: Interplay of Chemical Reaction and Aerosol Coagulation in the FreeMolecular Regime,” Ind. Eng. Chem. Res., 28:1474–1481 (1989)
Ladesma, R., Compo, P., and Isaacs, L. L., “Thermal Characterization of Coal Ash Powders,” Mat. Res. Society Symp. Proc., 86:127 (1987)
Landrock, A. H., Encyclopedia of Polymer Science and Technology, 3:808–830, Wiley, New York (1965)
Landrock, A. H., “Fluidized Bed Coating with Plastics,” Chem. Eng. Progr., 63:67–74 (1967)
Lefebvre, A. H., Atomization and Sprays, Hemisphere Publishing Corp., New York (1989)
Lauenberger, H., Bier, H. P., and Sucker, H., Pharm. Ind., 41:375 (1979)
Litster, J. D., and Ennis, B. J., Granulation, Pelletisation, and Particle Coating, short course given at IChemE - Australia, Gold Beach, Australia (1994)
Litster, J. D., Smit, D. J., and Hounslow, M. J., “Adjustable Discretized Population Balance for Growth and Aggregation,” AIChE J., 41:591–603 (1995)
Liu, L. X., and Litster, J. D., “The Effect of Particle Shape on the Spouting Properties of Non-Spherical Particles,” Powd. Technol., 66:59–67 (1991)
Liu, L. X., and Litster, J. D., “Coating Mass Distribution from a Spouted Bed Seed Coater: Experimental and Modelling Studies,” Powder Technol., 74:259–270 (1993a)
Liu, L. X., and Litster, J. D., “Spouted Bed Seed Coating: the Effect of Process Variables on Maximum Coating Rate and Elutriation,” Powder Technol., 74:215–230 (1993b)
Mann, U., Coating of Particulate Solids by Air Suspension, Ph.D. Thesis, University of Wisconsin (1972)
Mann, U., Crosby, E. J., and Rubinovitch, M., “Number of Cycles Distribution in Circulating Systems,” Chem. Eng. Sci., 29, 761–765 (1974)
Mann, U., Rubinovitch and Crosby, E. J., “Characterization and Analysis of Continuous Recycle Systems: Part II. Cascade,” AIChE J., 27:829–836 (1981)
432 Fluidization, Solids Handling, and Processing
Mann, U., “Analysis of Spouted-Bed Coating and Granulation. 1. Batch Operation,” I.&E.C. Proc. Des. Dev., 22:288–292 (1983)
Marshall, W. R., “Atomization and Spray Drying,” Chem. Eng. Prog. Monograph Series, 50:2 (1954)
Masters, K., “Industrial Fluid Bed Drying: Trends and Developments,” Fluidization VII, (O. E. Potter, and D. J. Nicklin, eds.); Proceedings of the Engineering Foundation Conference, pp. 59–72, Brisbane, Australia (1992)
Mathur, K. B., and Epstein, N., Spouted Beds, Academic Press, New York (1974)
McGinity, J. W., Aqueous Polymeric Coatings for Pharmaceutical Dosage Forms, Marcel Dekker (1989)
Mehta, A. M., and Jones, D. M., “Coated Pellets under the Microscope,” Pharm. Tech., 9(6):52–60 (1985)
Mehta, A. M., “Scale-Up Considerations in the Fluid-Bed Process for Controlled Release Products,” Pharm. Tech., 12:46–52 (1988)
Olsen, K. W., “Batch Fluid-Bed Processing Equipment - A Design Overview: Part I,” Pharm. Tech., 13(1):34–46 (1989a)
Olsen, K. W., “Batch Fluid-Bed Processing Equipment - A Design Overview: Part II,” Pharm. Tech., 13(6):39–50 (1989b)
Nicolaescu, I. V., Tardos, G. I., and Riman, R. E., “Thermogravimetric Determination of Carbon, Nitrogen and Oxygen in Aluminum Nitride,” J. Am. Ceramic Soc., 77(9):2265–72, (1994)
Nienow, A. W., “Fluidized Bed Granulation,” Enlargement and Composition of Particulate Solids, (N. G. Stanley-Wood, ed.), Butterworth and Co., London (1983)
Nienow, A. "W. and Rowe, P. M., Particle Growth and Coating in Gas-Fluidized Beds, in Fluidization, (J. F. Davidson, R. Clift, and D. Harrison, eds.), 2nd ed., Academic Press, London (1985)
Nienow, A. W., “Fluidized Bed Granulation and Coating: Application to Materials, Agriculture and Biotechnology,” Proceedings of the First International Particle Technology, Forum, Denver, CO., USA (1994).
Ramkrishna, D., “The Status of Population Balances,” Review in Chem. Eng., 3(1):49–95 (1985)
Randolph, A. D. and Larson, M. A., Theory of Particulate Processes, 2nd Ed., Academic Press, New York (1988)
Ranney, M. W., Powder Coatings and Fluidized Bed Techniques, Noyes Data Corp., Park Ridge, NJ (1971)
Rekhi, G. S., Mendes, R. W., Porter, S. C., and Jambhekar, S. S., “Aqueous Polymeric Dispersions for Controlled Drug Delivery - Wurster Process,” Pharm. Technol., 13(3):112–125 (1989)
Coating and Granulation 433
Ritala, M., Jungersen, O., Holm, P., Schaefer, T., and Kristensen, H. G., “A Comparison Between Binders in the Wet Phase of Granulation in a High Shear Mixer,” Drug Development and Industrial Pharmacy, 12:(11–13), 1685–1700, Marcel Dekker, Inc. (1986)
Ritala, M., Holm, P., Schaefer, T., and Kristensen, H. G., “Influence of Liquid Bonding Strength on Power Consumption during Granulation in a High Shear Mixer,” Drug Development and Industrial Pharmacy, 14(8):1041– 1060 (1988)
Robinson, T., and Waldie, B., “Particle Cycle Times in a Spouted Bed of Polydisperse Particles,” Can. J. Chem. Eng., 56:632–635 (1978)
Robinson, T. and Waldie, B., “Dependency of Growth on Granule Size in a Spouted Bed Granulator,” Trans. I. Chem. E., 57:121–127 (1979)
Rumpf, H., Particle Technology, Chapman and Hall, London (1975)
Sastry K. V. S., “Similarity Size Distribution of Agglomerates During Their Growth by Coalescence in Granulation or Green Pelletization,” Int. J. Min. Processing, 2:187–203 (1975)
Sastry K. V. S., and Fuersteau, D. W., “Mechanisms of Agglomerate Growth in Green Pelletization,” Powder. Tech., 7:97–105 (1973)
Schaefer, T., “Equipment for Wet Granulation,” Acta Pharm. Soc., 25:205–228 (1988)
Schaefer, T., Holm, P., and Kristensen, H. G., “Wet Granulation in a Laboratory Scale High Shear Mixer,” Pharm. Ind., 52(9):1147 (1990)
Schaefer, T., Holm, P., and Kristensen, H. G., “Melt Granulation in a Laboratory Scale High Shear Mixer,” Drug Development and Industrial Pharmacy, 16(8):1249–1277 (1990)
Siegell, J. H., “High Temperature Defluidization,” Powder Technol., 38:13–22 (1984)
Smith, P. G., and Nienow, A. W., “On Atomizing a Liquid into a Gas Fluidised Bed,” Chem. Eng. Sci., 37:950–954 (1982)
Tardos, G. I., Mazzone, D., and Pfeffer, R., “Measurement of Surface Viscosities using a Dilatometer,” Can. J. of Chem. Eng., 62:884–887 (1984)
Tardos, G. I., Mazzone, D., and Pfeffer, R., “Destabilization of Fluidized Beds Due to Agglomeration, Part I: Theoretical Analysis,” Can. J. of Chem. Eng., 63:377–383 (1985a)
Tardos, G. I., Mazzone, D., and Pfeffer, R., “Destabilization of Fluidized Beds Due to Agglomeration, Part II: Experimental Verification,” Can. J. of Chem. Eng., 63:384–389 (1985b)
Tardos, G. I., Pfeffer, R., and Ennis, B. J., “A Microlevel-Based Study of Granulation,” Proc. of the Powder and Bulk Solids Conf., pp. 221–230, Rosemont, Illinois (1991)
434 Fluidization, Solids Handling, and Processing
Tardos, G. I., Garcia, J., Ahart, R., and Ratuiste, F., “How and Why Some Flow Aids Promote Bulk Powder Flow,” AIChE Symp. Series, 296(89):18–34 (1993)
Tardos, G. I., “Measurement of Powder and Binder Characteristics which Determine Agglomerate Growth during Granulation,” Proc. of the 25th Israel Conf. on Mech. Eng., Haifa, Israel (1994)
Tardos, G. I., “A Review of High Shear Mixer Granulation,” Proc. of the First Israel Conf. for Conveying and Handling of Particulate Solids, Herzliya, Israel (1995)
Tardos, G. I., and Khan, M. I., “Study of Granulation in a Constant Shear Granular Flow Couette Device,” Paper presented at the Annual AIChE Meeting, Miami Beach, Florida (1995)
Tardos, G .I., and Pfeffer, R., “Chemical Reaction Induced Agglomeration and Defluidization of Fluidized Beds, Powder Technology, 85:29–35 (1995)
Tardos, G. I., Klan, M. I., and Mort, P. R., “Critical Parameters and Limiting Conditions in Binder Granulation of Fine Powders,” Powder Tech., 94:245– 258 (1997)
Tsutsumi, A., Nakmoto, S., Mineo,T., and Yoshida, K., “A Novel Fluidized-Bed Coating of Fine Particles by Rapid Expansion of Supercritical Fluid Solutions,” Proc. 1st Int. Particle Technol. Forum, pp. 452–455, Denver, CO (1994)
Waldie, B., “Growth Mechanism and the Dependence of Granule Size on Drop Size in Fluidized-Bed Granulation,” Chem. Eng. Sci., 46:2781–2785 (1991)
Waldie, B., and Wilkinson, D., “Measurement of Particle Movement in a Spouted Bed Using a New Microprocessor Based Technique,” Can. J. Chem. Eng., 64:944–949 (1986)
Wan, L. S. C., and Lai, W. F., “Factors Affecting Drug Release from Drug-Coated Granules Prepared by Fluidized-Bed Coating,” Int. J. Pharmaceutics, 72:163–174 (1991)
Weiss, P. J., and Meisen, A., “Laboratory Studies on Sulphur-Coating Urea by the Spouted Bed Process,” Can. J. Chem. Eng., 61:440–447 (1983)
Wurster, D., U.S. Patent 2,799,241 (1957)
Wurster, D., U.S. Patent 3,253,944 (1966)
Xu, M., “A Theoretical and Experimental Investigation of Spouted Beds with Draft Tubes,” Ph.D. Dissertation, West Virginia University, Morgantown, WV (1993)
Yuregir, K. R., Ghadiri, M., and Clift, R., “Impact Attrition of Sodium Chloride Crystals,” Chem. Eng. Sci., 42:843–853 (1987)