Chapter 4 – Powder Compression via Tapping 4.1 Introduction
7.6 Fluidization
For fluidization and bed collapse experiments under ambient conditions, an in-house fluidized bed equipped with a pressure transducer for measurements of bed pressure drop and pressure fluctuations, a hot-wire anemometer for measurement of superficial gas velocity, and a double- drainage system for bed collapse experiments were specifically designed and built. The custom built hot-wire anemometer was highly sensitive to small changes in superficial gas velocity in both increasing and decreasing gas flow orders. Superficial velocities Umf, Umb,v, Umb,, and Ubv were measured and the powders were classified into Groups A, A/B, and B according to Geldart Fluidization Diagram (Geldart, 1973) and based on Umb,v/Umf. Three internal states of powder
beds were observed visually during fluidization; correlations between the internal states and the values of Umf, Umb,v, Ubv, and also pressure fluctuations data gave the following: packed bed state, U<Umb,v, transitional state, Umb,vU<Ubv, and fully bubbling state, UbvU. When two statistical
tools, namely standard deviation, , and the inverse of von Neumann ratio, T–1, were applied in
the manipulation of pressure fluctuations data, correlated with Umf, Umb,v, Umb,, and Ubv, and subsequently compared, T–1 unequivocally peaked at or close to Umb,v. It was demonstrated that T–1 was a useful indicator for identifying the onset of bubbling in fluidized beds.
Bed collapse was used as a method to assess the fluidization quality of powders from Geldart Groups A, A/B, and B. Standardized collapse time, tc/Hmf, which gave a measure of a
powder’s ability to retain air, was determined and correlated with d*32 and C0, the cohesion at
zero pre obtained by shear testing. Parameter tc/Hmf for milled lactose powders showed a trend
different from those of spray-dried lactose powders, sand, and refractory dust; the exact reason for this observation was unknown but was attributed to the combined influence of particle size distribution, fines content, bed voidage, and particle density.
7.7 Tumbling
To assess the flowability of powders under controlled and unconfined conditions, powder tumbling in a novel Gravitational Displacement Rheometer, GDR, was carried out. Powder motion of Geldart Group C lactose, Group A sand, Group A refractory dust, Group A lactose, Group A/B lactose, and Group B glass beads was measured at drum speeds in the range 5 RPM to 30 RPM, and plots of standard deviation, ws, of the GDR load cell signal against drum speed
were used to represent powder avalanche activity. It was observed that ws increased with
increasing drum fill level, 20–50% on a volume basis, for Geldart Groups C and B powders, and the opposite trend occurred with Group A powders. Further observation of the ws profile at 50%
fill level for each powder, which was different from the ws data at other fill levels, revealed that
ws consistently showed changes between 10 RPM and 15 RPM.
In explaining and interpreting ws, information on d*32, span of particle size distribution, C0 measured by shear testing, tc/Hmf measured by fluidization and bed collapse, and powder bed
profiles during tumbling in the GDR were simultaneously taken into account and considered. In comparing the ws profiles of sand and refractory dust, both Group A powders, which had similar d*32 and span, the ws for sand at 15–25 RPM was higher; this was attributed to lower C0 and
higher tc/Hmf for sand. As for the Group A lactose, ws was lower and relatively constant;
observation of the bed profile during tumbling showed the absence of a horizontal bed surface, suggesting the lack of powder aeration. The Group A lactose also had a higher span and showed segregation when fluidized in the in-house fluidized bed. The ws values for the most cohesive
Group C lactose were highest; observation of the powder motion during tumbling showed that the powder moved as agglomerates. On the other hand, the ws for the free flowing glass beads
was lower; this material did not retain air and bed collapse was virtually instantaneous. The Geldart A/B lactose powder gave lower ws values than the free flowing glass beads; this was
thought to be influenced by higher level of fine particles and wider particle size distribution in the Group A/B lactose, and different avalanching mechanisms, as well as the fact that the two powders were very different.
Parameter ws and Flow Index were correlated with 1/d*32, a parameter that influenced
powder cohesion, C, measured by shear testing, Hausner ratio at 1,250 taps, HR,1250, and
standardized bed collapse time, tc/Hmf. Both ws and Flow Index generally increased with
increasing 1/d*32, and the increase in drum speed increased the scatter in the [1/d*32]:ws and
[1/d*32]:[Flow Index] plots. It was further proposed that ws at 5 RPM and 50% fill level could be
a better indicator for rapid powder flowability measurement and characterization; this was because in comparing the [1/d*32]:[ws at 5 RPM] and [1/d*32]:[Flow Index] plots, the
References
Abdullah, E. C., & Geldart, D. (1999). The use of bulk density measurements as flowability indicators. Powder Technology, 102(2), 151-165.
Abrahamsen, A. R., & Geldart, D. (1980a). Behavior of gas-fluidized beds of fine powders part I. Homogeneous expansion. Powder Technology, 26(1), 35-46.
Abrahamsen, A. R., & Geldart, D. (1980b). Behavior of gas-fluidized beds of fine powders part II. Voidage of the dense phase in bubbling beds. Powder Technology, 26(1), 47-55.
Alexander, A. W., Chaudhuri, B., Faqih, A., Muzzio, F. J., Davies, C., & Tomassone, M. S. (2006). Avalanching flow of cohesive powders. Powder Technology, 164(1), 13-21.
Ashton, M. D., Cheng, D. C.-H., Farley, R., & Valentin, F. H. H. (1965). Some investigations into the strength and flow properties of powders. Rheologica Acta, 4(3), 206-218.
Baeyens, J., & Geldart, D. (1974). An investigation into slugging fluidized beds. Chemical Engineering Science, 29(1), 255-265.
Berry, R. J., & Bradley, M. S. A. (2007). Investigation of the effect of test procedure factors on the failure loci and derived failure functions obtained from annular shear cells. Powder Technology, 174, 60-63.
Berry, R. J., Bradley, M. S. A., & McGregor, R. G. (2014). Brookfield powder flow tester - Results of round robin tests with CRM-116 limestone powder. Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering, 0(0), 1-16.
Billings, S. W., Bronlund, J. E., & Paterson, A. H. J. (2006). Effects of capillary condensation on the caking of bulk sucrose. Journal of Food Engineering, 77(4), 887-895.
Bronlund, J., & Paterson, T. (2004). Moisture sorption isotherms for crystalline, amorphous and predominantly crystalline lactose powders. International Dairy Journal, 14, 247-254.
Bruni, G., Lettieri, P., Newton, D., & Barletta, D. (2007). An investigation of the effect of the interparticle forces on the fluidization behaviour of fine powders linked with rheological studies. Chemical Engineering Science, 62, 387-396.
Carr, J. F., & Walker, D. M. (1968). An annular shear cell for granular materials. Powder Technology, 1(6), 369-373.
Carson, J. W., & Wilms, H. (2006). Development of an international standard for shear testing.
Powder Technology, 167(1), 1-9.
Castellanos, A., Valverde, J. M., & Quintanilla, M. A. S. (2002). Fine cohesive powders in rotating drums: Transition from rigid plastic flow to gas-fluidized regime. Physical Review E, 65, 061301.
Chaouki, J., Chavarie, C., & Klvana, D. (1985). Effect of interparticle forces on the hydrodynamic behaviour of fluidized aerogels. Powder Technology, 43, 117-125.
Cherntongchai, P., & Brandani, S. (2005). A model for the interpretation of the bed collapse experiment. Powder Technology, 151(1-3), 37-43.
Choi, H., Lee, W., Kim, D.-U., Kumar, S., Ha, J., Kim, S., et al. (2009). A comparative study of particle size analysis in fine powder: the effect of a polycomponent particulate system.
Korean Journal of Chemical Engineering, 26(1), 300-305.
Coulson, J. M., Richardson, J. F., Backhurst, J. R., & Harker, J. H. (2002). Coulson and Richardson's Chemical Engineering Volume 2, Particle Technology and Seperation Processes (5th ed.). Oxford: Butterworth Heinemann.
Davies, C. E., Carroll, A., & Flemmer, R. (2008). Particle size monitoring in a fluidized bed using pressure fluctuations. Powder Technology, 180(3), 307-311.
Davies, C. E., Jones, J. R., Hussein, K., Fievez, S., & Tallon, S. J. (2006). Flow mode characterization in a one metre diameter rotating drum. Developments in Chemical Engineering and Mineral Processing, 14(1/2), 135-141.
Davies, C. E., Krouse, D., & Carroll, A. (2007, 13-17 May). Particle size estimation and monitoring in a bubbling fluidized bed using pressure fluctuation measurements. Paper
presented at the 12th International Conference on Fluidization - New Horizons in Fluidization Engineering, Vancouver, Canada.
Davies, C. E., Krouse, D., & Carroll, A. (2010). A new approach to the identification of transitions in fluidized beds. Powder Technology, 199(1), 107-110.
Davies, C. E., Tallon, S. J., Fenton, K., Brown, N., & Peterson, M. (2002, 21-25 July). Direct sensing of the motion of solids in slowly rotating cylinders. Paper presented at the World
Congress on Particle Technology 4, Sydney, Australia.
Davies, C. E., Williams, A., Tallon, S. J., Fenton, K., & Brown, N. (2004). A new approach to monitoring the movement of particulate material in rotating drums. Developments in Chemical Engineering and Mineral Processing, 12(3-4), 263-275.
Dry, R. J., Judd, M. R., & Shingles, T. (1983). Two-phase theory and fine powders. Powder Technology, 34(2), 213-223.
Faqih, A. M., Chaudhuri, B., Alexander, A. W., Davies, C., Muzzio, F. J., & Tomassone, M. S. (2006). An experimental/computational approach for examining unconfined cohesive powder flow. International Journal of Pharmaceutics, 324(2), 116-127.
Faqih, A. M., Chaudhuri, B., Muzzio, F. J., Tomassone, M. S., Alexander, A., & Hammond, S. (2006). Flow-induced dilation of cohesive granular materials. AIChE Journal, 52(12),
4124-4132.
Faqih, A. N., Alexander, A. W., Muzzio, F. J., & Tomassone, M. S. (2007). A method for predicting hopper flow characteristics of pharmaceutical powders. Chemical Engineering Science, 62(5), 1536-1542.
Fitzpatrick, J. J., Barringer, S. A., & Iqbal, T. (2004). Flow property measurement of food powders and sensitivity of Jenike's hopper design methodology to the measured values.
Journal of Food Engineering, 61, 399-405.
Fu, X., Huck, D., Makein, L., Armstrong, B., Willen, U., & Freeman, T. (2012). Effect of particle shape and size on flow properties of lactose powders. Particuology, 10(2), 203-208.
Geldart, D. (1972). Effect of particle size and size distribution on behavior of gas-fluidized beds.
Powder Technology, 6(4), 201-215.
Geldart, D. (1973). Types of gas fluidization. Powder Technology, 7(5), 285-292.
Geldart, D. (1990). Estimation of basic particle properties for use in fluid particle process calculations. Powder Technology, 60(1), 1-13.
Geldart, D., Abdullah, E. C., Hassanpour, A., Nwoke, L. C., & Wouters, I. (2006). Characterization of powder flowability using measurement of angle of repose. China Particuology, 4(3-4), 104-107.
Geldart, D., Harnby, N., & Wong, A. C. (1984). Fluidization of cohesive powders. Powder Technology, 37, 25-37.
Geldart, D., & Wong, A. C. Y. (1984). Fluidization of powders showing degrees of cohesiveness–I. Bed expansion. Chemical Engineering Science, 39(10), 1481-1488.
Geldart, D., & Wong, A. C. Y. (1985). Fluidization of powders showing degrees of cohesiveness–II. Experiments on rates of de-aeration. Chemical Engineering Science, 40(4), 653-661.
Grace, J. R. (1992). Agricola aground: Characterization and interpretation of fluidization phenomena. AIChE Symposium Series 289, 88, 1-16.
Grey, R. O., & Beddow, J. K. (1969). On the Hausner ratio and its relationship to some properties of metal powders. Powder Technology, 2(6), 323-326.
Gu, Z. H., Arnold, P. C., & McLean, A. G. (1992). Consolidation-related bulk density and permeability models for bulk solids. Powder Technology, 72, 39-44.
Hausner, H. H. (1967). Friction conditions in a mass of metal powder. International Journal of Powder Metallurgy, 3, 3-17.
Hayes, G. D. (1987). Food Engineering Data Handbook. New York: John Wiley & Sons.
Henein, H., Brimacombe, J. K., & Watkinson, A. P. (1983). Experimental study of transverse bed motion in rotary kilns. Metallurgical Transactions B, 14B, 191-205.
Huang, Q., Zhang, H., & Zhu, J. (2009). Experimental study on fluidization of fine powders in rotating drums with various wall friction and baffled rotating drums. Chemical Engineering Science, 64(9), 2234-2244.
Huang, Q., Zhang, H., & Zhu, J. (2010). Onset of an innovative gasless fluidized bed - comparative study on the fluidization of fine powders in a rotating drum and a traditional fluidized bed. Chemical Engineering Science, 65, 1261-1273.
Ili, I., Kása Jr., P., Dreu, R., Pintye-Hódi, K., & Sri, S. (2009). The compressibility and compactibility of different types of lactose. Drug Development and Industrial Pharmacy, 35(10), 1271-1280.
Iyer, S. R., & Drzal, L. T. (1989). Behavior of cohesive powders in narrow-diameter fluidized beds. Powder Technology, 57, 127-133.
Jenike, A. W. (1964). Storage and flow of solids. Bulletin No. 123 of the Utah Engineering Experimental Station, 53(26).
Jenike, A. W. (1975). A measure of flowability for powders and other bulk solids. Powder Technology, 11(1), 89-90.
Kawakita, K., & Lüdde, K.-H. (1971). Some considerations on powder compression equations.
Powder Technology, 4(2), 61-68.
Kaye, B. H. (1997). Characterizing the flowability of a powder using the concepts of fractal geometry and chaos theory. Particle & Particle Systems Characterization, 14(2), 53-66.
Kaye, B. H., Gratton-Liimatainen, J., & Faddis, N. (1995). Studying the avalanching behaviour of a powder in a rotating disc. Particle & Particle Systems Characterization, 12(5), 232-
236.
Khoe, G. K., Ip, T. L., & Grace, J. R. (1991). Rheological and fluidization behavior of powders of different particle size distribution. Powder Technology, 66(2), 127-141.
Kunii, D., & Levenspiel, O. (1991). Fluidization Engineering. Stoneham: Butterworth-
Heinemann.
Kurz, H. P., & Münz, G. (1975). The influence of particle size distribution on the flow properties of limestone powders. Powder Technology, 11(1), 37-40.
Lavoie, F., Cartilier, L., & Thibert, R. (2002). New methods characterizing avalanche behavior to determine powder flow. Pharmaceutical Research, 19(6), 887-893.
Lee, Y. S. L., Poynter, R., Pedczeck, F., & Newton, J. M. (2000). Development of a dual approach to assess powder flow from avalanching behavior. AAPS PharmSciTech, 1(3),
Article 21.
Lindberg, N.-O., Pålsson, M., Pihl, A.-C., Freeman, R., Freeman, T., Zetzener, H., et al. (2004). Flowability measurements of pharmaceutical powder mixtures with poor flow using five different techniques. Drug Development and Industrial Pharmacy, 30(7), 785-791.
Lorences, M. J., Patience, G. S., Diez, F. V., & Coca, J. (2003). Fines effects on collapsing fluidized beds. Powder Technology, 131(2-3), 234-240.
Malave, J., Barbosa-Canovas, G. V., & Peleg, M. (1985). Comparison of the compaction characteristics of selected food powders by vibration, tapping and mechanical compression. Journal of Food Science, 50, 1473-1476.
McCabe, W. L., Smith, J. C., & Harriott, P. (2005). Unit Operations of Chemical Engineering
McGlinchey, D. (2005). Bulk property characterization. In D. McGlinchey (Ed.),
Characterisation of Bulk Solids (pp. 48-84). Oxford: Blackwell Publishing.
Mellmann, J. (2001). The transverse motion of solids in rotating cylinders - forms of motion and transition behavior. Powder Technology, 118(3), 251-270.
Molerus, O. (1975). Theory of yield of cohesive powders. Powder Technology, 12(3), 259-275.
Molerus, O. (1978). Effect of interparticle cohesive forces on the flow behaviour of powders.
Powder Technology, 20(2), 161-175.
Molerus, O. (1993). Principles of Flow in Disperse Systems. London: Chapman and Hall.
Nedderman, R. M. (1992). Statics and Kinematics of Granular Materials. Cambridge:
Cambridge University Press.
Niro (1978). Analytical methods for dry milk products, Method No. A2a - Packed bulk density by the Niro method for milk powders and protein products (pp. 2.3.1-2.3.4). Copenhagen,
Denmark: A/S Niro Atomizer.
Niro, G. (2012). Particle density, occluded air and interstitial air by air pycnometer. Retrieved 3 October, 2012, from http://www.niro.com/niro/cmsdoc.nsf/WebDoc/webb7ceec8
Orband, J. L. R., & Geldart, D. (1997). Direct measurement of powder cohesion using a torsional device. Powder Technology, 92(1), 25-33.
Park, J. J., Park, J. H., Chang, I. S., Kim, S. D., & Choi, C. S. (1991). A new bed-collapsing technique for measuring the dense phase properties of gas-fluidized beds. Powder Technology, 66(3), 249-257.
Peleg, M. (1978). Flowability of food powders and methods for its evaluation - a review. Journal of Food Process and Engineering, 1, 303-328.
Peleg, M., & Mannheim, C. H. (1973). Effect of conditioners on the flow properties of powdered sucrose. Powder Technology, 7(1), 45-50.
Peleg, M., Mannheim, C. H., & Passy, N. (1973). Flow properties of some food powders. Journal of Food Science, 38(6), 959-964.
Pingali, K., & Kick, C. (2013). Gravitational Displacement Rheometer: Operator's Guide:
Western Michigan University.
Punochá, M., Draho, J., ermák, J., & Seluck, K. (1985). Evaluation of minimum fluidizing velocity in gas fluidized bed from pressure fluctuations. Chemical Engineering Communications, 35(1), 81-87.
Rhodes, M. J. (1998). Introduction to particle technology. West Sussex: John Wiley & Sons Ltd.
Richardson, J. F. (1971). Incipient fluidization and particulate systems. In J. F. Davidson & D. Harrison (Eds.), Fluidization (pp. 26-64). London: Academic Press Inc.
Rietema, K. (1967). Application of mechanical stress theory to fluidization. In A. A. H. Drinkenberg (Ed.), International Symposium on Fluidization (pp. 154-175). Amsterdam,
Rietema, K. (1984). Powders, what are they? Powder Technology, 37, 5-23.
Santomaso, A., Lazzaro, P., & Canu, P. (2003). Powder flowability and density ratios: the impact of granules packing. Chemical Engineering Science, 58(13), 2857-2874.
SANZ (1986). NZS 3111:1986 - Methods of test for water and aggregate for concrete, Method for determining voids content, flow time and percentage oversize material in sand (pp.
44-45). Wellington, New Zealand: Standards Association of New Zealand.
Schulze, D. (2008). Powders and Bulk Solids: Behaviour, Characterization, Storage and Flow.
Berlin: Springer.
Schüssele, A., & Bauer-Brandl, A. (2003). Note on the measurement of flowability according to the European Pharmacopoeia. International Journal of Pharmaceutics, 257(1-2), 301-
304.
Schwedes, J. (2003). Review on testers for measuring flow properties of bulk solids. Granular Matter, 5(1), 1-43.
Shaffer, K., Paterson, A. H. J., Davies, C. E., & Hebbink, G. (2011). Stokes shape factor for lactose crystals. Advanced Powder Technology, 22(4), 454-457.
míd, J., Xuan, P. V., & Thn, J. (1993). Effect of filling method on the packing distribution of a catalyst bed. Chemical Engineering and Technology, 16(2), 114-118.
Soh, J. L. P., Liew, C. V., & Heng, P. W. S. (2006). New indices to characterize powder flow bases on their avalanching behavior. Pharmaceutical Development and Technology, 11(1), 93-102.
Stanley-Wood, N., Sarrafi, M., Mavere, Z., & Schaefer, M. (1993). The relationships between powder flowability, particle re-arrangement, bulk density and Jenike failure function.
Advanced Powder Technology, 4(1), 33-40.
Teunou, E., Fitzpatrick, J. J., & Synnott, E. C. (1999). Characterisation of food powder flowability. Journal of Food Engineering, 39(1), 31-37.
TSI (2005). Model 3250 Aero-Flow Automated Powder Flowability Analyzer. Retrieved 27 July,
2010, from www.kenelec.com.au/pdf/aeroflow.pdf
Tung, Y., & Kwauk, M. (1982). Dynamics of collapsing fluidized beds. In M. Kwauk & D. Kunii (Eds.), Fluidization Science and Technology (pp. 155-166). Beijing: Science Press.
USP-NF (2012). The United States Pharmacopeia and The National Formulary, <616> Bulk and Tapped Density (pp. 1-3). United States: The United States Pharmacopeial Convention.
Valverde, J. M., Ramos, A., Castellanos, A., & Watson, P. K. (1998). The tensile strength of cohesive powders and its relationship to consolidation, free volume and cohesivity.
Powder Technology, 97(3), 237-245.
Vasilenko, A., Glasser, B. J., & Muzzio, F. J. (2011). Shear and flow behaviour of pharmaceutical blends - Method comparison study. Powder Technology, 208, 628-636.
Vasilenko, A., Koynov, S., Glasser, B. J., & Muzzio, F. J. (2013). Role of consolidation state in the measurement of bulk density and cohesion. Powder Technology, 239, 366-373.
Wang, Z., Kwauk, M., & Li, H. (1998). Fluidization of fine particles. Chemical Engineering Science, 53(3), 377-395.
Webster, E. S., & Davies, C. E. (2006, 17-20 September). Behaviour of powders from different Geldart groups in a rotating drum. Paper presented at the 34th Australasian Chemical
Engineering Conference (Chemeca), Auckland, New Zealand.
Webster, E. S., & Davies, C. E. (2010, 16-21 May). Geldart group indication from powder measurements with a rotating drum instrument. Paper presented at the 13th International
Conference on Fluidization - New Paradigm in Fluidization Engineering, Gyeong-ju, Korea.
Wilkinson, D. (1995). Determination of minimum fluidization velocity by pressure fluctuation measurement. The Canadian Journal of Chemical Engineering, 73(4), 562-565.
Xie, H. Y. (1997). Pressure probes in the measurement of collapse rate and dense-phase properties in the fluidization of fine particles. Advanced Powder Technology, 8(3), 237-