Yang Fluidization, Solids Handling, and Processing

Attrition in Fluidized Beds and Pneumatic Conveying Lines 485

486 Fluidization, Solids Handling, and Processing

Greek Symbols

ηEfficiency of the cyclone abrasion process,

REFERENCES

Adams, M. J., Bellamy, G., and Briscoe, B. J., “The Wear of Particles in Pneumatic Conveying,” Wear Particles, (Downson, et al., eds.), Elsevier Science Publishers B.V. (1992)

Arastoopour, H., and Chen-Ya Chen, “Attrition of Char Agglomerates,” Powder Tech., 36:99 (1983)

Arena, U., D’Amore, M., and Massimilla, L., “Carbon Attrition during the Fluidized Combustion of Coal,” AIChE J., 29:40 (1983)

Bemrose, C. R., and Bridgwater, J., “A Review of Attrition and Attrition Test Methods,” Powder Tech., 49:97 (1987)

Blake T. R., Webb H., and Sunderland P. B., “The Nondimensionalization of Equations Describing Fluidization with Application to the Correlation of Jet Penetration Height,” Chem. Eng. Sci., 45:365 (1990)

Blinichev, V. N., Strel’tsov, V. V., and Lebedeva, E. S., “An Investigation of the Size Reduction of Granular Materials during their Processing in Fluidized Beds,” Int. Chem. Eng., 8:615 (1968)

Bond, F. C., “Crushing & Grinding Calculations, Part I,” Brit. Chem. Eng., 6:378 (1961)

Broadbent, S. R, and Calcott, T. G., J. Inst. of Fuel, 29:524 (1956)

Bridgwater, J., “Attrition of High-Density Polyethylenes,” Powder Tech., 50:243 (1987)

British Materials Handling Board, “Particle Attrition,” Trans Tech Publications Series on Bulk Mat. Handling, p. 5 (1987)

Chirone, R., Massimilla, L., and Salatino, P., “Comminution of Carbons in Fluidized Bed Combustion,” Progress in Energy and Comb. Sci., 17:297 (1991)

Cleaver, J. A. S., and Ghadiri, M., “Impact Attrition of Sodium Carbonate Monohydrate Crystals,” Powder Tech., 76:15 (1993)

Attrition in Fluidized Beds and Pneumatic Conveying Lines 487

Clift, R., “Powder Technology and Particle Science,” Powder Tech., 88:335 (1996)

Contractor, R. M., Bergna, H. E, Chowdhry, U., and Sleight, A. W., “Attrition Resistant Catalysts for Fluidized Bed-Systems,” Fluidization VI, (J. R. Grace, L. W. Shemilt, and M. A. Bergougnou, eds.), Banff, Alberta, Canada (1989)

Coppinger, E., Discepola, L., Tardos, G. I., and Bellamy, G., “The Influence of Granule Morphology on Attrition during Fluidization and Pneumatic Transport,” Advanced Powder Tech., 3:201 (1992)

Dessalces, G., Kolenda, F., and Reymond, J. P., “Attrition Evaluation for Catalysts used in Fluidized or Circulating Fluidized Bed Reactors,” AIChE: Preprints of the First Int. Particle Technol. Forum, II:190, Denver, Colorado (1994)

Forsythe, W. L., and Hertwig, W. R., “Attrition Characteristics of Fluid Chracking Catalysts,” Indust. and Eng. Chem., 41:1200 (1949)

Fuertes, A. B., Pis, J. J., Garcia, J. C., Rubiera, F., and Artos, V., “Prediction of Attrition in a Continous Fluid-Bed System,” Powder Tech., 67:291 (1991)

Ghadiri, M., Yuregir, K. R., Pollock, H. M., and Ross, J. D. J., “Influence of Processing Conditions on Attrition of NaCl Crystals,” Powder Tech., 65:311 (1991)

Ghadiri, M., Cleaver, J. A. S., and Yuregir, K. R., “Attrition of Sodium Chloride Christals in a Fluidized Bed,” Proc. Fluidization VII, (O. E. Potter, and D. J. Nicklin, eds.), p. 604, Brisbane, Australia (1992a)

Ghadiri, M., Cleaver, J. A. S., and Tuponogov, V. G., “Modelling Attrition Rates in the Jetting Region of a Fluidized Bed,” Preprint Symposium Attrition and Wear, Utrecht (1992b)

Ghadiri, M., Cleaver, J. A. S., Tuponogov, V. G., and Werther, J., “Attrition of FCC Powder in the Jetting Region of a Fluidized Bed,” Powder Tech., 80:175 (1994)

Ghadiri, M., Cleaver, J. A. S., and Tuponogov, V. G., “Influence of Distributor Orifice Size on Attrition in the Jetting Region of Fluidized Beds,” Preprint Fluidization VIII, 2:799 (1995)

Gwyn, J. E., “On the Particle Size Distribution Function and the Attrition of Cracking Catalysts,” AIChE J., 15:35 (1969)

Kato, K., Takaradu, T., Matsuo, N., and Suto, T., “Residence-Time Distribution of Fine Particles in a Powder-Particle Fluidized Bed,” Int. Chem. Eng., 34:605 (1994)

Knight, P. C., and Bridgwater, J., “Comparison of Methods for Assessing Powder Attrition,” Powder Tech., 44:99 (1985)

Knowlton, T. M., private communication (1996)

488 Fluidization, Solids Handling, and Processing

Kokkoris, A., and Turton, R., “The Reduction of Attrition in Fluidized Beds by the Addition of Solid Lubricants,” AIChE Symp. Ser., 281(87):20 (1991)

Kokkoris, A., and Turton, R., “A Phenomenological Model Predicting the Attrition and the Reduction of Attrition due to the Addition of Solid Lubricants in Slugging Beds,” Powder Tech., 84:39 (1995)

Kono, H., “Attrition Rates of Relatively Coarse Solid Particles in Various Types of Fluidized Beds”, AIChE Symp. Ser., 205(77):96 (1981)

Kunii, D., and Levenspiel, O., Fluidization Eng., (E. Robert, ed.), Krieger Publishing Company, Huntington, NY (1969)

Kunii, D., and Levenspiel, O., Fluidization Eng., 2nd Ed., Butterworth-Heinemann, Boston (1991)

Kutyavina, T. A., and Baskakov, A. P., “Grinding of Fine Granular Material with Fluidization,” Chem. a. Techn. of Fuels and Oils, 8:210 (1972)

Levenspiel, O., Kunii, D., and Fitzgerald, T., “The Processing of Solids of Changing Size in Bubbling Fluidized Beds,” Powder Tech., 2:87 (1968)

Lin L., Sears J. T., and Wen, C. Y., “ Elutriation and Attrition of Char from a Large FB,” Powder Tech., 27:105 (1980)

McKee, S. L., Dyakowski, T., Williams, R. A., and Bell, A., “Solids Flow Imaging and Attrition Studies in a Pneumatic Conveyor,” Powder Tech., 82:105 (1995)

Merrick, D., and Highley, J.,”Particle Size Reduction and Elutriation in a Fluidized Bed Process,” AIChE Symp. Ser., 137(70):367 (1974)

Merry, J. M. D., “Penetration of Vertical Jets into Fluidized Beds,” AIChE J., 21:507 (1975)

Mills, D., “Particle Degradation in Pneumatic Conveying,” 7th Int. Symp. on Freight Pipelines, Wollongong, NSW, Australia (1992)

Molerus, O., Siebenhaar, W., and Gericke, W., “Entwicklung eines pneumatische Förderverfahrens zum schonenden Transport bruchempfindlicher Güter,” Chem. Ing. Tech., 61:752 (1989)

Molerus, O., and Glückler, M., “Development of a Cyclone Separator with New Design,” Powder Tech., 86:37 (1996)

Nakagawa, N., Li, Z., Bai, D., and Kato, K., “Fundamental Study of Fine Particle Residence in a Powder-Particle Fluidized Bed / Effect of Fine Powder Concentration,” Preprint Fluidization VIII, 1:287 (1995)

Neil, A. U., and Bridgwater, J., “Attrition of Particulate Solids under Shear,” Powder Tech., 80:207 (1994)

Newby, R. A., Vaux, W. G., and Keairns, D. L., “Particle Attrition in FluidizedBed Systems,” Proc. Fluidization IV, (D. Kunii, and R. Toei, eds.), Kashikojima, Japan (1983)

Attrition in Fluidized Beds and Pneumatic Conveying Lines 489

Paramanathan, B. K., and Bridgwater, J., “Attrition of Solids-I”, Chem. Eng. Sci., 38:197 (1983)

Paramanathan, B. K., and Bridgwater J., “Attrition of Solids-II,” Chem. Eng. Sci., 38:207 (1983)

Parker, W. A., Gwyn, J. E., and McCullogh, G. R., US Patent 3 974 091 (1976) Parker, W. A., and Gwyn, J. E., US Patent 4 032 300 (1977)

Patience, G. S., and Mills, P. L., “Modelling of Propylene Oxidation in a Circulating Fluidized-Bed Reactor,” New Developments in Selective Oxidation II, p. 1 (1994)

Pell, M., Gas Fluidization, Chapt. 12: “Attrition in Fluidized Beds,” Handbook of Powder Tech., 1(8):97, Elsevier, Amsterdam (1990)

Perry, R. H., and Chilton, C. H., Chemical Engineers Handbook, 5:8–10, McGraw-Hill, Kogakusha, Tokyo (1973)

Pis, J. J., Fuertes, A. B., Artos, V., Suarez, A., and Rubiera, F., “Attrition of Coal and Ash Particles in a Fluidized Bed,” Powder Tech., 66:41 (1991)

Ray, Y.-C., Jiang, T.-S., and Wen, C.Y., “Particle Attrition Phenomena in a Fluidized Bed,” Powder Tech., 49:193 (1987a)

Ray, Y. C., Jiang, T. S., and Jiang T. L., “Particle Population Model for a Fluidized Bed with Attrition,” Powder Tech., 52:35 (1987b)

Reed, A. R., and Bradley, M. S., “Techniques for Minimising Particle Degradation in Pneumatic Conveying Systems,” Powder Handling & Processing, 3:49 (1991)

Reppenhagen, J., Werther, J., to be published (1997)

Salman, A. S., Verba, A., and Mills, D., “Particle Degradation in Dilute Phase Pneumatic Conveying Systems,” Proc. of the 1992 Powder & Bulk Solids Conf. and Exhibition, Rosemont, USA (1992)

Salman, A. S., Ph.D. Thesis on Product Degradation: Budapest Technical University, (1988)

Schruben, J. S., and Vaux, W. G., “ Attrition in the Bubbling Zone of a SteadyState Fluidized Bed,” Chem. Eng. Commun., 33:337 (1985)

Segler, G., “Pneumatic Grain Conveying,” 55, Braunschweig, Germany (1951)

Seville, J. P. K, Mullier, M. A., and Adams, M. J., “Attrition of Agglomerates in Fluidized Beds,” Proc. of the 7th Eng. Found. Conf. on Fluidization, Brisbane, Australia (1992)

Shipway, P. H., and Hutchings, I. M., “Attrition of Brittle Spheres by Fracture under Compression and Impact Loading,” Powder Tech., 76:23 (1993)

490 Fluidization, Solids Handling, and Processing

Sishtla, C., Findlay, J., Chan, I., and Knowlton, T. M., “The Effect of Temperature and Gas Velocity on Fines Generation in Non-Reactive Fluidized Beds of Coal Char,” Fluidization VI, (J. R. Grace, L. W. Shemilt, and M. A. Bergougnou, eds.), Banff, Alberta, Canada (1989)

Ulerich, N. H., Vaux, W. G., Newby R. A., and Keairns, L., Experimental/ Engineering Support for EPA’s FBC Program: Final report, Vol. 1, Sulfur Oxide Control, EPA-600/7-80-015a (1980)

Van Swaaij, W. P. M., de Vries, R. J., Mantovani, C., and Heijkoop, A., “Design Criteria and Performance of the Commercial Reactor for the Shell Chlorine Process,” V. Europ. Symp. on Chem. React. Eng., Amsterdam (1972)

Vaux, W. G., “Attrition of Particles in the Bubbling Zone of a Fluidized Bed,”

Proceed. of the Am. Power Conf., 40:793 (1978)

Vaux, W. G., and Keairns, D. L., “Particle Attrition in Fluid-Bed Processes,” Proc. Fluidization III, (J. R. Grace, and J. M. Matsen, eds.), p. 437, Henniker, USA (1980)

Vaux, W. G., and Fellers, A. W., “Measurement of Attrition Tendency in Fluidization,” AIChE Symp. Ser., 205(77):107 (1981)

Vaux, W. G., and Schruben, J. S., “Kinetics of Attrtion in the Bubbling Zone of a Fluidized Bed,” AIChE Symp. Ser., 222(79):97 (1983)

Villareal, J. A., and Klinzing, G. E., “Pickup Velocities under Higher Pressure Conditions,” Powder Tech., 80:179 (1994)

Weeks, S. A., and Dumbill, P., “Method Speeds FCC Catalyst Attrition Resistance Determinations,” Oil & Gas J., 88:38 (1990)

Werther, J., and Xi, W., “Jet Attrition of Catalyst Particles in Gas Fluidized Beds,” Powder Tech.; 76:15 (1993)

Werner, A., Haider, M., and Linzer, W., “Modelling of Particle Population in Fluidized Beds of Particles Differing in Size and Physico-chemical Behaviour,” Preprint Fluidization VIII, 1:557 (1995)

Wypych, P. W., and Arnold, P. C., “Minimising Wear and Particle Damage in Pneumatic Conveying,” Powder Handling & Processing, 5:129 (1993)

Wyszynski, M. L., and Bridgwater, J., “The Effect of Solid Lubricants on the Powder Attrition and Breakage”, Tribology Int., 26:311 (1993)

Xi, W., Ph.D. Thesis: “Katalysatorabrieb in Wirbelschichtreaktoren”: Technical University Hamburg-Harburg (1993)

Yates, J. G., Bejcek, V., and Cheesman, D. J. “Jet Penetration into Fluidized Beds at Elevated pressures,” Proc. Fluidization V, (K. Ostergaard, and Sorensen, A., eds.), p. 79, Elsinore, Denmark (1986)

Yuregir, K. R., Ghadiri, M., and Clift, R., “Observation of Impact Attrition of Granular Solids,” Powder Tech., 49:53 (1986)

Attrition in Fluidized Beds and Pneumatic Conveying Lines 491

Yuregir, K. R., Ghadiri, M., and Clift, R., “Impact Attrition of Sodium Chloride Crystals,” Chem. Eng. Sci., 42:843 (1987)

Zenz, F. A., “Bubble Formation and Grid Design,” Int. Chem. E. Symp. Ser., 30:136 (1968)

Zenz, F. A., “Find Attrition in Fluid Beds,” Hydrocarbon Processing, p. 103 (1971)

Zenz, F. A., and Smith, R., “When are Fines at Equilibrium?” Hydrocarbon Processing, p. 104 (1972)

Zenz, F. A., “Help from Project E-A-R-L,” Hydrocarbon Processing, p. 119 (1974)

Zenz, F. A., and Kelleher, E. G., “ Studies of Attrition Rates in Fluid-Particle Systems via Free Fall, Grid Jets, and Cyclone Impact,” J. of Powder & Bulk Technol., 4:13 (1980)

Figure 1a illustrates a typical fluidized leacher/washer. A slurry containing the solid particles to be leached and/or washed is fed at the top through a hydraulic distributor into an enlarged settling head where preliminary removal of excess liquor is accomplished. Solid particles then fall countercurrently against a rising stream of liquor into the fluidized leaching/ washing section, in which there is normally a dilute-phase region surmounting a dense-phase region. Both regions are fluidized, with a more or less well-defined interface between the two. Fresh leaching/washing liquor enters through special spargers located at the bottom of the dense-phase region. Below the dense-phase region, the solid slurry enters a compression zone in which as much liquor as possible is removed in order to discharge a highly concentrated underflow.

By comparing this simple diagram with the conventional continuous countercurrent decantation circuit, shown in Fig. 1b (Coulson and Richardson, 1968, 1978; Treybal, 1955, 1968, 1980) for carrying out the same duty, it is easy to deduce the following characteristics for fluidized leaching and washing:

*Complete hydraulic operation without any mechanical parts

*Continuous countercurrent operation in a single vertical column where longitudinal concentration gradient could be established

*Adaptability to extremely low flowing liquid-to-solid ratios, so that it is possible to obtain a relatively concentrated solution from a relatively lean solid parent material

*Low space requirement

*Ease of automation

Conceivably any granular solid containing a soluble component disseminated in an inert matrix could be leached rather efficiently in the fluidized state, and the leached pulp, or slurry, could again be washed in the fluidized state for removal of the remaining solution. Numerous solid particles of industrial significance are amenable to fluidized leaching and washing. In extractive metallurgy, for instance, certain low-grade copper ores could be leached with acid or ammoniacal solution advantageously in the fluidized state; cupriferous iron ores, after sulfatizing roasting, could