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Correlation to Predict the Effect of Particle Type on Axial Voidage Profile in Circulating Fluidized Beds

Authors: M. S. Khurram, S. A. Memon, S. Khan

Abstract:

Bed voidage behavior among different flow regimes for Geldart A, B, and D particles (fluid catalytic cracking catalyst (FCC), particle A and glass beads) of diameter range 57-872 μm, apparent density 1470-3092 kg/m3, and bulk density range 890-1773 kg/m3 were investigated in a gas-solid circulating fluidized bed of 0.1 m-i.d. and 2.56 m-height of plexi-glass. Effects of variables (gas velocity, particle properties, and static bed height) were analyzed on bed voidage. The axial voidage profile showed a typical trend along the riser: a dense bed at the lower part followed by a transition in the splash zone and a lean phase in the freeboard. Bed expansion and dense bed voidage increased with an increase of gas velocity as usual. From experimental results, a generalized model relationship based on inverse fluidization number for dense bed voidage from bubbling to fast fluidization regimes was presented.

Keywords: Axial voidage, circulating fluidized bed, splash zone, static bed.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1127326

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References:


[1] D. Escudero, and T. Heindel, "Bed height and material density effects on fluidized bed hydrodynamics,"Chem. Eng. Sci., vol. 66(16), Aug. 2011, pp. 3648–3655.
[2] Y. Li, and M. Kwauk, "The dynamics of fast fluidization," in Fluidization, J. R. Grace, and J. M. Matsen, Ed. New York: Plenum Press, 1980, pp. 537–544.
[3] E. U. Hartge, Y. Li, and J. Werther, "Analysis of the local structure of the two phase flow in a fast fluidized bed," in Circulating Fluidized Bed Technology, P. Basu, Ed. Toronto: Pergamon Press, 1986, pp. 153–160.
[4] H. Weinstein, R. A. Graff, M. Meller, and M. J. Shao, "The influence of imposed pressure drop across a fast fluidized bed," in Fluidization, D. Kunii and R. Toei, Ed. New York: Engineering Foundation, 1984, pp. 299–306.
[5] K. Kato, H. Shibasaki, k. Tamura, and T. Takarada,"Particle hold-up in a fast fluidized bed," J. Chem. Eng. Jpn., vol. 22(2), Apr. 1989, pp. 130–136.
[6] J. Yerushalmi, and A. Avidan, "High velocity fluidization," in Fluidization, 2nd ed. J. F. Davidson, R. Clift, D. Harrison, Ed. New York: Academic Press, 1985, pp. 274–278.
[7] J. H. Choi, C. K. Yi, and J. E. Son, "Axial voidage profile in a cold model circulating fluidized bed, "Korean J. Chem. Eng., vol 7(4), Oct. 1990, pp.306–309.
[8] K. Kato, T. Takarada, T. Tamura, and K. Nishino, "Particle hold-up distribution in a circulating fluidized bed, "in Circulating Fluidized Bed Technology III, P Basu, M. Horio, M. Hasatami, Ed. Oxford: Pergamon Press, 1990, pp. 145–150.
[9] N. S. Grewal, R. D. Maurer, and W. Fox, "Axial particle loading in a circulating fluidized bed,"in Proc. of Int. Conf. On Fluidized Bed Combustion, E. J. Anthony Ed. New York: ASME, 1991, pp. 317–323.
[10] D. R. Bai, Y. Jin, Z. Q. Yu, and J. X. Zhu, "The axial distribution of the cross-sectionally averaged voidage in fast fluidized beds," Powder Technol., vol. 71, Jul. 1992, pp. 51–58.
[11] J. Adanez, P. Gayan, L. F. Garcia, and L. F. Diego. "Axial voidage profiles in fast fluidized beds, "Powder Technol, vol. 81(3), Dec. 1994, pp. 259–268.
[12] M. G. Schnitzlein, and H. Weinstein. "Flow characterization in high-velocity fluidized beds using pressure fluctuations, "Chem. Eng. Sc., vol 43(10), Mar. 1988, pp. 2605–2614.
[13] J. Gan, C. Yang, C. Li, H. Zhao, Y. Liu, and X. Luo, "Gas–solid flow patterns in a novel multi-regime riser, "Chem. Eng. J., vol. 178, Dec. 2011, pp. 297–305.
[14] J. Gan, H. Zhao, A. S. Berrouk, C. Yang, and H. Shan, "Numerical simulation of hydrodynamics and cracking reactions in the feed mixing zone of a multi regime gas–solid riser reactor," Ind. Eng. Chem. Res., vol. 50(20), Aug. 2011, pp. 11511–11520.
[15] Q. Geng, X. Zhu, Y. Liu, Y. Liu, C. Li, and X. You, "Gas-solid flow behavior and contact efficiency in a circulating-turbulent fluidized bed," Powder Technol, vol. 245, Sep. 2013, pp. 134–145.
[16] Q. Geng, X. Zhu, J. Yang, X. You, Y. Liu, and C. Li, "Flow regime identification in a novel circulating-turbulent fluidized bed, "Chem. Eng. J., vol. 244, May. 2014, pp. 493–504.
[17] S. Shresthaa, B. S. Ali, B. M. Jana, M. T. Limb, and K. E. Sheikh," Hydrodynamic properties of a cold model of dual fluidized bed gasifier: A modeling and experimental investigation", Chem. Eng. Res. Des., vol. 1 0 9, May. 2016. pp. 791–805
[18] D. Kunii, and O. Levenspiel,"Entrainment of solids from fluidized beds I. Holdup of solids in the freeboard II. Operation of fast fluidized beds," Powder Technol., vol. 61(2), May. 1990, pp. 193–206.
[19] S. P Babu, B. Shah, and A. Talwalkar, "Fluidization correlations for coal gasification materials, minimum fluidization velocity and fluidized bed expansion ratio," AlChE Symp. Ser., vol. 74, Jan. 1978, pp. 176–184.
[20] G. S. Lee, and S. D. Kim. "Hydrodynamics properties of coal in turbulent fluidized beds," Korean J. Chem. Eng. vol. 6(4), Oct. 1989, pp. 338–346.
[21] H. Lofstrand, and A. E. Almsted, "Dimensionless expansion model for bubbling fluidized bed with and without internal heat exchanger tubes," Chem. Eng. Sci., vol. 50(2), Jan. 1995, pp. 245–253.
[22] J. H. Choi, I. Y. Chang, D. W. Shun, C. K. Yi, J. E. Son, and S. D. Kim. "Correlation on the particle entrainment rate in gas fluidized beds, "Ind. Eng. Chem. Res., vol. 38(6), Apr. 1999. pp. 2491–2496.
[23] D. Geldart, “Types of gas fluidization,” Powder Technol., vol. 7(5), May. 1973. pp. 285–292.