An Experimental Study on Holdup Measurement in Fluidized Bed by Light Transmission

Authors: E. Shahbazali, N. Afrasiabi, A. A. Safekordi

Abstract:

Nowadays, fluidized bed plays an important part in industry. The design of this kind of reactor requires knowing the interfacial area between two phases and this interfacial area leads to calculate the solid holdup in the bed. Consequently achieving interfacial area between gas and solid in the bed experimentally is so significant. On interfacial area measurement in fluidized bed with gas has been worked, but light transmission technique has been used less. Therefore, in the current research the possibility of using of this technique and its accuracy are investigated. Measuring, a fluidized bed was designed and the problems were averted as far as possible. By using fine solid with equal shape and diameter and installing an optical system, the absorption of light during the time of fluidization has been measured. Results indicate that this method that its validity has been proved in the gas-liquid system, by different reasons have less application in gas-solid system. One important reason could be non-uniformity in such systems.

Keywords: Fluidization, Holdup, Light Transmission, Two phase system.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1079678

References:

[1] Kunii, D., Levenspiel, O., "Fluidization Engineering", 2rd ed., Butterworth Heinemann, (1991).
[2] Matsuura, A., Fan, L., "Distribution of bubble properties in a Gas-liquidsolid fluidized bed", AICHE journal, vol. 30, No.6, pp. 894-903 (1984).
[3] Kitano, K., Fan, L., "Near-wake structure of a single gas bubble in a two-dimensional liquid-solid fluidized bed: Solids Holdup", Chemical Engineering Science, vol. 43, No. 6, pp. 1355-1361 (1988).
[4] Widyanto, M. R., Utomo, M. B., Kawamoto, K., Kusumoputro, B., Hirota, K., "Local gas holdup measurement of a bubble column using SONIA-ultrasonic non-invasive method", Sensors and Actuators A: Physical, vol. 126, Issue 2, pp. 447-454 (2005).
[5] Zheng, Y., Zhang, Q., "Simultaneous Measurement of Gas and Solid Holdups in Multiphase Systems Using Ultrasonic Technique", Chemical Engineering Sci. 59 3505-3514 (2004).
[6] Won Kim, S., & Kirbas, G., H.Bi, C. jim Lim, J. R. Grace, "Flow behavior and regime transition in a high-density circulating fluidized bed riser", Chemical Engineering Sci. 59. 3955-3963 (2004).
[7] Bhusarapu, S., Al-Dahhan, M. H., Dudukovic, M. P., "Solid flow mapping in a gas-solid riser: Mean holdup and velocity fields". Powder Technology, 163, 98-123 (2006).
[8] Jin, H., Yang, S., He, G., Guo, Z., Tong, Z., "An Experimental study of Holdup in large-scale p-xylene oxidation reactors using the ╬│-raye attenuation approach", Chemical Engineering Sci., 60, 5955-5961 (2005).
[9] Rose, H., Lloyd, h.," On the Measurement of the size Characteristics of Powders by Photo-Extinction Methods I. Theoretical Considerations", J. Soc. Chem. Ind., 65, 52 (1946).
[10] Boll, R. H., Sliepcevich, C. M., "Evaluation of Errors of Optical Origin Arising in the Size Analysis of a Dispersion by Light Transmission", J. Opt. Soc. Am., 46, 200 (1956).
[11] Dobbins, R. A. , Jizmagian, G. S., "Optical Scattering Cross Sections for Polydispersions of Dielectric Spheres", J. Opt. Soc. Am.,56, 1345 (1966).
[12] Calderbank, P. H., "Physical rate processes in industrial fermenters. Part I: The interfacial area in gas/liquid contacting with mechanical agitation." Transactions of the Institution of Chemical Engineers, 36, 443-463 (1958).
[13] Lee, J. C., and G. W. K. Ssali, "Bubble transport and Coalescence in a Vertical Pipe, Joint Meeting on Bubbles and Foams", S1-6.1, Verfahrenstechnische Gesellschaft im VDI-Inst. Chem. Engrs., Nurnberg (1971)
[14] Trice, V. G., and W. A. Rodger, "Light Transmission as a measure of Interfacial Area in Liquid-Liquid Dispersions", AIChE J., 2, 205 (1956)
[15] Lockett, M. J. , Safekourdi, A. A., "Light Transmission Through Bubble Swarms", AIChE Journal,vol. 23, No. 3 ,pp. 395-398 (1977).
[16] Mclaughlin, G. F., & Rushton, J. H., "Interfacial Area of liquid-liquid dispersions from Light Transmission Measurements", AIChE J., 19, 817 (1973).
[17] Curl, R. L., "Note on Light Transmission through a Polydisperse dispersion", AIChE J., 20, 184 (1974).
[18] Rizzuti, L., & Yue, P. L., " The measurement of Light Transmission through an irradiated fluidized bed", Chemical Engineering Science, 38, 8, 1241-1983 (1982).
[19] Mie, P. Ann. Phys. Lpz., 33, 1275 (1910).
[20] Sinclair, D., Handbook of Aerosols, Ch. 7 (Washington, D.C.: Atomic Energy Commission) (1950).
[21] Chiao-Min-Chu., J. phys. Chem., 59, 841 (1955).
[22] Clark, N. O. & Blackman, M., Trans. Faraday Soc., 44, 1 (1948).
[23] Vermeulen, T., Williams, G. M. & Langlois, G. E., Chem. Engng Progr., 51, 85 (1955).
[24] Wood, R. W. Optical Physics, (London: The MacMillan Co.), (1911)
[25] Walton, W. H. In Symposium on Particle Size Analysis, (London: The Institution of Chemical Engineers), p. 141 (1947).