Journal Article•
ELUTRIATION OF FINES FROM FLUIDIZED BED:Study of Transport Disengaging Height
01 Jan 1972-Journal of Chemical Engineering of Japan (The Society of Chemical Engineers, Japan)-Vol. 5, Iss: 1, pp 57-62
About: This article is published in Journal of Chemical Engineering of Japan.The article was published on 1972-01-01 and is currently open access. It has received 11 citations till now. The article focuses on the topics: Fluidized bed & Elutriation.
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TL;DR: In this article, a simplified theory for a bubble column is applied to understand particle circulation in the fluidized catalytic beds, and it is possible to analyze flow patterns of bubbles and emulsion.
Abstract: Publisher Summary Flow properties of the fluidized catalyst bed (FCB) are different from those of other conventional fluidized beds. The different treatment required is very significant for research and development on fluidized catalytic beds. This chapter discusses the factors affecting the flow properties. These properties include particle size distribution, also heat and mass transfer, and mixing properties. In the FCB, the dilute phase plays an important role in advancing the catalytic reaction when reaction rates are high. This factor provides a basis for identifying the appropriate reaction model and clarifying the effect of the dilute phase on selectivity and stability. The simplified theory for a bubble column is applied to understand particle circulation in the FCB. As a result, it is possible to analyze flow patterns of bubbles and “emulsion.” This chapter considers the uses of fluidized beds for catalytic reactions, using a viewpoint quite different from studies directed toward the physical handling of solid particles or toward gas–solid noncatalytic reaction. Particle size distribution has a great effect on most aspects of fluidization. Fluid beds are usually operated in the turbulent-flow region to obtain good contact and sufficient throughput of reactant gas. The uniformity and contact efficiency of a fluid bed can be improved by immersion of a surface within the bed.
80 citations
TL;DR: In this article, the total entrainment flux EZ and the elutriation rate constants Ki∞* are found to depend on the gas velocity in the form of EZ ∝ Un and Ki ∞* ∝ Um, respectively.
60 citations
TL;DR: In this article, a fine-grained optic fiber probe with a core diameter in excess of the particle diameter is used to detect free-falling particles at terminal velocity, and the carryover stream of a gas-fluidized bed is simultaneously probed and collected in a cyclone separator.
47 citations
TL;DR: In this article, atomised and milled Ferrosilicon with average particle diameters of 38 and 50µm respectively were fluidized with air at ambient conditions and the entrainment rate of more spherical atomised particles was on average six times that of irregularly shaped milled particles over the range of superficial velocities investigated.
15 citations
TL;DR: In this article, the qualitative effect of temperature on the particle entrainment rate has been measured in a gas fluidized bed (0.1 m i.d., 1.97 m height).
Abstract: The qualitative effect of temperature on the particle entrainment rate has been measured in a gas fluidized bed (0.1 m i.d., 1.97 m height). The gas velocity (0.65-2.3 m/s), the bed temperature (12-600 °C), the particle density (2509-6158 kg/m 3 ), and the particle size (0.091-0.363 mm) were considered as experimental variables. The particle entrainment rate increased after an initial decrease with increasing bed temperature. The effect of temperature on particle entrainment rate decreased as either the gas velocity or the particle density increased. Within the experimental range, it could be confirmed that the change of the particle entrainment rate with temperature was very similar to that of the particle size for which the terminal velocity was equal to the gas velocity.
14 citations