THE HYDRODYNAMICS OF A FAST FLUIDIZED BED CHARACTERIZED BY ITS PRESSURE SIGNALS (TRANSDUCER, HIGH VELOCITY, RISER).
Item
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Title
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THE HYDRODYNAMICS OF A FAST FLUIDIZED BED CHARACTERIZED BY ITS PRESSURE SIGNALS (TRANSDUCER, HIGH VELOCITY, RISER).
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Identifier
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AAI8708318
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identifier
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8708318
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Creator
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SCHNITZLEIN, MICHAEL GEORG.
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Contributor
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H. Weinstein
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Date
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1987
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Language
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English
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Publisher
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City University of New York.
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Subject
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Engineering, Chemical
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Abstract
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Fast fluidization flow characteristics were studied using instantaneous pressure signals in a fast fluidization unit with 0.152 m I.D. and 8.4 m height using as a solid a Zeolite FCC catalyst, HFZ-33 (dp = 59 um).;The data confirmed that a fast fluidized bed can usually be clearly divided into two main regions, a dense region at the bottom and a dilute region at the top of the bed. Within both regions the mean void fractions are essentially constant along the height and only dependent on flow parameters, i.e. superficial gas velocities and solid rate. In particular the void fraction in the dense region is even independent of the solid rate and varies only slightly with the superficial gas velocity.;The bed height, taken as the transition between dense and dilute regions, is clearly influenced both by flow parameters and flow conditions in the gas entrance section. This leaves the latter as a powerful tool for variations in solid hold-up under otherwise constant gas velocities and solid rates.;Upward moving instabilities were detected within the dense region of the bed with a wave speed being fairly constant over a wide range of flow parameters. There is a clear similarity to phenomena in slugging fluidized beds.;The presented results suggest that the solid in the dense regions of high-velocity fluidized beds is present in three different forms; fairly stagnant in a dense annulus region, very dilute in a core region and in the form of waves rolling upward between the core and dense annulus.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Engineering
