A study has been made of the effect of fixed packing on the properties of a gas-fluidized bed, including minimum fluidization velocity, pressure drop, and bed expansion. Experiments using a range of glass beads as fluidizing solid with smooth uniform spheres as packing indicate that both packing size and the ratio of particle to packing diameter are the main variables in correlating the results. Other solids of varying density and shape have also been used. In addition to smooth spherical packing, rough spheres and variously shaped packings such as Raschig rings, Bert saddles, and a cylindrical, open-ended screen packing have received preliminary study. With the screen packing, which occupies only 5% of the column volume, i t has been possible to operate a fluidized bed at a much higher gas throughput without slugging than is possible with a conventional bed.A preliminary study has also been made of heat transfer rates, and the results indicate that the same factors are significant. The fluidization of particulate material is a technique which has many industrial applications. Good mixing and high rates of heat and mass transfer are generally associated with its use. However, the nature of conventional gas-solid fluidization imposes certain restrictions on the design of fluid-bed reactors. For example, there is a limit to the length-to-diameter ratio which can be used without serious slugging. Also, if high gas flow rates are desired, the reactor depth must include a Iarge freeboard to allow for fluctuations in bed height. Although many proposals have been made for expanding the useful range of gas-solid fluidization, very little quantitative information about their effect on the behavior of fluidized beds has been published. The data which are available, including an extensive study by Massimilla into the use of screen baffles (9, 10, 11) and a paper by Gabor, et al. on heat transfer rates in fluidized beds containing fixed spherical packing ( 1 2 ) , indicate that the changes resulting from the insertion of these devices can be very marked. Reactor internals affect not only the overall quality of the fluidization but also the expansion and the flow pattens of both gas and solid. As a result, heat and mass transfer rates can deviate significantly from those occurring in conventional beds.The work described in this paper is an introductory investigation into the effect of fixed packing on the properties of gas-fluidized beds. Most of the experimental work was performed with beds of packed spheres, but a limited number of experiments were done using packings of different shapes, in particular a cylindrical screen packing which was felt to be particularly suitable for use in fluidized beds. Results are reported for unit pressure drop and gas velocity at incipient fluidization and for bed expansion. A limited number of results showing the effect of packing on heat transfer rates are also given.
APPARATUS AND PROCEDUREThe equipment used was of conventional design. The column consisted of a 3-in. I.D. plastic tube mou...
The possibility of the production of HCI by reactions involving inorganic chlorides present in municipal incinerators has been suggested. I t was proved thermodynamically that the presence of SO2 in the gas phase and SO2 and AI2O3 in the s o l i phase could contribute to the production of HCI. Then, a series of experknents was performed in a fused alumina tube reactor under conditions sknilar to those in incinerators using N e c k Si02, and AI& proved in this study to have strong potential for HCI production. The reaction kinetics of the HCI production in Incinerators has been also elucidated by the analysis of the experimental data obtained.
This study examines gender differences and laterality in maximal handgrip strength and controlled force exertion (CFE) in young adults. The subjects were 75 healthy young males (mean age 19.6 ± 1.6 yrs.) and 50 healthy young females (mean age 20.9 ± 1.9 yrs.). Maximal handgrip strength was measured twice. The subjects performed the CFE test three times after one practice trial. They matched their handgrip strengths to the demand values, which constantly changed and ranged from 5 to 25% of maximal handgrip strength. The difference between the demand value and the grip exertion value was used as an estimate of CFE. Maximal handgrip strength was significantly larger in males than in females in both the dominant and non-dominant hands, and was significantly larger in the dominant hand in both males and females. Insignificant gender differences were found in CFE of both hands. CFE was significantly superior in the dominant hand in both genders. In conclusions, gender differences are present in maximal handgrip strength of the dominant and non-dominant hands in young adults, but not in CFE of both hands. Laterality exists in maximal handgrip strength and in CFE for both genders
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