Catalytic Cracking of Methylcyclohexane Over Silica Alumina Catalyst in Gas Fluidized Bed

Tone, Setsuji; Seko, Hiroyasu; Maruyama, Hisao; Otake, Tsutao

doi:10.1252/jcej.7.44

Cited by 11 publications

(5 citation statements)

References 5 publications

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“…Toei et al (1974a) data show thatf: is proportional to d;o.6 or possibly to d;'.'. Tone et al (1974) reported that bubble diameter decreases with increasing temperature. This suggests that f : is also dependent on fluid viscosity.…”

Section: Description Of the Modelmentioning

confidence: 98%

A generalized bubble diameter correlation for gas‐solid fluidized beds

1987

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A new bubble diameter correlation is derived to predict bubbling characteristics of fluidized beds of varieties of powders. The present model is founded on the postulate that the steady bubble size, which is often called the maximum stable diameter, observed in a bed of Geldart group A powder is formed as a result of an equilibrium of successive coalescence and splitting. For the cases of group B powders the present correlation automatically converges to the conventional correlation of Mori and Wen (1975), whose predictions are close to those of Rowe (1976) and Darton et al. (1977). For group A powders the present correlation is validated by comparison with experimental data in the literature. Based on this correlation a theoretical explanation is presented for the fact that the maximum bubble diameters observed were up to 50 to 100 times as large as those from the stable bubble theory of Harrison et al. (1961).

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Section: Description Of the Modelmentioning

confidence: 98%

A generalized bubble diameter correlation for gas‐solid fluidized beds

1987

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“…It is known that the bubble size decreases with temperature, which is reflected in the reduced magnitude of pressure fluctuations at high temperatures Ž . Tone et al, 1974;Kai and Furusaki, 1985 . Therefore, at higher temperatures, more homogeneous flow behavior is obtained due to the bubble size reduction and the emulsion phase expansion yielding a higher bed voidage.…”

Section: Effect Of Temperature On the Phase Structure Measured By Thementioning

confidence: 99%

Bed nonhomogeneity in turbulent gas‐solid fluidization

Warsito

Fan

2003

AIChE Journal

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“…Recently, Mii et al9) pointed out that the bubble frequency in fluidized beds at high temperature became greater than that at room temperature. Tone et al 17) presented a correlation of effective bubble size with bed temperature.…”

Section: Models Of Gas Behavior In Fluidized Bedsmentioning

confidence: 99%

Behavior of Rising Bubbles in a Gas-Fluidized Bed at Elevated Temperature

Otake

Tone

Kawashima

et al. 1975

J. Chem. Eng. Japan

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Bubble size and the rise velocity of bubbles in fluidized beds at high temperature were measured by the electric capacitance method using an injection tube and a sintered-plate distributor. The bubble frequency increased with rise in temperature and the bubble size was rearranged as a function of bubble frequency and gas flow rate. The rise velocity of bubbles in swarms was divided into two terms, i.e., the rise velocity of isolated bubbles and the accelerated quantity due to bubble coalescence. The latter was correlated as a function of the ratio of distance between two successive bubbles to bubble radius. A model of bubble shape was proposed and effectively used to estimate the empirical coefficients included in the correlation for bubble size and rise velocity of bubbles. Intro ductionInformation on behavior of bubble motion is required to predict the performance of a fluidized catalytic reactor and to formulate an adequate model for design.Models of gas behavior in fluidized beds have been presented by many investigators4'6'8'11}, and theoretical and experimental evidence has shown that the coalescence of bubbles in swarms in a freely bubbling bed changes the bubble size, the rise velocity, the exchange of gas between bubble phase and dense In this study, measurements of bubble frequency, bubble size and rise velocity at high temperature in a fluidized bed were made by the electric capacitance method. Bubble size was correlated with bubble frequency and the rise velocity of isolated single bubbles was rearranged with the bubble size. Furthermore, the rise velocity of bubbles in swarms was correlated with the sum of the rise velocity of single bubbles and the term contributed to rise velocity by bubble coalescence. To explain the change in bubble size of coalesced bubbles, a new model for bubble shape is proposed. The relation between rise velocity and bubble size is discussed by considering the distance between the two successive bubbles and the change in bubble shape.

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Catalytic Cracking of Methylcyclohexane Over Silica Alumina Catalyst in Gas Fluidized Bed

Cited by 11 publications

References 5 publications

A generalized bubble diameter correlation for gas‐solid fluidized beds

A generalized bubble diameter correlation for gas‐solid fluidized beds

Bed nonhomogeneity in turbulent gas‐solid fluidization

Behavior of Rising Bubbles in a Gas-Fluidized Bed at Elevated Temperature

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