Effects of Decrease in Gas Volume due to Reactions on the Fluidization Quality in a Fluidized Catalyst Bed

Kai, Takami; Nishie, Kyouichi; Takahashi, Tetsuo; Nakajima, Mitsuyuki

doi:10.1252/kakoronbunshu.30.256

Cited by 10 publications

(4 citation statements)

References 12 publications

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“…By analyzing the signal pattern of the pressure fluctuations measured at the bed bottom, the presence of channeling and slugging was estimated. Recently, the phenomena occurring in the bed were directly observed6 when the hydrogenation of carbon dioxide was carried out in a fluidized catalyst bed. It was observed that the upper part of the emulsion phase was defluidized and this part was lifted up through the column as a moving piston.…”

Section: Introductionmentioning

confidence: 99%

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Effect of volume decrease on fluidization quality of fluidized catalyst beds

et al. 2006

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Section: Introductionmentioning

confidence: 99%

“…This part of the packed bed was lifted up like a moving piston in previous studies. Kai et al6 studied these effects and concluded that the cause of these phenomena was the reduction of the emulsion‐phase voidage caused by the reaction involving a decrease in the gas volume.…”

Section: Introductionmentioning

confidence: 99%

Effect of volume decrease on fluidization quality of fluidized catalyst beds

et al. 2006

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“…Recently, using glass reactors, phenomena occurring in the bed have been directly observed7, 8 during hydrogenation of CO 2 . The emulsion phase was defluidized and a packed bed was formed and then lifted through the column like a moving piston.…”

Section: Introductionmentioning

confidence: 99%

Analysis of fluidization quality of a fluidized bed with staged gas feed for reactions involving gas‐volume reduction

et al. 2010

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A significant defluidization occurs when carrying out reactions involving a decrease in gas volume in a fluidized catalyst bed. The cause of this phenomenon is a decrease in the gas velocity in the emulsion phase below the minimum fluidization velocity. Fluidization quality is improved by a staged gas feed when hydrogenation of CO 2 is carried out. To evaluate the experimental results, two parameters are introduced; gas-volume reduction rate and gas-volume ratio. Fluidization quality and defluidization zone are indicated as a map using these parameters. The vertical distributions of these parameters are calculated using a reactor model to obtain operating lines. The calculation shows that fluidization quality can be improved by operating the reactor by avoiding the operating lines of the defluidization zone in the map. For this purpose, it is required to control the gas-volume ratio at a level near unity and maintain the gasvolume reduction rate below 0.01/s.

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“…It has been reported that the fluidization quality was drastically decreased when the reactions involving a decrease in the gas volume were carried out in a fluidized catalyst bed (Kai and Furusaki, 1987;Kai et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Effects of Increase in Gas Volume on the Fluidization Properties in Fluidized Bed Reactors

Kai

Horinouchi

Nakazato

et al. 2009

J. Chem. Eng. Japan / JCEJ

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There are many industrially useful reactions accompanied by the change of the gas volume due to the stoichiometry. Although it is important to consider the effects of the gas-volume changes for the accurate estimation of the reactor performance, the effects on the fluidization properties have not been experimentally studied. In this study, experimental simulation was carried out to study the effects of the increase in gas volume on the fluidization properties. The gas volume was increased by the evaporation of water impregnated in the pores of alumina particles at elevated temperature. The effects on the expansion of the emulsion phase, average bubble holdup, bubble size and pressure fluctuations were studied. The bubble growth, splitting and coalescence would become vigorous, whereas the emulsion phase expansion was not affected and the bubble size was slightly increased.

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Effects of Decrease in Gas Volume due to Reactions on the Fluidization Quality in a Fluidized Catalyst Bed

Cited by 10 publications

References 12 publications

Effect of volume decrease on fluidization quality of fluidized catalyst beds

Effect of volume decrease on fluidization quality of fluidized catalyst beds

Analysis of fluidization quality of a fluidized bed with staged gas feed for reactions involving gas‐volume reduction

Effects of Increase in Gas Volume on the Fluidization Properties in Fluidized Bed Reactors

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