Countercurrent Backmixing Model for Fluidized Bed Catalytic Reactors. Applicability of Simplified Solutions

Fryer, Colin; Potter, O. E.

doi:10.1021/i160043a009

Cited by 68 publications

(24 citation statements)

References 2 publications

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“…The model bears close resemblance to the countercurrent backmixing model of Fryer andPotter (1972, 1976) for bubbling beds. The slugging bed consists of the slugs, a wake of solids, carried upward by the slugs, and a particulate phase of solids flowing downward which corresponds to the piston flow section of the interslug region.…”

Section: Proposed M O D E Lmentioning

confidence: 69%

“…It is then assunned that the gas in this wake region is also well mixed. The resultant model shows many similarities to the countercurrent backmixing model, Fryer and Potter (1976). The flow of solids in and out of the wake region is more easily calculated in the slugging model, since it is simply related to the rise velocity of the slug.…”

Section: Conclusion and Significancementioning

confidence: 74%

“…Fryer and Potter (1972, 1974, 1976 have shown that the countercurrent backmixing model provides a good description of the behavior of bubbling fluidized beds, with advantages over other models. A three-phase model based on the countercurrent backmixing model has been developed here for describing the slugging fluidized-bed reactor.…”

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confidence: 99%

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Countercurrent backmixing model for slugging fluidized‐bed reactors

Raghuraman

Potter

1978

AIChE Journal

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An effective compromise between these two objectives can be achieved by using ratio control on both the recycle and undedow streams. No sludge storage is required, variations in the sludge height are slight, and fluctuations in the reactor solids concentration are small relative to the uncontrolled case. Countercurrent Backmixing Model for Slugging Fluidized-Bed ReactorsA model is developed for slugging fluidized bed catalytic reaction which improves on the model of Hovmand and Davidson by incorporating the solids mixing. The model parallels the countercurrent backmixing model of Fryer and Potter. SoIids mixing is accounted for by the model of Thiel and Potter which assumes the rising slug is followed by a well-mixed wake into and out of which solids flow at a rate determined by the rise velocity of the slug. Comparison is made with experimental data reported by Hovmand and Davidson with good results.

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Section: Proposed M O D E Lmentioning

confidence: 69%

Section: Conclusion and Significancementioning

confidence: 74%

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Countercurrent backmixing model for slugging fluidized‐bed reactors

Raghuraman

Potter

1978

AIChE Journal

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“…The contribution of the diffusion VOL. 10 NO. 4 1977 term Khdc is greater than that of the circulating flow term Kbbe.…”

Section: Discussionmentioning

confidence: 99%

Hydrogenation of ethylene in two dimensional gas-solid fluidised bed with perforated plate.

Toei

Oichi

Hayashi

et al. 1977

J. Chem. Eng. Japan

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A fairly rapid chemical reaction, i.e., hydrogenation of ethylene by palladium catalyst, was carried out at a room temperature in a two dimensional fluidised bed with a perforated plate distributor.The results were considerably affected by the behaviour of the bed near its bottom.The measured hydrogen conversion was compared with that predicted by the so-called "coalescence model". Consistency of the experimental and calculated results was fairly good. The significance of various parameters included in the model was also investigated. The parameters examined were the gas interchange coefficients, the volume fraction of particles in the bubble, and the gas flow rate as bubbles.In conclusion, it was pointed out that the deviation of gas flow rate as bubbles from that predicted by the two phase theory at the bottom of bed aflFected significantly the conversion of a rapid chemical reaction.

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“…To illustrate the genesis of models for solid catalysed reactions, Table 2 shows how the other parameters and boundary conditions are assigned for four representative models, the May model (16), the two Orcutt models (17,18) (differing only in the assumed dense phase gas mixing pattern), and the two-phase bubbling bed model proposed by Grace (19) as an improved simplification of the three-phase bubbling bed model of Kunii and Levenspiel (20) and as an approximation to the countercurrent backmixing model of Fryer and Potter (21). All of these authors have given solutions for their models for the case of first order irreversible sections.…”

Section: Representative Modelsmentioning

confidence: 99%