Solids concentration profile in the bubble column slurry reactor

Farkas, E. J.; Leblond, Pierre

doi:10.1002/cjce.5450470308

Cited by 28 publications

(4 citation statements)

References 7 publications

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“…(1966), Imafuku et al (1968), Farkas and Leblond (1969), and Narayanan et al (1969). Cova (1966) studied the effects of liquid velocity, gas velocity, and liquid viscosity on the solid concentration profile and concluded that higher gas and liquid velocities and high viscosities all tend to give more uniform solid distributions.…”

Section: Resultsmentioning

confidence: 99%

Hydrodynamics and axial mixing in a three-phase bubble column

Kara¹,

Kelkar²,

Shah³

et al. 1982

Ind. Eng. Chem. Proc. Des. Dev.

119

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Section: Resultsmentioning

confidence: 99%

Hydrodynamics and axial mixing in a three-phase bubble column

Kara¹,

Kelkar²,

Shah³

et al. 1982

Ind. Eng. Chem. Proc. Des. Dev.

119

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“…Cova (1966) measured the steady state concentration distribution of solids in a three-phase reactor. Farkas and Leblond ( 1969) used such data to calculate the backmixing coefficient of solids.…”

Section: Ezlaul'"' (491mentioning

confidence: 99%

Backmixing in gas‐liquid reactors

1978

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This review evaluates the present state of the art on backmixing in gas-liquid and gas-liquid-solid reactors. A brief outline of numerous techniques for measuring residence time distribution (RTD) of various phases in a multiphase reactor is presented. This is followed by a brief description of differential and stagewise models for characterizing backmixing from RTD measurements. Both simple (that is, single-parameter axial dispersion model) and more complex (that is, two-, three-, or four-parameter models) models are evaluated. Backmixing characteristics of various gas-liquid columns such as trickle beds, spray columns, mechanically agitated columns, plate columns, fluidized bed columns, etc., are subsequently evaluated. The performance of a bubble column under various reaction conditions is analyzed. Criteria for the elimination of backmixing in packed-bed reactors are presented, and the effect of backmixing on the multiple steady states in a gas-liquid reactor is briefly reviewed. Finally, the scale-up problems associated with gas-liquid reactors with various degrees of backmixing and the recommendations for the future work in RTD and macromixing models are outlined. SCOPEIt is well known that backmixing is detrimental to the performance of a gas-liquid or a gas-liquid-solid reactor. This review outlines various aspects of backmixing in gas-liquid reactors.The review first outlines the methods for measuring residence time distributions for various phases in a gasliquid and a gas-liquid-solid reactor. The data for the residence time distributions (RTD) are evaluated by a variety of simple (for example, one-parameter axial dispersion model) and complex (for example, two-, three-, or four-parameter) differential or stagewise macromixing models. These models are briefly evaluated.From the point of view of backmixing, gay-liquid and gas-liquid-solid reactors can be classified into three broad categories: film reactors where the liquid is the dispersed phase and flows as a film, for example, trickle-bed reactors; gas dispersed as bubbles in a continuous liquid phase, for example, bubble column and slurry reactors; and liquid dispersed as droplets in a continuous gas phase, for example, spray column reactors. Backmixing characteristics of each of these types of reactors are briefly evaluated. The backmixing in these reactors has been largely characterized on the basis of axial dispersion model. Models for gas-liquid bubble column reactors are briefly reviewed. Slow, fast, and instantaneous gas-liquid reactions are considered. Criteria for eliminating the effect of backmixing on the performance of isothermal and adiabatic trickle-bed reactors are outlined. Unlike a singlephase reactor, an adiabatic gas-liquid reactor can lead to five steady states, and the literature on this unique feature of the gas-liquid reactor is briefly reviewed.Finally, there is a brief outline of the scale-up problems associated with RTD, and some recommendations for the future work on RTD and macromixing models are presented. CONCLUSIONS AND...

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“…It is recognized that a three-phase fluidized bed is rather difficult to design because the phase holdups are axially distributed in the column. Many works (Cova, 1966;Imafuku et al, 1968; Farkas and Leblond, 1969;Kato et al, 1985; Smith and Ruether, 1985;Smith et al, 1986; Morooka et al, 1986; Murray and Fan, 1989) have been published, especially on the behavior of solid particles in three-phase fluidization, but most were restricted to the case of particles with the same size and density. When a mixture of solid particles is used as the solid phase, on the other hand, segregation of components naturally occurs in the bed.…”

Section: Introductionmentioning

confidence: 99%