Backmixing and Liquid Holdup in a Gas-Liquid Cocurrent Upflow Packed Column

Stiegel, Gary J.; Shah, Y. T.

doi:10.1021/i260061a006

Cited by 65 publications

(38 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…0930-7516/90/0102-0027 $02,5010 Weber [23] Weber [23] Weber [23] Weber [23] Weber [23] Turpin, Huntington [22] Stiegel, Shah [21] Ford [24] Achwal,…”

Section: The Boundary Problemmentioning

confidence: 99%

Residence time distribution and hold‐up in a cocurrent upflow packed bed reactor at elevated pressure

Gelder

Westerterp

1990

Chem Eng & Technol

View full text Add to dashboard Cite

The residence time distribution in liquid phase was measured in a cocurrent upflow packed bed reactor for the system methanol-hydrogen at low Reynolds numbers and at elevated pressure. The plug flow with axial dispersion model was used to describe mixing in the system. The imperfect pulse method was used to measure the system response to a tracer pulse input. The parameters were calculated using the weighted moments method. The influence of the weighting factor was investigated. The experimental and theoretical outputs, as calculated by convolution, agreed very well. Different types of correlations were used for the Bodenstein number and liquid hold-up. From these correlations, the optimal one was selected for each parameter. A comparison was made between the ordinary moments and the weighted moments methods which led to the conclusion that the latter method is superior with respect to the accuracy of the estimated parameters and therefore strongly recommended.

show abstract

“…0930-7516/90/0102-0027 $02,5010 Weber [23] Weber [23] Weber [23] Weber [23] Weber [23] Turpin, Huntington [22] Stiegel, Shah [21] Ford [24] Achwal,…”

Section: The Boundary Problemmentioning

confidence: 99%

Residence time distribution and hold‐up in a cocurrent upflow packed bed reactor at elevated pressure

Gelder

Westerterp

1990

Chem Eng & Technol

View full text Add to dashboard Cite

show abstract

“…This relationship was also examined by Stiegel and Shah (1977b). All work reported in Table 5 has been carried out in cylindrical columns.…”

Section: (40)mentioning

confidence: 99%

Backmixing in gas‐liquid reactors

1978

Self Cite

View full text Add to dashboard Cite

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...

show abstract

“…The effect of various internals such as packing (150), screens (151), and vertically suspended tubes (152) on the axial dispersion coefficient was also studied by tracer methods. The effect of various internals such as packing (150), screens (151), and vertically suspended tubes (152) on the axial dispersion coefficient was also studied by tracer methods.…”

mentioning

confidence: 99%

Tracer Methods in Chemical Reactors. Techniques and Applications

Duduković

1986

Chemical Reactor Design and Technology

View full text Add to dashboard Cite

Backmixing and Liquid Holdup in a Gas-Liquid Cocurrent Upflow Packed Column

Cited by 65 publications

References 17 publications

Residence time distribution and hold‐up in a cocurrent upflow packed bed reactor at elevated pressure

Residence time distribution and hold‐up in a cocurrent upflow packed bed reactor at elevated pressure

Backmixing in gas‐liquid reactors

Tracer Methods in Chemical Reactors. Techniques and Applications

Contact Info

Product

Resources

About