Determination of mass transfer resistances of fast reactions in three‐phase mechanically agitated slurry reactors

Stamatiou, Ilias; Muller, Frans L.

doi:10.1002/aic.15540

Cited by 19 publications

(23 citation statements)

References 50 publications

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“…The data for calculating the mass transfer coefficients of hydrogen were found in the work of Stamatiou and Muller, 4 while the liquid-solid mass transfer coefficients of styrene and ethylbenzene were correlated to the liquid-solid mass transfer coefficient of hydrogen based on the values of the square root of their diffusion coefficients in methanol, since the surface renewal model suggests that k D i …”

Section: Resultsmentioning

confidence: 99%

“…Regarding the first set of constrains, the observed chemical reaction constant,  k obs , and its 95% confidence intervals were calculated from the data in the work of Stamatiou and Muller. 4 The  k obs needs to lie between 0.059 mol L g s Regarding the second set of constrains, the concentration profile of styrene is divided into two different regimes ( Fig. 4).…”

Section: Objective Function and Constrainsmentioning

confidence: 99%

“…The confidence bounds of the simulated concentration profiles are calculated based on linear regression models found in the work of Stamatiou and Muller. 4…”

Section: View Article Onlinementioning

confidence: 99%

“…The three-phase reaction involves hydrogen mass transfer from gas to the bulk of the liquid phase, substrate and hydrogen mass transfer from the bulk to the surface of the solid phase and pore diffusion within the solid phase and finally transfer and adsorption onto the catalytic metal nanoparticles dispersed over the pore surface. [2][3][4] The chemical reaction occurs on the nanoparticles: adsorbed reactants migrate to active sites where the reaction activation energy is lowest. Each of the mass transfer processes and the chemical reaction affect the overall rate to different extents.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, when a fast chemical reaction takes place the mass transfer is likely to affect strongly the overall rate. 4 The objective of this work is to develop a model to describe the heterogeneous hydrogenation of styrene over a commercial Pd/C in a semi-batch dead-end stirred tank reactor and approximate the surface kinetics of the reaction by comparing the simulated concentration profile of styrene to experimental data for which the experimental methodology, material details, and results are in the work of Stamatiou and Muller. 4…”

Section: Introductionmentioning

confidence: 99%

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Determination of styrene hydrogenation surface kinetics through detailed simulation of the hydrogen uptake curve

2019

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The styrene hydrogenation over Pd/C in a three-phase dead-end stirred tank reactor has been simulated.The mass transfer coefficients were calculated based on experimental data. The fast intrinsic reaction kinetics did not allow the effects of the gas-liquid and liquid-solid mass transfer to be ignored. A rigorous model is described which includes all mass transfer steps with a Langmuir-Hinshelwood model of the surface chemical reaction. The adsorption constants of hydrogen, styrene and ethylbenzene on catalyst active sites were estimated from a single experimental reaction profile. The parameterised model was validated against 6 further sets of experimental data which were not included in the parameters' estimation procedure. Results indicate the ethylbenzene, styrene and hydrogen adsorption to have an equilibrium constant of 148.34 L mol −1 , 847.72 L mol −1 and 19 984 L mol −1 , respectively. The intrinsic rate constant for the 4.63%Pd/C catalyst is 0.0542 mol g cat −1 s or 1.17 mol g Pd −1 s −1 . This work demonstrates that the analysis of the whole hydrogenation reaction profile in combination with detailed mass transfer resistance evaluation can provide fundamental system properties.

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Section: Resultsmentioning

confidence: 99%

Section: Objective Function and Constrainsmentioning

confidence: 99%

“…The confidence bounds of the simulated concentration profiles are calculated based on linear regression models found in the work of Stamatiou and Muller. 4…”

Section: View Article Onlinementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of styrene hydrogenation surface kinetics through detailed simulation of the hydrogen uptake curve

2019

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Two‐ and Three‐Phase Chemical Reactors

Pangarkar¹

2018

Kirk-Othmer Encyclopedia of Chemical Technology

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This article presents a discussion on three major types of two/three‐phase reactors: bubble column or two/three‐phase sparged reactor, stirred reactor, and venturi loop reactor. The aim is to provide appropriate process design philosophy. The basics of mass transfer accompanied by a chemical reaction are initially presented followed by experimental methods used for discerning reaction kinetics of a multiphase reaction. Metrics for reactor selection have been outlined. A simplified design philosophy that is based on identification of the rate‐controlling step and the associated rate equation has been presented. The intrinsic reaction kinetics do not vary with the type/size of the reactors used. Therefore, the problem reduces to prediction of reactor type and size‐dependent mass transfer coefficients. Subsequent discussion deals with individual reactors with respect to (i) advantages/drawbacks, (ii) areas of application, (iii) hydrodynamic regimes, (iv) gas‐phase holdup, (v) gas–liquid and solid–liquid mass transfer coefficients, k L a and K SL , respectively. The focus is on presenting reliable correlations for k L a and K SL that allow estimation of the rates of corresponding mass transfer steps. Comparison of these with the intrinsic reaction rate yields the rate‐controlling step and associated rate expression for reactor design. The article concludes with a comparison of the performance of the three types chosen for discussion. For the specific reaction chosen, it is concluded that the venturi loop system yields superior performance.

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Measuring gas hold‐up in gas–liquid/gas–solid–liquid stirred tanks with an electrical resistance tomography linear probe

et al. 2019

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An electrical resistance tomography (ERT) linear probe was used to measure gas holdup in a two-phase (gas-liquid) and three phase (gas-solid-liquid) stirred-tank system equipped with a Rushton turbine. The ERT linear probe was chosen rather than the more commonly used ring cage geometry to achieve higher resolution in the axial direction as well as its potential for use on manufacturing plant. Gas-phase distribution was measured as a function of flow regime by varying both impeller speed and gas flow rate. Global and local gas holdup values were calculated using ERT data by applying Maxwell's equation for conduction through heterogeneous media. The results were compared with correlations, hard-field tomography data, and computational fluid dynamic simulations available in the literature, showing good agreement. This study thus demonstrates the capability of ERT using a linear probe to offer, besides qualitative tomographic images, reliable quantitative data regarding phase distribution in gas-liquid systems.

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Determination of mass transfer resistances of fast reactions in three‐phase mechanically agitated slurry reactors

Cited by 19 publications

References 50 publications

Determination of styrene hydrogenation surface kinetics through detailed simulation of the hydrogen uptake curve

Determination of styrene hydrogenation surface kinetics through detailed simulation of the hydrogen uptake curve

Two‐ and Three‐Phase Chemical Reactors

Measuring gas hold‐up in gas–liquid/gas–solid–liquid stirred tanks with an electrical resistance tomography linear probe

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