Multiplicity Behavior of Trickle Flow Liquid−Solid Mass Transfer

Joubert, Rita; Nicol, Willie

doi:10.1021/ie9002552

Cited by 9 publications

(7 citation statements)

References 20 publications

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“…Although the instantaneous mass transfer coefficients in this subfigure are not affected by wetting efficiency, a marked difference between Levec and extensively pre‐wetted beds still persist. This finding is in direct agreement with the results from Joubert and Nicol41 who observed slower liquid–solid mass transfer in a Levec prewetted bed than in an extensively prewetted bed, even though the interstitial velocity is higher (lower liquid holdup). This suggests that the difference in flow structure between the Levec and extensively prewetted beds24, 42–45 has a severe impact on the liquid–solid mass transfer characteristics.…”

Section: Resultssupporting

confidence: 92%

Parallel hydrogenation for the quantification of wetting efficiency and liquid–solid mass transfer in a trickle‐bed reactor

Houwelingen

Nicol

2011

AIChE Journal

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A novel method for the measurement of wetting efficiency in a trickle-bed reactor under reaction conditions is introduced. The method exploits reaction rate differences of two first-order liquid-limited reactions occurring in parallel, to infer wetting efficiencies without any other knowledge of the reaction kinetics or external mass transfer characteristics. Using the hydrogenation of linear-and isooctenes, wetting efficiency is measured in a 50-mm internal diameter, high-pressure trickle-bed reactor. Liquidsolid mass transfer coefficients are also estimated from the experimental conversion data. Measurements were performed for upflow operation and two literature-defined boundaries of hydrodynamic multiplicity in trickle flow. Hydrodynamic multiplicity in trickle flow gave rise to as much as 10% variation in wetting efficiency, and 10-20% variation in the specific liquid-solid mass transfer coefficient. Conversions for upflow operation were significantly higher in trickle-flow operation, because of complete wetting and better liquid-solid mass transfer characteristics.

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Section: Resultssupporting

confidence: 92%

Parallel hydrogenation for the quantification of wetting efficiency and liquid–solid mass transfer in a trickle‐bed reactor

Houwelingen

Nicol

2011

AIChE Journal

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“…Thus, a "co-current-flow" configuration with the cathode and anode stacked at different axial positions [26,43,44] between polyurethane foam blocks was chosen. To minimize the ohmic potential drop, the electrodes were installed above and below one polyurethane foam block 100 mm in height.…”

Section: Experimental Set-up and Conditionsmentioning

confidence: 99%

“…The influence of the initial distribution on the wetting fraction was investigated with three different liquid distributors: single-point and multi-point distributors, and a spray nozzle. Oxidation occurred at the anode (A), while reduction (reverse reaction) occurred at the cathode (B): Thus, a "co-current-flow" configuration with the cathode and anode stacked at different axial positions [26,43,44] between polyurethane foam blocks was chosen. To minimize the ohmic potential drop, the electrodes were installed above and below one polyurethane foam block 100 mm in height.…”

Section: Experimental Set-up and Conditionsmentioning

confidence: 99%

Wetting Fraction in a Tubular Reactor with Solid Foam Packing and Gas/Liquid Co-Current Downflow

Mohammed

Hampel

2018

Catalysts

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The performance of fixed-bed reactors with structured catalysts depends heavily on the gas–liquid–solid contacting pattern. For a broad range of flow conditions, the liquid phase does not cover the solid surface of the packing homogeneously; this is known as partial wetting. The wetting fraction in solid foams was obtained using a modified electrochemical measurement method with adaption of the limiting-current technique in different pre-wetting scenarios. The external wetting fraction, which is defined as fraction of the external solid-foam area covered by the liquid phase to the total external solid-foam area, is directly linked to the overall rate of reaction through the overall liquid mass transfer rate. The wetting fraction decreased with an increase in foam density, a process which was related to decreasing the strut thickness, increasing foam surface area, and consequently, decreasing the wetted area. Additionally, the results indicate that a better distribution of liquid and an increased wetting fraction occurred when a spray nozzle distributor was applied. A new wetting correlation for solid foams is proposed to estimate the wetting fraction with consideration of foam morphology and flow regime.

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“…As such, the experimental results of Babu and coworkers ) cannot be included due to the fact that conditions for individual data points have not been reported. It is worth commenting that packing procedure (Zou and Yu 1995) and start-up operation (Loudon et al 2006, Joubert andNicol 2009) may also influence thermal conductivity values, but no systematic studies were found in the literature to undertake a reliable analysis.…”

Section: Analysis Of the Available Experimental Information And Corrementioning

confidence: 99%

A critical review on heat transfer in trickle bed reactors

Taulamet¹,

Mariani²,

Barreto³

et al. 2015

Reviews in Chemical Engineering

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AbstractA critical review of the available information about heat transfer between a packed bed with cocurrent downflow of gas and liquid and an external medium was undertaken. Several aspects such as experimental set-ups and methods employed to study heat transfer in trickle bed reactors, models used to interpret experimental data, and literature correlations of heat transfer parameters are addressed. From the analysis of the available experimental information, a refined database has been built, which allows comparing the performance of the existing correlations for the parameters of the extensively employed two-dimensional pseudohomogeneous plug flow model (i.e., effective radial thermal conductivity and wall heat transfer coefficient). In addition, new correlations for effective thermal conductivity have been developed. Identification of gaps in the current knowledge and recommendations for future works are summarized.

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Multiplicity Behavior of Trickle Flow Liquid−Solid Mass Transfer

Cited by 9 publications

References 20 publications

Parallel hydrogenation for the quantification of wetting efficiency and liquid–solid mass transfer in a trickle‐bed reactor

Parallel hydrogenation for the quantification of wetting efficiency and liquid–solid mass transfer in a trickle‐bed reactor

Wetting Fraction in a Tubular Reactor with Solid Foam Packing and Gas/Liquid Co-Current Downflow

A critical review on heat transfer in trickle bed reactors

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