Effect of pulsing on reaction outcome in a gas–liquid catalytic packed-bed reactor

Wu, Ruiyun; McCready, Mark J.; Varma, Arvind

doi:10.1016/s0920-5861(98)00373-3

Cited by 14 publications

(6 citation statements)

References 7 publications

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“…Figure compares the transition point from steady flow to pulsing flow with a regime map originally proposed by Charpentier in 1975 . Even though it has been shown that operating in a pulsing flow regime can improve performance, doing so complicates the interpretation of mass transfer and kinetic data . Therefore, for all of the experimental kinetic data reported here, the reactor was operated in the steady cocurrent flow regime.…”

Section: Resultsmentioning

confidence: 81%

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Microfabricated Multiphase Packed-Bed Reactors: Characterization of Mass Transfer and Reactions

Losey

Schmidt

Jensen

2001

Ind. Eng. Chem. Res.

410

332

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A microchemical device has been built in silicon and glass by using microfabrication methods including deep-reactive-ion etch technology, photolithography, and multiple wafer bonding. The microchemical system consists of a microfluidic distribution manifold, a microchannel array, and a 25-µm microfilter for immobilizing solid particulate material within the reactor chip and carrying out different heterogeneous chemistries. Multiple reagent streams (specifically, gas and liquid streams) are mixed on-chip, and the fluid streams are brought into contact by a series of interleaved, high-aspect-ratio inlet channels. These inlet channels deliver the reactants continuously and cocurrently to 10 reactor chambers containing standard catalytic particles. The performance of the microfabricated "packed-bed" reactor is compared to that of traditional multiphase packed-bed reactors in terms of fluid flow regimes, pressure drop, and mass transfer. The hydrogenation of cyclohexene is used as a model reaction to measure the mass transfer resistances. Overall mass transfer coefficients (K L a) are measured to range from 5 to 15 s -1 snearly 2 orders of magnitude larger than values reported in the literature for standard laboratory-scale reactors.

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Section: Resultsmentioning

confidence: 81%

“…20 Even though it has been shown that operating in a pulsing flow regime can improve performance, doing so complicates the interpretation of mass transfer and kinetic data. 21 Therefore, for all of the experimental kinetic data reported here, the reactor was operated in the steady cocurrent flow regime. Reaction Results.…”

Section: Resultsmentioning

confidence: 99%

Microfabricated Multiphase Packed-Bed Reactors: Characterization of Mass Transfer and Reactions

Losey

Schmidt

Jensen

2001

Ind. Eng. Chem. Res.

410

332

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“…The purpose of pulsing liquid is effectively to "hold" bubbles for a fraction of time (e.g., 0.5 Hz), this enhances overall heat and mass transport while reducing axial dispersion. Keeping all other parameters constant, reactor operation in the presence of pulses resulted in up to 30% increase in reaction rate, 44 15% increase in styrene concentration, 51 and 45% improvement in styrene selectivity in hydrogenation of phenylacetylene over Pt/γ-Al 2 O 3 catalyst compared with that without. Some mass transfer data in pulsed trickle bed reactors were reported, [52][53][54] once again, no information was given on both where dissolved gas concentration was measured and energy dissipation rate.…”

Section: Pulsed Trickle Bed Reactormentioning

confidence: 99%

Another Critical Look at Three-Phase Catalysis

2020

Pharmaceutical Fronts

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Three-phase catalysis, for example, hydrogenation, is a special branch of chemical reactions involving a hydrogen reactant (gas) and a solvent (liquid) in the presence of a metal porous catalyst (solid) to produce a liquid product. Currently, many reactors are being used for three-phase catalysis from packed bed to slurry vessel; the uniqueness for this type of reaction in countless processes is the requirement of transferring gas into liquid, as yet there is not a unified system of quantifying and comparing reactor performances. This article reviews current methodologies in carrying out such heterogeneous catalysis in different reactors and focuses on how to enhance reactor performance from gas transfer perspectives. This article also suggests that the mass transfer rate over energy dissipation may represent a fairer method for comparison of reactor performance accounting for different types/designs of reactors and catalyst structures as well as operating conditions.

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“…In particular, under microgravity conditions and for packing sizes greater than 2 mm, pulse flow has been shown to exist over a much wider range of flow conditions. From a practical perspective, it is important to characterize the behavior of average pulse velocity and frequency as a function of flow conditions and system/fluid properties in order to develop predictive models for mass (and heat) transfer and reaction yield/selectivity (see, for instance, Wu et al, 1995Wu et al, , 1999. In this regard, we note that the columns that are currently in use for space applications have typical dimensions that are comparable to lab-scale packed beds and, hence, exhibit similar pulsing properties.…”

Section: Introductionmentioning

confidence: 99%

Pulse properties in gas–liquid flow through randomly packed beds under microgravity conditions

Salgi

Balakotaiah

Ramé

et al. 2015

International Journal of Multiphase Flow

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Effect of pulsing on reaction outcome in a gas–liquid catalytic packed-bed reactor

Cited by 14 publications

References 7 publications

Microfabricated Multiphase Packed-Bed Reactors: Characterization of Mass Transfer and Reactions

Microfabricated Multiphase Packed-Bed Reactors: Characterization of Mass Transfer and Reactions

Another Critical Look at Three-Phase Catalysis

Pulse properties in gas–liquid flow through randomly packed beds under microgravity conditions

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