Pressure drop and liquid hold-up in multiphase monolithic reactor with different distributors

Xu, Min; Huang, Hai; Zhan, Xiangpeng; Liu, Hui; Ji, Shengfu; Li, Chengyue

doi:10.1016/j.cattod.2009.07.025

Cited by 11 publications

(6 citation statements)

References 17 publications

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“…In particular, the last two techniques provide not only the time-averaged liquid distribution over the monolith cross-section but also the dynamic features of Taylor flow within individual channels. Associated with a lateral or coaxial gas feed in the injection chamber, many liquid distribution systems have been tested: showerhead [35,33], spray nozzle [41,35,42,43,33], openpipe [32], perforated plates [44], multi-capillary system [45,33] and liquid ejector [46]. In addition, a packed bed [32,42,43], static mixer [47], a stack of monolith slices [45,48,49] and ceramic or metallic foam [35] have been used to further homogenize the feeding flow.…”

Section: Monolith Set-upmentioning

confidence: 99%

Hydrodynamic study of a monolith-type reactor for intensification of gas-liquid applications

Devatine

Chaumat

Simon

et al. 2017

Chemical Engineering and Processing: Process Intensification

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A B S T R A C TTwo-phase monolith-type reactors allow intensified heat and mass transfer rates, but often suffer from fluid maldistribution and undesired flow regimes in channels. A cold-flow monolith reactor (0.1 m diameter, 84 channels) is used here to assess liquid distribution and flow regimes at various air and water velocities: resistive probes give an insight of the flow patterns within 5 representative channels located at different radial positions, showing that regime transition to Taylor flow occurs in these channels simultaneously at lower gas and liquid superficial velocities than predicted by single capillary studies (namely u L and u G < 0.1 m s −1 ).A full mapping of the partial liquid flow rates in the monolith channels is derived by a gravimetric method via specifically designed collectors. In the identified Taylor flow domain, liquid distribution exhibits a W-shaped profile with marked peaks at low liquid velocity (u L = 0.04 m s −1 ). Increasing the liquid flow rate significantly (u L = 0.1 m s −1 ) smooths liquid distribution, reducing the maldistribution factor by half. Gas velocity also helps phase uniformity but to a smaller extent. It is estimated that even higher fluid velocities (at least tripled) would be required to feed all channels equally. Adding stack of distribution plates of variable cell density at the top of the monolith does not enhance the quality of the liquid distribution, except at low liquid velocity.

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Section: Monolith Set-upmentioning

confidence: 99%

Hydrodynamic study of a monolith-type reactor for intensification of gas-liquid applications

Devatine

Chaumat

Simon

et al. 2017

Chemical Engineering and Processing: Process Intensification

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“…However, the results are contradictory. While the higher pressure drop and liquid holdup obtained with a packed bed distributor by Xu et al witnessed a better distribution capability compared to spray nozzles, Roy and Al‐Dahhan as well as Heibel et al in turn observed a better performance with spray nozzles at least as long as the nozzle‐to‐monolith distance is adjusted properly. It should be mentioned that there are further approaches, such as the orifice plate distributor to create a bubble dispersion and the liquid‐motive ejector to distribute gas and liquid at higher velocities than those attainable with gravity‐driven flow.…”

Section: Introductionmentioning

confidence: 99%

“…At larger scale, rather conventional approaches are used to irrigate monolithic blocks, i.e., perforated plates, showerheads and spray nozzles . In addition, packings of spherical particles, monolithic slices and solid foams were installed above the monolith block to break the liquid phase into rivulets and to distribute the fluids.…”

Section: Introductionmentioning

confidence: 99%

Maldistribution susceptibility of monolith reactors: Case study of glucose hydrogenation performance

et al. 2016

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In this work an ultrafast electron beam X-ray modality was applied for the first time to characterize the gas-liquid Taylor flow inside each channel of an opaque honeycomb monolith structure (65 cpsi) for u G;S 50:1 . . . 0:5 m=s and u L;S 50:2 m=s. Significant spatial and temporal deviations in the phase holdup as well as in the gas bubble and liquid slug lengths were found. To evaluate the impact of Taylor flow maldistribution on the reactor performance, the data of more than 125; 000 unit cells were used to simulate the reactor productivity in the hydrogenation of glucose. The results verify that a monolith reactor solely designed by using superficial velocities and empirical correlations for gas bubble and liquid slug lengths fails significantly in achieving high product selectivity and the desired conversion. The developed methods are a solid base to design and select proper distributors ensuring the favorable flow configurations for specific chemical processes.

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“…However, in the gas-liquid monolith reactor, particularly at large scale, the maldistribution of gas and liquid over the multiple channels is a challenging issue due to its detrimental impact on the reactor performance [17]. Therefore, many researchers have investigated the flow distribution characteristics and examined various distributors to achieve a homogeneous distribution of gas and liquid [18,19,20,21].…”

Section: Introductionmentioning

confidence: 99%

Comparison of a monolith and a confined Taylor flow (CTF) reactor for propene epoxidation

Shin

Chadwick

2018

Chemical Engineering and Processing - Process Intensification

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Heterogeneous catalytic epoxidation of propene to propene oxide with hydrogen peroxide was investigated in a monolith and a confined Taylor flow (CTF) reactor in which titanium silicalite (TS-1) catalyst was coated on the walls. The influence of gas and liquid superficial velocity on the hydrodynamic characteristics of the monolith and CTF reactor was also investigated under Taylor flow regime at atmospheric and high pressure. The reactors showed distinctly different hydrodynamic properties which in turn led to different performance for propene epoxidation. The production rate of propene oxide was higher in the monolith reactor due to its larger catalyst coating area, larger mass-transfer surface area and more frequent recycling of liquid flow. A variation of reactor column structures confirmed that the propene oxide production was highly dependent on the catalyst coating area and cross-sectional area of the reactor column. High operating pressure made a significant impact on the length of Taylor bubbles and the propene oxide production rate was found to increase in proportion to the operating pressure.

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Pressure drop and liquid hold-up in multiphase monolithic reactor with different distributors

Cited by 11 publications

References 17 publications

Hydrodynamic study of a monolith-type reactor for intensification of gas-liquid applications

Hydrodynamic study of a monolith-type reactor for intensification of gas-liquid applications

Maldistribution susceptibility of monolith reactors: Case study of glucose hydrogenation performance

Comparison of a monolith and a confined Taylor flow (CTF) reactor for propene epoxidation

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