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

Abstract

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.

Reactor Selection for Upgrading Hemicelluloses: Conventional and Miniaturised Reactors for Hydrogenations

“…However, this approach requires a proper design of the gas-liquid-distributor [158]. Several feasible designs have been presented in the literature [159][160][161][162][163][164][165], but functionality has not been proven at the industrial scale.…”

Effect of substrate geometry and flow condition on the turbulence generation after a monolith

“…Honeycomb‐type substrates have several advantages over other catalyst supports, such as a lower pressure drop and a better flow distribution. They are commonly made of ceramic and are extensively used in automotive catalytic converters and other industrial applications . At a macro scale, many important variables, such as the conversion efficiency, ageing, and pressure drop of the reactor, depend on the flow distribution across the substrate.…”

Proposal of Index for Reaction Improvement Using Structured Catalyst

“…e most typical structured catalysts are the monolith-type catalysts. eir greatest feature is that the pressure loss is very low, and the inner wall of the ow path is coated with catalyst particles (Devatine et al, 2017;Fukuhara et al, 2017;Ratchahat et al, 2018). Structured catalysts such as gauze-type and grid-type are brous knitted catalysts (Reymond, 2001;Balzhinimaev et al, 2010;Zagoruiko and Lopatin, 2014).…”