Modelling gas‐liquid mass transfer in a two‐phase jet flow

Abstract

The efficiency and selectivity of chemical reactions are influenced by the mixing characteristic of the reactor. Existing models for reactor precalculation are often based on mean values, e.g. for the energy dissipation rate or the volumetric mass transfer coefficient, and assume a homogeneous mass transfer behaviour. As a result, process optimization by avoiding mass transfer limitations is not efficient, due to the missing knowledge of local limitations. Jet reactors typically provide inhomogeneous mixing and mass transfer behaviour, where the highest rates occur in the jet vicinity. Hence, the mass transfer processes in the jet flow, which cannot be properly characterized in gas‐liquid two‐phase flow, dominate the reactor performance. Experimental results concerning the volumetric mass transfer coefficient in the jet vicinity of the Jetzone‐Loopreactor are discussed, and a model approach for describing the phenomenon is presented. It is shown that the mass transfer rates strongly depend on the hydrodynamics of the loop flow. The normalknormalLa model is adapted to the loop flow determining mechanisms, the drag coefficient, and the density difference between the circulation and the jet flow.

Process Intensification in Gas–Liquid Mass Transfer by Modification of Reactor Design: A Review

“…The advantages of ELR are shown in Figure 9 . [ 63 ] There seems to be no consensus in the scientific literature on the naming of ELRs, which include terms such as ELR, [ 64 ] jet loop reactor (JLR), [ 65 ] jet‐zone loop reactor, [ 66 ] jet bubbling reactor, [ 67 ] loop venturi reactor, [ 68 ] plunging jet reactor, [ 68 ] and so on ( Figure 10 ). Despite their different names, they all shared a common element an ejector.…”

“…Figure 11 shows a typical ejector system consisting of nozzle. [69] ELRs were employed for the application that required the gas-liquid mass transfer, [70,71] such as microbial fermentation [64,72] and wastewater treatment, [73] and the application in chemical and biochemical processes, [74] such as the hydroformylation of α-olefins, [65,74] hydroaminomethylation, [74] and ammoximation of 2-butanone. [75] Opletal et al [76] developed an up-flow ELR that considers the different energy dissipations and mechanisms of mass transfer.…”

Experimental investigation on multiscale hydrodynamics in a novel gas–Liquid–Solid three phase jet‐Loop reactor

“…Three phase JLRs (gas–liquid–solid) are novel compared to the relatively widely studied gas–liquid bubble column, gas–liquid airlift reactor, gas–liquid JLRs, gas–liquid–solid bubble column, or gas–liquid–solid airlift reactor . Recently, studies on JLRs were mostly relevant to gas–liquid two‐phase flow, while gas–liquid–solid three‐phase systems were rarely studied, in comparison . Fan et al distinguished three flow modes (packed bed, fluidized bed, and circulated bed mode) according to the solids suspension performance in a JLR.…”

Chemical effects induced by gas–liquid jet flow

“…Over the past decades, physical effects introduced by gas–liquid jet flow have been extensively investigated, including the fluid morphology, 2 mass- and heat-transfer characteristics, 11,13,14 flow patterns, 1 mixing performance, 15 and hydrodynamic behavior. 16,17 However, its possible chemical consequences have not yet drawn enough attention.…”