Micromixing Efficiency in the Presence of an Inert Gas in a Rotor–Stator Spinning Disk Reactor

Abstract

The effects on micromixing of co-feeding an inert gas with the bulk liquid are studied for a rotor–stator spinning disk reactor by means of the Villermaux–Dushman test reaction. The results of varying rotational speeds and gas–liquid ratios are reported for three configurations: injecting the acid into the dispersed region, into the bottom thin-film region, and into the upper thin-film region. The results show that injecting in the dispersed region is the optimal configuration, as the liquid experiences the shear stress between the rotor and the stator, and with increasing rotational speed, micromixing efficiency subsequently increases. Injecting in the thin-film regions leads to poor micromixing efficiency, since the gas layer reduces the turbulence levels experienced by the liquid. For the bottom thin film, increasing rotational speed improves micromixing efficiency due to inertial rotation of the liquid film. However, in the upper thin film, micromixing is significantly worse, being affected by the dripping of liquid on the stator at the injection point. Gas holdup measurements are compared to previous studies, showing that most of the gas volume is present in the thin-film regions. These results are relevant for the design of modular chemical processes using the spinning disk technology, when fast competitive chemical reactions occur in the presence of gas and liquid.

Scale-Up of a Heterogeneous Photocatalytic Degradation Using a Photochemical Rotor–Stator Spinning Disk Reactor

“…For multiphase continuous-flow processes, the liquid volume in the reactor is determined by the G/L ratio of the feed and the solid volume fraction. The residence time in the pRS-SDR is relatively independent of the rotation as the differences in holdup are typically small for varying rotation speeds. ,,, The rotation speed directly affects the mixing and mass transfer, effectively decoupling the mass transfer from the flow rate or residence time, which distinguishes spinning disk reactors from nonagitated flow reactors. A relatively high catalyst concentration of 10 mg/mL (∼1.0 w % of the suspension) was chosen for the standard conditions in order to illustrate the ability of the pRS-SDR to handle high solid concentrations.…”

Novelty in fossil fuel carbon abatement technologies in the 21st Century: post‐combustion carbon capture

“…Rotorstator spinning disc technology is a novel multiphase reactor that has the ability to improve micromixing, increasing gas-liquid, liquid-liquid and liquid-solid mass transfer rates significantly compared to conventional PB columns. [90][91][92][93][94][95][96][97] Spinning disc technology also intensifies the rate of heat transfer in a process. Spinning disc reactors (SDR) have great potential in processes that are mass-transfer and heat-transfer limited, such as carbon capture, polymerization and crystallization.…”

“…The CO 2 capture process using chemical solvents is a mass‐transfer limited process and the mass transfer performance can be improved significantly by intensification of micromixing between the flue gas stream and the chemical solvent. Rotor‐stator spinning disc technology is a novel multiphase reactor that has the ability to improve micromixing, increasing gas–liquid, liquid–liquid and liquid–solid mass transfer rates significantly compared to conventional PB columns 90‐97 . Spinning disc technology also intensifies the rate of heat transfer in a process.…”

Image‐based measurement of engulfment vortex to quantitatively assess micromixing efficiency in a gas–liquid stirred tank

“…Typical test reactions listed in Table 1 are widely utilized not only in the stirred tank, but also in other single phase reactors such as the rotating packed bed reactor, 3 rotating millimeter channel reactor, 4 micro‐impinging stream reactor, 5 rotor‐stator spinning disc reactor, 6 T‐jet mixer, 7 torus reactor, 8 and so on. However, there are few studies of micromixing in multiphase reactors, especially in gas–liquid reactors 9,10 . For one thing, bubbles as the randomly dispersed phase disturb the flow field of liquid phase, making the analysis of turbulent characteristics more complicated.…”