Micromixing of Solid‐liquid Systems in a Stirred Tank with Double Impellers

Abstract

The effect of solid particles on micromixing has been studied using the competitive iodide/iodate reaction system in stirred, multi-impeller, solid-liquid systems. The influences of particle size, impeller speed, solid holdup, feed position, and energy input have been investigated. The change of the segregation index with the power input was more distinguishable only for the 450-600 lm particles as compared with the large ones, at the same solid holdups. Also, for the small ones, cloud formation was observed at a particle concentration of 12.1 wt %. However, the influence of larger particles of 1-1.25 mm on micromixing was negligible, though both energy input and solid loading were increased. Besides, the optimal feed position was identified, and multiple feeds were also explored.

Performance Evaluation of Two High‐Shear Impellers in an Unbaffled Stirred Tank

“…Therefore, HSIs are used in applications such as pigment dispersion where very high shear is required 1, 2. Despite their wide range of applications compared with common impellers which have been widely investigated (see 3–9 and references therein for a review), literature information about standard HSIs operating in the low Re transitional regime is scarce. Thus, only general information about their performance is discussed in few references 1–3 or is directly provided by suppliers, but the hydrodynamic performance of HSIs is relatively unknown.…”

Energy Dissipation Rates of Newtonian and Non‐Newtonian Fluids in a Stirred Vessel

“…The energy dissipation rate ϵ is crucial to the quality and efficiency of the mixing process in stirred vessels, especially in the case of micromixing. The maximum and minimum values of ϵ and its distribution determine the mixing performance in processing vessels 1–3. The point where energy dissipates the most is always the optimum feeding location in fast reaction systems.…”

Monolithic 3D micromixer with an impeller for glass microfluidic systems

“…In particular, active mixers using a rotating structure such as an impeller effectively eliminate laminar flow, enabling them to stir larger volumes through a short mixing channel. 16,[19][20][21][22][23][24][25][26] Since the first demonstration of an impeller mixer using a micro-stirrer composed of a ferromagnetic material (Permalloy) by Lu et al in 2001, 24 numerous studies have examined various impeller types without wire leads. [24][25][26] However, most of these impellers were metallic, and thus had poor chemical resistance in the cavity.…”

“…Moreover, to embed an impeller inside the channel, the moving parts must be assembled separately. [20][21][22][23][24][25][26] In this paper, we introduce a novel passive 3D impeller (3DI) micromixer that is more easily fabricated than conventional mixers and improves on their limited performance. The proposed device has three advantages.…”