Micromixing performance in a rotating bar reactor

Abstract

A rotating bar reactor (RBR) was designed for adjusting micromixing efficiency. It consists of two concentric cylinders of inner rotating and outer fixed cylinders. Two feeding modes, named as radial and tangential feeding modes, were applied to modify the feeding at the bottom section of the RBR. The influence of feeding modes on the micromixing performance was measured with different rotational speeds, flow rates, viscosities, volumetric flow ratios, and hydrogen ion concentrations. Experimental results reveal that the RBR with tangential feeding mode has better micromixing performance than that with radial mode. The higher rotational speed has a positive impact on the segregation index (Xs). The values of Xs increased with the decrease of the flow rate, and the increase of the viscosity, volumetric flow ratio, and hydrogen ion concentration. The micromixing time, estimated by using an incorporation model, was in the range of 5.00 × 10−6‐1.13 × 10−5 seconds in the RBR with a tangential feeding mode, which indicates a promising prospect of the RBR for process intensification of fast and complex reactions.

Micromixing Performance in a Taylor–Couette Reactor with Ribbed Rotors

“…The miniaturization of the TCR was in line with the concept of a process-enhanced flow reactor device, which significantly improved the device's mixing performance while maintaining the reactant flux. The TCR used a tangential feed system that enhanced micromixing performance [13,14]. The fluid entered the reactor's annular gap from the bottom, generating a series of flow structures that exited the reactor from above.…”

“…Firstly, an increase in Ta enhances the fluid shear force due to the rotation of the rotor, which is beneficial to fluid dispersion and leads to a larger fluid contact area [29]. Secondly, an increase in rotational speed splits the fluid into finer fluid elements, reducing the local concentration of injected hydrogen ions [13]. Thirdly, an increase in rotational speed enhances the fluid circumferential flow velocity, which increases the degree of fluid collision and the energy dissipation rate.…”

“…Reactors or Mixers Rotational Speed (rpm) Micromixing Time (s) Martínez [30] Rotor-stator spinning disk reactor 100-2000 1.1 × 10 −4 -8.8 × 10 −3 Wang [17] Rotor-stator spinning disc extractor 600-1400 10 −5 -10 −4 Banaga [13] Rotating bar reactor 500-2500 5.0 × 10 −6 -1.1 × 10 −5 Chu [31] Rotating packed bed reactor 200-1600 3.3 × 10 −3 -4.6 × 10 −3 Liu [12] Taylor-Couette reactor 0-300 2.0 × 10 −3 -4.0 Chen [14] Annular rotating flow mixer 0-5400 2.7 × 10 Meanwhile, rib is an adjustable parameter that greatly broadens the range of the micromixing performance of the TCR, and the rib structure can be precisely designed for different applicable scenarios and reaction types to achieve the best target product yields and conversions.…”

“…They found that the rotor speed had little impact on micromixing efficiency under laminar Couette flow, but significantly improved micromixing efficiency under laminar Taylor vortex flow and weakly turbulent wave Taylor vortex flow. Banaga [13] and colleagues studied the effect of feeding methods on micromixing performance in a rotating bar reactor (RBR), which has a similar structure to the TCR but uses a higher rotor speed. They found that tangential feed resulted in better micromixing performance than radial feed, and increasing rotational speed and flow rate reduced micromixing time.…”

Intensification of the Absorption of Oxygen by Water Using a Rotor-Pulsating Apparatus

“…The work (Banaga et al, 2020) presents a rotating bar reactor (RBR), which consists of two concentric cylinders, has been developed. The inner cylinder of the RBR always rotates and the outer cylinder is fixed, which is different from other rotating reactors.…”