Experimental study of gas-liquid-solid flow characteristics in slurry Taylor flow-based multiphase microreactors

The gas-liquid-solid (G-L-S) three-phase flow characteristics are essentially linked to the design of slurry Taylor flow (STF)-based multiphase microreactors (STFRs), thus directly dictating the reactor operating performance. In this study, we examine the G-L-S flow patterns, solid spatial distribution, liquid-solid slurry stability, slug length (L_S), bubble size (L_B) and rising velocity (V_B) in STFRs and their dependence on operating conditions. Under high Reynolds numbers (Re'≥681), many particles are present in the liquid film and significant bubble surface wave disturbance is observed even when the Capillary number is low (Ca'<0.01). Depending on whether bubble surface distorts (BSD) and/or particles travel between slugs (PTS), four STF patterns are identified and mapped against the flow conditions, with pattern I (with no BSD or PTS) and pattern IV (with both BSD and PTS) occurring at low and high fluids velocities, respectively. The STF patterns are independent of solid loading (when <10%v/v) but show dependency on particle size and flow conditions. Both solid loading and particle size marginally affect V_B, yet have a profound impact on L_B and L_S. Empirical correlations for predicting V_B, L_B and L_S in STFRs are developed. The correlation of V_B proves valid for both slurry and standard Taylor flow systems covering 1.2≤Re'≤3551 and 0.0002≤Ca'≤0.39 for a wide range of fluids in both circular and square channels with size of 480µm-3.02mm.