Two‐phase downflow through catalyst beds: Part I. Flow maps

TLDR: In this article, a flow map for nonfoaming and foaming two-phase downflow through catalyst beds was correlated in terms of the superficial volumetric gas-to-liquid ratio and a force ratio relating inertia plus gravity forces to viscous plus interphase forces.

Abstract: Flow regimes for nonfoaming and foaming two-phase downflow through catalyst beds were correlated in terms of the superficial volumetric gas-to-liquid ratio and a force ratio relating inertia plus gravity forces to viscous plus interphase forces. For nonfoaming systems, the resulting flow map identified five regimes: two continuous phases (trickling flow), gas continuous (spray or blurring flow), liquid continuous (dispersed bubble), pulsing, and bubbling/pulsing; for foaming systems, the regimes were two continuous phases, gas continuous, foaming, and pulsing with and without foaming. Several orders of magnitude variations in the Froude, Weber, and Reynolds numbers were covered by data obtained in a 29.2 cm dia bed for aqueous 0-46% glycerol solutions and literature data obtained during downflow in smaller diameter beds for nonfoaming systems, including air/diethylene glycol, natural gas/lubricating oil, carbon dioxide/lubricating oil, and Freon 12/silicone oil and for foaming systems, including air/silicone oil and natural gas/kerosine. In the pulsing flow regime, the frequency of pulses leaving large (29.2 cm) and small (6.58 cm) dia beds were correlated with the flow map coordinates. The results are applicable to existing or new pilot and commercial reactors. Diagram, graphs, and 17 references.