Hydrodynamics of cocurrent two‐phase flows in slanted porous media—Modulation of pulse flow via bed obliquity

Abstract

A packed bed operated with descending gas-liquid cocurrent flows in slanted configuration to force trickle flow pattern to segregate due to gravity was studied, in addition to dependences to inclination angle of liquid saturation and pressure drop. Inception of pulse flow regime could take place regardless of inclination angle and the transition from segregated/trickle regime to pulse flow regime was experimentally determined. The Grosser et al. flow regime transition model was modified by considering only axial components of the gas and liquid superficial velocities to predict the slant-dependent shifts in transition from segregated/trickle to pulse flow and was found to agree with experimental data. Pulse flow regime at different inclinations was characterized with respect to frequency, velocity, and shape of pulses. Bed obliquity was unveiled as a new artifice to pulse flow modulation with possible prospects for catalytic reactions requiring antagonistically high-interaction regime mass transfer coefficients and partial catalyst wetting. V V C 2010 American Institute of Chemical Engineers AIChE J, 56: [3189][3190][3191][3192][3193][3194][3195][3196][3197][3198][3199][3200][3201][3202][3203][3204][3205] 2010

Hydrodynamics of gas–liquid cocurrent downflow in floating packed beds

“…Two-phase segregation in inclined trickle beds and its dependency to tilt angle were investigated experimentally by Schubert et al (2010a). The results revealed that bed deviation from verticality prompted remarkable phase stratification accompanied with reduction in liquid saturation.…”

“…Moreover, pulse flow regime properties such as pulse frequency and propagation velocity were found to decrease as compared to conventional vertical trickle beds. Atta et al (2010) conducted, in parallel to Schubert et al (2010a) experimental work, numerical simulations to identify the main causes for stratification in tilted trickle beds. Among the several drag force closures in trickle beds (Wang et al, 2013), use was made of the relative permeability model within an Eulerian computational fluid dynamics framework to capture the physics of local flow and liquid holdup distribution inside the slanted trickle beds.…”

“…In recent years, a great deal of efforts is being directed towards the design of suitable distributors and/or selection of appropriate packings and internals to minimize fluid maldistribution during ship motion (Armstrong et al, 2000;Darredeau, 2001;Duss and Roza, 2014;Fraysse and Werlen, 2002;Haroun et al, 2013;Kalbassi and Zone, 2005). Other research groups have chosen to study the hydrodynamics prevailing inside stationary inclined packed bedsconjectured to be limiting column postures on a ship - (Atta et al, 2010;Bouteldja et al, 2013;Schubert et al, 2010a) or when packed columns are subjected to slow axial vessel rotations (Bieberle et al, 2013;Härting et al, 2015).…”

Offshore Floating Packed‐Bed Reactors: Key Challenges and Potential Solutions

“…The effect of tilt angle on the gas-liquid distribution for the static packed bed was first investigated by analyzing the cross- Contrarily, column deviations from verticality by 5°, 10°, and 15°resulted in the development of gas-liquid segregation zones leading to phase maldistribution similar to literature findings for other types of inclined packed bed [18,19,21]. Increasing the tilt angle intensified the gravity-driven force, whereby liquid moved to the lower-wall zone forcing the gas phase to migrate to the upper-wall zone, thereby giving rise to a segregated flow pattern in the bed.…”

“…Meanwhile, flow dynamics and phase maldistributions in static tilted configurations viewed as limiting column postures on floating systems have been thoroughly investigated and are referred as the worst-case performance scenario [17][18][19][20][21].…”