Fast-mode alternating cyclic operation in trickle beds at elevated temperature for foaming systems

Trickle bed mechanistic model for (non-)Newtonian power-law foaming liquids

“…However, increased temperatures have a tendency to reduce liquid holdup as well (Fig. 4b) in accordance with Aydin and Larachi (2008) Aydin et al (2007) have shown using simple atmospheric foam collapse tests that foams persist a longer period of time at 25 • C than at 90 • C where no foam was left after 15 s. The viscosity decrease of liquid with increasing temperatures causes the liquid on the bubble surface to drain faster, thus reaching dry and unstable bubbles at an earlier moment and causing foam collapse. This would align with the findings of declining pressure drops in the bed, the higher the temperatures resulting from a loss of additional frictional interfaces due to lesser bubbles.…”

Cyclic operation strategies in inclined and moving packed beds—Potential marine applications for floating systems

“…For instance, Hamidipour et al applied ON–OFF liquid, ON–OFF gas, and alternating gas/liquid cyclic modes to reduce fines deposition and extend the cycle life of trickle beds under filtration conditions. Moreover, Aydin et al experimentally demonstrated capability of alternating gas/liquid fast‐mode cyclic operation for controlling foam formation and stability in trickle‐bed reactors operating at high temperature and pressure. In the context of heterogeneous catalytic reactions, an increase in the conversion up to 15 and 18% was reported, respectively, for the hydrogenation of α‐methyl styrene and styrene as a result of implementation of liquid flow modulation .…”

Hydrodynamics of inclined packed beds under flow modulation ‐ CFD simulation and experimental validation

“…ffiffi ffi 3 p p 2 1 2 1 2 d p the minimum equivalent diameter of the area between three contacting spheres (13) Capillary liquid dispersionr P c 5 2 3 r l ð 1 12e…”

“…12 These experimental findings thus highlight the fact that cyclic operation can be regarded as a potential method for process intensification in offshore floating packed bed reactors extending it beyond the realm of conventional trickle beds where cyclic operation has been successfully applied to enhance mass transfer, improve phase distribution, reduce fines deposition, or control foam formation, to name just a few examples. [13][14][15] Several researchers successfully applied the Eulerian multifluid CFD model along with well-established interphase interaction forces as closure laws to predict bed overall pressure drop and liquid holdup in conventional vertical gas-liquid cocurrent downflow packed beds (i.e., trickle-bed reactors) under steadystate (i.e., iso-flow) [16][17][18][19][20][21][22][23][24][25] and unsteady-state cyclic operation. 17,26 Hamidipour et al 17 were able to precisely capture the transient hydrodynamic behaviors of trickle-bed reactors under gas, liquid, and gas/liquid alternating cyclic operations using an unsteady multifluid Euler framework combined with the closure laws developed by Attou et al 27 for fluid-solid drag forces and fluid-fluid interaction force.…”