Experimental investigation on the generic effects of gas permeation through flat vertical membranes

Effect of gas extraction on the hydrodynamics in a fluidized bed membrane reactor at elevated temperatures

“…Moreover, the coupling of the operational factors with the configuration, location, and arrangement of the membranes makes these interactions more complex. The formation of a densified layer, the variation of the bubble properties, and the gas back‐mixing in an FBMR have been preliminarily investigated, but the experimental results of different studies are not very consistent. De Jong et al and Dang et al found that stagnant/densified zones readily formed near the membranes during gas extraction through flat membranes, which usually also acted as reactor walls and this phenomenon was enhanced by an increase in the extraction fraction.…”

“…De Jong et al and Dang et al found that stagnant/densified zones readily formed near the membranes during gas extraction through flat membranes, which usually also acted as reactor walls and this phenomenon was enhanced by an increase in the extraction fraction. On the other hand, Wassie et al experimentally demonstrated that a stable densified zone in the bed consisted of only smaller particles when the gas was extracted via flat vertical membranes placed at the back of the column; this was especially noticeable at high extraction rates. No densified layers were observed during the gas extraction when Geldart B‐type particles (400–600 μm) were used as the bed material in experiments carried out by Helmi et al When flat membranes were installed, both a reduction and a slight increase in the average bubble size were observed during the gas extraction from the fluidized bed.…”

“…No densified layers were observed during the gas extraction when Geldart B‐type particles (400–600 μm) were used as the bed material in experiments carried out by Helmi et al When flat membranes were installed, both a reduction and a slight increase in the average bubble size were observed during the gas extraction from the fluidized bed. In addition, most available studies on the hydrodynamics of FBMR have been carried out at room temperature . The characteristics of the bubble phase or emulsion phase in FBMR have been investigated using experimental techniques such as particle image velocimetry, digital image analysis, electrical capacity, magnetic resonance tomography, and optical fiber detection .…”

“…Aside from this advantage, pressure measurements record not only the dynamic information of the gas–solid flow in a local bed but also in other regions at the specified instant . This feature is important because the influences of the gas permeation on the hydrodynamics vary in different regions of a fluidized bed . The application of the other detection techniques is limited in a large fluidized bed reactor due to the spatial resolution, but pressure measurements do not suffer from this drawback because many measurements can be obtained in the bed.…”

Analysis of the Hydrodynamic Effects of Gas Permeation in a Pilot-Scale Fluidized Bed Membrane Reactor

“…De Jong et al [16] and Dang et al [17] found that stagnant/densified zones readily formed near the membranes during gas extraction with flat membranes, which usually also acted as reactor walls, and would be improved by increasing the extraction fraction. On the other hand, Wassie et al [18,19] experimentally demonstrated that the formation of a stable densified zone in the bed while extracting gas via flat vertical membranes only occurred with smaller particles, especially at high extraction rates. No densified layers were observed during gas extraction when Geldart B type particles (400~600 µm) were used as bed material in experiments conducted by Helmi et al [20].…”