Effect of vertical internals on the pressure drop in a gas‐solid fluidized bed

Abstract

In this work, the pressure drop at the wall and the radial profiles of pressure drop along the bed height have been measured using a differential pressure transducer and pressure probe‐differential pressure transducer in a gas‐solid fluidized bed with a 0.14 m inside diameter. Two types of circular arrangements of intense vertical internals (0.0254 and 0.0127 m diameter), two kinds of solid particles of Geldart B type (glass beads and aluminum oxide), and four selected superficial gas velocities in terms of u/umf have been used to study the impact of these different designs, as well as the physical and operating variables on the pressure drop measured at the wall of the bed and the radial pressure drop inside the fluidized bed. It has been experimentally demonstrated that the 0.0254 m internals can reduce the pressure drop at the wall and the radial pressure drop inside the bed by about 10 % when compared to without internals, and this result holds true for both kinds of solids used. However, the implementation of 0.0127 m internals inside the gas‐solid fluidized bed leads to a decrease in the pressure drop and radial pressure drop in the case of glass bead solid particles and an increase in the pressure drop in the case of aluminum oxide solid particles. The experimental results in the form of relevant dimensionless groups have been correlated using the statistical analysis software of JMP 12, due to the big difference between the experimental results of this work and the predicted values from the available correlations in the literature. The new correlation has been developed with a mean relative deviation value of 1.08 % between the experimental and predicted values.

Pairing Experimental and Mathematical Modeling Studies on Fluidized Beds for Enhancement of Models Predictive Quality: A Current Status Overview

“…Furthermore, considering that each of the coupled sub-models is intended to capture a specific phenomenon in the multiphase flow, each sub-model has a corresponding representative physical length scale, and therefore, a proper selection of the multiscale coupling scheme is needed. For example, the pressure gradient (∇P) has a representative physical length scale corresponding to the reactor length (L C ) (Equation ( 1)), since the observable changes in the pressure profiles will be dominant along the axial position of the column [26]; whereas if particle clustering is modeled dn in dt (where n in is the number of particles captured by a cluster), the sub-model will have a representative physical length scale corresponding to the effective collision volume between particles (V) (Equation ( 2)) [36].…”

“…This led to a phenomenological sub-model that could be adapted for bubbly, droplet or particulate flows. Their proposed sub-model defines K σβ according to Equation (32), and the drag coefficient (C D ) according to Equations ( 33) and (34), where µ eff is usually defined according to Equation (26).…”

“…As an alternative, to obtain local scale pressure information, Taofeeq and Al-Dahhan [26] implemented a Differential Pressure Transducer Probe, which measured pressure drops at different radial locations inside a fluidized bed column. The DPTP consisted of two stainless steel probes connected to a differential pressure transducer.…”

“…Vast experimental studies have been conducted to characterize the key hydrodynamic and design parameters of fluidized beds, in order to identify the conditions and phenomena that have adverse effects on the two-phase hydrodynamic phenomena, kinetic throughput, and thermal behavior [22][23][24]. However, most of the applied experimental techniques have important limitations in the level of detail and accuracy in the description of the local scale phenomena and are limited to a restricted number of locations inside the bed [25], only allowing us to measure macroscopic parameters, such as implementing absolute or differential pressure transducers [26], or fail to provide detailed time resolved measurements of the local fields [14]. This represents a fundamental limitation when characterizing the hydrodynamics of chaotic fluidized systems, such as FB reactors where strong pointwise and timewise variations of the local fields have been observed [20,27].…”

A Journey across Food & Chemical Engineering Dyad: Symposium in memory of Professor Khaled Belkacemi

“…The special section consists of sixteen accepted articles that were organized in four topics. The first gathers contributions on industrially important catalysis applications and energy conversion (Fischer‐Tropsch synthesis, molybdenum carbide catalysis, coal pyrolysis and gasification, biorefinery transformations, carbon dioxide biomass gasification, and baffled fluidized and bubble column reactors). The second topic picked up a couple of biotechnology applications (enzyme immobilization on magnetic nanoparticles and cell adhesion on collagen scaffolds).…”