E.C. Wagner
33 records found
1
Horizontal stirred bed reactors are widely used in the commercial manufacturing of polypropylene. However, a comprehensive understanding of the particle dynamics in horizontal stirred bed reactors remains elusive, primarily due to the lack of detailed experimental data. In thi ...
Fluidization behavior of stirred gas–solid fluidized beds
A combined X-ray and CFD–DEM–IBM study
Vibro-assisted fluidization of cohesive micro-silica has been studied by means of X-ray imaging, pressure drop measurements, and off-line determination of the agglomerate size. Pressure drop and bed height development could be explained by observable phenomena taking place in ...
Stirrer design for improving fluidization of cohesive powder
A time-resolved X-ray study
Stirring has been recognized in the literature as a promising technique for facilitating fluidization of cohesive powders, via inputting additional energy to counteract interparticle forces. However, the influence of operating conditions and stirrer configurations on flow beha ...
Evaluation of the hydrodynamics of opaque multi-phase flows remains a challenging task, with implications for various industrial processes such as chemical processing, pharmaceutical, and mineral processing. Understanding how design and operational variables affect the complex ...
A new X-ray computed tomography technique for the purpose of imaging fluidized beds is presented. It consists of an experimental set-up with three stationary X-ray source and flat panel detector pairs, a geometric calibration and data processing workflow, and an image reconstr ...
Time-resolved X-ray study of assisted fluidization of cohesive micron powder
On the role of mechanical vibration
Mechanical vibration has been broadly used to assist fluidization of cohesive powders, because of its capability to disrupt gas channels and agglomerates. However, the improvement reported in literature is mostly deduced from bulk response and ex-situ measurements, whereas the ...
In many industrial applications, particles used in fluidized bed clearly deviate from ideal spheres. This leads to an increasing need for better understanding and developing better simulation models for fluidization of non-spherical particles. So far, the literature is quite s ...
Cavitation is a complicated multiphase phenomenon, where the production of vapor cavities leads to an opaque flow. Exploring the internal structures of the cavitating flows is one of the most significant challenges in this field of study. While it is not possible to visualize ...
Fluidization dynamics of cohesive Geldart B particles. Part I
X-ray tomography analysis
Due to the presence of inter-particle cohesive force, cohesive particles reveal totally different fluidization behaviors as compared to the non-cohesive system. This paper studies the fluidization dynamics of Geldart B particles with varying thermal-induced cohesive forces. Mu ...
Electrolyte effects on recirculating dense bubbly flow
An experimental study using X-ray imaging
In this work, the effect of an electrolyte (up to 2 M of NaCl dissolved in water) on a homogeneous dense bubbly flow, in an airlift bubble column, is studied using nonintrusive techniques. X-ray and high-speed imaging are used to investigate the bubble size distribution, the l ...
The performance of fluidized bed reactors strongly depends on the bubble behavior, for which reason knowledge concerning the bubble properties is important for modeling and reactor optimization. X-ray measurements can be used to characterize bubbles within the cross-section of ...
The application of membrane assisted fluidized bed reactors for distributed energy production has generated considerable research interest during the past few years. It is widely accepted that, due to better heat and mass transfer characteristics inside fluidized bed reactors, ...
The hydrodynamic behavior of a cold-flow gas–solid fluidized bed with an inner diameter of 22 cm is investigated by means of an ultra-fast X-ray tomographic setup. In the case of an exothermal reaction, heat exchanger tubes are required to remove the reaction heat out of the b ...
The fluidization of TiO2-P25 nanoparticles is characterized by studying the X-ray attenuation through the bed and the dynamic response of pressure fluctuations to the influence of the gas velocity. The X-ray results are based on a flat detector capable of measuring ...
heat exchanger tubes in bubbling fluidized bed reactors are necessary to remove the reaction heat of exothermal reactions. Vertical internals that mimic the heat exchanger tubes in cold-flow models, proofed to reduce the bubble size and lead to a more even distribution of the ...
A new tomographic reconstruction algorithm is proposed for fast image reconstruction. The results are based on a high speed X-ray tomography system, consisting of 3 X-ray sources and 32 detectors for each source. The proposed algorithm combines void measurements of each X-ray ...