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Graas, Adriaan B.M. (author), Wagner, E.C. (author), van Leeuwen, Tristan (author), van Ommen, J.R. (author), Batenburg, K. Joost (author), Lucka, Felix (author), Portela, L. (author)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 reconstruction algorithm. The technique enables sparse-angular tomographic...journal article 2024
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Kamphorst, R. (author), van der Sande, P.C. (author), Wu, K. (author), Wagner, E.C. (author), David, M.K. (author), Meesters, G.M.H. (author), van Ommen, J.R. (author)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 the bed; slugging, channeling, fluidization or densification. It...journal article 2024
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Kamphorst, R. (author), Wu, K. (author), van Baarlen, M. (author), Meesters, G.M.H. (author), van Ommen, J.R. (author)In this study, the impact of different vibrational modes on the fluidization characteristics of cohesive micro- and nano-silica powder was examined. Fractional pressure drop, bed expansion measurements, and X-ray imaging were utilized to characterize the fluidization quality. The densities of the emulsion phase at the top and bottom of the...journal article 2024
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Tsekos, C. (author), de Voogt, D. (author), de Jong, W. (author), Padding, J.T. (author)This work focuses on the numerical modelling and experimental validation of the hydrodynamic behaviour of a novel 50 kW<sub>th</sub> indirectly heated bubbling fluidized bed steam reformer. The hydrodynamic behaviour of fluidized beds with immersed vertical tubes and complex fluidized bed geometries in general have not been thoroughly...journal article 2022
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Kosaka, Fumihiko (author), Sasayama, Tomone (author), Liu, Yanyong (author), Chen, S. (author), Mochizuki, Takehisa (author), Matsuoka, Koichi (author), Urakawa, A. (author), Kuramoto, Koji (author)Carbon capture and utilization (CCU) technologies, such as CO<sub>2</sub> methanation, generally require energy-intensive CO<sub>2</sub> capture and separation processes prior to catalytic CO<sub>2</sub> conversion. In contrast, integrated CO<sub>2</sub> capture and reduction (CCR) technologies that use dual function materials (DFM) can...journal article 2022
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Kamphorst, R. (author), Wu, K. (author), Salameh, S. (author), Meesters, G.M.H. (author), van Ommen, J.R. (author)The fluidization of cohesive powders has been extensively researched over the years. When looking at literature on the fluidization of cohesive particles, one will often find papers concerned with only micro- or only nano-sized powders. It is, however, unclear whether they should be treated differently at all. In this paper, we look at...journal article 2022
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Mema, I. (author), Padding, J.T. (author)Having proper correlations for hydrodynamic forces is essential for successful CFD-DEM simulations of a fluidized bed. For spherical particles in a fluidized bed, efficient correlations for predicting the drag force, including the crowding effect caused by surrounding particles, are already available and well tested. However, for elongated...journal article 2021
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Mema, I. (author)For the past century, fluidized beds have been standard equipment in many branches of industry. In most applications they are used to manipulate granular and powder-like materials, whose particles can roughly be approximated as spheres. Therefore, numerical models and investigations have focused mainly on fluidized beds with spherical particles....doctoral thesis 2020
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Vikrant, V. (author), Padding, J.T. (author)A novel approach to Multiphase-Particle-in-Cell (MP-PIC), called Continuum Particle Model (CPM), is developed for dense gas-particle flows. CPM has high computational speed, comparable to that of MP-PIC, but a robustness and accuracy closer to that of a Discrete Element Model (DEM). The gas phase is treated as a continuum phase and particles...journal article 2020
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Mema, I. (author), Padding, J.T. (author)The possibility to offer good intermixing between particles is one of the main properties that make fluidized beds such an important industrial appliance. In this work, we use CFD-DEM simulations to compare mixing characteristics of spherical (AR-1) to elongated spherocylindrical particles (AR-4) of aspect ratio In simulation of AR-4...journal article 2020
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Chiou, Eleftheria (author)One of the main targets of Waternet, the water-cycle company of Amsterdam, is to increase the sustainability of water treatment. To achieve this goal, it is necessary to improve the efficiency and to decrease the use of chemicals during pellet softening process. However, the model of Van Schagen et al. (2008 b,c) that is currently used to...master thesis 2018
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Grillo, F. (author)Atomic layer deposition (ALD) is a gas-phase thin film technology that boasts atomic-level control over the amount of material being deposited. A great deal of research effort has been devoted to the exploitation of ALD precision for the synthesis of nanostructures other than thin films such as supported nanoparticles (NPs). ALD is not only...doctoral thesis 2018
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Guo, J. (author), Bui, H.V. (author), Valdesueiro Gonzalez, D. (author), Yuan, Shaojun (author), Liang, Bin (author), van Ommen, J.R. (author)This work investigated the suppression of photocatalytic activity of titanium dioxide (TiO2) pigment powders by extremely thin aluminum oxide (Al2O3) films deposited via an atomic-layer-deposition-type process using trimethylaluminum (TMA) and H2O as precursors. The deposition was performed on multiple grams of TiO2 powder at room temperature...journal article 2018
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Schillinger, F. (author), Schildhauer, TJ (author), Maurer, S. (author), Wagner, E.C. (author), Mudde, R.F. (author), van Ommen, J.R. (author)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 a fluidized bed on a laboratory scale, but cannot easily be...journal article 2018
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Boer, L. (author), Buist, K. A. (author), Deen, N. G. (author), Padding, J.T. (author), Kuipers, J. A.M. (author)In this experimental study the segregation behavior for fluidized mixtures of spherical and cylindrical particles is investigated. In industry, fluidization of particles featuring a wide range of shapes is common in various applications such as biomass gasification, drying applications, food processing and production of pharmaceuticals....journal article 2018
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Helmi, A. (author), Wagner, E.C. (author), Gallucci, F. (author), Van Sint Annaland, Martin (author), van Ommen, J.R. (author), Mudde, R.F. (author)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 reactor efficiency can outperform other reactor configurations...journal article 2017
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Gomez Hernandez, J. (author), Sánchez-Delgado, Sergio (author), Wagner, E.C. (author), Mudde, R.F. (author), van Ommen, J.R. (author)The fluidization of TiO<sub>2</sub>-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 a 2D projection of the column from a height of 3cm above the...journal article 2017
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Di Marcello, M. (author), Tsalidis, G.A. (author), Spinelli, G. (author), de Jong, W. (author), Kiel, J.H.A. (author)Torrefaction is a promising biomass upgrading technology as it makes biomass more coal alike and offers benefits in logistics and handling operations. Gasification is an attractive thermochemical conversion technology due to its flexibility in the product gas end-uses. Therefore, it is valuable to investigate whether additional benefits are...journal article 2017
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Tsalidis, G.A. (author), Di Marcello, M. (author), Spinelli, G. (author), de Jong, W. (author), Kiel, J.H.A. (author)Torrefaction is a promising biomass upgrading method, offering advantages in logistics and handling. Gasification is an attractive thermochemical conversion technology due to its flexibility in the product gas end-use. The aim of this paper is to investigate the impact of torrefaction on the gasification performance of a softwood (spruce) and...journal article 2017
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Didden, A. (author), Hillebrand, P. (author), Wollgarten, M. (author), Dam, B. (author), Van de Krol, R. (author)Conductive TiN shells have been deposited on SiO2 nanoparticles (10–20 nm primary particle size) with fluidized bed atomic layer deposition using TDMAT and NH3 as precursors. Analysis of the powders confirms that shell growth saturates at approximately 0.4 nm/cycle at TDMAT doses of >1.2 mmol/g of powder. TEM and XPS analysis showed that all...journal article 2016