This study reports a comprehensive multiphase gas-solid dynamic mathematical model that successfully describes the batch growth of silicon particles in a CVD submerged spouted bed reactor. This multiphase reactor model takes into account the hydrodynamics and interphase mass exchange between the different fluidized bed regions (spout or grid zone, bubbles and emulsion phase) and uses applicable kinetic rate models to describe both heterogeneous and homogeneous reactions. The model also incorporates a population balance equation representing particle growth and agglomeration.The CVD submerged spouted bed reactor operation is simulated by means of a sequential modular procedure, which involves the solution of the reactor model and the population balance equation.It is shown that the proposed CVD multiphase reactor model successfully simulates experimental data obtained from batch operation in a pilot scale reactor at REC Silicon Inc. The modeling of experiments obtained for different operating conditions allows correlating the scavenging factor as a function of the silane concentration for short- and long-term operations.
Hydrodynamics of a turbulent fluidized bed is studied by means of the concurrent application of fiber optic sensors It is observed that in the vicinity of the column wall there is a high bubble activity region. Low bubble activity and A temperature increase from 22 to 145°C results in a more homogeneous turbulent fluidized bed with smaller bubbles Mass transfer coefficients between bubble-emulsion (kbe) and bubble-annulus (kh) are evaluated. The dominant mass and a helium tracer. negative bubble velocities are reported for the dense phase near the column centre-line region. and more gas flowing through an expanded dense bed emulsion phase.transfer path was the one from the bubbles to the annular region with kba being several times greater than kbe.On a etudi6 I'hydrodynamique d'un lit fluidise turbulent au moyen de I'application simultanee de capteurs a fibres On a observe dans la region de la paroi de la colonne une zone de forte activite de bullage. Une faible activite de bullage Une augmentation de la temperature de 22 a 145°C rend le lit fluidise turbulent plus homogene avec des bulles plus (Nakajima et al., 1991). Thus, there is limited data on turbulent fluidized beds operated at conditions other than room temperature. Studies at more elevated temperatures and relatively low superficial gas velocities were mainly concerned with the effect of temperature on minimum fluidization velocity and bed voidage (Otake et al., 1975; Mii et al., 1973;Sishtla et al., 1986). Reactor size, in most of these studies, was limited to bench scale or laboratory scale units (Kai and Furusaki, 1985;Yamazaki et al., 1986;Cai et al., 1988; Hatate et al., 1988; Rapagna et al., 1994).Modelling of fluidized beds requires the use of data from bubble sensors and tracers. Ege et al. (1999, in through a gate valve (V4). This valve was used to adjust the air flow. Air, before being fed to the fluidized bed, was heated using an electrical oven (0). Conditions of the preheated air were selected to adjust the fluidized bed reactor temperature. Air exiting the oven expanded into a plenum chamber,
This study contributes with a computational fluid dynamic simulation based on the numerical solution of continuity and momentum balance equations in a three‐dimensional (3‐D) framework. The proposed down flow gas–solid suspension model includes a unit configuration and CD drag coefficients recommended for these units. Computational particle fluid dynamics (CPFD) calculations using suitable boundary conditions and a Barracuda (version: 14.5.2) software allow predicting local solid densification and asymmetric “wavy flows.” In addition, this model forecasts for the conditions of this study higher particle velocity than gas velocity, once the flow reaches 1 m from the gas injector. These findings are accompanied with observations about the intrinsic rotational character of the flow. CPFD numerical 3‐D calculations show that both gas and particle velocities involve the following: (a) an axial velocity component, (b) a radial velocity component (about 5% of axial velocity component), and (c) an angular velocity component. The calculated velocity components and the rotational flow pattern are established for a wide range of solid flux/gas flux ratios. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1635–1647, 2013
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