A comparative study of charcoal gasification in two types of spouted bed reactors

Salam, P. Abdul; Bhattacharya, S.C.

doi:10.1016/j.energy.2005.01.004

Cited by 33 publications

(3 citation statements)

References 8 publications

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“…Many valuable experimental and theoretical investigations on spouted beds have been carried out in the past 50 years, for the applications of the spouted bed for drying, , granulation and coating, , combustion and gasification, − pyrolysis, , electrochemical reaction, , catalytic reaction, , etc. However, the spouted bed technique has difficulty in being applied in a larger scale industrial process until now, because of some limitations, in particular the lack of full knowledge on the hydrodynamic characteristics.…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics (CFD)–Discrete Element Method (DEM) Simulation of Gas–Solid Turbulent Flow in a Cylindrical Spouted Bed with a Conical Base

et al. 2011

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Three dimensionally coupled computational fluid dynamics (CFD) and discrete element method (DEM) were studied for modeling the turbulent gasÀsolid flow in a cylindrical spouted bed with a conical base. The particle motion was modeled by the DEM, and the gas motion was modeled by the kÀε two-equation turbulent model. Drag force, contact force, Saffman lift force, Magnus lift force, and gravitational force acting on an individual particle were considered in establishing the mathematical models. Calculations on the cylindrical spouted bed with an inside diameter of 152 mm, a height of 700 mm, and a conical base of 60°were carried out. Experimental results from the University of British Columbia [He, Y. L.; Qin, S. Z.; Lim, C. J.; Grace, J. R. Particle velocity profiles and solid flow patterns in spouted beds. Can. J. Chem. Eng. 1994, 72 (8), 561À568] were used as a numerical benchmark to quantitatively assess the simulations. Despite the somewhat larger simulated spout diameter found, the present simulated results were in well-agreement with the experiments. The average error of particle velocity was less than 15%. On the basis of the simulations, the development of spout with time and distributions of particle velocity, particle concentration, and spout diameters at various spouting gas velocities were obtained. Besides, detailed information on particle collision and drag forces adding on particles at different bed regions was discussed. The results showed that particle velocity gradually decreases along the radial direction, with speeds of particles moving upward decreasing with an increasing bed height, while in the annulus region, particles decelerate downward in the cylindrical section and then accelerate in the conical base. The particle concentration increases in the spout region, is kept nearly constant in the annulus region, but decreases in the fountain region along the radial axis. An increasing bed height leads to an increasing particle concentration in the spout region but a decreasing particle concentration in the annulus and fountain regions. Particle collision number, particle turbulent intensity, and the transient collision force and drag force are significantly larger in the spout region than in the annulus and fountain regions. Besides, an increasing spouting gas velocity leads to a remarkable increased speed of particles moving upward or downward, spout diameter, particle collision, drag force, and particle turbulent intensity but decreased particle concentrations.

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Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics (CFD)–Discrete Element Method (DEM) Simulation of Gas–Solid Turbulent Flow in a Cylindrical Spouted Bed with a Conical Base

et al. 2011

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“…The estimated gas composition for each feedstock is computed by using the equilibrium model averaged over a range of temperatures measured in the reaction zone of the gasifier and the Zainal's approach [45]. The model is validated with experimental data available from the literature as [31,64,94,95]. [47] is developed to predict the performance of a downdraft heavy fuel oil gasifier.…”

Section: Zainal's Model (1997)mentioning

confidence: 99%

Modelling approaches to biomass gasification: A review with emphasis on the stoichiometric method

Villetta

Costa

Massarotti

2017

Renewable and Sustainable Energy Reviews

173

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“…As a promising approach to process particles, the spouting technology has been widely adopted in many physical and chemical processes, such as the drying of agriculture grains and porous material, coating of partices, pyrolysis of sawdust and plastics, ultra‐pyrolysis of propane, charcoal gasification, and so on. In the industry, various kinds of spouting configurations, such as the conically spouted bed, slot‐rectangular spouted bed, spouted bed with draft tube, spout‐fluid bed, are available.…”

Section: Introductionmentioning

confidence: 99%

CFD–DEM investigation into the scaling up of spout‐fluid beds via two interconnected chambers

et al. 2016

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The hydrodynamics and chamber interaction in a three-dimensional spout-fluid bed with two interconnected chambers are investigated via computational fluid dynamics coupled with discrete element method (CFD-DEM), because multiple interconnected chambers are key to scaling up spout-fluid beds. The overall solid motion, spouting evolution, and spoutannulus interface is studied, followed by time-averaged hydrodynamics, particle-scale information, spout-annulus interaction, and inter-chamber interaction. The results show that inter-chamber interactions lead to unique characteristics distinct from that for a single-chamber system, including (1) asymmetry of the hydrodynamics within each chamber, (2) alternative spouting behavior in the two chambers, (3) smaller pressure drop in terms of magnitude and fluctuations, (4) two peaks in the solid residence time (SRT) frequency histogram of the annulus, (5) average SRT in the spout is twice that in a single-chamber, and (6) larger solid dispersion in all three directions. The results provide meaningful understanding for the scale-up of spout-fluid beds.In view of its excellent performance and widespread application, numerous experimental efforts have unsurprisingly focused on various aspects of this apparatus, spanning the hydrodynamics, 11,12 solid circulation, 13,14 particle velocity profile, 15 pressure drop 16 and fluctuation, 17 flow reigme, 18-20 maximum bed height, 21 particle mixing, 22 minimum spouting velocity, 23 effect of draft plates, 24-26 thermal behavior, 27 and so on. In tandem with experimental investigations, the numerical simulation of the dense two-phase flow has progressed too. As is well-acknowledged, two approaches, namely, the twofluid model (TFM) and computational fluid dynamics combined with discrete element method (CFD-DEM), are available to model the dense gas-solid flow. 28,29 The critical difference between these two approaches lies in the resolution of the solid motion: the solid phase is treated as a continuum and tracked individually in the Lagrangian framework in TFM and CFD-DEM, respectively. Zhong et al. 30 numerically explored the gas/solid flow in the three-dimensional (3-D) spout-fluid bed using TFM, wherein the kinetic theory of granular flow provided the closures. The results demonstrated that the simulation results are strongly affected by the restitution

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A comparative study of charcoal gasification in two types of spouted bed reactors

Cited by 33 publications

References 8 publications

Computational Fluid Dynamics (CFD)–Discrete Element Method (DEM) Simulation of Gas–Solid Turbulent Flow in a Cylindrical Spouted Bed with a Conical Base

Computational Fluid Dynamics (CFD)–Discrete Element Method (DEM) Simulation of Gas–Solid Turbulent Flow in a Cylindrical Spouted Bed with a Conical Base

Modelling approaches to biomass gasification: A review with emphasis on the stoichiometric method

CFD–DEM investigation into the scaling up of spout‐fluid beds via two interconnected chambers

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