Hydrodynamic characteristics of a circulating fluidized bed

1985 ◽  
Vol 2 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Gui Young Han ◽  
Geun Seong Lee ◽  
Sang Done Kim
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Hydrodynamic Characteristics

Hydrodynamic characteristics of fine particles in the riser and standpipe of a circulating fluidized bed

1995 ◽  
Vol 12 (2) ◽  
pp. 141-145 ◽  
Author(s):  
Jong-Hyeun Choi ◽  
Jin-Ho Park ◽  
Won-Myung Choung ◽  
Yong Kang ◽  
Sang Done Kim
Keyword(s):  
Fluidized Bed ◽  
Fine Particles ◽  
Circulating Fluidized Bed ◽  
Hydrodynamic Characteristics

Co-Combustion of Biomass and Coal in Circulating Fluidized Bed: Modeling and Validation

2003 ◽  
Author(s):  
Juan Ada´nez ◽  
Luis F. de Diego ◽  
Pilar Gaya´n ◽  
Francisco Garci´a-Labiano ◽  
Andre´s Cabanillas ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Plug Flow ◽  
Weighted Average ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Experimental Results ◽  
Hydrodynamic Characteristics ◽  
Particle Model ◽  
Carbon Combustion

In this work carbon combustion efficiencies in circulating fluidized bed combustion (CFBC) when co-firing biomass and coal mixtures were studied. Experimental results were obtained from the combustion of two kind of coals with a forest residue (Pine bark) in a CBF pilot plant (0.3MWth) with 20-cm i.d. and 6.5-m height. The effect of operating conditions such as percentage of biomass in the feed, temperature, excess air, air velocity and percentage of secondary air on carbon combustion efficiency was studied. A mathematical model for the co-combustion of coal and biomass in a circulating fluidized bed boiler has been developed. The riser is divided in three zones with different hydrodynamic characteristics: bottom, splash and freeboard. The bottom bed has a constant voidage, determined by a modified two-phase theory. The solids are considered in perfect mixing and the gas in plug flow. The voidage in the splash region follows an exponential decay model. In the freeboard region, the solids and the gas are in plug flow, and a core-annulus structure is considered. Devolatilization of solid fuels is modeled with a particle reaction model which allows to determine the volatiles generation rate as a function of time and operating conditions. Kinetics of char combustion is modeled with the shrinking particle model with mixed control by chemical reaction and gas film diffusion, assuming that the ashes separate once formed. To consider that the char particles are a mixture of coal and biomass char particles, a weighted average combustion rate is defined taking into account the individual combustion rates. Population balances of char particles in the different regions were developed to calculate carbon concentrations. The developed model can predict the different gas concentrations along the riser, such as oxygen, SO2, CO, CH4, etc..., and the carbon combustion efficiency. The experimental results of carbon combustion efficiencies and gas emissions were compared with those predicted by the model and a good correlation was found for all the conditions used.

scholarly journals Novel multistage solid–liquid circulating fluidized bed: Hydrodynamic characteristics

Particuology ◽  
2018 ◽  
Vol 38 ◽  
pp. 134-142 ◽  
Author(s):  
Prakash V. Chavan ◽  
Manjusha A. Thombare ◽  
Sandip B. Bankar ◽  
Dinesh V. Kalaga ◽  
Veena A. Patil-Shinde
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Hydrodynamic Characteristics ◽  
Solid Liquid

Hydrodynamic Characteristics of a Novel Circulating Fluidized Bed Steam Reformer Operating in the Fast Fluidization Regime

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Moataz Bellah M. Mousa ◽  
Seif-Eddeen K. Fateen ◽  
Essam A. Ibrahim
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Numerical Approach ◽  
Hydrodynamic Characteristics ◽  
Two Phase ◽  
Radial Segregation ◽  
Fluidization Regime ◽  
Computational Fluid Dynamics Cfd ◽  
Model Equations ◽  
Steam Reformers

Circulating Fluidized Bed Steam Reformers (CFBSRs) represent an important alternative for the production of syngas for the Fisher-Tropsch (FT) process and for hydrogen production. Most research regarding this novel CFBSRs did not consider its hydrodynamic characteristics. In this work, the riser Computational Fluid Dynamics (CFD) simulations were investigated using two phase Eulerian-Eulerian approach coupled with kinetic theory of granular flow with k-epsilon model to describe the turbulence of each phase. The model equations were solved via the commercial CFD package FLUENT, which uses the finite volume numerical approach. Cold flow simulations were carried out under the fast fluidization regime and results were validated qualitatively against available experimental data. The radial segregation of the catalyst, the velocity distribution of both phases and other characteristics of the flow were captured by the simulation. This work showed that for operation under high density and high flux conditions, solids flux should be higher than 300 kg/m2s and inlet void fraction lower than 85%.

Computational fluid dynamics of circulating fluidized bed downer: Study of modeling parameters and system hydrodynamic characteristics

2012 ◽  
Vol 189-190 ◽  
pp. 314-335 ◽  
Author(s):  
Benjapon Chalermsinsuwan ◽  
Titinan Chanchuey ◽  
Waraporn Buakhao ◽  
Dimitri Gidaspow ◽  
Pornpote Piumsomboon
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Hydrodynamic Characteristics

Hydrodynamic characteristics of a large-scale triple-bed combined circulating fluidized bed

2011 ◽  
Vol 209 (1-3) ◽  
pp. 1-8 ◽  
Author(s):  
Chihiro Fushimi ◽  
Guoqing Guan ◽  
Yu Nakamura ◽  
Masanori Ishizuka ◽  
Atsushi Tsutsumi ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Large Scale ◽  
Circulating Fluidized Bed ◽  
Hydrodynamic Characteristics
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