Simulation of Coal and Biomass Cofiring with Different Particle Density and Diameter in Bubbling Fluidized Bed under O2/CO2 Atmospheres

A 2D dynamic model for a bubbling fluidized bed (BFB) combustor has been developed for simulating the coal and biomass cofiring process under 21% O2/79% CO2 atmosphere in a 6 kWth bubbling fluidized bed, coupled with the Euler-Euler two-phase flow model. The kinetic theory of binary granular mixture...

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Main Authors: Chao Chen, Xuan Wu, Lingling Zhao
Format: Article
Language:English
Published: Wiley 2018-01-01
Series:Journal of Combustion
Online Access:http://dx.doi.org/10.1155/2018/6931483
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author Chao Chen
Xuan Wu
Lingling Zhao
author_facet Chao Chen
Xuan Wu
Lingling Zhao
author_sort Chao Chen
collection DOAJ
description A 2D dynamic model for a bubbling fluidized bed (BFB) combustor has been developed for simulating the coal and biomass cofiring process under 21% O2/79% CO2 atmosphere in a 6 kWth bubbling fluidized bed, coupled with the Euler-Euler two-phase flow model. The kinetic theory of binary granular mixtures is employed for the solid phase in order to map the effect of particle size and density. The distribution of temperature, volume fraction, velocity, gas species concentration, and reaction rates are studied with numerical calculations. The simulated temperature distribution along the height of the combustor and outlet gas concentrations show good agreement with experimental data, validating the accuracy and reliability of the developed cofiring simulation model. As indicated in the results, there are two high temperature zones in the combustor, which separately exist at the fuel inlet and dilute phase. The reaction rates are related to the species concentration and temperature. The higher concentration and temperature lead to the larger reaction rates. It can be seen that all of the homogeneous reaction rates are larger at the fuel inlet region because of rich O2 and volatiles. High mass fraction of volatile gas is found at the fuel inlet, and the main reburning gas at the dilute phase is CH4. The mass fraction distribution of CO is related to the volume fraction of fuel which is due to the fact that the source of CO is not only from the devolatilization but also from the gasification. On the basis of this theoretical study, a better understanding of flow and combustion characteristics in biomass and coal cofiring under oxy-fuel atmospheres could be achieved.
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institution Kabale University
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publishDate 2018-01-01
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series Journal of Combustion
spelling doaj-art-e68149643dbc432a8ce6abfb0875b01f2025-08-20T03:26:03ZengWileyJournal of Combustion2090-19682090-19762018-01-01201810.1155/2018/69314836931483Simulation of Coal and Biomass Cofiring with Different Particle Density and Diameter in Bubbling Fluidized Bed under O2/CO2 AtmospheresChao Chen0Xuan Wu1Lingling Zhao2School of Energy & Environment, Southeast University, Nanjing, Jiangsu 210096, ChinaSchool of Energy & Environment, Southeast University, Nanjing, Jiangsu 210096, ChinaSchool of Energy & Environment, Southeast University, Nanjing, Jiangsu 210096, ChinaA 2D dynamic model for a bubbling fluidized bed (BFB) combustor has been developed for simulating the coal and biomass cofiring process under 21% O2/79% CO2 atmosphere in a 6 kWth bubbling fluidized bed, coupled with the Euler-Euler two-phase flow model. The kinetic theory of binary granular mixtures is employed for the solid phase in order to map the effect of particle size and density. The distribution of temperature, volume fraction, velocity, gas species concentration, and reaction rates are studied with numerical calculations. The simulated temperature distribution along the height of the combustor and outlet gas concentrations show good agreement with experimental data, validating the accuracy and reliability of the developed cofiring simulation model. As indicated in the results, there are two high temperature zones in the combustor, which separately exist at the fuel inlet and dilute phase. The reaction rates are related to the species concentration and temperature. The higher concentration and temperature lead to the larger reaction rates. It can be seen that all of the homogeneous reaction rates are larger at the fuel inlet region because of rich O2 and volatiles. High mass fraction of volatile gas is found at the fuel inlet, and the main reburning gas at the dilute phase is CH4. The mass fraction distribution of CO is related to the volume fraction of fuel which is due to the fact that the source of CO is not only from the devolatilization but also from the gasification. On the basis of this theoretical study, a better understanding of flow and combustion characteristics in biomass and coal cofiring under oxy-fuel atmospheres could be achieved.http://dx.doi.org/10.1155/2018/6931483
spellingShingle Chao Chen
Xuan Wu
Lingling Zhao
Simulation of Coal and Biomass Cofiring with Different Particle Density and Diameter in Bubbling Fluidized Bed under O2/CO2 Atmospheres
Journal of Combustion
title Simulation of Coal and Biomass Cofiring with Different Particle Density and Diameter in Bubbling Fluidized Bed under O2/CO2 Atmospheres
title_full Simulation of Coal and Biomass Cofiring with Different Particle Density and Diameter in Bubbling Fluidized Bed under O2/CO2 Atmospheres
title_fullStr Simulation of Coal and Biomass Cofiring with Different Particle Density and Diameter in Bubbling Fluidized Bed under O2/CO2 Atmospheres
title_full_unstemmed Simulation of Coal and Biomass Cofiring with Different Particle Density and Diameter in Bubbling Fluidized Bed under O2/CO2 Atmospheres
title_short Simulation of Coal and Biomass Cofiring with Different Particle Density and Diameter in Bubbling Fluidized Bed under O2/CO2 Atmospheres
title_sort simulation of coal and biomass cofiring with different particle density and diameter in bubbling fluidized bed under o2 co2 atmospheres
url http://dx.doi.org/10.1155/2018/6931483
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AT xuanwu simulationofcoalandbiomasscofiringwithdifferentparticledensityanddiameterinbubblingfluidizedbedundero2co2atmospheres
AT linglingzhao simulationofcoalandbiomasscofiringwithdifferentparticledensityanddiameterinbubblingfluidizedbedundero2co2atmospheres