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Abstract: The
computational fluid dynamics (CFD) code, PHOENICS 3.5, is employed to
evaluate horizontal pulverized coal bias combustion process in a 200 MW
tangential firing boiler. Multi-fluid two-phase model and coal
comprehensive combustion model are integrated in the code. Gas
temperature, particle distribution, gas species concentration and
radiation heat flux at different sections of furnace are obtained from
the numerical simulation at different secondary air (SA) vertical
distribution. The calculation results show that a high particle
concentration and high gas temperature zone exist, together with the
separation of particle and gas downstream primary air (PA) nozzles,
which ensure suitable ignition time, high temperature level of PA
mixture and resistance to slag on the water-cooled walls. The calculated
burnout of coal particles, O2 concentration at furnace exit and gas
averaged temperature in furnace are compared with in situ measurement
data, resulting in good agreement. The simulation results of staged SA
distribution case show that gas temperature of down part of furnace
increase and the final burnout of char is decreased for the postponing
mixing between fuel and oxygen. Simulation results are also compared
with in situ measurement data, resulting in good agreement with each
other. Thus the comprehensive coal combustion model has reasonably
simulated PF combustion process in large boiler furnace, which is
benefit for optimizing unit operation conditions and reducing pollutants
emission.
Key words:Pulverized-coal
bias combustion Gas particle two-phase flow Tangential
firing Numerical simulation
CLC No: TK224
国家863计划(2002AA526012)和2005年度教育部新世纪优秀人才支持计划基金资助项目.Received
20050818,received in revised form 20060210
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