Review on CFD based models for co-firing coal and biomass

Biomass co-firing withintheexistinginfrastructureofpulverizedcoalutilityboilersisviewedasa practical near-termmeansofencouragingrenewableenergywhileminimizingcapitalrequirementsand maintaining thehighefficiency ofpulverizedcoalboilers. Coal/biomass co-firing isacomplexproblemthatinvolvesgasandparticlephases,alongwiththe effect ofturbulenceonchemicalreactions. Computation FluidDynamic(CFD)simulationscanprovideinsighttodesignandoperationalissues, such asco-firing percentage,loadswings,injectionlocation,excessairandair/fuelstaging,and predictions relatedtoheatrelease,unburnedcarbon,andNOx emissions. The CFDbasedco-firing toolsconsistofmodelsforturbulent flow,gasphasecombustion,particles dispersion byturbulent flow,coal/biomassparticlesdevolatilization,heterogeneouscharreactionand radiation. Additionalmodelsrelatedtoslaggingandfoulingcanalsobefound. This paperpresentsareviewonCFDbasedmodelingapproachesusedtopredictthecombustion characteristicsofco-firing biomasswithpulverizedcoalunderairandoxy-fuelconditions