As a kind of slag-tap boiler

cyclone-fired boilers exhibit significantly different aerodynamics comparing with pulverized coal(PC) boilers. However

by far there are still lack of CFD models that are able to provide effective guidance to the design and operation of cyclone-fired boilers. A CFD model of cyclone-fired boilers was developed in which the capture of coal particles by the molten slag layer was considered through a slag layer coal particle capture model. This model was then employed to investigate the aerodynamics and flue gas recirculation(FGR) optimization design of a 550 MW cyclone-fired boiler. The results demonstrate the highly nonuniform characteristics of furnace aerodynamics of cyclone-fired boilers due to the strong swirling flows created by the cyclones leads to the formation of localized high temperature zones and severe boiler fouling problems at the entrance of boiler convection pass. Thus

it is critical to adapt the FGR design with the nonuniform furnace flow and temperature distributions. The simulation results show that

with the optimized FGR design

the high temperature zones and the resulting severe fouling problems were effectively mitigated.