In order to effectively prevent the slagging of a supercritical 650 MW opposed firing boiler

the influence of different coal types on the flue gas temperature at the furnace outlet and the heat load of the boiler was checked by thermodynamic checking calculation

and the influence of the air distribution in the furnace and the coneexpanding angle of the burner on the flue gas dynamic field and flue temperature of the furnace was analyzed by CFD simulation. The results of the thermodynamic checking calculation showed that the boiler and the coal type were not the main reason for slagging. The variable air volume simulation showed that adjusting the ratio of internal and external secondary air could have effect on the dynamic field of flue gas. But in operation

changing the air volume did not solve the slagging problem well. The simulation results pointed out that the heat load of the water wall area could be reduced by reducing the cone-expanding angle of the burner from 45° to 30°

so as to inhibit the slagging. In the actual adjustment

after changing the cone expansion angle of the burner from 45° to 30° and adjusting the air distribution

the slagging situation of the boiler was greatly improved.The calculation results of variable SOFA wind showed that the appropriate reduction of SOFA wind proportion could reduce the flame height and the flue gas outlet temperature. The simulation of variable secondary air rotation showed that the secondary air rotation had a significant influence on the flow field and the slagging risk would significantly increase if the rotation of the burner was not arranged according to designed value. Further adjustments to SOFA wind ratio and secondary wind swirl could be considered in following adjustments.