On the basis of the former Soviet Union boiler thermal calculation standard

the burner area of the opposed-firing boiler in a 660MW unit was divided into three heat release sections.Considering the heat balance and consistence with the standard

calculation equations for each section were deduced.On this basis

the distributions of gas temperature

furnace emissiity and surface mean radiation against the furnace height were calculated.The results showed that

the W coal(Wuganglongping coal)was most close to the design coal in combustion temperature.Its furnace emissivity distribution along the furnace height was the most stable.The W coal was priority when the boiler only fire one kind of coal

from the furnace temperature field and surface mean radiation aspects.The mixed ratio had great effect on furnace temperature field and surface mean radiation.Firing SS coal(the Shixiajiang A coal mixed with Dashanling coal)with mixed ratio of8∶2

the temperature in section III where the combustion was the most exuberant was1 810.39℃

the highest and closest to the design coal.