In order to satisfy the requirements of drying capacity of medium speed pulverizing system for the tangentially fired lignite boiler

primary air flow of the mill must be increased.The Tascflow software was adopted to analyze the variation law of relative diameter of tangential circle

under the condition that the primary air ratio of medium speed pulverizing system in tangentially fired boiler with high moisture lignite as the fuel was increasing.The results showed that

when the primary air ratio increased from 25% to 45%

the relative diameter of tangential circle(the ratio of tangential circle diameter to furnace width) gradually increased form 0.5 to 0.75

which would probably cause slagging on the wall.Thus

when the primary air ratio was increasing

increasing the primary air speed from 18 m/s to more than 30m/s

even up to 35 m/s

at the same time

and decreasing the relative diameter of tangential circle on the premise of satisfying the dry oulet of tangentially fired boiler

can realize good combustion dynamic field.