锅炉燃用褐煤一次风率变化对切圆的影响

The influence of primary air rate variation on performance of a tangentially fired lignite boiler

为满足燃用褐煤的四角切圆燃烧锅炉中速磨煤机制粉系统的干燥出力,必须增加磨煤机一次风量。运用Tascflow软件分析燃用高水分褐煤的四角切圆燃烧锅炉中速磨煤机制粉系统在一次风率升高的情况下,炉内切圆相对直径的变化规律。结果表明,一次风率由25%提高到45%时,炉膛内切圆相对直径由0.5逐渐增大到0.75,可能导致炉墙结焦。为此,在增大一次风率的同时,将一次风速由18 m/s升至30m/s以上,甚至达到35m/s,在满足燃用高水分褐煤四角切圆燃烧锅炉中速磨煤机制粉系统干燥出力的同时,减小切圆相对直径,使炉膛内具有良好的燃烧动力场。

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.