褐煤干燥挥发分析出的数值模拟与试验

Numerical simulation and experimental study on volatiles release during lignite drying process

通过数值模拟的方法,研究传统风扇磨煤机直吹式制粉系统下降干燥管内炉烟干燥褐煤过程中挥发分析出的情况,并通过现场采集干燥介质混合室出口、风扇磨煤机入口、风扇磨煤机出口处的气体进行色谱分析比对。结果表明:在恶劣的干燥环境下,才会有极少量的褐煤达到挥发分析出温度;在正常运行工况下,在色谱分析仪检测范围内,并没有检测到挥发分气体的产生。因此,将传统的风扇磨煤机直吹式系统改造为采用炉烟干燥的水回收风扇磨煤机仓储式制粉系统是安全可行的。

By numerical simulation,the volatiles release during lignite drying process（dried by flue gas）in decline drying tube of the conventional fan mill pulverizing system was investigated.The results indicate that,only in relatively harsh dry conditions,a very small amount of lignite would reach the volatiles release temperature.Moreover,field tests were performed to collect the gas from dry medium mixing chamber outlet and fan mill entrance and outlet.Then chromatographic analysis was conducted for the collected gas.Comparison between the chromatographic analysis results and the simulation results shows that,under normal operation conditions and within the chromatographic analyzer＇s detection range,no volatile gas was detected.Therefore,transformation of the conventional direct-fired fan mill pulverizing system into open pulverizing system with flue gas drying and water recovery is completely safe and feasible.