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.