The result indicates coal powder accumulated in pipe when the milling system o ut of service for a long time.The coal powder remained in pipe oxidated and hea ted.

• 分析认为,磨煤机停运时煤粉未抽清,长时间停运使积粉氧化发热,再次启动倒风时,风粉充分混合引发了爆炸。