褐煤热解过程中汞的迁移规律研究

Mercury migration law in pyrolysis process of lignite

汞是煤中普遍存在的一种痕量元素,煤燃烧过程中痕量元素的排放不仅与元素的性质、含量有关,而且与煤中痕量元素的赋存形态有关。基于固定床热解反应系统,研究了神华褐煤热解过程中汞的迁移规律。结果表明,汞的迁移率随热解终温的升高而急剧上升,当热解终温在350℃以上时,热解终温再升高,汞的迁移率的升高幅度变缓,当热解终温达到500℃时,汞的迁移率已达95%左右。原煤和热解半焦的逐级化学提取实验表明,经热解后,煤中可交换态、硫化物结合态和有机物结合态的汞含量大大降低,且在400℃以前已基本释放。

Mercury is one kind of trace elements in coal.The emission of trace elements during coal combustion process is connected with the characteristics, content and occurrence of elements.Based on the fixed-bed pyrolysis reactor system, investigate the mercury migration law in the pyrolysis process of China Shenhua lignite.The results show that, the mobility of mercury rises sharply with the rise of pyrolysis terminal temperature.When the pyrolysis temperature is above 350℃ ,the mercury migration rate increases slowly with the rise of temperature.Mercury migration rate reaches to about 95 percent when the pyrolysis temperature is 500℃ .The sequential chemical extraction experiment on coal and semieoke indicate that, the amount of exchangeable mercury, bound-organic mercury and bound-sulfide mercury in coal reduce greatly after pyrolysis, and the content of mercury in coal is almost zero before the pyrolysis temperature reaches to 400℃.