浮选对煤热解过程中NH_3生成的影响

介绍了采用固定床反应器对神东、新疆和小龙潭原煤及其浮选后所得精煤和尾煤在873K～1 173K温度、420mL/min Ar气氛下热解NH_3生成的实验研究。结果表明,浮选得到的精煤和尾煤在热解过程中释放的NH_3量与原煤释放的NH_3量相比不同,且随煤的变质程度的变化而变化;浮选改变了NH_3的生成率,但没有改变其随温度的变化趋势。精煤、尾煤与原煤一样,在快速热解过程中,NH_3的生成由进样阶段决定。煤氮生成NH_3的转化率均随着温度的升高而增大,但高于1 173K时,NH_3的生成率变化不大;精煤在程序升温热解和快速升温热解过程中,生成的NH_3均比原煤少,尾煤在两种热解条件下表现不同。实验证明,浮选改变了NH_3的生成率,而且NH_3的生成率和煤中所含的S及矿物质有关。

Effect of Flotation on Formation of NH3 During Coal Pyrolysis

Three Chinese coals （Shendong coal , Xinjiang coal and Xiaolongtan coal） and the clean coal and waste coal gained after flotation were put under pyrolysis in a fixed bed reactor under Ar gas, 420mL/min flow rate to investigate the formation of NH3. Experimental results show that the effect of the flotation on the yields of NH3 was different with the coal types. Yields of NH3 were changed after floatation, but flotation did not change the variation trend of the yields of NH3 based on temperature change. The formation of NH3 came mainly from the feeding period during fast heating pyrolysis of the remaining coal and refined coal, which is similar to the raw coal. The formation of NH3 from raw coal and flotation coals increased with the pyrolysis temperature, but the change of NH3 yield was not obvious during fast heating pyrolysis when the temperature was over 1 173K. Comparing to raw coal, yields of NH3 from refined coal is low during programmed- heating pyrolysis and fast heating pyrolysis, but yields of NH3 from remained coal is different during programmed-heating pyrolysis and fast heating pyrolysis. This should be due to different sulfur content and ash content in the coal.