焦煤、塑料和粉尘共热解失重分析

在以N₂载气,其流量为30mL/min、升温速率为5℃/min、热解终温为1000℃的条件下,运用Setaram Lab-sysYM热重分析仪系统分析了塑料、冶金粉尘和焦煤的热解过程以及它们之间的相互影响.不同配比的塑料、冶金粉尘和焦煤混合热解过程分析表明:在低温段,煤和塑料热解产生大量活泼自由基,然后通过自由基内部重排或自由基间相互结合的方式稳定化,其中的硫元素主要形成气态硫化物(如H₂S、COS等),并与粉尘中的金属氧化物作用生成固态金属硫化物而固硫;高温段产生的H₂、CO及粉尘中所含有的C等增强了反应体系的还原性,加剧了粉尘中金属氧化物的还原气化,从而更有利于实现焦炭的有效脱硫可见,运用添加塑料、冶金粉尘到焦煤中的方法可以实现炼焦过程中的焦炭和煤气同时脱硫的双重效果.

Study on Co-pyrolysis of Coking-coal, Plastic and Dust

The co-pyrolysis processes of different proportions of coking-coal, plastic, metallurgical dust (MD) were investigated using thermal analyzer (Setaram Labsys) under a neutral atmosphere of N2 at the sweep rate of 30 mL/min, the linear heating rate and the final pyrolysis temperature were 5 degrees C/min and 1000 degrees C respectively in this study. The experimental results indicated that both the pyrolysis process of coking-coal and that of plastic were radical mechanism. In other word, within the relatively lower temperature range, a large amount of radicals were generated during their pyrolysis processes and stabilized through the intra-radical rearrangement reactions or inter-radical combination reactions. This means that sulfur containing in coal and plastic tends to formed gaseous sulfides, such as H2S, COS, CS2, etc. When co-existing with MD, these sulfides will react with metal oxides containing in MD to form metal sulfide with high stability and the cleaner coke oven gas (COG) were obtained. Within higher temperature interval of 500 degrees C-1000 degrees C, some of the gaseous products after pyrolysis (e.g. H2, CO and C) reinforce the reduction atmosphere that the coking reaction system needs and accelerate the reduction of metal oxides in MD and gasification of metal, which were conductive to the effective removal of sulfur in coke. Therefore, it is definitely feasible to adding waste plastic and MD into coking-coal to remove the sulfur in COG and coke simultaneously.