碱酸处理对褐煤结构的影响

EFFECT OF ALKALI-ACID TREATMENT ON STRUCTURE OF LIGNITE

采用碱酸法对鄂尔多斯褐煤进行了不同温度下的脱灰处理,通过元素分析、FTIR、TG和SEM等分析手段比较了脱灰前后煤的结构变化.结果表明,煤经过碱酸处理后,水含量和灰含量降低,经高温(240℃)酸碱处理,灰分降低到0.84%.碱酸处理过程减少了煤的含氧量,提高了碳含量和发热量.室温碱酸处理会加速煤的热解,使煤的粒度更加均匀.高温碱酸处理降低了煤的挥发分,热失重曲线变缓,小分子间发生聚合反应,增强了煤的紧密性,使煤表面变得粗糙.说明碱酸处理在一定程度上改变了煤的物理化学结构,且高温下更加明显.

Alkali-acid deashing treatment on Ordos coal at different temperatures is carried out, and the changes of the structure before and after demineralization of coal are compared by elemental analysis, FTIR, TG and SEM. After alkali-acid treatment, the water content and ash content of coal reduce greatly, and the ash content reduce to 0. 84% at high temperature （240 ~C）. The treatment reduces the oxygen content and meanwhile enhance the carbon content and calorific value of coal. Room temperature alkali-acid treatment could accelerate coal pyroly- sis, making the particle size of coal more evenly. High temperature alkali-acid treatment reduces the volatile matter of coal, slows the thermo-gravimetric curve, and promotes polymerization re- action between small molecules, increases the compactness of the coal, therefore the coal surface is rough. It indicates that alkali-acid treatment plays a good role in upgrading coal, and the effect is more remarkable at high temperature.