煤粉中内在矿物对煤焦燃烧反应活性的影响

Influence of Included Minerals on Combustion Reactivity of Chars

用浮沉法分选出中等密度级别的煤粉,在马弗炉上以900℃制焦,用HCl-HF-HCl法对煤焦进行脱灰处理,用TGA研究煤焦脱灰前后燃烧反应活性的变化,用N2吸附法研究孔结构的变化,用可溶离子萃取法研究可溶金属离子含量的变化.结果发现,含内在矿物的无烟煤煤焦和褐煤煤焦脱灰后低温反应速率明显降低,而含内在矿物的烟煤煤焦脱灰后低温反应速率变化不大,所有样品脱灰后高温反应速率都明显提高.机理研究表明,这些变化是煤焦比表面积、孔容、颗粒粒径变化和可溶离子含量在不同温度下综合影响的结果.

Pulverized coal particles with medium density were separated by a sink-float method and then charred in a muffle furnace under 900 ℃.The HCl-HF-HCl treatment was employed to remove ash in the chars.The chars before and after demineralization were subjected to TGA study for their change in combustion reactivity,to N2 adsorption study for their change in pore structure,and to ion extraction for their change in soluble metallic ion concentration.The results indicate that the combustion reactivity of anthracite chars and lignite char with included minerals decreased markedly after demineralization at a low temperature while that of bituminous chars changed negligibly under the same condition.The combustion reactivity of all the chars with included minerals increased greatly after demineralization at a high temperature.The mechanism study shows that the above results are the composite influence of the change in specific surface area,soluble metallic ion concentration,pore size and particle size of the samples under different temperature.