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选取我们国家主要褐煤的产区的不同煤阶的3种典型的褐煤,用水热处理的方法对褐煤进行脱水改性并且研究改性前后褐煤的CO2气体特性的变化。实验结果表明,经过水热处理后,褐煤中的所含水分大幅度下降,最高降幅可以达87.31%,固定热值和碳上升,氧含量明显下降,褐煤煤阶上升,煤阶参数(O/C原子比)下降。水热处理过程中煤质结构的复杂重整可以导致煤焦孔径向微孔的方向发展,先降低后增加,而表面积和孔容则呈现先上升后下降的趋势。煤阶的上升和煤质结构的深度变化使得改性后的褐煤的气体特性曲线呈现向高温区的移动,碳转化率达到50%的时候的气化的温度上升。动力学计算的结果表明,经过水热改性后气体反应活化可以上升,反应级数也发生变化。较高的水热处理终温和相对较低的原煤煤阶都使得水热脱水改性的效果更为显著。
Three kinds of typical lignite with different coal rank in the producing area of our country’s main lignite were chosen to dehydrate and modify the lignite by means of hydrothermal treatment and to study the change of CO2 gas characteristics of lignite before and after modification. The experimental results show that after hydrothermal treatment, the moisture content of lignite decreases sharply, the maximum decrease can reach 87.31%, the fixed calorific value and carbon increase, the oxygen content decrease obviously, the rank of lignite increases, the coal rank parameter (O / C Atomic ratio) decreased. The complex reforming of the coal structure during the hydrothermal treatment can lead to the direction of the micropore of the coal coke, and then decrease and then increase. However, the surface area and pore volume tend to increase and then decrease. The increase of coal rank and the depth change of coal structure make the gas characteristic curve of the modified lignite move to high temperature region, and the gasification temperature rises when the carbon conversion rate reaches 50%. The results of kinetic calculation show that the gas reaction activation can be increased after hydrothermal modification and the reaction order also changes. The higher final hydrothermal treatment temperature and the relatively lower raw coal rank make the effect of hydrothermal dehydration more pronounced.