煤岩显微组分分离富集物热化学反应特性

依据煤中不同类型有机质性质差异对其进行分离,进而分质利用是实现煤炭清洁高效利用的有效手段。论文利用重选法将一种低变质烟煤分质得到镜质组较原煤48.25%增加至76.02%的富镜样,惰质组较原煤43.96%增加至63.98%的富惰样,以及矿物质含量高于61.99%的富矿样。利用热重-质谱分析仪,考察了分离富集物的热解反应特性及气体逸出规律,及其燃烧和气化反应特性。结果表明,分离所得富镜样热解反应失重量及热解过程中逸出的小分子挥发分的量及组成与富惰样和富矿样均有明显差异,表明分质实现了煤中不同类型官能团的分离富集。而由分离所得富镜样、富惰样和原煤热解失重峰温基本一致则表明分质所得煤的主体官能团结构仍较为接近,但含量有明显差距。富镜、富惰与原煤的燃烧曲线整体趋势较为类似,燃烧活性差别不大。以气化反应峰值温度高低判断,富镜样气化反应活性最低,富惰样与原煤气化反应活性较为接近,富矿样气化反应活性最高。将原煤在对应热反应时的理论反应曲线与实验曲线进行对比,发现煤分质过程及煤中镜质组、惰质组和矿物质的分离与否对热解过程挥发分的逸出影响较小,但导致了其燃烧和气化反应活性有所降低。

Thermal chemical reaction behavior of the coal maceral concentrates

Pre-separation of different macerals in coal based on the physical properties and then quality-based utilization are effective process to realize clean and efficient use of coal. According to the density difference of different macerals in coal, a sub-bituminous coal was separated by gravity separation method into maceral concentrates that was enriched in vitrinite, inertinite and mineral, respectively. Compared with the raw coal, the vitrinite increased from 48.25% to 76.02% in the vitrinite-rich sample, the inertinite increased from 43.96% to 63.98% in the inertinite-rich sample, and the minerals content increased from 10.47% to 61.99% in the mineral-rich sample. By thermogravimetry-mass spectrometry analysis, the pyrolysis behavior and the gas evolution of different maceral concentrates were investigated, and the combustion and gasification reaction characteristics were also discussed. The results show that the amount of volatiles from pyrolysis of vitrinite-rich sample is significantly higher than that of raw coal and inertinite-rich sample, indicating that the separation processes successfully separate and enrich some of the functional groups of the coal. Moreover, the pyrolysis characteristic temperatures of the maceral concentrates are basically the same, indicating that the main reaction components of the vitrinite-rich and inertinite-rich sample are similar, but the contents are different. Combustion experiments show that the overall trend of combustion curves of the vitrinite-rich, inertinite-rich sample and raw coal are similar, reflecting little difference in combustion activity. CO₂ gasification experiments show that the gasification reactivity of vitrinite-rich sample is the lowest, and the gasification reactivity of inertinite-rich sample is close to that of the raw coal gasification. Comparing the calculated reaction curve of raw coal with the experimental curve, it is found that the coal separation process and the separation of vitrinite, inertinite and minerals have little effect on the volatile liberation in the pyrolysis process, while decreasing the combustion and gasification reaction activity.