Inner Mongolia Key Laboratory of High-Value Funtional Utilization of Low Rank Carbon Resources, Inner Mongolia University of Technology

Suppressing the spontaneous combustion of lignite is of great significance for safe transportation and efficientutilization of lignite. Taking the Shengli lignite as the research object, two different macerals, inertinite and huminite, wereselected by optical microscope, and treated with NaOH respectively to study the relationship between the structure andcombustion reaction performance of different macerals and lignite treated with NaOH. The structure of the prepared coalsamples was characterized by SEM-EDS, XPS, FT-IR, XRD and Raman, and the changes of the main functional groupswere analyzed. The effect of NaOH treatment on the combustion performance of different maceral lignite was investigated by TGA. The results showed that the ignition temperature of huminite lignite was about 10 ℃ earlier than that of inertinite,but the comprehensive combustion characteristic index of inertinite lignite was slightly higher than that of huminite.After the NaOH treatment, the lignite of different macerals showed a hysteresis of combustion, there were two obviousweight losses in the range of 200−500 ℃ and 650−800 ℃, respectively, and the mass loss was mainly concentrated inthe second weight loss, in particular, the effect of huminite lignite was more significant, and the temperature correspondingto the maximum combustion reaction rate was about 60 ℃ behind that of inertinite. The kinetic analysis of the combustionprocess of the coal samples showed that the activation energy of combustion reaction of lignite with different maceralssignificantly increased after the NaOH treatment, and the huminite lignite was higher than that of inertinite lignite.The XPS/FT-IR results revealed that the contents of carboxylic oxygen-containing functional groups in different maceralsof lignite treated by NaOH decreased, the main reason is that in the process of NaOH treatment, Na+ interacted with thecarboxylic oxygen-containing functional groups in lignite to form the sodium carboxylate structure, and the relativeamount of the sodium carboxylate structure in huminite coal was relatively large. It is believed that the inhibitory effect onthe combustion of lignite with different macerals is attributed to the stability of the sodium carboxylate structure, and thenumber of the sodium carboxylate structure formed by combining with Na is the main reason for the difference in its combustionperformance. The XRD/Raman analysis indicates that the formation of the sodium carboxylate structure in ligniteleads to the increase of the order degree of carbon microcrystalline structure, and the order degree of huminite lignite ishigher than that in inertinite.

内蒙古科技计划资助项目(2020GG0289, 2019GG268)；内蒙古自然科学基金资助项目(2019MS02025)

王延君，赵云飞，何润霞，等. 褐煤显微组分及碱处理对其结构和燃烧性能的影响[J]. 煤炭学报，2023，48(4)：1736−1746

WANG Yanjun，ZHAO Yunfei，HE Runxia，et al. Macerals of lignite and the effect of alkali treatment on the structure and combustion performance of lignite[J]. Journal of China Coal Society，2023，48(4)：1736−1746