Identifying contaminants of coal inertinite in charcoal briquettes: Preliminary findings of microscopic analysis

Submitted data was used to write an article: Jelonek, Z., Jelonek, I., Identifying coal-derived inertinite in charcoal briquettes: Preliminary findings of microscopic analysis – article sent for review to the International Journal of Coal Geology. Funding acknowledgments: The project is co-financed by the Polish National Agency for Academic Exchange within the Polish Returns Programme (BPN/PPO/2021/1/00005/DEC/1), the National Science Center, Poland (2022/01/1/ST10/00024), and the research activities co-financed by the funds granted under the Research Excellence Initiative of the University of Silesia in Katowice, Poland. Article Abstract: Despite the widespread popularity of charcoal-based grilling fuels, extensive studies have highlighted various pollutants linked to their production and combustion, posing potential risks to human health and the environment. Since the presence of impurities has been identified as a factor contributing to elevated emissions of harmful gases and particulate matter, a comprehensive quality assessment of grilling fuels is imperative to effectively manage and minimize potential risks to customer health and safety. While identifying many impurities in solid biomass fuels is possible through microscopic analysis, identifying fossil coal contaminants in charcoal briquettes can be challenging. The biggest difficulty arises when coal-derived inertinite and man-made charcoal need to be distinguished as both exhibit numerous visual similarities in microscopic images. Therefore, the goal of this study was to examine the optical morphology of inertinite and charcoal with the aim of differentiating them when they co-occur in charcoal briquettes. The results show that employing high differential interference (DIC) and fluorescence filters, coupled with reflected white light in microscopic analysis, can enhance the observations allowing for easier detection of impurities of inertinite in charcoal-based grilling fuels. Among the most notable distinctions are the high degree of cellular structure preservation and the presence of small pores and protrusions in man-made charcoal; these characteristics are typically absent in the inertinite fragments.提交的数据集用于撰写以下论文：Jelonek, Z.、Jelonek, I.，《炭饼中煤源惰性体（inertinite）的识别：显微分析初步研究》——已投稿至《国际煤地质学杂志》等待评审。 资助说明：本项目由波兰国家学术交流局波兰归国学者计划（BPN/PPO/2021/1/00005/DEC/1）、波兰国家科学中心（2022/01/1/ST10/00024），以及波兰卡托维兹西里西亚大学研究卓越倡议项目资助的研究工作共同资助。 论文摘要： 尽管以木炭为原料的烧烤燃料广受市场青睐，但大量研究已揭示其生产与燃烧过程中产生的多种污染物会对人类健康与环境构成潜在威胁。由于杂质被证实是有害气体与颗粒物排放升高的关键诱因之一，因此对烧烤燃料开展全面的质量评估，对于有效管控并降低其对消费者健康与安全的潜在风险至关重要。 尽管通过显微分析可识别固态生物质燃料中的多数杂质，但在炭饼中识别化石煤污染物却颇具挑战。其中最大的难点在于区分煤源惰性体（inertinite）与人工木炭——二者在显微图像中存在诸多视觉相似性。因此，本研究旨在探究惰性体与木炭的光学形态特征，以实现二者在炭饼中共存时的精准区分。 研究结果表明，在显微分析中采用高微分干涉（DIC）滤镜与荧光滤镜，并配合反射白光进行观测，可优化成像效果，从而更便捷地检测出木炭基烧烤燃料中的煤源惰性体杂质。其中最显著的区别在于：人工木炭保留了高度完整的细胞结构，并存在细小孔隙与凸起特征，而这些特征在惰性体碎片中通常并不存在。