Xu Zhen, Wang Shijie, Fang Hongming, Wu Xiaoxiong, Qu Likai
College of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, China.
Hubei Key Laboratory of Coal Conversion and New Carbon Materials, Wuhan University of Science and Technology, Wuhan 430081, China.
ACS Omega. 2023 Feb 15;8(8):7922-7931. doi: 10.1021/acsomega.2c07678. eCollection 2023 Feb 28.
This study focuses on the petrographic analysis method to evaluate semi-coke and its combustion behavior in the sintering process, which has been seldom conducted before. Semi-cokes are different in morphological features, porosity, pore structure, and wall thickness, because of differences in the vitrinite and inertinite of the raw coal. Semi-coke displayed isotropy, and even after the drop tube furnace (DTF) and sintering process, it still retained its optical properties. Eight kinds of sintered ash were observed using reflected light microscopy. Petrographic analyzes for the combustion properties of semi-coke were based on its optical structure, morphological development, and unburned char. The results indicated that microscopic morphology was an important characteristic when trying to understand the behavior and burnout of semi-coke. These characteristics can be used to trace the origin of the unburned char in fly ash. The unburned semi-coke mostly existed in the form of inertoid, mixed dense and mixed porous. Meanwhile, it was found that most of the unburned chars were melted into sinter, resulting in inefficient fuel combustion.
本研究聚焦于采用岩相分析方法来评估半焦及其在烧结过程中的燃烧行为，此前很少有人开展此类研究。由于原煤镜质体和惰质体存在差异，半焦在形态特征、孔隙率、孔隙结构和壁厚方面也各不相同。半焦呈现各向同性，即便经过沉降炉（DTF）和烧结过程后，其光学性质仍得以保留。利用反射光显微镜观察了八种烧结灰。基于半焦的光学结构、形态发育和未燃尽焦炭对其燃烧特性进行了岩相分析。结果表明，微观形态是理解半焦行为和燃尽情况时的一个重要特征。这些特征可用于追踪飞灰中未燃尽焦炭的来源。未燃尽的半焦大多以惰质体、混合致密和混合多孔的形式存在。同时还发现，大多数未燃尽焦炭熔入烧结矿中，导致燃料燃烧效率低下。
