Abstract In this study, experiments were conducted to systematically determine how the surface morphology, microcrystalline and thermal transformation characteristics of coal change during acid treatment. HCl-HF acid washing was applied to pretreat the raw coal. The effects of the demineralization treatment on the carbonaceous structure and functional groups were first tested using X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). The results show that the demineralization treatment significantly removes the peaks of inherent mineral matter (based on XRD), enhances the disorder in the structure of the coal (based on Raman spectroscopy), and changes the structure of C O, the aromatic structure and the aliphatic side chains (based on FTIR). The surface morphologies of the raw coal and demineralized coal were then studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that the demineralized coal has a greater surface roughness than the raw coal. The surface morphology of the macerals show that the demineralization treatment transforms the vitrinite peaks to valleys and increases the depths of the valleys; furthermore, the demineralization treatment cause the peaks and valleys of the surface roughness to interchange. Finally, pyrolysis experiments of the raw coal and demineralized coal were conducted with thermogravimetric analysis (TGA) and a fixed-bed reactor, and the subsequent gas and tar compositions were characterized by gas chromatography (GC) and gas chromatography–mass spectrometry (GC MS). The results show that the pyrolysis reactivity of coal is decreased by demineralization treatment. The pyrolysis experiments in the fixed-bed reactor indicate that the pyrolysis conversion rate increases with the base-acid ratio of the inherent mineral matter. The pyrolysis products show that the amounts of H2 and CH4 increases due to the presence of the inherent mineral matter. The inherent mineral matter can also promote the cracking of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and oxygen-containing compounds in the pyrolysis tar.

中文翻译：

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脱矿对煤表面形貌、微晶和热转变特性的影响

摘要 本研究通过实验系统地确定了酸处理过程中煤的表面形貌、微晶和热转变特性如何变化。采用HCl-HF酸洗对原煤进行预处理。首先使用 X 射线衍射 (XRD)、拉曼光谱和傅里叶变换红外光谱 (FTIR) 测试脱矿处理对碳质结构和官能团的影响。结果表明，脱矿处理显着去除了固有矿物的峰（基于XRD），增强了煤结构的无序（基于拉曼光谱），并改变了CO的结构、芳族结构和脂肪族结构。侧链（基于 FTIR）。然后通过扫描电子显微镜 (SEM) 和原子力显微镜 (AFM) 研究原煤和脱矿煤的表面形貌。结果表明，脱矿煤比原煤具有更大的表面粗糙度。微晶表面形貌表明，脱矿处理使镜质峰向谷转变，谷深增加；此外，脱矿处理使表面粗糙度的峰谷互换。最后，采用热重分析 (TGA) 和固定床反应器对原煤和脱矿煤进行热解实验，随后通过气相色谱 (GC) 和气相色谱-质谱 (GC MS) 表征了随后的气体和焦油组成。 ）。结果表明，脱矿处理降低了煤的热解反应活性。固定床反应器中的热解实验表明，热解转化率随着固有矿物质的碱酸比的增加而增加。热解产物表明，由于固有矿物质的存在，H2 和 CH4 的量增加。固有的矿物质还能促进热解焦油中脂肪烃、多环芳烃和含氧化合物的裂解。热解产物表明，由于固有矿物质的存在，H2 和 CH4 的量增加。固有的矿物质还能促进热解焦油中脂肪烃、多环芳烃和含氧化合物的裂解。热解产物表明，由于固有矿物质的存在，H2 和 CH4 的量增加。固有的矿物质还能促进热解焦油中脂肪烃、多环芳烃和含氧化合物的裂解。