煤尘表面碳、氧基团随变质增加的演化规律及其对润湿性的影响

为探究煤自身结构差异对润湿性造成的影响,针对煤尘中碳、氧两大主要元素展开研究。通过NMR以及XPS实验分别获得六种不同变质程度煤尘表面碳(氧)基团的分布特征,利用距离分析得到碳(氧)基团的演化规律,发现随变质程度加深,一种基团的增减会伴随着其他基团的变化,是聚类变化的过程。碳基团中的芳烃碳(Ar-C,H)与羧基碳(-COOH)、次甲基碳(CH2)、醚基碳(Ar-O、R-O)演化规律接近,氧基团中的羟基氧(-OH)和醚基氧(C-O-C)的演化规律接近。利用因子分析研究碳、氧基团演化对润湿性的影响,发现芳香基团(Ar-C,H)作为解释碳基团对煤尘润湿性(接触角)影响程度的公因子,贡献95.366%的因素,是碳基团的主要影响因子,羟基(-OH)作为解释氧基团对煤尘润湿性(接触角)影响程度的公因子,贡献94.818%的因素,是氧基团的主要影响因子。

Evolution law of carbon and oxygen groups on coal surface with increasing metamorphic grade and its effect on wettability

Carbon and oxygen elements were studied to explore the effect of structural differences on wettability of coal dust. Surface distribution characteristics of carbon and oxygen groups in 6 coal dusts with different metamorphic grades were examined through NMR and XPS. The evolution of different types of carbon and oxygen groups was obtained using distance analysis. With increasing metamorphic degree a kind of group changes along with variation of other groups in most case, which is a process of clustering. The carbon in Ar-C, -COOH, CH₂ and Ar-O (R-O) has the similar evolution law, the oxygen in -OH and C-O-C is the same case. Factor analysis was used to know effect of group evolution on wettability of coal dust. It is found that Ar-C, as the common factor covering 95.366% to explain coal dust wettability (contact angle), is the main factor of carbon groups; while -OH covering 94.818% is the main factor of oxygen groups.