【作者】 王祖山；

【导师】 王知彩；

【作者基本信息】 安徽工业大学 ， 分析化学， 2010， 硕士

【摘要】 为了研究煤直接液化中间重质产物化学转化行为,探索煤直接液化机理,本文通过柱色谱法分别对不同煤种和液化工艺条件下制备的前沥青烯（PA）和沥青烯（AS）进行了分离,并通过元素分析、红外光谱、荧光光谱和凝胶色谱等分析方法对分离组份进行了结构表征,探讨了各因素对PA和AS结构与组成的影响。此外,利用荧光光谱对PA中的缔合作用进行了初步探索。研究结果表明:PA中甲苯和THF混合溶剂洗脱组分I和II含量高,并且组分I^III元素组成差异小,C %高、O %较低,甲醇洗脱组分IV含量较低,主要是以非共价键缔合的强极性含氧化合物;所有AS都以甲苯或甲苯/THF（4∶1）洗脱的弱极性组分为主,随洗脱溶剂极性增大,所得次组分C %逐渐降低,O %增大,尤其是甲醇洗脱组分E中O %显著高于其他组分;提高液化温度、延长液化时间以及强供氢体系（H₂气氛和FeS+S催化剂）都有利于促进加氢和脱氧作用,增大AS和PA中弱极性组分含量,降低次组分中的O %;褐煤液化AS和PA中极性组分含量显著高于次烟煤,并且褐煤液化AS和PA中C %高于原煤,O %显著低于原煤;AS和PA中含氧官能团存在形式非常复杂,不仅含有大量的酚羟基、醚键和芳香酮羰基,而且存在一定量的羧酸酯和少量的羧酸、酸酐和脂肪醇羟基,芳香酮羰基、酚羟基等含氧官能团反应活性相对较低,难以裂解脱除;AS和PA次组分中都存在两类不同能态的荧光发色体,组分间的荧光特性差异主要是能态分布和荧光效率不同,次组分的荧光效率明显低于未分离AS和PA;PA中芳香环主要为单环结构,同时存在少量2-3环稠环结构,AS中除了单环以外还存在大量的2-3环稠环结构,并且主要存在于弱极性组分中;煤液化重质产物AS和PA中存在显著的非共价键缔合作用,并影响其分离性能和表观分子量,溶液中PA的缔合过程为逐步缔合。更多还原

【Abstract】 In order to study the conversion behaviors of heavy intermediate products of coal direct liquefaction and the mechanism of coal direct liquefaction, the heavy products of coal liquefaction such as asphaltene and preasphaltene, which are obtained by the liquefaction of different raw coal under different liquefaction conditions, are separated by column chromatography in this paper. The structures of all sub-components are characterized by ultimate analyses, FTIR, UV/Vis, fluorescence spectrum and GPC. The influence of each factor on the composition and distribution of liquefied products is also explored. In addition, the aggregation behavior of preasphaltene is discussed preliminarily by fluorescence photometry.The results indicate that the content of component I and II, which are obtained by column chromatography with a mixture solvent (toluene and tetrahydrofuran) as the eluents, are higher than that of component IV obtained with methanol as the eluent in preasphaltene. Ultimate analyses show that element components of I, II and III are very similar, in which the content of carbon is high but the content of oxygen is low. The component IV is mainly strong polarity compound containing oxygen which consists in preasphaltene through aggregation of the non-covalent bonds. The primary component of all asphaltenes is weak polarity component obtained with toluene or toluene/ tetrahydrofuran (4:1) as the eluent. The higher the polarity of the eluent is, the content of carbon of the sub-component is lower, but the content of oxygen is higher, especially the component E obtained with methanol as the eluent is evidently higher than other components. The hydrogenation and removal of heteroatom for the asphaltene and preasphaltene can be promoted by increasing the liquefaction temperature, time and atmosphere with strong supply hydrogen (H2 atmosphere and FeS+S catalyst), so that the content of weak polarity components increase and the content of oxygen decreases. The content of strong polarity component separated from asphaltenes and preasphaltenes of lignite liquefaction is evidently higher than that of subbituminous liquefaction, in which the content of carbon is higher than raw coal but the content of oxygen is lower. The oxygen-containing functional groups are extremely complicated. They not only contain large numbers of phenolic hydroxyl group, ether bond and aromatic ketone carbonyl group, but also carboxylic ester, carboxylic acid, acid anhydride and aliphatic alcohol hydroxyl group. The oxygen-containing functional groups such as aromatic ketone carbonyl group and phenolic hydroxyl group is show comparatively low reactivity and are difficult to remove. There are two different fluorophores with different energy state in all sub-components of asphaltene and prasphaltene. The difference of fluorescence characteristic of different components is mainly originated from different distribution of energy state and fluorescence efficiency. Fluorescence efficiency of sub-component is evidently lower than its parent asphaltene and prasphaltene. Aromatic ring of preasphaltene is mainly single ring structure. Meanwhile, there is few 2-3 aromatic fused ring structures in preasphaltene. Except for single ring structure, asphaltene shows abundant 2-3 aromatic fused ring structures which are mainly existed in weak polarity component. Non-covalent bond aggregation exists extensively in asphaltene and preasphaltene of heavy intermediate products of coal liquefaction. It can influence the separation performance and apparent molecular weight of heavy intermediate products. The aggregation of preasphaltene in solution is a progressive process.更多还原