【作者】 王秀红；

【导师】 冯杰；

【作者基本信息】 太原理工大学 ， 化学工艺， 2011， 硕士

【摘要】 以煤为原料生产液体燃料是缓解我国燃料短缺的有效途径。煤液化油粗油的主要组成为芳烃及其衍生物(60～70%),其次为饱和烃(25%)、烯烃以及杂原子化合物(不到10%)。芳烃及其衍生物具有密度高、低反应性的特点,如将煤液化油直接用作液体燃料,芳烃及其衍生物在高温下容易裂解发生结焦,增加的固体沉积物会使燃料热稳定性变差,为此,各国都对燃料中的芳烃含量限定一定范围(通常<18%)。煤液化油中芳烃同其他组分的分离富集成为煤液化油精制的一个重要内容。将煤直接液化粗油中的芳烃进行有效的分离,可以控制液化油中芳烃含量、优化燃料性能、降低液化油粗油精制过程的氢耗。为研究煤液化油中芳烃分离的方法、分离过程机理及传质规律,形成液体产物萃取分离理论和绿色工艺,实现对煤液化油加氢精制生产液体燃料油品质的提升,本研究选择神华煤直接液化油粗油中油馏分中富含芳烃和环烷烃的(200～220℃)馏分段,并通过对其GC/MS测定的数据分析,以其中含量较高的甲苯和甲基环己烷作为芳烃和环烷烃的替代模型化合物研究分离过程。以γ-丁内酯为萃取剂,通过液液相平衡实验,绘制了三元体系溶解度相图,对Y-丁内酯在甲苯／甲基环己烷中的溶解性进行了测定,发现其选择性良好。利用汽液平衡装置进行了三元汽液平衡实验,对不同分离条件下甲苯、甲基环己烷和γ-丁内酯进行三元汽液平衡测定,发现在溶剂比为0.5：1～1：1范围内,甲苯含量为60%以内(甲苯甲基环己烷混合液中甲苯的体积分数)时分离效果较好。应用Aspen计算三元混合体系中二元交互作用系数,得到甲苯和γ-丁内酯之间交互系数最大,即偏离理想程度比较大,归其主要原因在于分子间作用力的不同,并通过量子化学计算,证实分离过程的本质为分子间作用力。甲基环己烷、甲苯由于和γ-丁内酯分子间相互作用力不同,因而γ-丁内酯的加入影响了相对挥发度的改变,进而使目标混合物得到分离。更多还原

【Abstract】 Producing liquid fuel from raw coal is analternative method to alleviate shortage of liquid fuel. The main composition of coal liquefied oil are aromatic hydrocarbon and its derivatives(60-70%), saturated hydrocarbon(25%), olefin and heteroatomic compound(<10%). For the higher density and lower reactivity, aromatic hydrocarbon and its derivatives largely existing in coal liquefied oil are easily to be cracked and coke under high temperature if the coal liquefied oil used as liquefied fuel directly. As a result, various countries set the value of 18% as maximum content of aromatic hydrocarbon in fuel. Thus, separating or enriching aromatic hydrocarbonof coal liquid effectively is critical work of coal liquefied oil purification, which can improve conversion rates of aromatic hydrocarbon, control content of aromatic hydrocarbon, optimize properties of fuel and decrease hydrogen consumption.In order to study approach of separation process, methylbenzene and methylcyclohexane, which riched in the 200～220℃fractions of Shenhua coal liquefied oil, was selected as model compounds to study the phase equilibrium rules of the extracting agent.Usingγ-butyrolactone as an extraction agent, the ternary equilibrium phase of methylenenzene and mehtylcyclohexane was diagramed. Furthermore, the amount ofγ-butyrolactone used in extraction was calculated based on the ternary diagram. The equilibrium parameters were measured by D-B apparatus in the different experiment condition. The results showed the best separation was at the solvent ratio of 0.5:1 and toluene less than 60%. According to the caculation of Aspen, the coefficient of these three mixture phase was the most existed between toluene andγ-butyrolactone. It is proved by the quantum chemistry calculation that the separation mechanism was from the inter-molecular force. Different steric hindrance of methylcyclohexane and toluene leads to different inter-molecular force withγ-butyrolactone and the changes of relative volatility. These results in the separation of toluene and methylcyclohexane easily.更多还原