咪唑类离子液体辅助溶剂萃取油砂沥青研究

Solvent Extraction for Bitumen Recovery from Oil Sands Assisted with Imidazole Ionic Liquids

采用阴离子为BF_4^-,阳离子为1-烷基-3-甲基咪唑类的离子液体(Ionic Liquids,ILs)辅助丙酮/正庚烷复合溶剂和甲苯2种溶剂萃取加拿大油砂中的沥青,考察了ILs辅助2种溶剂萃取油砂沥青过程中,ILs阳离子咪唑环一取代位上的碳链长度对沥青萃取率和固体夹带的影响。实验结果表明,随着ILs阳离子咪唑环一取代位上碳链的增长,沥青的萃取率总体逐渐降低。碳链从甲基变化到正己基,在丙酮/正庚烷复合溶剂体系中,沥青萃取率由9.29%降到8.55%;在甲苯体系中,沥青萃取率由10.05%降低到9.45%。但在2种体系中,加入碳链为正丁基的IL的沥青萃取率高于碳链为正丙基的IL。采用红外光谱对不同萃取体系中所萃出的沥青相进行分析发现,纯甲苯萃出的沥青相中检测到砂砾物质,而6种ILs辅助甲苯所萃取出的沥青中的砂砾含量则在红外检出限以下。丙酮/正庚烷复合溶剂及在6种ILs辅助下萃出的沥青相中均未检测到细小砂砾物质。实验结果为如何筛选适当ILs应用于非常规石油分离提供了科学基础。

Six kinds of ionic liquids （ILs） with anion of BF4- and cation of 1-alkyl-3-methylimidazole were applied to extract bitumen from oil sands as additive agent combined with toluene or acetone/hep- tane composite solvent. The effect of the carbon chain length of the 1-position imidazole ring on the ex- traction of bitumen and solid entrainment was investigated. The results demonstrate that the extraction ra- tios are reduced with the increase of the length of 1-position carbon chain of cation in both acetone/hep- tane and toluene systems. The extraction ratio is reduced from 9.29% to 8.55% in aeetone/heptane composite solvent system, and reduced from 10.05% to 9.45% in toluene system. But, in both systems, the extraction ratio assisted with ionic liquids of which 1-positon carbon chain is n-butyl was higher than that of which 1-position carbon chain is n-propyl. In addition, the FTIR spectrum results indicate that assisted with the 6 kinds of ILs, much less clay fines in the recovered bitumen are found than that using toluene extraction alone.