离子液体协同PVCap抑制天然气水合物生成实验研究

Experimental study on inhibition effect of natural gas hydrate formation by mixing ionic liquid with PVCap

利用自制的高压反应釜实验研究了离子液体N-丁基-N-甲基吡咯烷四氟硼酸盐([BMP][BF_(4)])、动力学抑制剂聚乙烯己内酰胺(PVCap)及其二元复合物对CH_(4)/C_(2)H_(6)/C_(3)H_(8)混合气体水合物生成动力学的影响,发现在任何浓度下(0.25%~2.0%,质量分数),[BMP][BF_(4)]对混合气体水合物抑制能力远弱于PVCap,但对PVCap具有显著协同效应,且随着PVCap占比增大而增强。粉末X射线衍射(PXRD)和低温激光拉曼光谱测试结果证实,所有体系中形成的样品中均含sⅡ型和sⅠ型两种结构水合物,含PVCap体系中sⅡ/sⅠ水合物相对含量降低。低温冷冻电镜(Cryo-SEM)观测结果显示,添加单一PVCap及其与[BMP][BF_(4)]的混合物会使水合物晶体的微观形貌更粗糙且多孔。

An investigation on the effect of an ionic liquid N-butyl-N-methylpyrrolidine tetrafluoroborate([BMP][BF_(4)]),a commercial kinetic hydrate inhibitor poly(N-vinylcaprolactam)(PVCap)and their binary mixture on the hydrate formation process from methane/ethane/propane ternary mixture was carried out by using a self-designed high-pressure apparatus.It was found that at any concentration[0.25%—2.0%(mass)],[BMP][BF_(4)]had a much weaker inhibitory effect on mixed gas hydrate than PVCap,but had a significant synergistic effect on PVCap,which was enhanced as the proportion of PVCap increased.Moreover,with the increasing proportion of PVCap,the compound inhibitor performed better.Both powder X-ray diffraction patterns and low-temperature Raman spectra indicated that sⅠand sⅡhydrates coexisted in all tested systems.The inhibitors containing PVCap reduced the relative contents of sⅠand sⅡhydrates in the samples.The images observed from scanning electron cryomicroscopy(Cryo-SEM)indicated that the presence of PVCap and its mixture with[BMP][BF_(4)]made the formed hydrates more coarse and porous.