Research Initiation: Direct Viscosity Enhancement of Dense Carbon Dioxide

这项拟议研究的主要目的是通过溶解可能在流体阶段聚集并形成长大分子样结构的少量化合物来诱导液体二氧化碳粘度的显着增加。三种类型的化合物将被评估使用一种新的，高压，目视下降气缸粘度计和高压PVT装置。各种油溶性非离子和半氟表面活性剂将与少量水一起溶解在二氧化碳中，试图形成长圆柱形的反胶束和微乳液。半氟化烷烃构成第二类候选化合物。最后，将三丁基氟化锡和助溶剂引入液态二氧化碳中。提高二氧化碳的粘度对于开发油藏中的驱油介质可能是有价值的，因为目前的低粘度二氧化碳溶液会导致旁路或窜流，采收率低。对表面活性剂在超临界流体中的行为的认识也可能导致表面活性剂技术与超临界流体技术相结合的新分离纯化工艺。

The primary objective of this proposed research is to induce a significant increase in the viscosity of liquid carbon dioxide by dissolving small amounts of chemical compounds which may aggregate in the fluid phase and form long macromolecule-like structures. Three types of compounds will be evaluated using a novel, high pressure, visual falling cylinder viscometer and a high pressure PVT apparatus. Various oil soluble nonionic and semi-fluorinated surfactants will be dissolved in carbon dioxide along with small amounts of water, in an attempt to form long, cylindrical reverse micelles and microemulsions. Semi-fluorinated alkanes constitute the second category of candidate compounds. Finally, tri-n-butyltin fluoride and a cosolvent will be introduced into the liquid carbon dioxide. Increasing the viscosity of carbon dioxide may be of value in developing displacement media in oil reservoirs where current low viscosity carbon dioxide solutions lead to by-passing or channeling and low recovery efficiencies. An understanding of surfactant behavior in supercritical fluids may also lead to new separation and purification processes combining surfactant technology and supercritical fluid technology.