The Phase Behavior of Athabasca Vacuum Bottoms + n-Alkane Mixtures

摘要

The phase behavior of Athabasca vacuum bottomsrn(ABVB), a 798.15+ K (525+ ℃) boiling fraction comprisingrn32 wt. % pentane asphaltenes, + pentane mixtures isrnelucidated using x-ray transmission tomography. Thesernpseudo binary mixtures are models for the development ofrnnovel heavy oil/bitumen production and refining processes.rnDepending on the overall composition, these mixtures arernshown to exhibit three and four phase equilibria including bothrnexpected (L1L2V) and unexpected (L2L3V) phase behaviorrnseparated by a small L1L2L3V zone. These multiphasernequilibria provide challenges in production environments,rnwhere miscible flooding is typically desired, but afford newrnopportunities for the development of separation technologiesrnin refining. Example pressure-temperature at constantrncomposition phase diagrams and pressure-composition atrnconstant temperature phase diagrams, which focus on thernbubble pressure region where multiphase regions arise, arernpresented. Limited phase equilibria data sets for ABVB +rnheptane, decane and dodecane are also presented so that trendsrnfor ABVB + alkane mixtures with the size of the alkanerndiluent can be explored. We expect these phase diagrams tornprovide insights to heavy oil producers and refiners in additionrnto providing a benchmark for testing phase behaviour modelsrnfor these and related complex hydrocarbon mixtures.