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

摘要

The phase behavior of Athabasca vacuum bottoms (ABVB),a 798.15+K(525+oC)boiling fraction comprising 32 wt.%pentane asphaltenes,+pentane mixtures is elucidated using x-ray transmission tomography.These pseudo binary mixtures are models for the development of novel heavy oil/bitumen production and refining processes. Depending on the overall composition,these mixtures are shown to exhibit three and four phase equilibria including both expected(L1L2V)and unexpected(L2L3V)phase behavior separated by a small L1L2L3V zone.These multiphase equilibria provide challenges in production environments, where miscible flooding is typically desired,but afford new opportunities for the development of separation technologies in refining.Example pressure-temperature at constant composition phase diagrams and pressure-composition at constant temperature phase diagrams,which focus on the bubble pressure region where multiphase regions arise,are presented.Limited phase equilibria data sets for ABVB+ heptane,decane and dodecane are also presented so that trends for ABVB+alkane mixtures with the size of the alkane diluent can be explored.We expect these phase diagrams to provide insights to heavy oil producers and refiners in addition to providing a benchmark for testing phase behaviour models for these and related complex hydrocarbon mixtures.