The objective of this research was to develop a model to describe the removal of dispersed petroleum hydrocarbons from oil-field brines using carbon dioxide in a sieve tray extraction column. The model consists of two parts: hydrodynamics of bubble flow and flocculation. The flocculation part of the model will be presented in this work. The system studied in this work was a brine from a California steamflood. The California brine contained a nominal 1000 mg/L of a heavy, asphaltic crude oil (13.2 °API) and had a total salinity of approximately 500 mg/L. The flocculation model was tested with experimental runs at pressures of 83.75 and 97.54 bar and temperarures of 23.9,37.8 and 65.6 °C. Additional flocculation runs were made at pressures of 14.80,42.38, and 69.96 bar at 65.6 °C. It was determined that the flocculation of the dispersed oil droplets was the result of two separate effects: a pH effect due to the acidity of carbon dioxide and a shear effect due to the rising carbon dioxide bubbles. . It was necessary to use an empirical flocculation efficiency in the model in order to effectively predict removal efficiencies for each operating condition.

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