Carbon dioxide assisted paraffinic froth treatment

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In paraffinic froth treatment (PFT), large amount of paraffinic solvent is used to induce asphaltene precipitation in order to maintain the quality of bitumen product. The high solvent usage demands more capacity in tailings solvent recovery unit, increasing operation cost dramatically. In addition, asphaltene precipitation results in hydrocarbon loss. It is therefore desirable to improve the PFT process without using large volume of paraffinic solvent and to achieve high bitumen recovery. In this context, we propose to use carbon dioxide (CO2) as a process aid in PFT treatment. CO2 will be introduced to the solvent-diluted bitumen froth at PFT operation temperature and pressure. The performance of treatment will be evaluated by solvent/bitumen ratio at onset of asphaltene precipitation, settling rate of asphaltene/water/solids aggregates, and bitumen properties (viscosity, density, total acid number, asphaltene content, coke index). The interactions between CO2 and bitumen components, water, mineral solids in solvent will be investigated. We anticipate the process developed will reduce the use of paraffinic solvent and improve bitumen recovery while maintain bitumen quality.