The experimental study of bitumen extraction from Nigerian oil sand by supercritical carbon dioxide was carried out using a high-pressure extractor. Fifty grams (50 g) of oil sand was placed into a 100-mL extractor at a temperature of 110 °C and pressures of 50, 60, or 65 MPa for the interaction with pure carbon dioxide or modified by the addition of 3 g of ethanol or 2-propanol in three runs to investigate the co-solvent effect on recovery. The liquid recovery of bitumen, using pure carbon dioxide, was determined to be equal to 16.3%, on average, after three runs over the entire pressure range, with a maximum of 18.5% at 50 MPa. The addition of ethanol improved liquid recovery, while the addition of 2-propanol worsened it by ∼5% (on average). The maximum liquid recovery of 24.5% after three runs, using ethanol-modified carbon dioxide, was observed at 60 MPa. The average outgassing losses obtained with the addition of co-solvents increased in the following order: pure carbon dioxide (16.1%), ethanol (19.5%), 2-propanol (24.93%). The obtained bitumen fractions were upgraded by rejection of asphaltenes and petcoke. Chromatographic analysis (gas chromatography-mass spectroscopy, coupled with total ion chromatography (GC-MS TIC)) has shown that the composition of the collected fractions after the first runs is lighter than that observed after the subsequent runs. The fuel-related physicochemical properties of the extracted bitumen fractions were calculated using Khans correlations based on the refractive indices. The obtained characteristics matched those observed in the published data of maltene of Athabasca bitumen.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Energy Engineering and Power Technology
- Fuel Technology