Supercritical fluid extraction of bitumen from Beke oil sand

The results of a study of the composition of bitumen from Beke oil sand (Kazakhstan) and products obtained in the process of supercritical fluid (SCF) extraction in n-hexane and its mixture with isopropanol are presented. It has been shown that the content of high-molecular heteroatomic compounds – resins and asphaltenes in bitumen reaches 50 wt. %. The amount of saturated compounds in bitumen exceeds the content of aromatic hydrocarbons by 3 times. Among aromatic hydrocarbons, monoarenes are found in the highest concentrations. It has been established that SCF extraction leads to the formation of 0.7-1.0% solid and 7.0-7.1% gaseous products, the total yield of liquid components is 91.9-92.3 wt. %. As a result of SCF extraction, the composition of liquid products noticeably changes - the content of asphaltenes decreases by more than 2-5 times, oils from 60.3 to 55.0-44.7 wt. %. The resins content in the products of the SCF extraction is influenced by the nature of the solvent: the use of a mixture of n-hexane and isopropanol helps to increase the yield of resins from 35.1 to 46.4 wt. %. It has been shown that the destruction of resins and asphaltenes molecules during the SCF extraction of bitumen leads to a change in the hydrocarbon composition.