Structural Changes of the Bitumen From Inner Mongolia Oil Sand During Thermal Conversion

The properties and structures of bitumen eluted from Inner Mongolia oil sands and their liquid products derived from fluid thermal conversion were analyzed by using 1H NMR and infrared spectroscopy techniques.The average structural parameters,the fraction of aromatic carbon(fA),cycloparaffinic carbon(fN) and paraffinic carbon(fp),of eluted bitumen and their liquid products were obtained by 1H NMR data and the modified Brown-Ladner's method.Compared to bitumen,the liquid products from fluid thermal conversion had a significant difference in average structural parameters.The fA of liquid products increased slightly,and the fN of liquid products increased obviously,while the fp decreased noticeably.Moreover,the total ring number(RT),aromatic ring number(RA) and cycle ring number(RN) decreased from 6.10-8.64 to 2,from 3.13-6.10 to 1 and from 2.22-3.42 to 1,respectively.In addition,the changes of average structural parameters of the three different oil sand bitumen showed the similar tendency due to coking formation of polycyclic aromatic and cleavage of long paraffin side-chain during fluid thermal conversion.