Indonesian Oil Sands Pyrolysis Microcosmic Behaviors And Its Vacuum Pyrolysis Characteristics By Comparison

Oil sand is a kind of unconventional oil resources with huge reserves,with the continuous consumption of the conventional oil resources,the development and utilization of oil sand attracts more and more attention.The oil sand pyrolysis technique can be widely suitable with no contamination or tailing ponds,and it is easy to conduct with promising industrialization prospect.The basic research on oil sand pyrolysis behaviors has profound guiding significance for actual production.The comparison among different pyrolysis technologies contributes to the determination of the specific technology route,which is helpful to the oil sand pyrolysis process.In this study,a conception of oil sand particle cluster was raised as the basic pyrolysis unit,the pyrolysis dynamic behaviors were captured by a digital camera.It was found that,during the pyrolysis progress,the bitumen film formation phenomenon appeared twice.The pyrolysis solid products obtained by splat cooling with varying final temperatures were characterized.A scanning electric microscope was applied to observe the oil sand micro channels,and the specific surface area and pore volume analysis was employed to analyze the variations inside the channels.The relevance between the acceleration curve of weight loss and the accumulated liquid amount was analyzed.The specific surface area and pore volume was not kept increasing,but varied with the accumulated liquid in the channels.At the heating rate of 10°C/min,the accumulated liquid amount reached the maximum value respectively at 230°C and 460°C,the first was caused by the melting of the bitumen,while the second was caused by the violence of the cracking reaction.Based on the analysis above,an oil sand pyrolysis physical progress model was proposed.As such,vacuum pyrolysis was studied by comparison of nitrogen sweeping pyrolysis and retorting on the yields and products properties.The effects of final temperature,vacuum degrees and heating rates on the products yields were studied,showing that the vacuum pyrolysis yield was better than that of nitrogen sweeping pyrolysis better than that of retorting.In the lower heating rate range(<50°C/min),increasing heating rates could not obviously decrease the coke yield,on the contrary,higher heating rates decreased the liquid yield due to the secondary reactions of the organic vapors.And on this basis,a coupling of retorting and vacuum pyrolysis technique was proposed and the transition temperature from retorting to vacuum pyrolysis was examined.In the coupling of retorting and vacuum pyrolysis process,at the heating rate of 10°C/min,500°C can be treated as the critical transition temperature with little sacrifice of the liquid yield.The pyrolysis oil products has lower initial boiling points,heavy oil was the main component of the bitumen,while distillates was the main component of the pyrolysis liquid products.Based on the abovementioned analysis,the mass transfer behaviors of the organic vapors were analyzed and the main factors affecting the liquid yields were indicated.