Study On Characteristics Of Oil Shale Pyrolysis Intermediates And Products

Due to the rapid growth of global energy consumption, the oil shale has been chosen as an important alternative energy source in many countries. Because of its huge reserves and various modes of development and utilization, the oil shale has become one of the focuses of national energy development strategy. In China, oil shale is mainly used to produce shale oil, but the pyrolysis technology used is less advanced than that in other countries. Therefore, it need to deeply investigate the pyrolysis process of oil shale and reveal the reaction mechanism. To study the characteristic of pyrolysis intermediates will play an important role in understanding the relationship between oil shale and pyrolysis products.In this paper, the pyrolysis intermediate is determined as a nondescript derivative of kergen that has been thermally degraded to be soluble but not volatilizable. The pyrolysis experiments of Huadian oil shale and deashing kerogen was carried out in Fischer assay. The low temperatures at 300 – 450 o C were used to obtain the pyrolysis intermediates, and oil products were collected under the corresponding temperatures.The results showed that the yield of pyrolysis intermediates increased up to a maximum value at 375 oC, and then decreased with the temperature elevated successively, indicating that the decomposition rate of intermediates was larger than the formation rate of those at high temperatures. The yield of oils presented a growth trend under the pyrolysis temperatures, and their compositions were mainly chain alkane and olefin, also including a small amount of heteroatomic compounds. With the increase of temperature, the proportion of saturated alkane was shrinking, the proportion of olefin was growing, and long chain aliphatic hydrocarbons would transform into short chain compounds.The thermogravimetric results of kerogen showed no obvious peak of minerals decomposition. Under the condition of same temperature, the yields of kerogen pyrolysis intermediates and oil were larger than that in oil shale, the compositions of kerogen and oil shale pyrolysis products were also different.