CHARACTERIZATION OF PYROLYSIS OF NONG’AN OIL SHALE AT DIFFERENT TEMPERATURES AND ANALYSIS OF PYROLYSATE

Abstract

In this work, the thermal behavior of Nong'an oil shale of China was investigated and its pyrolysate analyzed in order to provide optimal pyrolysis parameters for the oil shale in-situ pyrolysis pilot project. Through thermogravimetric analysis (TGA) it was noted that the main mass loss of oil shale was in the temperature range of 310-600 degrees C and the maximum mass loss temperature was 465 degrees C. The retorting experiments showed that temperature had an important influence on shale oil yield and the maximum oil yield was obtained at 550 degrees C. The oil yield was reduced at higher temperatures, resulting in an increase in gas yield. According to the analysis of shale oil composition the high pyrolysis temperature could promote the formation of short-chain hydrocarbons. Meanwhile, more alkenes and aromatics and less heteroatomic compounds were found at high temperature. The long-chain hydrocarbons and heteroatomic compounds were proved to be secondary products decomposed at higher temperature. In addition, the results of nitrogen adsorption/desorption and scanning electron microscopy (SEM) indicated that the shale surface became more porous due to the decomposition of kerogen and more micro-and mesopores were found after the treatment at high temperature.