Investigation on the characteristics and interaction of co-pyrolysis of oil shale and peanut shell

Abstract

Aiming at the low oil yield of oil shale, and the high content of oxygen in biomass pyrolysis oil, the co-pyrolysis of oil shale and peanut shell were studied by thermogravimetric analyzer and fixed bed reactor. Based on the co-pyrolysis characteristics, kinetic and oil phase products analysis, a series of co-pyrolysis interaction mechanism has been proposed. The co-pyrolysis caused the earlier decomposition of oil shale and higher conversion rate of blended feedstock. The contribution of co-pyrolysis to the total conversion and oil phase products yield was most significant with biomass blending ratio of 50 %, while the contribution to the activation energy and the generation of aliphatic hydrocarbons was most significant when the ratio was 25 %. The co-pyrolysis interaction at low-temperature (160–400 °C) is dominated by oil shale radicals promoting biomass bond breaking and the minerals catalysis on biomass decomposition. For high-temperature (400–600 °C), it is dominated by biomass alkali/alkaline earth metals which catalyze oil shale decomposition. The interaction promotes the formation of aliphatic and aromatic hydrocarbons in the oil, reduces the average carbon chain length and increases the light oil content.