The Characteristics And Kinetic Study Of The Estonia Oil Shale Pyrolysis

In this paper,the basic properties of Estonia oil shale are analyzed.The results show that the oil contents of Estonia oil shale is 26.42%.The yield of retorting gas is 8.57%,among which,the content of methane,C1 and C2 are over 10%,respectively,while the content of H2 is 7.12%.The Proximate analysis shows that the volatile content of Estonia oil shale reaches up to 53.83%,while ash and fixed carbon take 38.82% and 5.59% respectively.The heat value of the oil shale is at a high level,15576kJ/mol.According to the ultimate analysis,Estonia oil shale has a high oxygen content,at 17.71%.These results will provide an important reference for the comprehensive machining utilization of the oil shale.The pyrolysis experiment is conducted with a self-designed fixed bed reactor.Pyrolysates at different temperatures are collected by quickly terminating the reaction,and the properties of those products are analyzed.The Proximate analysis of semi-coke shows that the contents of volatile decreased gradually with the increase of temperature,while that of ash shows an upward trend.The heat value and specific heat of the retorting gas are positively associated with temperature.On the contrary,the molecular weight is negatively correlated with temperature.According to the thermo gravimetric analysis(TGA)of semi-coke,weight loss of the semi-coke becomes not obvious with the increase of temperature.All the analysis results indicate that the properties of different products change a lot between 340℃ and 380℃。According to the pyrolysis mechanism of oil shale,the parameters of kinetic model are calculated by solving a group of differential equations.The apparent activation energy of kerogen pyrolysis is 126.12kJ/mol.Thermal bitumen is main product from kerogen pyrosis,take a proportion of 65.8%,while the productive rate of shale oil and gas from kerogen pyrolysis are 18.3% and 15.7%,respectively.The apparent activation energy of the further pyrolysis of thermal bitumen is 192.77kJ/mol.The main product from thermal bitumen is shale oil,about 89.0%,and the proportion of gas generated by thermal bitumen is 10.6%.Electron Paramagnetic Resonance(EPR)is used to characterize the properties of free radicals in the thermal bitumen,shale oil and semi-coke,and standard curve is built to calculate the free radical concentrations(Ng).Through the analysis of the radical parameters,pyrolysis mechanism of the model assumption is further verified and explained.