The Pyrolysis Characteristics and Pore Structure of Oil Shale of Different Densities

This study has been undertaken to provide an insight into the proximate and ultimate analysis, mineral matter distributions, pyrolysis characteristics and pore structure of three density fractions of Huadian oil shale. XRD analysis shows that the major phases in oil shale of different densities are present as clays, quartz and calcite. Low-density pulverized oil shale predominantly contains organic matter and a small amount of mineral matter while high-density pulverized oil shale contains an abundance of mineral matter. The difference is that the former contains mainly internal mineral matter, but in the latter a large quantity of excluded mineral matter predominates. The pyrolysis curves of oil shale of three densities indicate that the light density fraction assumes a most intense pyrolysis and the weight loss, and the decomposition rate becomes ever weaker with an increase of density in the range of 250–550 C. Clays have a catalytic effect on the reactivity of oil shale pyrolysis, causing the degradation of the medium and high fraction to start at a lower temperature. Pore structure of oil shale was measured by using a N2 isothermal adsorption/desorption method. The pore shapes of oil shale of different densities all present slit types. The pore volume and BET surface area of the medium density fraction is higher than that of the light and high density fraction.