348620 Reactivity of Oil Shale Semicoke in Oxy-Fuel Combustion Conditions

Monday, November 4, 2013
Grand Ballroom B (Hilton)
Christopher Culin1, Indrek Kulaots1 and Kevin Tente2, (1)Chemical Engineering, Brown University, Providence, RI, (2)Brown University, Providence, RI

As the interest in alternative fuel sources grows, oil shale has been studied as a possibly viable form of energy.  Combustion of oil shale for electricity generation must not only be economically feasible, but must also be environmentally responsible in order to become widely utilized.  Oxy-fuel combustion in electricity generation is a reasonable option for alternative conventional fuels such as oil shale because it offers higher overall process efficiency in addition to full CO2 capture.  In order to determine the reactivity of oil shale under oxy-fuel combustion conditions, we studied kinetic parameters such as critical temperature (alternative rate measure), activation energy, and pre-exponential factor of oil shale semicokes in air, CO2, and in a 75% CO2 / 25% O2 mixture that corresponds to the gas phase environment in oxy-fuel combustion.  Oil shale samples applied in this study were obtained globally from China, Estonia, and US Colorado, and pyrolyzed at 500 and 1000 °C. The kinetic parameters of oil shale semicoke were compared to kinetic parameters obtained by gasifying Argonne Premium sample bank coal chars.  As expected, the char samples were significantly less reactive in an atmosphere of pure CO2 than in air.  However, most oil shale char samples displayed similar levels of reactivity in the simulated oxy-fuel, 75% CO2 / 25% O2, combustion environment as in air.

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