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Reactivity of CO2 during thermal cracking of heavy paraffins under supercritical conditions

Thermal cracking of n-hexadecane was investigated in a temperature range of 450-600 degrees C in the presence of CO2. Effects of pressure and temperature on product distribution were experimentally determined under both subcritical and supercritical conditions. At 1.2 MPa and with a CO2 to n-C-16 mole ratio of 25, C-6-C-14 olefins, C-10-C-17 paraffins, and C-5-C-10 fatty acids were identified in the liquid product. Experiments conducted at 4.5 MPa (supercritical) yielded higher selectivities for fatty acids and paraffins. The product distribution of fatty acids and olefins was found to be very sensitive to pressure and temperature. It was also concluded that heterogeneous carbon formation on the reactor surface was inhibited by the supercritical phase.