REACTIVITY OF CO2 DURING THERMAL-CRACKING OF HEAVY PARAFFINS UNDER SUPERCRITICAL CONDITIONS

Thermal cracking of n-hexadecane was investigated in a temperature ran ge of 450-600 degrees C in the presence of CO2. Effects of pressure an d temperature on product distribution were experimentally determined u nder both subcritical and supercritical conditions. At 1.2 MPa and wit h a CO2 to n-C-16 mole ratio of 25, C-6-C-14 olefins, C-10-C-17 paraff ins, and C-5-C-10 fatty acids were identified in the liquid product. E xperiments conducted at 4.5 MPa (supercritical) yielded higher selecti vities for fatty acids and paraffins. The product distribution of fatt y acids and olefins was found to be very sensitive to pressure and tem perature. It was also concluded that heterogeneous carbon formation on the reactor surface was inhibited by the supercritical phase.