Carbonization of pitches in air blowing batch reactor Original Research Article

Carbonization of petroleum and coal tar pitches to toluene insoluble fraction (TI) was investigated under air and nitrogen gas blowing systems. The TI yield was evaluated on the basis of the weight of pitch loaded. Changes of the yield with the reaction time were analyzed by a kinetic model of carbonization. The model assumes that pitch as a reactant contains a reactive component, P1, which converts to active thermal fragment, P∗, and gas and tar, G, more quickly than the residual component, P2, exhibiting a nonlinear decrease of pitch in semilogarithmic plot against the reaction time in an early stage of the reaction. The activation energies for P1, and P2 conversions depended on pitch and gas atmosphere. In particular, activation energies for P1 conversion in the air blowing system was found to be appreciably smaller than those in the nitrogen blowing system. This less temperature-sensitive carbonization in the former system may be attributed to pitch reactivity improved by oxygen in air.