COKING KINETICS OF A CR2O3 AL2O3 CATALYST DURING 1-BUTENE DEHYDROGENATION - EFFECT OF H-2 PARTIAL-PRESSURE/

The influence has been studied of the partial pressure of hydrogen (0- 30 kPa) upon the coking rate of a Cr2O3/Al2O3 commercial catalyst duri ng 1-butene dehydrogenation. Coke deposition has been analysed using a monolayer-multilayer reversible coke growth model (MMRC model). This model provides good fits to the experimental data, within the range of partial pressure of H-2 studied, and allows us to estimate the main k inetic parameters involved in the coking-deactivation process. The res ults obtained reveal a dual effect of hydrogen: competition against 1- butene for the active sites and the removal of coke precursors from th e catalyst surface. Both effects diminish the coking rate as the H-2, partial pressure is increased.