The reaction heats for upgrading and catalytic pyrolysis of FCC gasoline were calculated from the formation enthalpies of the reactants and products.The effects of temperature

residence time and catalyst to oil ratio on the reaction heat were investigated.The calculation showed that upgrading and catalytic pyrolysis of FCC gasoline were all endothermic processes.The reaction heat was 80—150 kJ·kg-1 for upgrading of FCC gasoline and 370—620 kJ·kg-1 for catalytic pyrolysis.The reaction heat was related to reaction conditions

i.e.

conversion of gasoline and product distribution.With rising reaction temperature

increasing catalyst to oil ratio

and expanding residence time，the reaction heat increased under the experimental conditions.If the catalyst to oil ratio was large enough

the increase of reaction heat became slower with further increasing catalyst to oil ratio.