A process and apparatus for heating catalyst is presented. Cooler catalyst is removed from a reactor and heated with a hot gas in a riser, heated in a heating tube or heated in a heating chamber. Heated catalyst is disengaged from the hot gas if necessary and returned to the reactor. The process and apparatus can be used for producing light olefins. The hot gas may be a flue gas from an FCC regenerator or a combustion gas from a heater.