In at least one embodiment of the present invention, a method of heating a
FCC unit having a regenerator and a reactor for over CO.sub.2 reduction
is provided. The method comprises compressing syngas to define compressed
syngas. CO.sub.2 is separated from the compressed syngas to provide a
first stream of gas comprising CO.sub.2. The first stream of gas is
expanded with a second stream of gas comprising O.sub.2 to define a feed
gas. The feed gas and an injected hydrocarbon feed are introduced to the
regenerator having spent catalyst from the reactor. The regenerator is at
gasification conditions to burn the injected hydrocarbon feed and coke
from the spent catalyst producing the syngas and heat for operating the
reactor at reaction temperatures.