Patent ID: 7921631

Claim:
A system for recovering energy from a fluid catalytic cracking unit having a reactor and a regenerator for overall carbon dioxide reduction, the system comprising: a cooling unit in fluid communication with the regenerator at gasification conditions, the regenerator producing syngas comprising CO 2 , CO, H 2 O, H 2 S and COS and the cooling unit configured to cool the syngas to a predetermined low temperature to define cooled syngas; a turbo-expander train including a first compressor in fluid communication with the cooling unit, a first expander for expanding a first stream of gas comprising CO 2 a combustion zone for receiving O 2 , the expanded first stream of gas comprising CO 2 , and a second stream of gas comprising CO and for combusting the O 2 and the second stream of gas, a second expander for the expanding the first stream of gas and the combustion product of the second stream of gas with the O 2 to recover energy, a shaft for driving the first compressor to compress the cooled syngas to a predetermined high pressure to define compressed syngas and for producing feed gas comprising O 2 and CO 2 ; and a separator unit in fluid communication with the turbo-expander train and configured to separate from the compressed syngas the first and second streams of gas.