Patent ID: 7811446

Claim:
A method of recovering energy from a fluid catalytic cracking unit having a reactor and a regenerator for overall carbon dioxide reduction, the method comprising: cooling syngas comprising CO 2 , CO, H 2 O, H 2 S and COS to a predetermined low temperature to define cooled syngas, the syngas produced by the regenerator at gasification conditions; providing a turbo-expander train including a first compressor, the turbo-expander train being configured to combust and expand gas to drive the first compressor; compressing the cooled syngas with the first compressor to a predetermined high pressure to define compressed syngas; separating from the compressed syngas a first stream of gas comprising CO 2 and a second stream of gas comprising CO; and introducing O 2 and the first and second streams of gas to the turbo-expander train including expanding the first stream of gas and combusting and expanding the second stream of gas with the O 2 to recover energy, driving the first compressor and producing feed gas comprising O 2 and CO 2 .