Patent ID: 7458218

Claim:
A cascade power system comprising: an energy extraction subsystem, a separation subsystem, a heat exchange subsystem, a heat recovery vapor generator (HRVG) subsystem and a condensation thermal compression (CTCSS) subsystem, where the system is adapted to establish two interacting working fluid cycles, one cycle utilizes a rich multi-component working fluid stream having a higher concentration of a lower boiling component and the other cycle utilizes a lean working multi-component working fluid stream having a lower concentration of the lower boiling component, where each stream is derived from a fully condensed incoming multi-component stream, where the separation subsystem is adapted to produce the lean working fluid stream and a rich make-up working fluid streams, which is combined with the fully condensed incoming multi-component stream to form the rich multi-component working fluid stream, where the heat exchange subsystem and the heat recovery vapor generator (HRVG) subsystem are adapted to heat and vaporize the lean working fluid stream and the rich working fluid stream from heat derived directly and/or indirectly from an external flue gas stream, where the energy extraction subsystem is adapted to extract energy from the lean working fluid stream and the rich working fluid stream in separate turbine or turbine stages, where the CTCSS subsystem is adapted to condense a spent rich stream to form the fully condensed incoming multi-component stream, where a flue gas flow rate is the same throughout the entire HRVG subsystem or is different in different portions of the HRVG subsystem and where an initial hot flue gas stream is cooled by a re-circulated portion of a spent flue gas stream exiting the HRVG subsystem prior to the flue gas stream entering the HRVG subsystem.