Systems and methods for power generation with carbon dioxide isolation

A power generation system comprising:

• a first turbine system comprising:
• a first compressor section comprising at least two stages, said at least two stages comprising a first low pressure compressor fluidly coupled to a first high pressure compressor configured to supply a first portion of compressed oxidant and a second portion of compressed oxidant;
• a first combustion chamber configured to combust said first portion of compressed oxidant and a first fuel stream comprising carbon-based fuels and to generate a first hot flue gas;
• a first expander section having an inlet for receiving said first hot flue gas, said first expander section comprising at least two stages, said at least two stages comprising a first high pressure expander configured to generate a first expanded exhaust gas rich in CO2, said first high pressure expander fluidly coupled to a first low pressure expander configured to generate a first exhaust and electrical energy;
• a CO2 separation system directly coupled to the high pressure expander for receiving said first expanded exhaust gas from said first high pressure expander and providing a CO2 lean gas that is then fed to said first low pressure expander;
• a second turbine system comprising:
• a second compressor section comprising at least two stages, said at least two stages comprising a second low pressure compressor fluidly coupled to a second high pressure compressor;
• a second combustion chamber configured to combust said second portion of compressed oxidant and a second fuel stream comprising carbon-based fuels and to generate a second hot flue gas;
• and
• a second expander section configured to receive said second hot flue gas, said second expander section comprising at least two stages, said at least two stages comprising a second high pressure expander configured to generate a second expanded exhaust gas, said second high pressure expander fluidly coupled to a second low pressure expander configured to generate a second final exhaust and electrical energy,
• wherein said second compressor section is configured to receive said second final exhaust comprising carbon dioxide and to discharge a recycle stream to said second combustion chamber and a split stream to said first combustion chamber.

A method for generating power comprising:

• compressing an oxidant in a compressor section to produce a compressed oxidant;
• combusting a first fuel and said compressed oxidant to produce a hot flue gas;
• expanding said hot flue gas in an expander section to generate electrical energy wherein said expander section is configured to receive said hot flue gas, wherein said expander section comprises at least two stages, the at least two stages comprising a high pressure expander configured to generate a first expanded exhaust gas rich in CO2, said high pressure expander fluidly coupled to a low pressure expander configured to generate a first exhaust and electrical energy;
• separating CO2 from said first expanded exhaust gas in a CO2 separation system to generate a CO2 lean gas, wherein the CO2 separation system is directly coupled to the high pressure expander;
• and
• introducing said CO2 lean gas to said low pressure expander.