The present invention provides methods and system for power generation using a high efficiency combustor in combination with a CO.sub.2 circulating fluid. The methods and systems advantageously can make use of a low pressure ratio power turbine and an economizer heat exchanger in specific embodiments. Additional low grade heat from an external source can be used to provide part of an amount of heat needed for heating the recycle CO.sub.2 circulating fluid. Fuel derived CO.sub.2 can be captured and delivered at pipeline pressure. Other impurities can be captured.

The present invention provides methods and system for power generation using a high efficiency combustor in combination with a CO.sub.2 circulating fluid. The methods and systems advantageously can make use of a low pressure ratio power turbine and an economizer heat exchanger in specific embodiments. Additional low grade heat from an external source can be used to provide part of an amount of heat needed for heating the recycle CO.sub.2 circulating fluid. Fuel derived CO.sub.2 can be captured and delivered at pipeline pressure. Other impurities can be captured.

The present invention provides methods and system for power generation using a high efficiency combustor in combination with a CO.sub.2 circulating fluid. The methods and systems advantageously can make use of a low pressure ratio power turbine and an economizer heat exchanger in specific embodiments. Additional low grade heat from an external source can be used to provide part of an amount of heat needed for heating the recycle CO.sub.2 circulating fluid. Fuel derived CO.sub.2 can be captured and delivered at pipeline pressure. Other impurities can be captured.

The present invention provides methods and system for power generation using a high efficiency combustor in combination with a CO.sub.2 circulating fluid. The methods and systems advantageously can make use of a low pressure ratio power turbine and an economizer heat exchanger in specific embodiments. Additional low grade heat from an external source can be used to provide part of an amount of heat needed for heating the recycle CO.sub.2 circulating fluid. Fuel derived CO.sub.2 can be captured and delivered at pipeline pressure. Other impurities can be captured.

The present invention provides methods and system for power generation using a high efficiency combustor in combination with a CO.sub.2 circulating fluid. The methods and systems advantageously can make use of a low pressure ratio power turbine and an economizer heat exchanger in specific embodiments. Additional low grade heat from an external source can be used to provide part of an amount of heat needed for heating the recycle CO.sub.2 circulating fluid. Fuel derived CO.sub.2 can be captured and delivered at pipeline pressure. Other impurities can be captured.

An apparatus for compressing air and producing a carbon dioxide-rich fluid includes an air compressor, an element for bringing the air bound for the air compressor into contact with water to produce humidified air and cooled water, a pipe for sending the humidified compressed air from the air compressor to an installation producing a carbon dioxide-rich gas, a carbon dioxide-rich gas compressor for compressing the carbon dioxide-rich gas, at least one heat exchanger upstream and/or downstream the carbon dioxide-rich gas compressor and pipes for conveying into the heat exchanger water cooled in the contact element and the carbon dioxide-rich gas.

In a method for supplying nitrogen to a combustion chamber, gaseous nitrogen (9) is drawn off from an air separation unit (7) at a first pressure, the nitrogen is compressed in at least two stages (C1, C2) of a nitrogen compressor and sent to a combustion chamber (25) at a second pressure, which is the output pressure of the last stage (C3) of the nitrogen compressor, between two stages of the nitrogen compressor the nitrogen is humidified by direct contact in passing through a contactor (17) supplied at its top with water, and the humidified nitrogen is compressed in at least one stage of the nitrogen compressor and sent to the combustion chamber.

The present disclosure relates to a power production system that is adapted to achieve high efficiency power production with complete carbon capture when using a solid or liquid hydrocarbon or carbonaceous fuel. More particularly, the solid or liquid fuel first is partially oxidized in a partial oxidation reactor. The resulting partially oxidized stream that comprises a fuel gas is quenched, filtered, cooled, and then directed to a combustor of a power production system as the combustion fuel. The partially oxidized stream is combined with a compressed recycle CO.sub.2 stream and oxygen. The combustion stream is expanded across a turbine to produce power and passed through a recuperator heat exchanger. The expanded and cooled exhaust stream is scrubbed to provide the recycle CO.sub.2 stream, which is compressed and passed through the recuperator heat exchanger and the POX heat exchanger in a manner useful to provide increased efficiency to the combined systems.