Low emission power generation systems and methods incorporating carbon dioxide separation

摘要

Methods and systems for CO2 separation in low emission power plants are provided. One system includes a gas turbine system that combusts a fuel and an oxidant in the presence of a compressed recycle stream to provide mechanical power and a gaseous exhaust. A purge stream is taken from the compressed recycle stream and directed to a CO2 separator configured to absorb CO2 from the purge stream using a potassium carbonate solvent. Volatiles are removed from the rich solvent by stripping or by flashing to an intermediate pressure before the rich solvent is regenerated and CO2 is removed.

主权项

1. An integrated power generation system, comprising:
a gas turbine system comprising a combustion chamber configured to combust a compressed oxidant and a fuel in the presence of a compressed recycle stream to generate a discharge stream that is expanded in an expander, thereby generating a gaseous exhaust stream; an exhaust gas recirculation system comprising a boost compressor and one or more cooling units fluidly coupled to the boost compressor, the boost compressor being configured to receive and increase the pressure of the gaseous exhaust stream and the one or more cooling units being configured to cool the gaseous exhaust stream and provide a cooled recycle gas to a main compressor, wherein the main compressor compresses the cooled recycle gas and generates the compressed recycle stream; a purge stream fluidly coupled to the compressed recycle stream having a heat exchanger configured to reduce the temperature of the purge stream and generate a cooled purge stream; and a CO2 separation system fluidly coupled to the heat exchanger, the CO2 separation system comprising:
an absorption column configured to receive the cooled purge stream and absorb CO2 from the cooled purge stream with a potassium carbonate solvent to generate a nitrogen-rich residual stream and a bicarbonate solvent solution;a first valve fluidly coupled to the absorption column configured to flash the bicarbonate solvent solution to a pressure sufficient to separate volatile components from the bicarbonate solvent solution, thereby generating a dual phase reduced-pressure solvent solution having a gaseous phase comprising the volatile components and a liquid phase comprising the bicarbonate solvent solution;a flash vessel fluidly coupled to the first valve configured to receive the reduced-pressure solvent solution and remove the gaseous phase of the reduced-pressure solvent solution from the liquid phase of the reduced-pressure solvent solution, wherein at least a portion of the gaseous phase of the reduced-pressure solution removed from the flash vessel is recycled to the exhaust gas recirculation system;a second valve fluidly coupled to the flash vessel configured to receive the liquid phase of the reduced-pressure solvent solution and flash the liquid phase to a near-atmospheric pressure, thereby generating a near-atmospheric bicarbonate solvent solution; anda regeneration column fluidly coupled to the second valve configured to receive and boil the near-atmospheric bicarbonate solvent solution to remove CO2 and water therefrom, producing a regenerated potassium carbonate solvent to be recycled to the absorption column.