Cogeneration of electricity and liquid carbon dioxide by combustion of methane-rich gas

A cogeneration system for the combustion of methane-rich fuel gas to produce electricity and liquid carbon dioxide, which comprises:

• a gas turbine driven by the combustion of said fuel gas and excess air at elevated pressure,
• an electric generator driven by said gas turbine,
• a high-pressure steam boiler in which the exhaust gases from said gas turbine and an additional quantity of said fuel gas are burned to eliminate substantially all of the excess oxygen in said exhaust gases,
• a steam turbine driven by high-pressure steam from said boiler,
• a second generator driven by said steam turbine,
• a blower to force flue gas from said boiler through an amine absorption column to scrub carbon dioxide from said flue gas,
• a stripping column connected to said amine absorption column to strip absorbed carbon dioxide from amine solution flowing from said amine absorption column to said stripping column,
• a reboiler to heat said amine solution in said stripping column,
• a steam pipe connected to an intermediate stage of said steam turbine for the flow of steam to said rebolier,
• said steam pipe being also connected for the flow of steam to an ammonia absorption refrigeration unit,
• a steam condensate pipe connected to said ammonia refrigeration unit for the flow of steam condensate therefrom to said boiler, said steam condensate pipe being also connected for the flow of steam condensate from said reboiler to said boiler,
• a water-cooler steam condenser connected to draw completely expanded steam from said steam turbine and to return steam condensate to said boiler,
• a carbon dioxide compressor connected to draw carbon dioxide from said stripping column and force said carbon dioxide through cooling and drying means, and
• a carbon dioxide condenser connected to receive dry carbon dioxide from said drying means for the delivery of liquid carbon dioxide,
• said ammonia refrigeration unit being connected to supply refrigeration to said carbon dioxide condenser.

A cogeneration process yielding electricity and liquid carbon dioxide by the combustion of methane-rich fuel gas, which comprises:

• combusting said fuel gas with excess air for the performance of work by a gas turbine, thereby forming combustion products containing residual oxygen,
• utilizing said performance of work to drive an electric generator to yield electricity,
• combusting an additional quantity of said fuel gas with said combustion products to produce high-pressure steam and a flue gas containing at most a fractional percentage of residual oxygen, said additional quantity of said fuel gas being controller to be substantially just enough to consume said residual oxygen in said combustion products,
• passing said high-pressure steam through a steam turbine thereby performing additional work,
• utilizing said additional work to drive an additional electric generator to yield additional electricity,
• scrubbing said flue gas with amine solution to absorb carbon dioxide therefrom,
• stripping absorbed carbon dioxide from said amine solution by heating with steam drawn from an intermediate stage of said steam turbine,
• compressing and drying the stripped carbon dioxide,
• applying refrigeration to the compressed, dry carbon dioxide to yield liquid carbon dioxide, and
• producing said refrigeration with an ammonia absoption refrigeration unit wherein the required heat for the operation of said unit is supplied by steam drawn from said intermediate stage of said steam turbine.

A cogeneration process for the production of electricity and liquid carbon dioxide, which comprises:

• burning pressurized methane-rich fuel gas and excess air in a gas turbine to drive an electric generator thereby producing electricity and combustion products containing residual oxygen,
• burning said combustion products and an additional quantity of said fuel gas to yield a flue gas substantially free of said residual oxygen while generating high-pressure steam,
• feeding said high-pressure steam to a steam turbine to drive an additional electric generator thereby producing additional electricity,
• absorbing carbon dioxide of said flue gas in amine solution,
• stripping absorbed carbon dioxide from said amine solution by heating said amine solution with steam drawn from an intermediate pressure stage of said steam turbine,
• compressing, cooling and drying the stripped carbon dioxide,
• generating refrigeration in an ammonia absorption refrigeration unit by supplying the required heat with steam drawn from said intermediate pressure stage of said steam turbine, and
• applying said refrigeration to the compressed, cooled and dry carbon dioxide to produce liquid carbon dioxide.