The present disclosure relates to systems and methods useful for power production. In particular, a power production cycle utilizing CO.sub.2 as a working fluid may be configured for simultaneous hydrogen production. Beneficially, substantially all carbon arising from combustion in power production and hydrogen production is captured in the form of carbon dioxide. Further, produced hydrogen (optionally mixed with nitrogen received from an air separation unit) can be input as fuel in a gas turbine combined cycle unit for additional power production therein without any atmospheric CO.sub.2 discharge.

The present disclosure relates to systems and methods useful for power production. In particular, a power production cycle utilizing CO.sub.2 as a working fluid may be configured for simultaneous hydrogen production. Beneficially, substantially all carbon arising from combustion in power production and hydrogen production is captured in the form of carbon dioxide. Further, produced hydrogen (optionally mixed with nitrogen received from an air separation unit) can be input as fuel in a gas turbine combined cycle unit for additional power production therein without any atmospheric CO.sub.2 discharge.

A combined cycle plant includes: a gas turbine having a compressor, a combustor, and a turbine; a supplementary firing burner configured to raise a temperature of an exhaust gas of the gas turbine; a heat recovery steam generator configured to generate a steam using an exhaust heat of the exhaust gas; a steam turbine configured to be driven by the steam generated by the heat recovery steam generator; and a control device configured to change both an output of the combustor and an output of the supplementary firing burner when an output of the combined cycle plant is to be changed.

A combined cycle plant includes: a gas turbine having a compressor, a combustor, and a turbine; a supplementary firing burner configured to raise a temperature of an exhaust gas of the gas turbine; a heat recovery steam generator configured to generate a steam using an exhaust heat of the exhaust gas; a steam turbine configured to be driven by the steam generated by the heat recovery steam generator; and a control device configured to change both an output of the combustor and an output of the supplementary firing burner when an output of the combined cycle plant is to be changed.

Gas turbine engines are described. The gas turbine engines include a compressor section, a combustor section, a turbine section, and a nozzle, wherein the compressor section, the combustor section, the turbine section, and the nozzle define a core flow path that expels through the nozzle. A waste heat recovery system is operably connected to the gas turbine engine, the waste heat recovery system having a working fluid. An auxiliary cooling system is configured to provide cooling to a working fluid of the waste heat recovery system.

A propulsion system is provided and includes a solid hydride storage unit from which gaseous hydrogen fuel is drawn, an engine comprising a combustion chamber and a piping system to draw the gaseous hydrogen fuel from the solid hydride storage unit, the piping system being interposed between the solid hydride storage unit and the combustion chamber. The combustion chamber is receptive of the gaseous hydrogen fuel drawn from the solid hydride storage unit by the piping system and is configured to combust the gaseous hydrogen fuel to drive an operation of the engine.

A propulsion system is provided and includes a solid hydride storage unit from which gaseous hydrogen fuel is drawn, an engine comprising a combustion chamber and a piping system to draw the gaseous hydrogen fuel from the solid hydride storage unit, the piping system being interposed between the solid hydride storage unit and the combustion chamber. The combustion chamber is receptive of the gaseous hydrogen fuel drawn from the solid hydride storage unit by the piping system and is configured to combust the gaseous hydrogen fuel to drive an operation of the engine.

A system may include a turbine and a recuperative heat exchanger system. The recuperative heat exchanger system is configured to receive exhaust gases from the turbine. The recuperative heat exchanger system may include a precool section to cool the exhaust gases, a major heating section to receive the cooled the exhaust gases, and a minor heating section to receive the cooled the exhaust gases.

A system may include a turbine and a recuperative heat exchanger system. The recuperative heat exchanger system is configured to receive exhaust gases from the turbine. The recuperative heat exchanger system may include a precool section to cool the exhaust gases, a major heating section to receive the cooled the exhaust gases, and a minor heating section to receive the cooled the exhaust gases.

The present disclosure provides a novel turbine design for converting a high-pressure fluid stream into useful energy, the turbine comprising a cylindrical housing having a fluid inlet and fluid outlets on opposing ends and being constrained by rotational bearings, with the housing containing a multi-helical structure for efficiently directing the fluid flow from the inlet to the outlets with minimal strain on the moving components. A method of use of the turbine for generating energy is also provided.