Embodiments of the disclosure provide a method for operating a combined cycle power plant (CCPP). The method may include creating a variant control profile for the CCPP for a power plant model of the CCPP. The method may include modifying the variant control profile in response to the variant control profile not reducing the fuel consumption or meeting the quality threshold. The method may also include adjusting the CCPP to use the variant control profile in response to the variant control profile reducing the fuel consumption and meeting the quality threshold. Using the variant control profile adjusts a turbine section inlet temperature schedule or an exhaust temperature schedule for the CCPP.

Embodiments of the disclosure provide a method for operating a combined cycle power plant (CCPP). The method may include creating a variant control profile for the CCPP for a power plant model of the CCPP. The method may include modifying the variant control profile in response to the variant control profile not reducing the fuel consumption or meeting the quality threshold. The method may also include adjusting the CCPP to use the variant control profile in response to the variant control profile reducing the fuel consumption and meeting the quality threshold. Using the variant control profile adjusts a turbine section inlet temperature schedule or an exhaust temperature schedule for the CCPP.

Embodiments of the present disclosure can include a system for generating steam. The system can include a direct steam generator configured to generate saturated steam and combustion exhaust constituents. A close coupled heat exchanger can be fluidly coupled to the direct steam generator, the close coupled heat exchanger can be configured to route the saturated or superheated steam and combustion exhaust constituents through an exhaust constituent removal system. The system can include an energy recovery system that reclaims the energy from the exhaust constituents.

Embodiments of the present disclosure can include a system for generating steam. The system can include a direct steam generator configured to generate saturated steam and combustion exhaust constituents. A close coupled heat exchanger can be fluidly coupled to the direct steam generator, the close coupled heat exchanger can be configured to route the saturated or superheated steam and combustion exhaust constituents through an exhaust constituent removal system. The system can include an energy recovery system that reclaims the energy from the exhaust constituents.

Disclosed is a Once-Through Steam Generator (OTSG) coil (52) and method, comprising a plurality of vertically arranged serpentine conduits (90) in a horizontal heat recovery steam generator (HRSG) that replaces a traditional natural circulation HP evaporator for producing super-critical steam. The OTSG comprises a lower equalization header system (130) that promotes system stability in multiple operating conditions. The equalization header allows a partial flow of fluid from the lower serpentine curved flow path (120) through an equalization conduit (125) into the equalization header (130) Disclosed also are: a flow restriction device in serpentine conduits; drainage structure from serpentine conduits through the equalization header, a drainage expansion section to accommodate stresses, and drainage bypass connections; and flow through serpentine conduits in upstream and downstream directions, mixed flow directions and longitudinally staggered directions.

Disclosed is a Once-Through Steam Generator (OTSG) coil (52) and method, comprising a plurality of vertically arranged serpentine conduits (90) in a horizontal heat recovery steam generator (HRSG) that replaces a traditional natural circulation HP evaporator for producing super-critical steam. The OTSG comprises a lower equalization header system (130) that promotes system stability in multiple operating conditions. The equalization header allows a partial flow of fluid from the lower serpentine curved flow path (120) through an equalization conduit (125) into the equalization header (130) Disclosed also are: a flow restriction device in serpentine conduits; drainage structure from serpentine conduits through the equalization header, a drainage expansion section to accommodate stresses, and drainage bypass connections; and flow through serpentine conduits in upstream and downstream directions, mixed flow directions and longitudinally staggered directions.

Embodiments of the present disclosure can include a system for generating steam. The system can include a direct steam generator configured to generate saturated steam and combustion exhaust constituents. A close coupled heat exchanger can be fluidly coupled to the direct steam generator, the close coupled heat exchanger can be configured to route the saturated or superheated steam and combustion exhaust constituents through an exhaust constituent removal system. The system can include an energy recovery system that reclaims the energy from the exhaust constituents.

Embodiments of the present disclosure can include a system for generating steam. The system can include a direct steam generator configured to generate saturated steam and combustion exhaust constituents. A close coupled heat exchanger can be fluidly coupled to the direct steam generator, the close coupled heat exchanger can be configured to route the saturated or superheated steam and combustion exhaust constituents through an exhaust constituent removal system. The system can include an energy recovery system that reclaims the energy from the exhaust constituents.

Embodiments of the present disclosure can include a system for generating steam. The system can include a direct steam generator configured to generate saturated steam and combustion exhaust constituents. A close coupled heat exchanger can be fluidly coupled to the direct steam generator, the close coupled heat exchanger can be configured to route the saturated or superheated steam and combustion exhaust constituents through an exhaust constituent removal system. The system can include an energy recovery system that reclaims the energy from the exhaust constituents.

Embodiments of the present disclosure can include a system for generating steam. The system can include a direct steam generator configured to generate saturated steam and combustion exhaust constituents. A close coupled heat exchanger can be fluidly coupled to the direct steam generator, the close coupled heat exchanger can be configured to route the saturated or superheated steam and combustion exhaust constituents through an exhaust constituent removal system. The system can include an energy recovery system that reclaims the energy from the exhaust constituents.