In a cryogenic combined cycle power plant electric power drives a cryogenic refrigerator to store energy by cooling air to a liquid state for storage within tanks, followed by subsequent release of the stored energy by first pressurizing the liquid air, then regasifying the liquid air and raising the temperature of the regasified air at least in part with heat exhausted from a combustion turbine, and then expanding the heated regasified air through a hot gas expander to generate power. The expanded regasified air exhausted from the expander may be used to cool and make denser the inlet air to the combustion turbine. The combustion turbine exhaust gases may be used to drive an organic Rankine bottoming cycle. An alternative source of heat such as thermal storage, for example, may be used in place of or in addition to the combustion turbine.

In a cryogenic combined cycle power plant electric power drives a cryogenic refrigerator to store energy by cooling air to a liquid state for storage within tanks, followed by subsequent release of the stored energy by first pressurizing the liquid air, then regasifying the liquid air and raising the temperature of the regasified air at least in part with heat exhausted from a combustion turbine, and then expanding the heated regasified air through a hot gas expander to generate power. The expanded regasified air exhausted from the expander may be used to cool and make denser the inlet air to the combustion turbine. The combustion turbine exhaust gases may be used to drive an organic Rankine bottoming cycle. An alternative source of heat such as thermal storage, for example, may be used in place of or in addition to the combustion turbine.

Provided herein is a power generation system and method for transforming thermal energy, such as waste heat, into mechanical energy and/or electrical energy. The system employs features designed to accelerate start times, reduce size, lower cost, and be more environmentally friendly. Tire system may include multiple compressors on separate pinion shafts with multiple expanders, a temperature valve upstream of compressors with a mass management system downstream, an intercooler between compressors, and a cascade exchanger. In one embodiment, the system is configured to drive a synchronous generator, with the separate pinion shafts rotating at two separate, but constant, speeds.

A heat engine is disclosed. The heat engine comprises a housing, a first liquid and a second liquid located within the housing. The first liquid has a higher density and lower boiling point than the second liquid. The heat engine further comprises a heat exchanger which transfers heat to the first liquid to evaporate the first liquid to form a first liquid vapour. The heat engine also comprises at least one fluid flow member which to moves in response to a fluid flow created by the interaction of the first liquid vapour and the second liquid. The liquid-gas phase change of the first fluid provides an alternative mechanism for converting heat into work with numerous advantages. The heat engine has minimal moving parts, a relatively long lifetime, does not require a specific fuel, does not directly release toxic or un-environmentally friendly gases, and can be adapted to a specific source of waste heat.

Operating coal fired energy systems. A method of operating a coal fired energy system comprises operating a coal fired steam generator comprising a coal feed system and a main air feed system to provide a coal-air mixture as a heating source for a boiler for generating steam. The method includes operating an auxiliary air compression system comprising a fueled engine coupled to a compressor for providing an auxiliary supply of compressed air to a soot blower of the coal-fired steam generator. The method comprises injecting the auxiliary supply of compressed air along walls of the boiler to remove soot and ash buildup from the boiler.

Operating coal fired energy systems. A method of operating a coal fired energy system comprises operating a coal fired steam generator comprising a coal feed system and a main air feed system to provide a coal-air mixture as a heating source for a boiler for generating steam. The method includes operating an auxiliary air compression system comprising a fueled engine coupled to a compressor for providing an auxiliary supply of compressed air to a soot blower of the coal-fired steam generator. The method comprises injecting the auxiliary supply of compressed air along walls of the boiler to remove soot and ash buildup from the boiler.

A start-up method of a steam turbine plant includes a first step and a second step. The first step is performed at an aeration start time. In the first step, a reheat steam pressure of an aeration boiler is set to be a reheat steam pressure required by a steam turbine or less. Besides, a reheat steam pressure of a standby boiler is set to be a reheat steam pressure required for the standby boiler or more. The second step is performed when a load of the steam turbine becomes a predetermined value. In the second step, the reheat steam pressure of the aeration boiler is increased to the same degree as the reheat steam pressure of the standby boiler. After that, steam from the aeration boiler and steam from the standby boiler are merged to be supplied to the steam turbine.

A method for operating a turbine unit having at least two partial turbines, wherein a steam volumetric flow is conducted by a steam transfer device from the partial turbine arranged upstream to a partial turbine arranged downstream, which is connected after the partial turbine arranged upstream, wherein a pressure level within the steam transfer device is manipulated in accordance with a load range in which the turbine unit is operated, in such a way that the exhaust steam of the partial turbine arranged upstream remains superheated in the event of operation of the turbine unit in a partial-load range below the IGV point and/or in the event of a quick increase in the partial load.

A method and a turbine for expanding an organic operating fluid in a Rankine cycle includes the step of feeding the operating fluid to a turbine provided with a plurality of arrays of stator blades alternating with a plurality of arrays of rotor blades, to define corresponding turbine stages, constrained to a shaft which rotates on the respective rotation axis. The method also includes: a) causing a first expansion of the operating fluid in one or more radial stages of the turbine, b) diverting the operating fluid exiting from the radial stages in a direction axial and tangential with respect to the rotation axis, and c) causing a second fluid expansion in one or more axial stages of the turbine. Step b) corresponds to an enthalpy change of the operating fluid equal to at least 50% of the average enthalpy change provided for completing the fluid expansion in the turbine.

A method and a turbine for expanding an organic operating fluid in a Rankine cycle includes the step of feeding the operating fluid to a turbine provided with a plurality of arrays of stator blades alternating with a plurality of arrays of rotor blades, to define corresponding turbine stages, constrained to a shaft which rotates on the respective rotation axis. The method also includes: a) causing a first expansion of the operating fluid in one or more radial stages of the turbine, b) diverting the operating fluid exiting from the radial stages in a direction axial and tangential with respect to the rotation axis, and c) causing a second fluid expansion in one or more axial stages of the turbine. Step b) corresponds to an enthalpy change of the operating fluid equal to at least 50% of the average enthalpy change provided for completing the fluid expansion in the turbine.