A vacuum pump includes a housing, a rotor cylindrical portion, and a stator cylindrical portion. The housing has an inlet port for sucking gas and an outlet port for discharging the sucked gas. The rotor cylindrical portion is housed in the housing. The stator cylindrical portion is housed in the housing, and is arranged to face the rotor cylindrical portion. A screw groove is formed on one of opposing surfaces of the stator cylindrical portion and the rotor cylindrical portion. The groove depth D of the screw groove is smaller at an end on an exhaust side than at an end on a suction side. The decrement of the groove depth D is greater on the suction side than on the exhaust side.

In a combined cycle plant and a method for operating the same, the combined cycle plant is provided with a gas turbine, a waste heat recovery boiler, and a steam turbine, and is also provided with a low-pressure gland steam line for supplying steam to a low-pressure gland portion of a low-pressure turbine, and a first heat exchanging unit which performs heat exchange between gland steam flowing through the low-pressure gland steam line, and fuel gas to be supplied to a combustor.

A powerplant is provided that includes a pre-burner, a combustor, a power turbine, a mechanical load and a propellant system. The combustor is fluidly coupled with and downstream of the pre-burner. The power turbine is fluidly coupled with and downstream of the combustor. The mechanical load is rotatably driven by the power turbine. The propellant system is configured to direct fluid oxygen and fluid hydrogen to the pre-burner to provide an oxygen rich fuel mixture for combustion within the pre-burner. The propellant system is also configured to direct the fluid hydrogen to the combustor for combustion within the combustor with oxygen within combustion products received from the pre-burner.

Provided is a reciprocating compressor including a third-stage compression unit, a fifth-stage compression unit, a drive unit, a discharge mechanism, a pressure sensor, and a discharge control unit. The discharge mechanism is capable of discharging hydrogen gas from a second connection pipe that allows hydrogen gas to flow to be suctioned into the third-stage compression unit. The discharge control unit controls the discharge mechanism to discharge the hydrogen gas from the second connection pipe when pressure of the hydrogen gas detected by the pressure sensor is higher than a set value preset.

The present disclosure relates to systems and methods that provide a low pressure liquid CO.sub.2 stream. In particular, the present disclosure provides systems and methods wherein a high pressure CO.sub.2 stream, such as a recycle CO.sub.2 stream from a power production process using predominately CO.sub.2 as a working fluid, can be divided such that a portion thereof can be expanded and used as a cooling stream in a heat exchanger to cool the remaining portion of the high pressure CO.sub.2 stream, which can then be expanded to form a low pressure CO.sub.2 stream, which may be in a mixed form with CO.sub.2 vapor. The systems and methods can be utilized to provide net CO.sub.2 from combustion in a liquid form that is easily transportable.

Supercritical fluid systems and aircraft power systems are described. The systems include a compressor, a turbine operably coupled to the compressor, a generator operably coupled to the turbine and configured to generate power, a primary working fluid flow path having a primary working fluid configured to pass through the compressor, a separator, the turbine, and back to the compressor, and a secondary working fluid flow path passing through the generator, the compressor, the separator, and back to the generator. The primary working fluid is supercritical carbon dioxide (sCO.sub.2) and the secondary working fluid is a fluid having at least one of a density less than the primary working fluid and a molecular size smaller than the primary working fluid.

Embodiments of systems and methods for air recovery are disclosed. The diverted pressurized air may be used to supply a hydrostatic purge to the unutilized portion of a turbine engine fuel manifold circuit to ensure that exhaust gases from the utilized side of the fuel manifold circuit do not enter the portion of the alternative fuel manifold circuit rack. The assembly used to remove compressor section pressurized air may include a flow control orifice, line pressure measuring instrumentation, non-return valves, isolation valves and hard stainless-steel tubing assemblies. In some embodiments, a turbine compressor section diverter system may include a small air receiver used to increase the volume of air supplying the manifold to aid in potential pressure and flow disruptions from a turbine engine compressor section.

The invention relates to a method for storing energy and for dispensing energy into an energy supply grid by means of a pressurized gas storage power plant, which has at least one first storage chamber and at least one second storage chamber separate from the first, wherein in order to store energy pressurized gas is taken from the lower-pressure storage chamber, is compressed by means of a compression machine and the compressed pressurized gas exiting the compression machine is routed into the other storage chamber; in order to dispense energy pressurized gas is taken from the higher-pressure storage chamber, is routed through an expansion machine and the expanded pressurized gas exiting the expansion machine is transferred into the other storage chamber, wherein the expansion machine dispenses energy to the energy supply grid, wherein the pressurized gas is heated by means of a heating device prior to or upon supply to the expansion machine. The invention also relates to a corresponding pressurized gas storage power plant and to a computer program for carrying out the method.

A high-efficiency power generation system includes: a combustor configured to generate a circulating fluid by burning a fuel; an expander configured to generate power by expanding the circulating fluid; a power generator configured to generate electricity using the power generated by the expander; a compressor configured to compress the expanded circulating fluid; a pump configured to circulate the compressed circulating fluid; a heat exchanger configured to allow the expanded circulating fluid passing through the expander and the compressed circulating fluid passing through the compressor to exchange heat with each other; and a power transmitter including a driving shaft, and configured to rotate a driven shaft, which includes shafts of the compressor and the pump, to transmit the power generated by the expander to the compressor and the pump.

This disclosure describes a power system that includes a first compressor with an air inlet and a compressed air outlet; a nitrogen separator coupled to the compressed air outlet, the nitrogen separator comprising a nitrogen concentrate outlet and a byproduct outlet; a second compressor coupled to the nitrogen concentrate outlet, the second compressor having a high pressure outlet for supplying high pressure concentrated nitrogen to an underground storage; and a turbine generator with an inlet for high pressure concentrated nitrogen for coupling to an underground storage.