An inlet air cooling system used in a gas turbine for supplying power to a refrigerant compressor for compressing refrigerant in a natural gas liquefaction plant includes: an inlet air cooler for cooling inlet air of the gas turbine; chiller motors used for a chiller for cooling coolant supplied to the inlet air cooler; a first variable speed driver for supplying electric power to each of the one or more chiller motors; and an electric generator driven by the gas turbine, wherein the electric generator is electrically connected to the first variable speed driver, and electric power generated by the electric generator can be supplied to each of the chiller motors from the first variable speed driver without using a main power line of an electric power system, which enables efficient electric power supply to the motors via the variable speed driver.

The system comprises: a main driver configured for rotating at a substantially constant rotational speed; a rotating load configured to be driven into rotation by the main driver; a controller, for controllably adjusting a load rotational speed; a variable speed transmission, arranged between the main driver and the load and comprised of a speed summing gear arrangement having a first input shaft, a second input shaft and an output shaft; an auxiliary driver, mechanically coupled to the second input shaft of the speed summing gear arrangement. The first input shaft of the speed summing gear arrangement is drivingly coupled to the main driver. The output shaft of the speed summing gear arrangement is drivingly coupled to the rotating load. The speed of the output shaft is a combination of a speed of the main driver and of a speed of the auxiliary driver.

A proposed method for thermally assisted electric energy storage is intended for increase in round-trip efficiency through recovery of waste heat energy streams from the co-located power generation and industrial facilities, combustion of renewable or fossil fuels, or harnessing the renewable energy sources. In the charge operation mode, it is achieved by superheating and expansion of recirculating air stream in the liquid air energy storage with self-producing a part of power required for air liquefaction. In the discharge operation mode, it is attained through the repeated use of a stream of discharged air for production of an additional power in auxiliary discharge cycle.

A split mixed refrigerant (MR) natural gas liquefication system, where low-pressure (LP) and medium pressure (MP) MR compressors are driven by a first gas turbine and a propane compressor and a high-pressure (HP) MR compressor is driven by a second gas turbine, is disclosed. The split MR liquefication system is configured to adjust the characteristics of the HP MR compressor to require less power when less power is available and more power when more power is available compared to the system's design point. Such adjustments allow for shifting the balance of power between the propane compressor and the HP MR compressor to improve LNG production efficiency.

A control device for a rotary machine, which is driven by a turbine output torque which is an output of a turbine and an electric motor output torque which is an output of an induction motor, includes: a required output setting unit configured to set a required torque for driving the rotary machine; and a drive source command unit configured to set the electric motor output torque to a minimum torque or higher of the induction motor and to set the turbine output torque to a value obtained by subtracting the electric motor output torque from the required torque when the turbine output torque is greater than or equal to a lower limit in a stable output range of the turbine.

The present techniques are directed to a flexible liquefied natural gas (LNG) plant that may be tied to an external electric grid for importing or exporting electric power. Exemplary embodiments provide a method for producing LNG that includes producing a base load capacity of refrigeration capacity for LNG production from a first compression system. Electricity may be produced from a second compressor string if electricity is needed by an external power grid, or a second amount of refrigeration capacity may be provided by the second compressor string is natural gas feed is available and the external grid does not need power.

An inlet air cooling system used in a gas turbine for supplying power to a refrigerant compressor for compressing refrigerant in a natural gas liquefaction plant includes: an inlet air cooler for cooling inlet air of the gas turbine; chiller motors used for a chiller for cooling coolant supplied to the inlet air cooler; a first variable speed driver for supplying electric power to each of the one or more chiller motors; and an electric generator driven by the gas turbine, wherein the electric generator is electrically connected to the first variable speed driver, and electric power generated by the electric generator can be supplied to each of the chiller motors from the first variable speed driver without using a main power line of an electric power system, which enables efficient electric power supply to the motors via the variable speed driver.

A drive system for liquefied natural gas (LNG) refrigeration compressors in a LNG liquefaction plant. Each of three refrigeration compression strings include refrigeration compressors and a multi-shaft gas turbine capable of non-synchronous operation. The multi-shaft gas turbine is operationally connected to the refrigeration compressors and is configured to drive the one or more refrigeration compressors. The multi-shaft gas turbine uses its inherent speed turndown range to start the one or more refrigeration compressors from rest, bring the one or more refrigeration compressors up to an operating rotational speed, and adjust compressor operating points to maximize efficiency of the one or more refrigeration compressors, without assistance from electrical motors with drive-through capability and variable frequency drives.

Disclosed herein is an integrated power generation and load driving system, comprising in combination a multi-shaft gas turbine engine comprising a high-pressure turbine mechanically coupled to an air compressor; and a low-pressure turbine, fluidly coupled to but mechanically separated from the high-pressure turbine and mechanically coupled to an output power shaft wherein the output power shaft is connected to a shaft line an electric generator, mechanically coupled to the shaft line and driven into rotation by the gas turbine engine a rotating load, mechanically coupled to the shaft line and driven into rotation by the gas turbine engine a load control arrangement, configured for controlling at least one operating parameter of the rotating load to adapt the operating condition of the rotating load to process requirements from a process, whereof the rotating load forms part, while the low-pressure turbine and the electric generator rotate at a substantially constant speed.

A proposed method for thermally assisted electric energy storage is characterized by a significant increase in round-trip efficiency through a profitable use of waste heat energy streams from the co-located power generation and industrial facilities, combustion of renewable or fossil fuels, or harnessing the renewable energy sources. In the charge operation mode it is achieved by superheating and expansion of recirculating air stream in the liquid air energy storage with self-producing a part of power required for air liquefaction. In the discharge operation mode it is attained through the repeated and efficient use of a stream of discharged air in auxiliary power production cycle.