A method for operating a power plant having a gas turbine and an emergency fuel system where in a normal operating state, gas is supplied from a supply line to the combustion process of the gas turbine, and in addition gas is supplied from the supply line to a gas liquefaction plant where it is liquefied, forming a liquid gas which is stored in a liquid gas store. In special operating state, liquefied gas is drawn from the liquid gas store and is evaporated in an evaporator, and is fed in the gaseous state into the combustion process of the gas turbine.

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.

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.

An LNG production system including a boil off gas recondenser that can recondense boil off gas without using a BOG compressor and without depending on an LNG liquefaction process is provided.

A system for storing or producing electricity, which allows stabilization of a power network under conditions of excess availability of electricity or lack thereof and for producing liquefied natural gas is provided.

A novel concept for a high energy and material efficient nitric acid production process and system is provided, wherein the nitric acid production process and system, particularly integrated with an ammonia production process and system, is configured to recover a high amount of energy out of the ammonia that it is consuming, particularly in the form of electricity, while maintaining a high nitric acid recovery in the conversion of ammonia to nitric acid. The energy recovery and electricity generation process comprises pressurizing a liquid gas, such as air, oxygen and/or N.sub.2, subsequently evaporating and heating the pressurized liquid gas, particularly using low grade waste heat generated in the production of nitric acid and/or ammonia, and subsequently expanding the evaporated pressurized liquid gas over a turbine. In particular, the generated electricity is at least partially used to power an electrolyzer to generate the hydrogen needed for the production of ammonia. The novel concepts set out in the present application are particularly useful in the production of nitric acid based on renewable energy sources.

The present disclosure provides a supercritical compressed air energy storage system. The supercritical compressed air energy storage system includes a supercritical liquefaction subsystem, an evaporation and expansion subsystem, a staged cryogenic storage subsystem, a heat storage and heat exchange subsystem, and a cryogenic energy compensation subsystem, the staged cryogenic storage subsystem being used for implementing the staged storage and release of cryogenic energy, improving efficiency of recovering cryogenic energy during energy release and energy storage, and thereby improving cycle efficiency of the system. The present disclosure does not need to provide any inputs of additional cryogenic energy and heat energy input externally, and has the advantages of high cycle efficiency, low cost, independent operation, environmental friendliness, and no limitation on terrain conditions, and it is suitable for large-scale commercial applications.

A method for operating a heat exchanger, in which a first operating mode is carried out in first time periods, and a second operating mode is carried out in second time periods that alternate with the first time periods; in the first operating mode a first fluid flow is formed at a first temperature, is fed into the heat exchanger in a first region at the first temperature, and is partially or completely cooled in the heat exchanger; in the first operating mode a second fluid flow is formed at a second temperature, is fed into the heat exchanger in a second region at the second temperature, and is partially or completely heated in the heat exchanger; and in the second operating mode the feeding of the first fluid flow and of the second fluid flow into the heat exchanger is partially or completely halted.

The present invention relates to cryogenic energy storage systems for storing using high-grade heat-of-compression. The system includes a liquefaction sub-system (100) and thermal energy storage device (300). The liquefaction sub-system (100) includes a first compressor (102), a first, second and third heat exchanger (104, 116, 112) and second compressor (114). The first and second heat exchangers (104, 116) are configured to transfer the high-grade heat of compression from the first and second compressors (102, 114) respectively to the thermal energy storage device (300). The third heat exchanger (112) is configured to recuperate the low-grade heat of compression from the second compressor (114) back into the second compressor (114) enabling the second compressor (114) to generate high-grade heat of compression. Further systems use compressors (124) and expanders (122). Further systems include power recovery sub-systems (400). The present disclosure also relates to methods of heat-of-compression storage in cryogenic energy storage systems.

A method for liquid air and gas energy storage (LAGES) which integrates the processes of liquid air energy storage (LAES) and regasification of liquefied natural gas (LNG) at the Floating Storage, Regasification and Power (FSRP) facilities through the exchange of thermal energy between the streams of air and natural gas (NG) in their gaseous and liquid states and includes recovering a compression heat from air liquefier and low-grade waste heat of power train for LNG regasification with use of an intermediate heat carrier between the air and LNG streams and utilizing a cold thermal energy of liquid air being regasified for increase in LAGES operation efficiency through using a semi-closed CO.sub.2 bottoming cycle.