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.

The disclosure describes processes which include cooling a natural gas product stream to a cryogenic liquid storage temperature by way of refrigeration streams which include a primary refrigeration stream, a secondary refrigeration stream, and a tertiary refrigeration stream in a refrigeration system. After leaving the refrigeration system, the pressure of each refrigeration stream is increased, and upon reaching a sufficient pressure, the refrigeration streams are recycled to flow back into the refrigeration system as a recycle stream. The disclosure further describes systems capable of performing the processes. The processes and systems can include one or more sensors and one or more controls capable of adjusting a flow rate, flow volume, and/or flow ratio among one or more gas streams to maximize cooling efficiency based on monitoring from the one or more sensors. Mobile natural gas liquefaction systems are also described.

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 LNG liquefaction plant system includes concurrent power production, wherein the refrigeration content of the refrigerant or SMR is used to liquefy and sub-cool a natural gas stream in a cold box or cryogenic exchanger. For concurrent power production, the system uses waste heat from refrigerant compression to vaporize and superheat a waste heat working fluid that in turn drives a compressor for refrigerant compression. The refrigerant may be an external SMR or an internal LNG refrigerant working fluid expanded and compressed by a twin compander arrangement.

A device for separating a gas mixture containing at least 35 mol % carbon dioxide and also at least one gas lighter than carbon dioxide, comprising a first phase separator configured to receive a first partially condensed flow from an exchange line; a first phase separator configured to separate the gas phase from the liquid phase; a cooling means configured to receive the gas phase from the first phase separator and cool said gas phase to form a second partially condensed flow. The resulting liquid phase is then sent to a first valve and is expanded to a lower pressure that is at most 300 mbar lower in order to form a first expanded liquid, which is then mixed with a second liquid originating from the second phase separator in a mixing means that is located upstream of a third valve.

In a purification method, a carbon dioxide-rich gas is cooled in a first brazed aluminum plate-fin heat exchanger, the cooled gas or at least one fluid derived from the cooled gas is sent to a purification step comprising a distillation step, the purification step produces a carbon dioxide-rich liquid which is cooled, then expanded, then sent to a second heat exchanger where it is heated by means of a fluid of the method, the exchanger carrying out an indirect heat exchange only between the carbon dioxide-rich liquid and the fluid of the method, the carbon dioxide-rich liquid at least partially vaporizes in the second exchanger and the vaporized gas formed heats up again in the first exchanger to form a carbon dioxide-rich gas.

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 producing electrical energy in a combined energy generation plant which comprises an air treatment unit and a power station unit is proposed. In a first operating mode, air is liquefied to form an air liquefaction product and, in a second operating mode, an air liquefaction product is converted into a gaseous or supercritical state, in which said product is introduced into the power station unit and is used for producing electrical energy. In a third operating mode, air is condensed in the air treatment unit and used in the power station unit directly for producing electrical energy. It is envisaged that, in the first operating mode, the air is cooled to several temperature levels by two liquid coolants and the air liquefaction product is correspondingly heated. In addition, in the first operating mode, the air is condensed stepwise over several pressure levels.

The present invention relates to a gas storage apparatus and method, and more specifically to liquid air energy storage and its use to facilitate both Demand Side Reduction (DSR) and the use of reduced-cost electricity by industrial compressed-air users. A related electricity generating apparatus and method is also disclosed. The apparatus and method use a first sensible heat coolth store and second latent heat coolth store to first reduce the gas in temperature and then to change it into a liquid phase. Coolth top up devices are also disclosed.

Cryogenic energy storage systems, and particularly methods for capturing cold energy and re-using that captured cold energy, are disclosed. The systems allow cold thermal energy from the power recovery process of a cryogenic energy storage system to be captured effectively, to be stored, and to be effectively utilised. The captured cold energy could be reused in any co-located process, for example to enhance the efficiency of production of the cryogen, to enhance the efficiency of production of liquid natural gas, and/or to provide refrigeration. The systems are such that the cold energy can be stored at very low pressures, cold energy can be recovered from various components of the system, and/or cold energy can be stored in more than one thermal store.