A plant for the production of liquefied methane having, arranged in series, a means for the generation of methane from hydrogen and carbon dioxide, a means for drying the gas mixture produced by the methane generation means, a purification means configured to remove carbon dioxide from the gas mixture dried in the drying means, a liquefier configured to liquefy the methane contained in the gas mixture purified in the purification means, and a liquefied gas storage facility configured to store the methane liquefied by the liquefier.

Cryogenic removal of carbon dioxide from the atmosphere, or CryoDAC (Cryogenic Direct Air Capture), uses extremely low temperatures to convert atmospheric CO.sub.2 into a frozen solid while other components of air such as oxygen and nitrogen remain as gases. Air from the atmosphere is passed through a recuperative heat exchanger to cool the air to a temperature slightly above the deposition point of CO.sub.2. The cooled air is then passed over a deposition surface chilled to a temperature below the deposition point of CO.sub.2. Carbon dioxide in the air transitions from gas to solid form upon contact with the deposition surface. The frozen CO.sub.2 is collected and stored. The cold air with CO.sub.2 removed is passed back through the recuperative heat exchanger to cool incoming air and is then returned to the atmosphere. The deposition surface may be cooled by a cryogenic refrigerator.

A carbon dioxide electrolytic device in an embodiment includes: an electrochemical reaction cell including: a first accommodation part that accommodates gas or a first electrolytic solution containing CO.sub.2; a second accommodation part that accommodates a second electrolytic solution containing H.sub.2O; a diaphragm provided between the first and second accommodation parts; a cathode that is in contact with the gas or the first electrolytic solution; and an anode that is in contact with the second electrolytic solution; a first supply part that supplies the gas or the first electrolytic solution to the first accommodation part; a second supply part that supplies the second electrolytic solution to the second accommodation part; and a carbon dioxide separation part that is connected to a discharge portion of a discharge containing O.sub.2 and CO.sub.2 from the second accommodation part and includes a cryogenic separation device to separate CO.sub.2 from a gas component in the discharge.

A cryogenic carbon capture system includes a flue gas cooling device in fluid communication with a heat engine. The flue gas cooling device receives a fluid stream that is downstream from the heat engine and a cooled liquid coolant stream so that the fluid stream is cooled by the cooled liquid coolant stream and a cooled flue gas stream is formed. A cryogenic carbon capture unit receives at least a portion of the cooled flue gas stream and separates carbon dioxide from the first portion of the cooled flue gas stream so that a clean flue gas stream and a carbon dioxide stream are formed. A liquid coolant cooling device receives the clean flue gas stream and a liquid coolant stream and cools the liquid coolant stream using the clean flue gas stream so that the cooled liquid coolant stream is formed and provided to the flue gas cooling device. The heat engine is in fluid communication with the cryogenic carbon capture system and receives a portion of a split stream that is downstream from the flue gas cooling device as an exhaust gas recirculation stream and an air stream.

A CO2 separation and liquefaction system such as might be used in a carbon capture and sequestration system for a fossil fuel burning power plant is disclosed. The CO2 separation and liquefaction system includes a first cooling stage to cool flue gas with liquid CO2, a compression stage coupled to the first cooling stage to compress the cooled flue gas, a second cooling stage coupled to the compression stage and the first cooling stage to cool the compressed flue gas with a CO2 melt and provide the liquid CO2 to the first cooling stage, and an expansion stage coupled to the second cooling stage to extract solid CO2 from the flue gas that melts in the second cooling stage to provide the liquid CO2.

Methods and systems for separating a desublimatable compound from hydrocarbons is disclosed. A feed fluid stream, consisting of a hydrocarbon and a desublimatable compound, is passed into an upper chamber of a vessel. The feed fluid stream is cooled in the upper chamber, thereby desublimating a portion of the desublimatable compound out of the feed liquid stream to form a product gas stream and a desublimatable compound snow which is collected in the lower chamber of the vessel. A lower portion of the desublimatable compound snow is melted to form a liquid desublimatable compound stream such that an upper portion of the solid desublimatable compound snow remains as an insulative barrier between the upper chamber and the liquid desublimatable compound stream. The liquid desublimatable compound stream is removed at a rate that matches a production rate of the solid desublimatable compound snow, thereby maintaining the insulative barrier.

In a process for the recovery of cold from a methane-rich fluid for the cooling of a flow rich in carbon dioxide, cold is provided to a first heat exchanger for the cooling of the flow by the evaporation of an intermediate fluid by exchange of heat with the methane-rich fluid in order to form at least one condensed intermediate fluid flow at at least one pressure level; at least a part of the intermediate fluid evaporated in a second heat exchanger is condensed at at least one pressure into at least one flow.

A device includes a heat exchanger having one end connected to an air line through which air flows, and the other end connected to a hydrogen line through which liquid-state hydrogen flows. The heat exchanger is configured to produce liquid-state air as the air and the liquid-state hydrogen exchange heat with each other. The device also includes an air storage container connected to the heat exchanger via the air line and configured to store the liquid-state air discharged from the heat exchanger, and an evaporator connected to the air storage container via the air line and configured to evaporate the liquid-state air, supplied from the air storage container, through heat exchange. The device additionally includes a power generator configured to receive the air, discharged from the evaporator, via the air line, thereby producing electrical power.

An atmospheric water harvesting system includes a water-harvesting unit with an air mover and a heat exchanger. The water-harvesting unit may also include one or more screens on which water can condense. The water-harvesting unit is supplied by a coolant pathway, in which a non-cryogenic fluid coolant flows. A cryogenic cell is in the coolant pathway. The cryogenic cell receives the fluid coolant and removes heat from it by causing or allowing a controlled heat transfer between the fluid coolant and a first cryogen sealed within an inner vessel in the cryogenic cell. The coolant may be a liquid at operating temperatures, and the cryogenic cell may cool it to an appropriate temperature without a phase change, essentially acting as a “cold battery” to remove heat from the coolant.

An anaerobic digester is provided. The anaerobic digester includes a biogas storage container comprising a semi-permeable membrane separating the biogas storage container into a first space and a second space, such that the first space is configured to be methane enriched and the second space is configured to be CO.sub.2 enriched. The anaerobic digester further includes a cover positioned over the biogas storage container for protecting the biogas storage container against the elements.