Light gases such as helium are extracted from a carbon dioxide-containing feed stream by distillation. Costly dehydration steps are avoided by pumping the liquid bottoms stream leaving the distillation column without vaporization so as to ensure that any water present in the feed remains in solution with the bulk stream leaving the process. This prevents any liquid phase water causing corrosion or solid ice or hydrates forming to plug the flow.

In a method for separating a mixture containing carbon dioxide, the mixture is cooled in a heat exchanger and partially condensed and a first liquid is separated from the mixture in a first system operating at low temperature comprising at least one first phase separator and a gas from the first system is treated in a membrane system to produce a permeate and a non-permeate, the gas from the first system being divided into two portions, a first portion being sent to the membrane system without being heated and a second portion being heated to at least an intermediate temperature of the heat exchanger and then sent to the membrane system without being cooled.

Various illustrative embodiments of a system and process for recovering high-quality biomethane and carbon dioxide product streams from biogas sources and utilizing or sequestering the product streams are provided. The system and process synergistically yield a biomethane product which meets gas pipeline quality specifications and a carbon dioxide product of a quality and form that allows for its transport and sequestration or utilization and reduction in greenhouse gas emissions. The system and process result in improved access to gas pipelines for products, an improvement in the carbon intensity rating of the methane fuel, and improvements in generation of credits related to reductions in emissions of greenhouse gases.

The present disclosure provides systems and methods useful in capture of one more moieties (e.g., carbon dioxide) from a gas stream (i.e., direct air capture). In various embodiments, the systems and methods can utilize at least a scrubbing unit, a regeneration unit, and an electrolysis unit whereby an alkali solution can be used to strip the moiety (e.g., carbon dioxide) from the gas stream, the removed moiety can be regenerated and optionally purified for capture or other use, and a formed salt can be subjected to electrolysis to recycle the alkali solution back to the scrubber for re-use with simultaneous production of one or more further chemicals.

Various illustrative embodiments of a system and process for recovering high-quality biomethane and carbon dioxide product streams from biogas sources and utilizing or sequestering the product streams are provided. The system and process synergistically yield a biomethane product which meets gas pipeline quality specifications and a carbon dioxide product of a quality and form that allows for its transport and sequestration or utilization and reduction in greenhouse gas emissions. The system and process result in improved access to gas pipelines for products, an improvement in the carbon intensity rating of the methane fuel, and improvements in generation of credits related to reductions in emissions of greenhouse gases.

The disclosure relates generally to methods as well as configurations for cryogenically separating carbon dioxide and hydrogen and particularly to methods and configurations for cryogenically separating carbon dioxide and hydrogen from a syngas stream to produce high quality carbon dioxide stream(s) and/or high quality hydrogen stream(s). In an embodiment, a system for cryogenically separating carbon dioxide from a syngas stream comprises a pressure swing adsorption system, wherein the pressure swing adsorption (PSA) system separates a syngas input stream into a hydrogen-rich stream and a carbon dioxide-rich stream. The PSA unit outputs the hydrogen-rich stream and the carbon dioxide-rich stream and a carbon dioxide capturing unit cryogenically converts the carbon dioxide-rich stream to a dense phase. The hydrogen-rich stream may be used as a fuel source and/or a feedstock for chemical synthesis, and the dense phase carbon dioxide may be sequestered and stored, or used as a chemical feedstock.

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 bio-renewable conversion process for making fuel from bio-renewable feedstocks is combined with a hydrogen production process that includes recovery of CO.sub.2. The integrated process uses a purge gas stream comprising hydrogen from the bio-renewable hydrocarbon production process in the hydrogen production process.

Techniques for providing carbon dioxide include generating thermal energy, an exhaust fluid, and electrical power from a power plant; providing the exhaust fluid and the generated electrical power to an exhaust fluid scrubbing system to separate components of the exhaust fluid; capturing heat from a source of heat of an industrial process in a heating fluid; transferring the heat of the industrial process captured in the heating fluid to a carbon dioxide source material of a direct air capture (DAC) system; providing the generated electrical power from the power plant to the DAC system; providing the thermal energy from the power plant to the DAC system; and separating, with the transferred portion of the heat of the industrial process and the provided thermal energy, carbon dioxide from the carbon dioxide source material of the DAC system.

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.