A combined plant for cryogenic separation and liquefaction of methane and carbon dioxide in a biogas stream, including a mixing means, a compressor, a first exchanger, a distillation column, a second exchanger, a separating means, an expanding means, and a separator vessel. Wherein, the mixing means is configured such that the recycle gas is the overhead vapour stream, and the first exchanger and the expanding means are combined.

A combined plant for cryogenic separation and liquefaction of methane and carbon dioxide in a biogas stream, including a mixing means, a compressor, a first exchanger, a distillation column, a second exchanger, a separating means, an expanding means, and a separator vessel. Wherein, the mixing means is configured such that the recycle gas is the overhead vapour stream, and the first exchanger and the expanding means are combined.

Process for producing biomethane from a biogas stream including methane, carbon dioxide and at least one impurity chosen from ammonia, volatile organic compounds, water, sulfur-based impurities (H.sub.2S) and siloxanes. A biogas stream is dried, the at least one impurity is at least partially removed by solidification and removal of the impurity. The methane and the carbon dioxide contained in the biogas obtained from the second step are separated so as to produce a biomethane stream and a CO.sub.2 stream.

Disclosed in the present invention are a low energy consumption anhydrous CO.sub.2 phase change absorption agent, and a regeneration method and an application thereof, the absorption agent using a unitary diamine with a primary amine (NH.sub.2—) and a tertiary amine (—N—), and not containing any other organic solvent, water, and ionic liquid; two alkyl branches are linked to a nitrogen atom of the tertiary amine, forming a certain hydrophobicity; after absorbing the CO.sub.2, the diamine changes from a liquid phase to a solid phase, undergoing liquid-solid phase change to form white amino formate crystals.

Methods are provided for reducing the quantity of acid gas reinjected into a reservoir by partial CO.sub.2 removal processes. The methods include acid gas removal, acid gas enrichment, generation of a CO.sub.2 rich stream and an H.sub.2S rich stream, and reinjection of the H.sub.2S rich stream into the reservoir. The acid gas enrichment can be performed by a solvent-based acid gas enrichment unit, a membrane-based acid gas enrichment unit, or a combination of a solvent-based acid gas enrichment unit a and membrane-based acid gas enrichment unit. The system includes an acid gas removal unit, one or more acid gas enrichment units, and an acid gas reinjection compressor. The acid gas enrichment unit can be a solvent-based acid gas enrichment unit, a membrane-based acid gas enrichment unit, or a solvent-based acid gas enrichment unit and a membrane-based acid gas enrichment unit.

Facility and method for membrane permeation treatment of a feed gas stream containing at least methane and carbon dioxide including first, second, and third membrane separation units each including at least one membrane that is more permeable to carbon dioxide than to methane, wherein a permeate from the first membrane separation unit is fed to the third membrane separation unit and a retentate from the first membrane separation unit is fed to the second membrane separation unit. A compressor B adjusts the third-permeate suctioning pressure as a function of the feed gas stream pressure and the second retentate methane concentration.

A novel adsorbent and contactor material based on polymer functionalized with amidoxime and alkylamines moieties. Methods of making the material are also described. The material can be easily processed into any desired sorbent geometry such as solid fibers, electrospun fibers, hollow fibers, monoliths, etc. The adsorbent exhibits a very high affinity toward acidic gases such CO.sub.2 and can be used in direct air capture, power plant-based CO.sub.2 capture, and industrial CO.sub.2 capture applications. The material can also serve as a contactor that accommodates other adsorbents within its structure.

A method for improved operation of a natural gas liquids stabilizer column, particularly a small-scale, is provided. The method can include the steps of: introducing a first feed stream comprising heavy hydrocarbons and natural gas to a stabilizer column to produce a top gas and a bottoms liquid, wherein the top gas has a higher concentration of natural gas as compared to the first feed stream, and the bottoms liquid has a higher concentration of heavy hydrocarbons as compared to the first feed stream; introducing a second feed stream into the stabilizer column, wherein the second feed stream has a higher concentration of natural gas as compared to the first feed stream, wherein the second feed stream is at a warmer temperature than the first feed stream when introduced into the stabilizer column, wherein the second feed stream is a gaseous stream; withdrawing the top gas from a top portion of the stabilizer column; withdrawing the bottoms liquid from a bottom portion of the stabilizer column; and sending at least a portion of the bottoms liquid to a liquid storage tank.

The invention relates to a process and apparatus for separation of gas mixtures with reduced maintenance costs. The process and the apparatus consist of a feed stream separation stage (1), and a retentate separation stage (2), of which both are membrane separation stages, wherein the first retentate stream (7) is heated to temperature higher than the temperature of the feed stream (5), before it is introduced to the retentate separation stage (2), and the total capacity of the membranes used in the retentate separation stage (2) is higher than the total capacity of the membranes used in the feed stream stage (1).

A method of purifying gaseous mixtures, for example ternary or quaternary gaseous mixtures, using a sorbent media comprising two or more sorbent materials. The method involves obtaining a target gas from a gaseous composition comprising the target gas, a first gas and a second gas, and optionally further gases by contacting the gaseous composition with the sorbent media to remove at least some of the first gas and at least some of the second gas from the gaseous composition. The sorbent media comprises at least a first sorbent material and a second sorbent material; wherein the first sorbent material has a higher adsorption selectivity for the first gas than for the target gas; and wherein the second sorbent material has a higher adsorption selectivity for the second gas than for target gas. The method may be particularly useful for the separation of pure ethylene, methane or propylene from such gaseous mixtures. A sorbent media and an apparatus for obtaining a target gas from such a gaseous composition are also disclosed.