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.

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.

Embodiments may include a hydrogen sulfide scrubber system that includes a charging chamber, a reaction vessel, and a treated gas trap. Embodiments may include a mobile vehicle, vessel, or platform that includes a mobile vehicle, vessel, or platform with a mounted hydrogen sulfide scrubber system. The hydrogen sulfide scrubber system is configured as previously described. Embodiments may include a method of using a hydrogen sulfide scrubber system.

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.

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 gas processing system for recovering methane gas from a landfill includes a high pressure main absorber plus a relatively low pressure one. The low pressure absorber receives a gas stream from an equally low pressure flash tank. This low pressure gas stream consists mostly of carbon dioxide and methane. The methane would normally be lost due to the high cost of recompressing the carbon dioxide, but by running this mixture of carbon dioxide and methane through the low pressure absorber with a slip stream of cold absorbent, a large portion of the carbon dioxide can be removed with negligible methane losses. The remaining methane can be recycled through the high pressure main absorber without having to recompress the removed portion of carbon dioxide.

A system includes a first separator that separates water from a fluid material. The water settles on the bottom of the water knock-out tank. The system includes multiple compressors to boost the pressure of the fluid material. The system includes a second separator that separates condensate from the fluid material. The system includes a mixing pipe that mixes glycol with the fluid material and a first heat exchanger that cools the mixed fluid material and glycol. The system includes a third separator that separates gaseous components and liquid components of the mixed fluid material and glycol and a fourth separator that separates the liquid components of the mixed fluid material and glycol. The system includes a fractional distillation column that heats a first liquid from the fourth separator, gasifying a first portion of the first liquid. A second portion of the first liquid remains liquid and is natural gas liquids.