Disclosed is an absorbent containing an amine for absorption of an acid gas in a biogas, and a biogas purification system using the same.

Embodiments of the disclosure provide a method and system for sulfur recovery. A Claus tail gas stream is fed to a hydrogenation reactor to produce a hydrogenated gas stream. The hydrogenated gas stream is fed to a quench tower to produce a quenched gas stream. The quenched gas stream is fed to a first stage adsorption vessel of first stage adsorption unit to produce a first outlet gas stream. The first outlet gas stream is fed to a second stage adsorption vessel of a second stage adsorption unit to produce a second byproduct gas stream. The first stage adsorption vessel is regenerated to produce a first byproduct gas stream. The second stage adsorption vessel is regenerated to produce a second outlet gas stream including hydrogen sulfide. Optionally, a portion of the second byproduct gas stream or nitrogen can be fed to the first stage adsorption vessel or the second stage adsorption vessel for regeneration. Optionally, a sales gas can be fed to the second stage adsorption vessel for regeneration. Optionally, vacuum can be applied to the first stage adsorption vessel or the second stage adsorption vessel for regeneration.

A method for producing and using an alkaline aqueous ferric iron carbonate solution is disclosed. The method broadly comprises reacting at least one ferric iron salt reagent with at least one alkali metal carbonate salt reagent and forming an alkaline aqueous ferric iron carbonate solution comprising an aqueous-soluble, ferric iron carbonate complex. The reacting generally includes reacting a solid with an aqueous solution. The reacting may include reacting a solid comprising one or both of the ferric iron salt reagent and alkali metal carbonate salt reagent with an aqueous solution. A method for removing reduced sulfur compounds from a reduced sulfur-containing fluid is also disclosed.

A treatment process for remediating; contaminants in a mixture of contaminated fluids, including at least one liquid fluid and at least one gaseous fluid, includes the steps of: preparing a treatment composition containing at least 80 volume % of an aqueous solution containing at least one hydroxide compound at a collective concentration of 35-55 weight percent, and at least one organic acid selected from the group consisting of fulvic acid and humic acid at a collective concentration of 0.1-5 wt % of the treatment composition; adding a dosage of the treatment composition to a mixture of contaminated fluids including a liquid portion and a gaseous portion; and allowing the treatment composition to react with the mixture of contaminated fluids for at least 10 minutes. A pH of the treatment composition is at least 12.0

A method for recovering sulfur within a gas processing system is described herein. The method includes contacting a natural gas stream including an acid gas with a solvent stream within a co-current contacting system to produce a sweetened natural gas stream and a rich solvent stream including an absorbed acid gas. The method also includes removing the absorbed acid gas from the rich solvent stream within a regenerator to produce a concentrated acid gas stream and a lean solvent stream. The method further includes recovering elemental sulfur from hydrogen sulfide (H.sub.2S) within the concentrated acid gas stream via a sulfur recovery unit.

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.

A process for treatment of gas mixtures containing acid gas, for the removal of said acid gas from the gas mixtures. The process has (A) an absorption step performed on a gas mixture containing acid gas by means of a solvent system containing at least one liquid absorption solvent for removing from the gas mixture the acid gas contained therein and forming a lean gas mixture, from which at least part of the acid gas have been removed, and an enriched solvent containing the acid gas and (B) a regeneration step, in which the enriched solvent is subjected to a gas/liquid separation step by a flash process to be separated from the absorbed acid gas and to produce an acid gas flow and a regenerated solvent, which is recirculated to the absorption step. The solvent system contains at least one liquid absorption solvent selected from switchable ionic liquids.

This invention relates to a method and a system for abating hydrogen sulfide (H.sub.2S) and carbon dioxide (CO.sub.2) from H.sub.2S and CO.sub.2rich gas mixtures such as geothermal non-condensable gas mixtures (NCG). The H.sub.2S and CO.sub.2 gas is separated from the remaining gases contained in the H.sub.2S and CO.sub.2rich gas mixtures by pressurizing the gas stream and feeding it into an absorption column where H.sub.2S and CO.sub.2 are preferentially dissolved in a water stream, resulting in water stream rich in H.sub.2S and CO.sub.2. The H.sub.2S and CO.sub.2 rich water stream may then be re-injected into a geological reservoir or used for pH modification of another water stream of geological origin.

An absorbent liquid which absorbs at least one of CO.sub.2 and H.sub.2S from a gas, including a secondary linear monoamine; a tertiary linear monoamine or a sterically hindered primary monoamine; and a secondary cyclic diamine, wherein a concentration of each of the secondary linear monoamine, the tertiary linear monoamine or the sterically hindered primary monoamine; and the secondary cyclic diamine is less than 30% by weight.

An alkaline aqueous ferric iron salt solution is disclosed. Generally, the alkaline aqueous ferric iron salt solution comprises ferric ions (Fe.sup.3+), potassium ions (K.sup.+), carbonate ions (CO.sub.3.sup.2−), bicarbonate ions (HCO.sub.3.sup.−), hydroxide ions (OH.sup.−), optionally nitrate ions (NO.sub.3.sup.−). Further, a molar ratio of the potassium ions to the ferric ions is generally at least 5.0. The ferric iron is complexed with carbonate, bicarbonate or both to form a water-soluble complex that is anionic in nature and highly soluble in the alkaline aqueous ferric iron salt solution at pH above 8.5, and a pH of the alkaline aqueous ferric iron salt solution is at least 8.5.