A composite amine absorbent according to the present invention is an absorbent for absorbing CO.sub.2 or H.sub.2S, or both of CO.sub.2 and H.sub.2S in a gas. The absorbent is obtained by dissolving (1) a linear monoamine, (2) a diamine, and (3) propylene glycol alkyl ether, for example, represented by the following chemical formula (I) in water. In the composite amine absorbent, the components complexly interact, and the synergistic effect thereof provides good absorbability of CO.sub.2 or H.sub.2S, or both of CO.sub.2 and H.sub.2S and good releasability of CO.sub.2 or H.sub.2S absorbed during regeneration of the absorbent. Furthermore, the amount of water vapor in a reboiler 26 used during regeneration of the absorbent in a CO.sub.2 recovery unit 12 can be reduced.
R.sup.1—O—(R.sup.2—O).sub.n—R.sup.3  (I)

A system and method for simultaneously removing water and acid gases from methane in a single process without requiring dehydration prior to acid gas removal. A feed stream comprising these components and little or no hydrocarbons heavier than methane is separated in a series of separators, including an absorber column using methanol as an absorber. A treated methane stream comprising at least 90%, more preferably at least 95%, most preferably at least 99%, of the methane from the feed stream and an acid gas waste stream comprising less than 10%, more preferably less than 5%, most preferably less than 1%, of the methane from the feed stream are produced. Using methanol as a physical solvent allows removal of water and acids gases in a single step using substantially less energy than conventional separation methods. The system and method are particularly useful in treating landfill gas feed streams.

The present disclosure relates to systems and methods for separation of sulfurous material(s) from a multi-component feed stream. The systems and methods can comprise contacting the multi-component feed stream with a solvent in a contacting column so that at least a portion of the sulfurous material(s) is transferred from the multi-component feed stream to the solvent. A stream of a substantially purified gas can thus be provided along with a liquid stream comprising at least a majority of the sulfurous material. In particular, the solvent can comprise liquid carbon dioxide, which can be particularly beneficial for removing sulfurous materials from multi-component feed streams.

In a reaction product of at least one phenol compound with aldehyde(s), the phenol compound(s) reply to formula (II): wherein-R represents a hydrogen atom or a hydrocarbyl group comprising from 1 to 30 carbon atoms, -x is 1 or 2, -R.sup.1 is a linear alkyl or alkenyl group having 15 carbon atoms if x is 1, -R.sup.1 is hydrogen if x is 2, -R.sup.2 represents a hydrogen atom or a hydrocarbyl group comprising from 1 to 30 carbon atoms, and its use as a hydrogen sulphide and/or mercaptans scavenger in hydrocarbon compositions and in water-based compositions such as water-based drilling fluids.

This invention provides compositions and methods that inhibit formation of alkenyl sulfide polymers and allow the hydrogen sulfide to be removed when scavenging hydrogen sulfide by reaction with aldehydes.

Provided is a method of introducing a scavenger composition into a fluid contaminated with a sulfur contaminant, mixing the scavenger composition with the fluid in a vessel, and recovering the fluid containing a reduced amount of sulfur contaminant from the effluent. The scavenger composition comprises a hydrogen sulfide scavenger and a linear anionic polymer. The linear anionic polymer is present in an amount of about 0.1% to about 50% by weight of the scavenger composition and has a number average molecular weight of about 1.0×10.sup.3 to about 2.0×10.sup.4 Daltons.

Disclosed is an adsorbent containing a metal oxide for adsorption of hydrogen sulfide in biogas, and a biogas purification system using the same.

A process is presented to treat a process gas stream containing hydrogen sulfide using a reverse jet absorber with a liquid treatment solution containing a chelated metal catalyst. A treat gas substantially free of the hydrogen sulfide is separated from a spent liquid treatment solution containing elemental sulfur which can then be regenerated in an oxidation vessel where it is contacted with an oxygen containing gas to convert the spent liquid treatment solution to a regenerated liquid treatment solution that can be recycled for introduction into the reverse jet absorber.

An absorbent for the selective removal of hydrogen sulfide over carbon dioxide from a fluid stream, wherein the absorbent contains an aqueous solution, comprising an amine of formula (I) and/or an amine of formula (II) wherein U—V—W is CH—O—CHR.sup.5, N—CO—CHR.sup.5 or N—CO—NR.sup.5; U′—V′—W is C—O—CR.sup.5; R.sup.1 is independently C.sub.1-C.sub.5-alkyl; R.sup.2 is selected from hydrogen and C.sub.1-C.sub.5-alkyl; R.sup.3 is independently selected from hydrogen and C.sub.1-C.sub.5-alkyl; R.sup.4 is independently selected from hydrogen and C.sub.1-C.sub.5-alkyl; R.sup.5 is selected from hydrogen, C.sub.1-C.sub.5-alkyl, (C.sub.1-C.sub.5-alkoxy)-C.sub.1-C.sub.5-alkyl, and hydroxy-C.sub.1-C.sub.5-alkyl; and x is an integer from 1 to 10. The absorbent has a reduced tendency for phase separation at temperatures falling within the usual range of regeneration temperatures for the aqueous amine mixtures and a low volatility in aqueous solvents. ##STR00001##

Provided is a composition for removal of a sulfur-containing compound in a liquid or gas, wherein the sulfur-containing compound is at least one selected from the group consisting of hydrogen sulfide and a compound containing an —SH group, and the composition contains an aldehyde and a polyvalent amine represented by the general formula (1).