The acid gas removal system for removing acidic gases from gaseous hydrocarbons (10) removes sour gases, such as hydrogen sulfide (H.sub.2S) and carbon dioxide (CO.sub.2), from an input gaseous stream. The system (10) includes a contactor (12) for contacting the input gaseous stream with an absorption liquid solvent (ALS), and a stripper (24) for recycling the absorption liquid solvent (ALS) and removing acidic gases (AG) therefrom, but with the addition of a pair of plate-plate heat exchangers (22, 26). The first heat exchanger (22) heats the used absorption liquid solvent (UALS) output from the contactor (12) prior to injection into the stripper (24). The used absorption liquid solvent (UALS) is heated via heat exchange with the acidic gases (AG) output from the stripper (24). The second heat exchanger (26) cools the recycled absorption liquid solvent (RALS) before injection back into the contactor (12).

To provide an aldehyde scavenger and a method for removing aldehydes by using the same, for quickly and continuously capturing aldehydes. An aldehyde scavenger comprising at least one O-substituted hydroxylamine or at least one chemically acceptable salt thereof, is used against an aldehyde generation source.

A process for sweetening a syngas stream, the process comprising the steps of: providing a syngas stream to a nonselective amine absorption unit, the sour syngas stream comprising syngas, carbon dioxide, and hydrogen sulfide; separating the syngas stream in the nonselective amine absorption unit to obtain an overhead syngas stream and an acid gas stream; introducing the acid gas stream to a membrane separation unit, the acid gas stream comprising hydrogen sulfide and carbon dioxide; separating the acid gas stream in the membrane separation unit to produce a retentate stream and a permeate stream, wherein the retentate stream comprises hydrogen sulfide, wherein the permeate stream comprises carbon dioxide; introducing the retentate stream to a sulfur recovery unit; processing the retentate stream in the sulfur recovery unit to produce a sulfur stream and a tail gas stream, wherein the sulfur stream comprises liquid sulfur.

The present invention relates to an additive composition for scavenging hydrogen sulfide in hydrocarbons, wherein said additive composition comprises a combination of (a) glyoxal and (b) at least one aliphatic tertiary amine or oxide treated derivative thereof, or a mixture of the aliphatic tertiary amine and the oxide treated derivative thereof. In one embodiment it also relates to a method for scavenging hydrogen sulfide in hydrocarbons, and in another embodiment it relates to a method of using an additive composition of the present invention for scavenging hydrogen sulfide in hydrocarbons. In yet another embodiment it relates to a composition for scavenging hydrogen sulfide in hydrocarbons comprising (A) a hydrocarbon and (B) a hydrogen sulfide scavenging additive composition of the present invention.

An aqueous solvent composition is provided, comprising a nucleophilic component having one or more sterically unhindered primary or secondary amine moieties, a Brønsted base component having one or more basic nitrogen moieties, a water-soluble organic solvent, and water. A biphasic composition is provided, comprising one or more carbamate compounds, one or more conjugate acids of Brønsted base, a water-soluble organic solvent, and water. A biphasic CO.sub.2 absorption process is also provided, utilizing the biphasic solvent composition.

A scrubbing solution for removing contaminants, including particularly hydrogen sulfide, from a fluid. The scrubbing solution includes at least one scrubbing reagent which has a primary or secondary amine and an acid, which may be phosphoric acid. The fluid being scrubbed is passed through the scrubbing solution. The contaminants react with the scrubbing reagent securing them in the scrubbing solution. The fluid being scrubbed and the scrubbing solution are then separated. The scrubbing solution is heated and, if the scrubbing solution is under pressure, the pressure is reduced. The acid facilitates thorough removal of the contaminants, and especially the hydrogen sulfide, from the scrubbing solution. The scrubbing solution is then ready for reuse. Because the scrubbing solution is rendered substantially free of hydrogen sulfides, it can absorb other sulfide contaminants that might not otherwise be absorbed.

The present invention relates to a novel phase transfer solvent composition for enhanced CO.sub.2 and/or H.sub.2S capture from flue gas and biogas having various gaseous compositions. Further, the present invention provides a process of preparing the phase transfer solvent composition of the present invention.

A process for removing hydrogen sulfide and carbon dioxide from a fluid stream comprises a) an absorption step in which the fluid stream is contacted with an absorbent comprising an aqueous solution (i) of an amine of the general formula (I) ##STR00001##
in which R.sub.1, R.sub.2 and R.sub.3 are each independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.4 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.5 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; X is OH or NH(CR.sub.1R.sub.2R.sub.3); m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is 0 or 1; and optionally (ii) at least one tertiary amine, where the molar ratio of (i) to (ii) is greater than 0.05; wherein at least 90% of the hydrogen sulfide is removed from the fluid stream and selectivity for hydrogen sulfide over carbon dioxide is not greater than 8, wherein a CO.sub.2— and H.sub.2S-laden absorbent is obtained; b) a regeneration step in which at least a substream of the CO.sub.2— and H.sub.2S-laden absorbent is regenerated and a regenerated absorbent is obtained; and c) a recycling step in which at least a substream of the regenerated absorbent is recycled into the absorption step a). The process allows a high level of hydrogen sulfide removal with a simultaneously high coabsorption of carbon dioxide.

Disclosed herein are acid gas absorbents that afford high acid gas (CO2) absorption amount per unit volume and high absorption speed and can prevent the absorbent components from diffusing. The acid gas absorbent contains an amine compound of the formula (1) and a cyclic amine compound of the formula (3) or (3′): ##STR00001##

The embodiments provide an acidic gas absorbent having low diffusibility, an acidic gas removal method, and an acidic gas removal apparatus. The acidic gas absorbent according to the embodiment comprises: an amine compound having a vapor pressure of 0.001 to 10 Pa at 20° C.; a water-soluble polymer compound having a mass-average molecular weight of 900 to 200000 and not containing a functional group having a pKa value greater than 7 except for hydroxy; and water.