A process for removal of acid gases from fluid stream, wherein the fluid stream is brought into contact with an absorbent to obtain a treated fluid stream and a laden absorbent, the absorbent comprising a diluent and a compound of the general formula (I) wherein R.sup.1 is selected from C.sub.1-C.sub.8-alkyl and C.sub.2-C.sub.8-hydroxyalkyl; R.sup.2 is selected from hydrogen and C.sub.1-C.sub.8-alkyl; R.sup.3 is selected from hydrogen and C.sub.1-C.sub.8-alkyl; R.sup.4 is selected from hydrogen and C.sub.1-C.sub.8-alkyl; R.sup.5 is C.sub.1-C.sub.8-alkyl; with the proviso that at least one of the following conditions (i) and (ii) is met: (i) R.sup.5 is C.sub.3-C.sub.8-alkyl bound to the nitrogen atom via a secondary or tertiary carbon atom; (ii) when R.sup.4 is hydrogen, R.sup.3 is C.sub.1-C.sub.8-alkyl; or when R.sup.4 is C.sub.1-C.sub.8-alkyl, at least one of R.sup.2 and R.sup.3 is C.sub.1-C.sub.8-alkyl; and n is an integer from 0 to 6. Further provided is an absorbent for the absorption of acid gases from a fluid stream, comprising a diluent and a compound of the general formula (I) as defined above, as well as the use of a compound of the general formula (I) as defined above for removal of acid gases from a fluid stream. The absorbents are useful for the selective removal of hydrogen sulfide from fluid streams and have high acid gas loading capacity, high stability, and low volatility.

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A cooling absorption tower for a CO.sub.2 recovery device, comprises: an outer shell; a cooling section for cooling a flue gas, the cooling section being disposed in the outer shell; and an absorbing section configured to cause CO.sub.2 in the flue gas cooled by the cooling section to be absorbed in an absorption solvent, the absorbing section being disposed in the outer shell and above the cooling section.

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 for absorbing carbon dioxide from a gas stream containing carbon dioxide, including the steps of contacting the gas stream with an aqueous composition including a substituted heteroaromatic compound having a six-membered heteroaromatic ring with from 1 to 3 nitrogen atoms in the heteroaromatic ring and at least one substituent wherein at least one of the substituents is of formula —R.sup.1NH.sub.2 wherein R.sup.1 is selected from C.sub.1 to C.sub.6 alkylene and ethers of formula —R.sup.2—O—R.sup.3— wherein R.sup.2 and R.sup.3 are C.sub.1 to C.sub.3 alkylene

The present invention relates to a method of capturing CO.sub.2 from a gas stream. The method uses a two liquid phase capture composition.

The invention pertains to methods of reducing dissolved elements such as arsenic, selenium and mercury in aqueous solutions using, for example, various barium compounds to partition said elements to a solid phase. Such methods are particularly useful for reducing such elements at various points in coal and oil-fired power plants prior to final waste water treatment.

Within a glycol contactor, a glycol stream is contacted with a wet gas stream including water in order to transfer at least a portion of the water from the wet gas stream to the glycol stream. The glycol stream entering the glycol contactor includes a mixture of triethylene glycol and tetraethylene glycol. The glycol stream exiting the glycol contactor includes the portion of the water from the wet gas stream. The glycol stream exiting the glycol contactor is flowed to a glycol regeneration system. By the glycol regeneration system and using a solvent including iso-octane, the glycol stream is fractionated to remove the portion of the water from the glycol stream. The fractionated glycol stream is recycled to the glycol contactor.

A solvent system for the removal of acid gases from mixed gas streams is provided. Also provided is a process for removing acid gases from mixed gas streams using the disclosed solvent systems. The solvent systems may be utilized within a gas processing system.

The present invention describes a process for capturing CO.sub.2 using an optimized mixture of water and alcohols with alkali hydroxides, such as KOH and NaOH, for absorption of CO.sub.2 from gaseous mixtures. The process shows high efficiency and low volatility and corrosivity rate of the solvent, in addition to allowing cost reduction for installation and maintenance of reactors and reducing solvent loss. The present invention also describes a process for regenerating solvent or its reuse, carried out by chemical precipitation, continuously and not in batch, through the reaction with alkaline earth oxides, such as CaO and MgO, and/or alkaline earth hydroxides, such as Ca(OH).sub.2 and Mg(OH).sub.2, for the formation of carbonates, such as CaCO.sub.3 and MgCO.sub.3, which can be discarded in nature without any environmental issue or can be used commercially in industry or agriculture.

A carbon capture system includes: (a) an absorber having an inorganic solvent carbon dioxide capture section, a water wash section between the organic solvent carbon dioxide capture section and the inorganic solvent carbon dioxide capture section, a flue gas inlet at the organic solvent carbon dioxide capture section and a treated flue gas outlet at the inorganic solvent carbon dioxide capture section, (b) a stripper, (c) a polishing circuit, and (d) a water wash circuit. A related method of carbon capture includes sequentially subjecting the flue gas to (i) organic solvent carbon dioxide capture, (ii) water washing and (iii) inorganic solvent carbon dioxide capture.