Embodiments of methods and associate system for removing acid gas from a sour gas stream are provided. The method includes (1) passing the sour gas stream in a counter-flow arrangement with an encapsulated phase change material and a lean amine based sorbent liquid configured to absorb the acid gas from the sour gas stream in an absorber; (2) separating the rich amine based sorbent liquid and the encapsulated phase change material; (3) passing the rich amine based sorbent liquid to an amine regenerator wherein the rich amine based sorbent liquid is heated to release the absorbed sour gas and regenerate the lean amine based sorbent liquid; and (4) passing the encapsulated phase change material and the regenerated lean amine based sorbent liquid through a cooler to reduce the temperature of the encapsulated phase change material such that the phase change material in the encapsulated phase change material solidifies.

Disclosed herein is a rotating packed bed, RPB, for mass transfer between a sorbent and a gas, the RPB comprising: a central chamber arranged to receive a flow of a sorbent that is a liquid; and a flow path for the sorbent between the central chamber and a region for mass transfer between a gas and the sorbent; wherein, in use, the flow of sorbent through the region for mass transfer is substantially in cross-flow with the flow of gas through the region for mass transfer. Advantageously, mass transfer between a liquid sorbent and a gas is improved.

A CO.sub.2 recovery apparatus includes: an absorption tower configured to remove CO.sub.2 in an exhaust gas by contacting with a CO.sub.2 absorption liquid containing an absorption agent; a regeneration tower for regenerating the CO.sub.2 absorption liquid from the absorption tower; a reflux water drum for separating CO.sub.2 gas released from the regeneration tower into CO.sub.2 gas and condensed water; a first cleaning device installed in a gas-phase part of the regeneration tower and configured to remove the absorption agent contained in the CO.sub.2 gas flowing through the gas-phase part, by using a first cleaning liquid containing at least the condensed water from the reflux water drum or a water obtained from the condensed water; and a control device configured to adjust a supply amount of the first cleaning liquid to the first cleaning device so that a concentration of the absorption agent in the condensed water is maintained to be not greater than a predetermined value.

An energy-efficient method of removing carbon dioxide, hydrogen sulfide, and other acid gases from a stream of flue gases. The flue stream is contacted with a predetermined sorbent system to remove acid gases from the flue stream. The acid gas-rich sorbent is then heated to desorb the acid gas for capture and regenerate the sorbent. Heat exchangers and heat pumps are used to reduce utility steam and/or cooling water consumption.

A process for treating an H.sub.2S- and CO.sub.2-comprising fluid stream, in which a) the fluid stream is treated in a first absorber at a pressure of 10 to 150 bar with a first substream of a regenerated H.sub.2S-selective absorbent to obtain a treated fluid stream and an H.sub.2S-laden absorbent; b) the H.sub.2S-laden absorbent is heated by indirect heat exchange with regenerated H.sub.2S-selective absorbent; c) the heated HS-laden absorbent is decompressed to a pressure of 1.2 to 10 bar in a low-pressure decompression vessel to obtain a first CO.sub.2-rich offgas and a partly regenerated absorbent; d) the partly regenerated absorbent is regenerated in a desorption column to obtain an H.sub.2S-rich offgas and regenerated absorbent; e) the H.sub.2S-rich offgas is fed to a Claus unit and the offgas from the Claus unit is fed to a hydrogenation unit to obtain hydrogenated Claus tail gas; f) the hydrogenated Claus tail gas and the first CO.sub.2-rich offgas are treated in a second absorber at a pressure of 1 to 4 bar with a second substream of the regenerated H.sub.2S-selective absorbent to obtain a second CO.sub.2-rich offgas and a second H.sub.2S-laden absorbent; and g) the second H.sub.2S-laden absorbent is guided into the first absorber. Also described is a plant suitable for performance of the process. The process is notable for a low energy requirement.

The invention relates to an absorbent solution and to a method using this solution for removing acid compounds contained in a gaseous effluent, comprising water and at least one diamine with general formula (I) as follows:

##STR00001## wherein: radicals R.sub.1, R.sub.2, R.sub.3 are each selected indiscriminately among a methyl radical and a hydroxyethyl radical, and at least one radical among R.sub.1, R.sub.2, R.sub.3 is a methyl radical.

The present invention relates to a carbon dioxide capture agent containing two types of amine compounds and a carbon dioxide capture method using the same, by which not only an effective and economically sustainable CO.sub.2 capture process can be performed but also an improved reaction rate is achieved.

A treatment process for remediating H.sub.2S and other contaminants in liquids includes: partially filling a closed vessel with a contaminated liquid containing 5 ppm H.sub.2S with a head space above the liquid within the vessel where gasses released from the liquid from the liquid collect; separately providing a treatment composition in the head space so that the gasses from the liquid may contact the treatment composition; and permitting the contact between the vapors from the liquid and the treatment composition to continue until a collective concentration of H.sub.2S in the liquid and in the head space is <5 ppm. The treatment composition includes an aqueous solution containing at least one hydroxide compound, a collective concentration of the at least one hydroxide compound in the aqueous solution is in a range of 35-55 weight %, and the aqueous solution constitutes at least 80 weight % of the treatment composition.

Certain implementations of amine sweetening of flash gas are described. Flash gas including acid gas is flowed from a flash drum through a column section connected to the flash drum. A lean amine stream is flowed through the column section. The lean amine stream is configured to treat the acid gas flowed from the flash drum through the column section. A quantity of the lean amine stream flowed through the column section is controlled based, in part, on a rate at which the flash gas including the acid gas is flowed from the flash drum through the column section and a concentration of the acid gas in the flash gas.

Disclosed is an absorbing liquid for separating and capturing carbon dioxide from a carbon dioxide-containing gas, the absorbing liquid containing: at least one alkanolamine represented by formula (1) ##STR00001##
wherein R.sup.1 represents hydrogen or C.sub.1-4 alkyl, R.sup.2 and R.sup.3 are identical or different and each represent hydrogen or C.sub.1-3 alkyl, R.sup.1, R.sup.2, and R.sup.3 are not all hydrogen, and n is 1 or 2; a low-molecular-weight diol compound and/or glycerin; and water.