Capture of hydrogen sulfide from a gas mixture may be accomplished using an aqueous solution comprising an amine. Certain sterically hindered amines may selectively form a reaction product with hydrogen sulfide under kinetically controlled contacting conditions and afford a light phase and a heavy phase above a critical solution temperature, wherein the hydrogen sulfide may be present in either phase. Upon separation of the light phase from the heavy phase, processing of one of the phases may take place to remove hydrogen sulfide therefrom. Recycling of the amine to an absorber tower may then take place to promote capture of additional hydrogen sulfide.

A method for revamping an ammonia-urea plant wherein: the ammonia section is modernized to produce an extra amount of low pressure steam; condensation stage of the high-pressure urea synthesis loop is modified to use part of the condensation heat of the urea stripper vapours to produce medium-pressure steam, said medium-pressure steam is fed to one or more steam users of the urea section, particularly for carbamate decomposition, the input of low-pressure steam to the urea section is balanced by importing the extra low-pressure steam produced in the ammonia section.

Disclosed in the present invention are a low energy consumption anhydrous CO.sub.2 phase change absorption agent, and a regeneration method and an application thereof, the absorption agent using a unitary diamine with a primary amine (NH.sub.2—) and a tertiary amine (—N—), and not containing any other organic solvent, water, and ionic liquid; two alkyl branches are linked to a nitrogen atom of the tertiary amine, forming a certain hydrophobicity; after absorbing the CO.sub.2, the diamine changes from a liquid phase to a solid phase, undergoing liquid-solid phase change to form white amino formate crystals.

Embodiments of the present disclosure are directed to systems and methods for removing formaldehyde from indoor air. Some embodiments include flowing an indoor airflow over and/or through a solid supported amine filtering medium, such that, at least a portion of formaldehyde entrained in the indoor airflow is removed therefrom. Some other embodiments include systems having one or more fans for providing velocity to one and/or another airflows (e.g., airflows to/from a formaldehyde filter).

A solvent composition for carbon capture according to a preferred embodiment comprises at least two of the following: diethylaminoethanol (DEAE), hexamethylenediamine (HMDA), and polyethylenimine (PEI). Another embodiment includes a method of performing carbon capture using the carbon capture solvent compositions described herein. Another embodiment provides an apparatus for performing carbon capture using the carbon capture compositions described herein and/or the carbon capture methods described herein.

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.

Provided is a carbon dioxide recovery device including an absorption part that produces a compound of carbon dioxide and an amine contained in an absorbing solution, and a regeneration part that includes an anode that desorbs the carbon dioxide from the compound to produce a complex compound of the amine, and a cathode that is electrically connected to the anode and regenerates the amine from the complex compound.

An aminal compound is injected into a fluid gas stream including at least one acid gas to reduce the amount of acid gas in the fluid gas stream. Having two reactive sites present in the aminal compound enables a much higher efficiency of acid gas capture than a simple alkanolamine, which isn't effective, for example, under dilute circumstances.

An absorption column including at least one external heat exchange circuit for cooling or heating the absorption liquid, including one or more serially connected heat exchangers, wherein the junction of the pipeline for withdrawal of the absorption liquid from the column is disposed above the junction of the pipeline into the first heat exchanger in the flow direction, wherein the pipeline also includes a dumped bed.

A method and apparatus for continuously treating acid gases including recovering absorbent chemicals by introducing streams leaving a regenerator and/or leaving an absorber into a static mixing zone wherein supplemental washing water is added to recover absorbent chemicals. Improvements to the prior art methods are provided where one or more absorbent chemical recovery units are included to increase the amount of recovered absorbent chemicals exiting the regenerator and/or exiting the absorber are increased and/or maximized. Absorbent chemical recovery units can include mixing units where liquid is added to the stream of sour gas and absorbent chemical to mix with and absorb the absorbent chemical from the stream.