The embodiments provide an acidic gas absorbent, an acidic gas removal method using the absorbent, and an acidic gas removal apparatus using the absorbent. The absorbent absorbs an acidic gas in a large amount and is hardly diffused. The acidic gas absorbent according to the embodiment comprises an amine compound represented by the following formula (1): ##STR00001##

Methods and compositions useful, for example, for physical solvent carbon capture. The solvents may include an aqueous mixture of 2-amino-2-methylproponol, 2-piperazine-1-ethylamine, diethylenetriamine, 2-methylamino-2-methyl-1-propanol, and potassium carbonate or potassium carbonate buffer salt. The solvent may also contain less than about 75% by weight of dissolving medium (i.e., water) and may have a single liquid phase. The solvents and methods have favourable regeneration energies, chemical stability, vapour pressure, total heat consumption, net cyclic capacity, and reaction kinetics.

The use of the combination of (a) an amino compound and (b) a compound including a soft electrophilic centre to scavenge and retain acidic sulfide species at a higher temperature and/or scavenge acidic sulfide species at an increased rate compared to that achieved using the amino compound alone.

An absorbent composition including an amino-siloxane is presented. The amino-siloxane includes structure (I): wherein R.sup.1 is independently at each occurrence a C.sub.1-C.sub.6 aliphatic or aromatic radical; R.sup.2 is independently at each occurrence a C.sub.2-C.sub.10 aliphatic or aromatic radical; and R.sup.3 is independently at each occurrence a C.sub.1-C.sub.18 aliphatic or aromatic radical or R.sup.4′ wherein R.sup.4 comprises structure (II): wherein X is independently at each occurrence an electron donating group; and n is at least 1. Methods of reducing an amount of carbon dioxide in a process stream using the absorbent composition are also presented.

##STR00001##

A method and a system for the removal of carbon dioxide from solvents.

A method of electrochemically reducing CO.sub.2 comprises introducing a first feed stream comprising H.sub.2O to a positive electrode of an electrolysis cell comprising the positive electrode, a negative electrode, and a proton conducting membrane. A second feed stream comprising a solvent and a non polar form of a switchable polarity material is directed into a CO.sub.2 capture apparatus. A third feed stream comprising CO.sub.2 is directed into the CO.sub.2 capture apparatus to interact with the second feed stream and form a first product stream comprising the solvent and a polar form of the switchable polarity material. The first product stream is introduced to the negative electrode. A potential difference is applied between the positive electrode and the negative electrode to convert the polar form of the switchable polarity material into CO.sub.2 and the non-polar form and to form products from the CO.sub.2 and the solvent. A CO.sub.2 treatment system is also described.

Disclosed is a carbon dioxide absorbent and a carbon dioxide separation method using the same that greatly reduces energy consumption due to a small amount of latent heat required in regeneration of absorbents, enhances CO.sub.2 absorption rate, undergoes almost no thermal denaturation even at high temperatures while absorbing carbon dioxide, and results in a considerable reduction of the cost associated with absorption of carbon dioxide.

A system and a process for capturing Carbon Dioxide (CO.sub.2) from flue gases are disclosed. The process comprises feeding a flue gas comprising CO.sub.2 to at least one Rotary Packed Bed (RPB) absorber rotating circularly. A solvent may be provided through an inner radius of the RPB absorber. The solvent may move towards an outer radius of the RPB absorber. The solvent may react with the flue gas in a counter-current flow. The process further includes passing the flue gas through at least one of a water wash and an acid wash to remove traces of the solvent present in the flue gas. Finally, the solvent reacted with the CO.sub.2 may be thermally regenerated for re-utilizing the solvent back in the process.

Provided is a composition for removing a sulfur-containing compound contained in at least one of a liquid and gas, the sulfur-containing compound being at least one selected from the group consisting of hydrogen sulfide and an SH group-containing compound, the composition containing an aldehyde and an amine whose conjugate acid has a pKa value of 11.3 or higher in water at 25 C.

The invention relates to a process for removing hydrogen sulfide and carbon dioxide from a feed gas stream. H2S in the feed gas stream is converted to elemental sulfur in a Claus unit. At least a part of the gas stream obtained is contacted with an aqueous lean absorbing medium in an absorption zone at a pressure between 0.9 and 2 bara. The aqueous lean absorbing medium used comprises one or more amines chosen from: a polyamine in the absence of tertiary amine functionalities having a pKa sufficient to neutralize carbamic acid, the polyamine having at least one primary amine functionality having a pKa smaller than 10.0 at 25 C., a polyamine in the absence of tertiary amine functionalities having a pKa sufficient to neutralize carbamic acid, the polyamine having at least one secondary amine functionality having a pKa for each sorbing nitrogen smaller than 10.0 at 25 C. The process is improved as compared to a process involving Claus off-gas treatment with (activated) MDEA. Effective CO2 removal is achieved while at the same time a simplified line-up with less equipment can be used.