The removal of acid gases (e.g., non-carbon dioxide acid gases) using sorbents that include salts in molten form, and related systems and methods, are generally described.

A continuous desulfurization process and process system are described for removal of reduced sulfur species at gas stream concentrations in a range of from about 5 to about 5000 ppmv, using fixed beds containing regenerable sorbents, and for regeneration of such regenerable sorbents. The desulfurization removes the reduced sulfur species of hydrogen sulfide, carbonyl sulfide, carbon disulfide, and/or thiols and disulfides with four or less carbon atoms, to ppbv concentrations. In specific disclosed implementations, regenerable metal oxide-based sorbents are integrated along with a functional and effective process to control the regeneration reaction and process while maintaining a stable dynamic sulfur capacity . A membrane-based process and system is described for producing regeneration and purge gas for the desulfurization.

A zeolite membrane composite includes a porous support and a zeolite membrane formed on the support. The zeolite membrane includes a low-density layer that covers the support, and a compact layer that covers the low-density layer. The compact layer has a higher content of a zeolite crystalline phase than the low-density layer. By in this way forming the compact layer on the low-density layer that covers the support, the thin compact layer with no defects can be formed more easily than in the case where a compact layer is formed directly on a support.

The present invention relates to an absorption solvent and, more particularly, to an absorption solvent for removing carbon dioxide from a gaseous mixture having high carbon dioxide partial pressure.

Systems and methods are described for removing solidifiable gas from a process gas stream by direct contact with a cold liquid. The process gas stream includes at least gas that is frozen by the cold liquid while one or more other gases of the process gas stream remain in a gaseous state. The process gas stream may include water, and will have a different composition than the cold liquid. The contacting of the cold liquid with the process gas stream may be at a pressure that is less than 200 psia, and optionally less than 100 psia, 50 psia, or even 30 psia, and the solidified gas may be removed from the contacting assembly as a slurry with cold liquid.

Disclosed are methods and systems for desulfurization of CO-rich streams. A method can include contacting a CO-rich gas stream with activated carbon and/or contacting the CO-rich gas stream with a zinc-oxide sorbent material at a temperature of 0 to 50° C. to remove at least a portion of the sulfur-containing compounds present in the stream.

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.

A premixture for producing an absorbent for removing acid gases from a fluid stream containing a) at least a tertiary amine and/or a sterically hindered secondary amine; b) a dicarboxylic acid in an amount, calculated as neutralization equivalent based on the protonatable nitrogen atoms in a), of at least 30%, wherein the dicarboxylic acid has a solubility in water at a temperature of 20° C. of not more than 15 g of dicarboxylic acid per 100 g of water; and c) 20 to 80 wt % of water. Also described is a process for producing an absorbent from the premixture. The premixture is a transportable and readily handleable solution of a dicarboxylic acid having poor solubility in water for producing an absorbent for removing acid gases from a fluid stream.

Embodiments provided herein are compositions directed to porous iron oxides, which are suitable for removing hydrogen sulfide and other sulfur-containing organic contaminants from hydrocarbon streams, and in which the iron oxide component of the composition contains both maghemite and hematite phases, with maghemite forming the greater portion of these phases. In some embodiments, magnetite, aluminum oxide, alumina silicate, and a binder comprised of an organic substance are homogenized, followed by calcining which burns away the organic and converts magnetite to a mix of maghemite and hematite.

A gas separator includes a separation membrane complex in which a separation membrane with pores having a mean pore diameter less than or equal to 1 nm is formed on a porous support, and a gas supply part that supplies a mixed gas including CO.sub.2 and another gas from the side of the separation membrane to the separation membrane complex. Then, CO.sub.2 in the mixed gas is caused to permeate through the separation membrane and the support and is separated from the mixed gas in a state in which at least part of a permeation surface of the support, from which a gas having permeated through the separation membrane is exhausted, has a temperature lower by 10° C. or more than the temperature of the mixed gas before being supplied to the separation membrane complex.