A composite material is used for desulfurization. The composite material contains activated carbon, alkali metal oxides, silicon oxides, iron oxides, and rare earth element oxides. The weight ratio among the activated carbon, iron oxides and rare earth element oxides is 100:(0.5-5):(1-10). The composite material, used as a sulfur adsorbent, has a higher sulfur breakthrough capacity and desulfurization rate.

A molecular sieve complex contains an oxide of aluminum, an oxide of an alkaline earth metal and a rare earth-modified molecular sieve. The rare earth-modified molecular sieve is a molecular sieve doped by a rare earth element. The percentage of the pore volume occupied by pores of 3 nm or less to the total pore volume in the molecular sieve complex is greater than or equal to 63.5%. The content of the rare earth element and the contents of the oxide of aluminum, the oxide of the alkaline earth metal and the molecular sieve satisfy a certain relationship. The composite material contains a molecular sieve complex and an auxiliary agent loaded on the molecular sieve complex, and the composite material may be applied to flue gas adsorption and desulfurization.

A process for recovering sulfur from a sour gas is provided. The process includes the steps of: providing the sour gas to a membrane separation unit having a carbon dioxide-selective membrane that comprises a perfluoropolymer, wherein the sour gas comprises carbon dioxide and at least 1 mol % hydrogen sulfide; separating the sour gas using the carbon dioxide-selective membrane in the membrane separation stage to obtain hydrogen sulfide-enriched gas and hydrogen sulfide-stripped gas, wherein the hydrogen sulfide-enriched gas has a hydrogen sulfide concentration of at least 20 mol %, and wherein the hydrogen sulfide-stripped gas comprises carbon dioxide; and processing the hydrogen sulfide-enriched gas in a sulfur recovery unit to obtain sulfur.

A system and method for sulfur recovery, including hydrogenating Claus tail gas, quenching the hydrogenated gas, adsorbing water and hydrogen sulfide from the quenched gas, and regenerating adsorbent with carbon dioxide and/or nitrogen and heating the adsorbent in a regeneration temperature ramp to desorb primarily hydrogen sulfide in a first part of the temperature ramp.

Methods and systems for converting ammonium waste streams into certifiably Organic ammonium salts having a variety of uses in greenhouse gas-reducing activities are herein described. The resulting ammonium salt compositions can be used to enhance crop yield.

A composite amine absorbent according to the present invention is an absorbent for absorbing CO.sub.2 or H.sub.2S, or both of CO.sub.2 and H.sub.2S in a gas. The absorbent is obtained by dissolving (1) a linear monoamine, (2) a diamine, and (3) propylene glycol alkyl ether, for example, represented by the following chemical formula (I) in water. In the composite amine absorbent, the components complexly interact, and the synergistic effect thereof provides good absorbability of CO.sub.2 or H.sub.2S, or both of CO.sub.2 and H.sub.2S and good releasability of CO.sub.2 or H.sub.2S absorbed during regeneration of the absorbent. Furthermore, the amount of water vapor in a reboiler 26 used during regeneration of the absorbent in a CO.sub.2 recovery unit 12 can be reduced.

R.sup.1—O—(R.sup.2—O).sub.n—R.sup.3  (I)

Methods and systems for converting ammonium waste streams into certifiably Organic ammonium salts having a variety of uses in greenhouse gas-reducing activities are herein described. The resulting ammonium salt compositions can be used to enhance crop yield.

An absorbent composition that is useful in the selective removal of hydrogen sulfide relative to carbon dioxide from gaseous mixtures that comprise both hydrogen sulfide and carbon dioxide and the use thereof. The absorbent composition includes an amine mixture of an amination reaction product of tert-butylamine with a polydispersed polyethylene glycol (PEG) mixture having an average molecular weight within a certain specified range of molecular weights. The amination reaction product may also comprise a first sterically hindered amine and a second sterically hindered amine. The absorbent composition, preferably, includes an organic co-solvent, such as a sulfone compound. A method is also provided for improving the operation of certain gas absorption processes by utilizing the absorbent composition.

Dry-scrubbing media compositions, methods of preparation and methods of use are provided. The compositions contain activated alumina and magnesium oxide. Optionally, activated carbon and other impregnates, such as hydroxides of group 1A metals, are included. The compositions exhibit improved efficiency and capacity for the removal of compounds, such as hydrogen sulfide, from an air-stream. The compositions are particularly useful for reducing or preventing the release of toxic gaseous compounds from the areas such as landfills, petroleum storage areas, refineries, drinking water systems, sewage treatment facilities, swimming pools, hospital morgues, animal rooms, and pulp and paper production sites.

Systems and methods for removing hydrogen sulfide from an ammonia stream in the NH3 purification and liquefaction stage of a conventional two-column sour water stripping system using an adsorbent bed.