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.

The present disclosure provides methods to use calcium cobalt zirconium perovskites as oxygen-selective sorbents for the separation of oxygen from a gas mixture such as air. Systems and high temperature oxygen detectors are also provided. In a preferred embodiment, the perovskite is configured as a membrane.

An ozonation-based method for producing a cementitious material comprises the steps of: (1) mixing a flue gas with an ozone-containing gas to form a mixed flue gas; and introducing the mixed flue gas into an absorption tower, where the mixed flue gas undergoes dry desulfurization and denitrification by reacting with a powdered desulfurizing and denitrificating agent and becomes a treated flue gas; (2) subjecting the treated flue gas to dust removal to generate by-products; and (3) uniformly mixing raw materials that comprise the first by-product, magnesium oxide, fly ash and an additive to give a cementitious material, wherein on the basis of 100 parts by weight of the cementitious material, the first by-product is 20-60 parts by weight, magnesium oxide is 16-33 parts by weight, the fly ash is 15-35 parts by weight, and the additive is 1-15 parts by weight.

The subject invention provides systems and methods for capturing carbon dioxide in a cyclic process of mechano-chemical reactions. The subject invention also provides systems and methods for synthesizing siderite, by means of mechano-chemical reactions, using mill rotation. Siderite acts as an efficient reversible sorbent and can be decomposed, generating magnetite, carbon and/or metallic iron as well as pure carbon dioxide. Said systems and methods employing carbon dioxide capture/release reactions in the carbonation-calcination cycles are suitable for using in any iron, steel and non-steel industries to reduce carbon dioxide emissions into the atmosphere.

A process is presented where a feed stream containing a hydrogen sulfide and another feed component is introduced into an absorber that the feed stream flows upward from the bottom of the absorber and contacts a liquid treatment solution, where the liquid treatment solution contains a sulfur dye catalyst. The hydrogen sulfide is absorbed into the liquid treatment solution and converted into sulfide ions. The other feed component is removed from the absorber vessel substantially free of the hydrogen sulfide and a spent treatment solution is also removed from the absorber vessel and fed to an oxidation vessel where it is contacted with an oxygen containing gas causing the sulfide ions to oxidize to thiosulfate and converting the spent sulfur dye catalyst to regenerated sulfur dye catalyst. The thiosulfate is recovered, and the regenerated sulfur dye catalyst can be recycled as part of the liquid treatment solution.

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.

An entirely water-based, energy self-sufficient, integrated in-line waste management system is provided for comprehensive conversion of all organic fractions of municipal and wider community waste to fuels suitable for use in transportation, with all solid residues converted to high nutrition compost. The system is based on a combination of pre-treatment, involving alkaline hydrolysis and saponification; three-way separation of the pre-treated waste into different streams that are each directed to suitable further processing including fuel production; which includes biodiesel generation in a continuous-flow catalytic esterification unit, and anaerobic digestion to produce methane or other small molecule biofuel. Remaining solids are converted to compost in a quasi-continuous process.

A system and method for the reduction of NOx and CO contaminants using an ion-exchange resin media having lower-valency ions of the transitional metal elements, such as ferrous ions, cuprous ions and/or manganese ions, such that gases containing NOx and/or CO contaminants may be passed over the media so that the contaminants are absorbed by the lower-valency ions of the transitional metal elements, the media configured so that it can be regenerated to remove the NOx and/or CO contaminants. Regeneration includes exposing the media to a heated stream of hydrogen gas or exposing the media to hydrogen ions in an electrochemical cell.

Slurries and methods of making slurries for modifying and extending relative humidity control ranges. The slurries may include a saturated aqueous salt and one or more other reagents selected to provide a controlled modifiable narrow range of relative humidity. The saturated aqueous salt may be one or more of sodium chloride, potassium chloride, potassium citrate, sodium formate, and/or magnesium chloride, and the one or more other reagents may be one or more of a lactate salt, glycerol, and/or an acetate salt, for example.

A process is presented where a feed stream containing a hydrogen sulfide and another feed component is introduced into an absorber that the feed stream flows upward from the bottom of the absorber and contacts a liquid treatment solution, where the liquid treatment solution contains a sulfur dye catalyst. The hydrogen sulfide is absorbed into the liquid treatment solution and converted into sulfide ions. The other feed component is removed from the absorber vessel substantially free of the hydrogen sulfide and a spent treatment solution is also removed from the absorber vessel and fed to an oxidation vessel where it is contacted with an oxygen containing gas causing the sulfide ions to oxidize to thiosulfate and converting the spent sulfur dye catalyst to regenerated sulfur dye catalyst. The thiosulfate is recovered, and the regenerated sulfur dye catalyst can be recycled as part of the liquid treatment solution.