Provided herein are methods of removing carbon dioxide from an aqueous stream or gaseous stream by: contacting the gaseous stream comprising carbon dioxide, when present, with an aqueous solution comprising ions capable of forming an insoluble carbonate salt; contacting the aqueous solution comprising carbon dioxide with an electroactive mesh that induces its alkalinization thereby forcing the precipitation of a carbonate solid from the solution and thereby the removal of dissolved inorganic carbon by electrolysis; and removing the precipitated carbonate solids from the solution, or the surface of the mesh where they may deposit. Also provided herein are flow-through electrolytic reactors comprising an intake device in fluid connection with a rotating cylinder comprising an electroactive mesh, and a scraping device and/or liquid-spray based device for separating a solid from the mesh surface.

A flue gas stream arising from fossil fuel fired sources containing nitrogen oxide contaminants is conveyed through an exhaust duct into a quencher. In the quencher aqueous medium is sprayed into contact with the flue gas stream. The quenched flue gas stream is mixed with ozone distributed at a high velocity in a sub-stoichiometric amount for partial oxidation of NO.sub.xto form NO.sub.2 and prevent the formation of N.sub.2O.sub.5. The flue gas containing NO.sub.2 is absorbed into an acidic medium of a wet scrubber to form nitrous acid. In the scrubber the nitrous acid is mixed with selected compounds of ammonia to decompose the nitrous acid for release of nitrogen. With this process the consumption of ozone and the operating costs associated therewith eliminate the requirement to dispose of nitrate recovered from the scrubber purge stream.

A method for the reduction and prevention of mercury emissions into the environment from combusted fossil fuels or other off-gases with the use of hypobromite is disclosed. The hypobromite is used for the capture of mercury from the resulting flue gases using a flue gas desulfurization system or scrubber. The method uses hypobromite in conjunction with a scrubber to capture mercury and lower its emission and/or re-emission with stack gases. The method allows the use of coal as a cleaner and environmentally friendlier fuel source as well as capturing mercury from other processing systems.

The present invention relates to a system and a method therefor capable of reducing the amount of heat which must be supplied to a regeneration tower for regenerating an absorbent in an acid gas capture process for such acid gas as carbon dioxide and provides a low energy-type acid gas capture system and method using recirculation of an absorbent capable of reducing energy consumption by recirculating the absorbent, from which acid gas has been pre-separated, to an absorption tower before supplying the absorbent to the regeneration tower in an acid gas capture system.

The invention relates to a process for preparing ammonia gas and CO.sub.2 for urea synthesis. In the process of the invention, a process gas containing nitrogen, hydrogen and carbon dioxide as main components is produced from a metallurgical gas. The metallurgical gas consists of blast furnace gas, or contains blast furnace gas at least as a mixing component. The process gas is fractionated to give a gas stream containing the CO.sub.2 component and a gas mixture consisting primarily of N.sub.2 and H.sub.2. An ammonia gas suitable for the urea synthesis is produced from the gas mixture by means of ammonia synthesis. CO.sub.2 is branched off from the CO.sub.2-containing gas stream in a purity and amount suitable for the urea synthesis.

Equipment and a method for circulating fluidized bed semidry simultaneous desulfurization and denitration of a sintering flue gas, comprising an ozone generator (2), a diluting blower (1), a mixing buffer tank (3), an ozone distributor (4), and a circulating fluidized bed (CFB) reactor tower (9). When evenly mixed by the mixing buffer tank (3), ozone is injected into a flue (4) via the ozone distributor (4); and, an oxidized flue gas is introduced into the CFB reactor tower (9), where NOx, SO.sub.2, and SO.sub.3 in the flue gas are reacted with a Ca-based absorbent under the action of atomized water in the reactor tower, thus implementing simultaneous removal of SO.sub.x and NOx. This provides the characteristics of a simple system, great performance, small footprint, and inexpensive investments.

The invention relates to an absorbent solution for absorbing acid compounds, such as hydrogen sulfide and carbon dioxide, in a gaseous effluent, containing water and a mixture of amines comprising 1,2-bis-(2-dimethylaminoethoxy)-ethane and 2-[2-(2-dimethylaminoethoxy)-ethoxy]-ethanol, of respective formulas (I) and (II) below, and to a method of removing acid compounds contained in a gaseous effluent using this solution.

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The present invention relates to a carbon dioxide capture apparatus having a temperature swing adsorption mode for selective separation of carbon dioxide from flue gases. The carbon dioxide capture apparatus comprises: a carbon dioxide sorption column including a carbon dioxide adsorption unit in which adsorption of carbon dioxide from flue gases occurs; a carbon dioxide desorption column connected to the carbon dioxide sorption column and including a carbon dioxide desorption unit in which desorption of the adsorbed carbon dioxide occurs; a carbon dioxide absorbent repeatedly adsorbing and desorbing carbon dioxide while circulating through the carbon dioxide sorption column and the carbon dioxide desorption column; and a heat exchange unit in which heat exchange occurs between the absorbent after carbon dioxide adsorption and the absorbent after carbon dioxide desorption.

A process for removing sulphur dioxide from the gaseous effluent of a smelter furnace comprising the steps of: providing the gaseous effluent from a smelter; separating the sulphur dioxide from the gaseous effluent to provide concentrated sulphur dioxide and effluent for discharge into the atmosphere; mixing the concentrated sulphur dioxide with a fuel gas; heating the mixture such that the concentrated sulphur dioxide and fuel gas react to form a gaseous product mixture comprising sulphur and hydrogen sulphide; and removing the majority of preferably substantially all of the sulphur and hydrogen sulphide from the gaseous product mixture; wherein the remaining gaseous product mixture is incinerated before being vented into the atmosphere or is recycled into the smelter furnace.

A method for capturing ammonia present in combustion flue gas subjected to carbon dioxide removal using a water wash unit included in a chilled ammonia process. The method includes combining a CO.sub.2 loaded liquid and a wash water liquid to form a CO.sub.2 enriched wash water liquid that is then brought into contact with the combustion flue gas.