Abstract: A flue gas desulfurization process and system that utilize ammonia as a reactant, and in which any hydrogen sulfide and/or mercaptans within the ammonia are separated during the desulfurization process so as to prevent their release into the atmosphere. The process and system entail absorbing acidic gases from a flue gas with a scrubbing media containing ammonium sulfate to produce a stream of scrubbed flue gas, collecting the scrubbing media containing the absorbed acidic gases, injecting into the collected scrubbing media a source of ammonia that is laden with hydrogen sulfide and/or mercaptans so that the injected ammonia is absorbed into and reacted with the collected scrubbing media, stripping the hydrogen sulfide and/or mercaptans from the collected scrubbing media by causing the hydrogen sulfide and/or mercaptans to exit the collected scrubbing media as stripped gases, and collecting the stripped gases without allowing the stripped gases to enter the stream of scrubbed flue gas.

Abstract: An apparatus and process for removing acidic gases and NOx from flue gases produced by utility and industrial plants. The process and apparatus convert NOx, and particularly nitric oxide, to nitrogen dioxide, which is then reacted to form a valuable byproduct. The process generally entails contacting a flue gas with a scrubbing medium to absorb acidic gases from flue gas and produce an intermediate flue gas. The intermediate flue gas is then cooled to cause nitric oxide present therein to be oxidized to form nitrogen dioxide, which is then absorbed from the flue gases to produce a nitrogen dioxide-containing solution and a scrubbed flue gas. The nitrogen dioxide in the nitrogen dioxide-containing solution is then reacted with ammonium hydroxide to form ammonium nitrate as a valuable byproduct.

Abstract: An apparatus and process for removing acidic gases and NOx from flue gases produced by utility and industrial plants. The process and apparatus convert NOx, and particularly nitric oxide, to nitrogen dioxide, which is then reacted to form a valuable byproduct. The process generally entails contacting a flue gas with a scrubbing medium to absorb acidic gases from flue gas and produce an intermediate flue gas. The intermediate flue gas is then cooled to cause nitric oxide present therein to be oxidized to form nitrogen dioxide, which is then absorbed from the flue gases to produce a nitrogen dioxide-containing solution and a scrubbed flue gas. The nitrogen dioxide in the nitrogen dioxide-containing solution is then reacted with ammonium hydroxide to form ammonium nitrate as a valuable byproduct.

Abstract: A process and system for producing fertilizers with reduced levels of contaminants, and particularly a flue gas scrubbing process and facility that produce a fertilizer byproduct which is treated to remove heavy metals originally present in the scrubbed flue gas. The process entails contacting a flue gas with a scrubbing solution to remove acidic gases and produce a byproduct containing a fertilizer compound precipitate and dissolved metals and/or metal compounds. A fertilizer solution containing dissolved fertilizer and dissolved metals and/or metal compounds is then produced by adding water to the byproduct, after which the pH of the fertilizer solution is adjusted one or more times with a gaseous and/or liquid alkali to form precipitates of one or more metal species. The precipitates are then removed from the fertilizer solution and the solution dewatered to yield a fertilizer product with lower contaminant levels.