Abstract: Method for controlling N.sub.2 O emissions from stationary combustion systems having variable flue gas temperatures are disclosed. The N.sub.2 O emissions are controlled by the introduction of a N.sub.2 O control agent, such as an alkaline compound, into the effluent stream. In addition, the present invention discloses methods for controlling N.sub.2 O emissions from stationary combustion systems having variable flue gas temperatures while reducing NO.sub.x emissions. Use of an NO.sub.x reducing agent and an N.sub.2 O control agent, such as urea and monosodium glutamate, enlarges the temperature window for effective selective noncatalytic NO.sub.x reduction while significantly eliminating N.sub.2 O emissions commonly experienced with urea injection. Further, the present invention discloses methods for controlling N.sub.2 O emissions from stationary combustion systems having variable flue gas temperatures while reducing SO.sub.x emissions. Use of an NO.sub.x reducing agent, an SO.sub.

Abstract: Techniques for enhancing the burnout zone chemistry for NO.sub.x reduction are disclosed. The key parameters for the enhancement of burnout zone chemistry are: (a) a reaction temperature in the range from about 1300.degree. F. to about 1900.degree. F., and optimally in the range from 1400.degree.-1700.degree. F.; (b) a carbon monoxide concentration below about 0.5 percent; and (c) the presence of nitrogenous reducing species. By controlling the stoichiometry associated with reburning to produce a slightly fuel-rich region for selective reducing agent injection, reductions can be achieved at relatively low temperatures which approach those obtained by conventional catalytic reduction.

Abstract: Methods for reducing NO.sub.x emissions from stationary combustion systems having variable flue gas temperatures are disclosed. Use of an annonium salt of an organic acid enlarges the temperature window for effective selective noncatalytic NO.sub.x reduction thereby accounting for variable flue gas temperatures. Currently preferred ammonium salts of organic acids include ammonium formate, ammonium acetate, and ammonium oxalate. Mixtures of urea and either an ammonium salt of an organic acid or a metallic salt of an organic acid provide an even greater temperature window for NO.sub.x reduction. Currently preferred metallic salts of organic acids include Ca(COOH).sub.2, Ca(CH.sub.3 COO).sub.2, Ca(C.sub.2 H.sub.5 COO).sub.2, Mg(COOH).sub.2, Mg(CH.sub.3 COO).sub.2, and Mg(C.sub.2 H.sub.5 COO).sub.2.

Abstract: The present invention relates to methods for selectively reducing NO.sub.x so that nitrogen can be removed from emission effluent streams and NO.sub.x emissions can be reduced to very low levels. In addition, the present invention teaches a method whereby NO.sub.x and SO.sub.x may be simultaneously removed from the effluent stream.The present invention teaches the reduction of NO.sub.x with cyanuric acid. Initially, cyanuric acid is decomposed to form decomposition products. The reaction of cyanuric acid to produce its decomposition products, such as isocyanic acid or related reaction intermediates, takes place in an oxygen-free, fuel rich, decomposition zone with the reaction temperature in the range of from about 1000.degree. F. to about 3000.degree. F.After the cyanuric acid is decomposed in the absence of oxygen, the decomposition stream is mixed with the effluent stream containing NO.sub.x. At this point the oxygen level of the stream must be carefully controlled to provide an excess of oxygen.

Abstract: The present invention relates to methods for selectively reducing NO.sub.x so that nitrogen can be removed from emission effluent streams and NO.sub.x emissions can be reduced to very low levels. In addition, the present invention teaches a method whereby NO.sub.x and SO.sub.x may be simultaneously removed from the effluent stream.The present invention teaches the reduction of NO.sub.x with --NH and --CN containing selective reducing agents such as ammonium sulfate, urea, and NH.sub.3. Initially, the selective reducing agent is decomposed in a fuel-rich environment to form highly reactive decomposition products. The reaction of the selective reducing agent to produce its decomposition products, such as NH, NH.sub.2, and related reaction intermediates, takes place in an oxygen-free, fuel-rich decomposition zone with the reaction temperature in the range of from about 300.degree. F. to about 2400.degree. F.