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US 4,867,954 AGranted
Catalytic reduction of nitrogen oxides
AssigneeUop LLC
InventorsMark T. Staniulis, Alan P. Risch, James G. Vassilakis, Donald F. Best
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AssigneeUop LLC
InventorsMark T. Staniulis, Alan P. Risch, James G. Vassilakis, Donald F. Best
Estimating the term…
This invention relates to a method for catalytically reducing one or more nitrogen oxides from a gaseous stream containing one or more nitrogen oxides and optionally one or more sulfur oxides which comprises contacting said gaseous stream and ammonia with a microporous molecular sieve composition at effective reduction conditions in which the amount of ammonia in said method is excessive over the stoichiometric amount necessary for catalytically reducing one or more nitrogen oxides from said gaseous stream, wherein said microporous molecular sieve composition is (i) optionally acid treated with an inorganic or organic acid, (ii) hydrogen-forming cation exchanged and (iii) optionally metal cation exchanged, prior to said contacting in said method, and wherein at least a portion of excessive ammonia in said method is oxidized without substantial adverse effect on catalytically reducing one or more nitrogen oxides from said gaseous stream.
A method for catalytically reducing one or more nitrogen oxides from a gaseous stream containing one or more nitrogen oxides and optionally one or more sulfur oxides which comprises contacting said gaseous stream and ammonia with a microporous molecular sieve composition selected from a zeolitic or silica molecular sieve or mixtures thereof at .RTM.effective reduction conditions in which the amount of ammonia in said method is excessive over the stoichimetric amount necessary for catalytically reducing one or more nitrogen oxides from said gaseous stream, wherein said microporous molecular sieve composition is (i) acid treated with an inorganic or organic acid, (ii) hydrogen-forming cation exchanged and (iii) metal cation exchanged, prior to said contacting in said method, and wherein at least a portion of excessive ammonia in said method is oxidized without substantial adverse effect on catalytically reducing one or more nitrogen oxides from said gaseous stream.
A method for catalytically reducing one or more nitrogen oxides from a gaseous stream containing one or more nitrogen oxides and optionally one or more sulfur oxides which comprises contacting said gaseous stream and ammonia with a microporous non-zeolitic molecular sieve composition at effective reduction conditions in which the amount of ammonia in said method is excessive over the stoichiometric amount necessary for catalytically reducing one or more nitrogen oxides from said gaseous stream, wherein said microporous non-zeolitic molecular sieve composition is (i) acid treated with an inorganic or organic acid, (ii) hydrogen-forming cation exchanged and (iii) metal cation exchanged, prior to said contracting in said method, and wherein at least a portion of excessive ammonia in said method is oxidized without substantial adverse effect on catalytically reducing one or more nitrogen oxides from said gaseous stream.
Dependencies are inferred from the claim text.