Patent ID: 8691170

Claim:
A method of removing nitrogen oxides (NOx) from combustion exhaust, comprising: synthesizing a fuel gas containing hydrogen by gasification of a carbonaceous material; separating some of the hydrogen from the fuel gas; mixing at least some of the separated hydrogen into the combustion exhaust; catalyzing a reaction between NOx in the combustion exhaust and the hydrogen that removes NOx from the exhaust at temperatures up to about 260° C.; separating nitrogen from air; synthesizing ammonia from at least some of the separated hydrogen and nitrogen; mixing the ammonia into the combustion exhaust; catalyzing a reduction reaction between NOx in the combustion exhaust and the ammonia that removes NOx from the exhaust at exhaust temperatures above about 200° C., wherein the catalyzing the reduction reaction between NOx and the ammonia comprises transitioning from primarily adding separated hydrogen to the combustion exhaust to primarily catalyze a reaction between NOx and the hydrogen in the combustion exhaust to primarily adding ammonia to the combustion exhaust to primarily catalyze the reduction reaction between NOx and the ammonia over a temperature range of between 200° C. and 260° C.; and catalyzing oxidation reactions of ammonia, carbon monoxide, and volatile organic compounds in the exhaust downstream of the NOx-ammonia reaction at exhaust temperatures above about 200° C.