Model-supported fine tuning of a ammonia distribution and regulation, in order to operating costs of a selective catalytic reduction, to reduce

摘要

Method and system for reducing the proportion of nitrogen oxides (no_x) in a combustion exhaust gas stream by: (1) analyzing the waste stream, in order that the proportion of no_x ; (2) determining the stoichiometric amount of ammonia, which is required in order to the no_x-Concentration of up to a required level to reduce or less; (3) determining the flow rates profile of no.sub.x._x-Components by the combustion exhaust gas flow, upstream of an ammonia injection grid (25); (4) selecting special locations in the ammonia injection grid (25), in order to ammonia valves (24a, 24b, 26a and 26b) to activate; (5) injecting a controlled amounts of ammonia vapor in the gas stream at grid points which the location of no.sub.x._x in the gas stream; and (6) treating the gas flow by means of a selective catalytic reduction unit (34), in order that the proportion of no_x to reduce to appropriate levels.