EXHAUST EMISSION CONTROL SYSTEM FOR DENOXING EXHAUST GASES FROM COMBUSTION UNITS AND METHOD THEREFOR

摘要

An exhaust emission control system for denoxing exhaust gases from combustion units on a SCR converter comprising a heateable, pressure-resistant converter containing a substace or a corresponding mixture of substances that thermolytically separate(s) NH3, an NH3 store for intermediate storage of NH3 separated by the substance or mixture of substances, a feed line that connects the converter to the exhaust line so that the NH3 can be fed into the exhaust gas flow, and a metering device that is integrated into feed line for meterering the amount of NH3 that is to be introduced into the exhaust gas flow. The invention is characterized in that a heatable cold-start store is associated with the feed line, whereby a certain amount of the substance or mixture of substances that separate(s) the NH3 is contained in said store and the open end of the cold-start store runs into the feed line in the direction of the NH3 flow, upstream from the metering device and is arranged in relation to the feed line in such a way that NH3 or the NH3-separating substance is captured when the system is operated. The invention is also characterized in that an air feeding device comprising two air lines provided with valves is associated with the feed line and that a storage tank is associated with the exhaust emission control system to store the NH3-separating substance or mixture of substances, whereby the storage tank impinges upon a metering device on the outlet side and the outlet of said metering device is connected to a filling nozzle that runs into the converter.