SYSTEM FOR SELECTIVE CATALYTIC REUCTION AND METHOD FOR SELECTIVE CATALYTIC REUCTION

摘要

The present invention relates to a selective catalytic reduction system for reducing nitrogen oxides (NOx) contained in an exhaust gas discharged from an engine, and a selective catalytic reduction system according to an embodiment of the present invention includes an exhaust gas containing nitrogen oxides (NOx) A main exhaust flow passage through which the gas flows and a catalyst provided on the main exhaust flow passage for reducing NOx contained in the exhaust gas; a reducing agent injecting section for injecting a reducing agent into the exhaust gas flowing into the reactor; A concentration sensor for measuring the concentration of NOx contained in the exhaust gas passed through the reactor, and a target value of a mass flow rate of NOx contained in the exhaust gas passing through the reactor for each load of the engine, (Ppm) contained in the exhaust gas passed through the reactor according to the information, and when the NOx concentration actually measured through the concentration sensor is higher than the upper limit So as to follow the calculated NOx concentration and a controller for correcting the injection amount of said reducing agent, the reducing agent injection.