EXHAUST-GAS DENITRATION SYSTEM, SHIP EQUIPPED THEREWITH, AND METHOD FOR CONTROLLING EXHAUST-GAS DENITRATION SYSTEM

An exhaust gas denitration system is provided to prevent clogging of a urea water injection nozzle and an exhaust tube and avoid poisoning of an exhaust gas denitration catalyst. The exhaust gas denitration system includes: an exhaust gas turbocharger (5) driven by exhaust gas from a marine diesel engine (3); a reactor (2) producing ammonia from a urea water; a urea water injection nozzle (32) for supplying the urea water into the reactor (2); an SCR catalyst part (4) provided in an exhaust gas path on a downstream side of the exhaust gas turbocharger (5) for denitrating the exhaust gas using the ammonia supplied from the reactor (2); an exhaust gas bypass path (Bl) through which a part of the exhaust gas obtained by partly extracting the exhaust gas being supplied to the exhaust gas turbocharger (5) from the diesel engine (3) flows into the reactor (2); and a burner (50) for heating the exhaust gas inside the reactor (2).