EXHAUST GAS PURIFICATION METHOD AND EXHAUST GAS PURIFICATION SYSTEM FOR RECIPROCATING INTERNAL COMBUSTION ENGINE

摘要

In order to suppress extreme deterioration in the properties of a reciprocating internal combustion engine and enable the removal of NOx in exhaust gas in cases in which the NOx within the exhaust gas of a reciprocating internal combustion engine equipped with a supercharger is removed with an SCR system, a reciprocating marine diesel engine (10) in which a supercharger (30) has been disposed in an exhaust pipe (38, 44, 48) is provided with an aqueous urea solution supply unit (42) in the exhaust pipe (38) upstream of a turbine (34), whereby an aqueous urea solution (b) is supplied from an aqueous urea solution tank (40). The aqueous urea solution (b) is evaporated by the reserved heat of the exhaust gas and is hydrolyzed into ammonia gas. The ammonia gas is uniformly stirred and mixed with the exhaust gas in a highly turbulent flow field of the turbine (34). Thereafter, the ammonia gas deoxidizes the NOx within the exhaust gas in an SCR catalyst converter (46), which is disposed in the exhaust pipe (44) downstream of the supercharger (30), and converts the NOx to nitrogen and water vapor. Since the aqueous urea solution (b) is supplied to the exhaust pipe (38) upstream of the turbine (34), ammonia gas can be generated without installing additional heating equipment such as an auxiliary burner.