METHOD AND DEVICE FOR CLEANING ENGINE EXHAUST GAS

PROBLEM TO BE SOLVED: To provide a method and a device for cleaning engine exhaust gas, which device prevent fused solidification of urea when an aqueous solution of urea is supplied into the system, is little in heat consumption, reactively decomposes the aqueous solution of urea to ammonia, furthermore, decomposes the aqueous solution of urea to ammonia at a lower reaction temperature, is improved in the operation and is cost- reduced. SOLUTION: The device comprises a nozzle which is housed in a covering member is arranged on a position having approximately normal temperature, the aqueous solution of urea is supplied into the system and the fused solidification of the aqueous solution of urea is prevented. Further, the engine exhaust gas is introduced into an evaporation part and the aqueous solution of urea is heated up to a reaction temperature at which the aqueous solution can be decomposed to ammonia. Because the engine exhaust gas is made a heating source, this device for cleaning engine exhaust gas is permitted to be little in heat consumption and reactively decomposes the aqueous solution of urea with high efficiency. Furthermore, a catalyst for decomposing the aqueous solution of urea is arranged on the upper surface of the evaporation part, and as a result, the aqueous solution of urea is decomposed into ammonia at a further lower reaction temperature.