Two technicians are explaining SCR (selective catalyst reduction) operation. Technician A says that after the urea decomposes into ammonia in the mixing chamber, the ammonia-exhaust gas composition passes over an SCR catalyst containing either copper or iron to break apart NOx molecules. Technician B says that blades or screens in the mixing device are used to create exhaust gas turbulence ahead of the mixing chamber. Who is right?

Question

Quizplus · Accepted Answer

Technician A is correct about the role of the SCR catalyst in breaking apart NOx molecules using ammonia. Technician B is also correct that blades or screens are used to create turbulence for better mixing of exhaust gases and ammonia.

Two Technicians Are Explaining SCR (Selective Catalyst Reduction) Operation