US Patent 8071037 Catalytic devices for converting urea to ammonia

Described are apparatuses, systems, and methods for treating exhaust. The described apparatus and systems typically include a catalytic device for converting aqueous urea to ammonia. The catalytic device may include a pyrolysis catalyst and a hydrolysis catalyst for converting aqueous urea to ammonia. The catalytic device typically includes an upstream face that is positioned at an angle relative to exhaust flow when the device is positioned in a selective catalytic reduction (SCR) system.