SELECTIVE CATALYTIC NOx REDUCTION UTILIZING UREA WITHOUT CATALYST FOULING

摘要

Urea is used to reduce NOx in an SCR process with no risk of catalyst fouling. The urea is introduced from tank (128), through line (132) into the combustion gases as an aqueous urea solution at a location in the exhaust manifold/passage (120) where the combustion gases exhibit a temperature of from 250 DEG to 1200 DEG F. Following the introduction of the aqueous solution of urea, the combustion gases in the exhaust manifold/passage (120) are directed through a foraminous structure (124) that traps any water or urea that have not been gasified. Then, the combustion gases are directed through an NOx-reducing catalyst structure (126).