| abstract |
A method for reduction of NO x in a lean gaseous stream includes passing the gaseous stream at a temperature within the NO x sorbing temperature range through a catalyzed trap member having an oxidation catalyst intimately combined with a sorbent material. The sorbed NO x is periodically removed by introducing a combustible component into the gaseous stream and oxidizing it on the trap member to thermally desorb the NO x . The amount of combustible component introduced is limited to maintain the gaseous stream bulk composition lean and to avoid increasing the bulk temperature of the gaseous stream to a temperature which is too high for effective lean NO x abatement treatment. A suitable NO x abatement catalyst is used to reduce the desorbed NO x . Sorbing (trapping) and desorbing periods are alternated, usually in response to the temperature of the gaseous stream, and an apparatus to carry out the process is provided. |