Application of a New Selective Noncatalytic NO Reduction System to Diesel Exhaust.

Abstract

The chemical gas-phase reduction process used to reduce nitric oxide (NO) in diesel engine exhaust has been applied to a high-speed, light-duty diesel engine. The chemical gas-phase reduction process involves adding methylamine (CH3NH2) in water solution to the exhaust gas as an NO reduction agent. In this study, an experimental selective noncatalytic NO reduction system designed to be used with a diesel engine was applied to evaluate this technique for practical use. The NOx reduction ratio (RNOx) of methylamine processes with and without the installation of a particulate filter was investigated. Two different mixing chambers with different volumes and residence times (0.1s and 0.17s) were also tested. Longer residence times were required to achieve a given level of NOx reduction in unfiltered exhaust, suggesting that the presence of particulate matter inhibits NO reduction. For the standard residence time (0.1s), the process achieved 64% NO reduction in unfiltered diesel exhaust, which increased to 80% NO reduction when a particle filter was fitted to the system.