Study of Ammonia Storage and Delivery Methods for SCR System

Abstract

The purpose of this study is to evaluate two methods of directly supplying ammonia for a selective catalytic reduction (SCR) deNOx system of a diesel engine. Unlike urea-SCR, direct ammonia supply methods for SCR enable NOx reduction in low temperature ranges. One supply method uses an ammonia salt called ammonia carbamate. This method generates large amounts of ammonia, but requires an apparatus temperature higher than 80°C to avoid re-precipitation of the ammonia carbamate. In contrast, a method utilizing an ammonia storage material is more compact than liquid urea and re-precipitation does not occur.