An Environmentally Friendly Configuration for Ammonium Nitrate Decomposition

Abstract

Because of environmental concerns about nitrate and NOx emissions, the present study proposes a novel configuration in order to enhance thermal decomposition of ammonium nitrate (AN) in an environmentally friendly manner. Conventional thermal decomposition of AN takes place in a fluidized-bed reactor (FR) at high temperature, causing high AN conversions as well as considerable amount of NOx formation. The novel configuration considered in this work consists of two cascading fixed-bed and fluidized-bed dual reactors (CFFDRs). Thermal decomposition of AN occurs in the first reactor or the fluidized bed one and NOx is produced as a result. The following fixed bed reactor is a place for the selective catalytic reduction of NO with NH3. Operating conditions for the proposed CFFDR are optimized to achieve a minimum amount of AN as well as NOx via differential evolution (DE) method. Results illustrate that the AN conversion in this novel configuration reaches 98%, which is 42% in the conventional FR. Furthermore, ∼30 ppm NOx exits the conventional FR while in the proposed dual configuration 6 ppm NOx is produced. Therefore, in this novel concept, not only is AN decomposition enhanced, but NOx emission also is reduced.