MATHEMATICAL SIMULATION OF ADJACENT-COUPLING AMMONIA ABSORPTIVE REACTOR

Abstract

The development of an efficient process for ammonia synthesis is a goal that has been long sought after; therefore, the application of an absorptive reactor for ammonia synthesis is important since it allows the reaction to occur under milder conditions. In the adjacent-coupling absorptive reactor, absorbent particles are positioned downstream the fixed ammonia synthesis catalyst bed. This kind of absorptive reactor leads to the enhanced conversion of ammonia synthesis under milder conditions, compared to the equivalent reactor used without absorbent. Here, we present the transient backflow cell model (BCM) to explain and analyse the phenomenon of absorption-enhanced reaction. The transient BCM, based on the first principle of mass balances, is developed to simulate that the backflow existing through the absorptive reactor. As a reference, the transient cell model (CM) is also implemented to simulate the absorptive reactor when assuming no existing backflow existing. These two models demonstrated that backflow through the absorptive reactor promotes the ammonia reaction conversion via two mechanisms: longer residence time for reaction and faster reaction rate due to the absorption of ammonia absorbed.