STABILITY ANALYSIS OF AMMONIA SYNTHESIS REACTOR

Abstract

Ammonia is produced by catalytic reaction of H2 and N2 in mole ratio of approximately 3 : 1. at elevated pressures (100 - 1000 ATM) and temperatures (673 - 923 K). In practice, over the last 50 years the optimum pressure for economic operation has been in the range of 150 to 350 ATM. The reaction is carried out over a doubly promot-ed iron catalyst. The principal material used to make most commercially available catalyst is usually magnetite, Fe304' and a typical catalyst originated as impurities in percent in the magnetite (ICI catalyst 35-4) contains approximately K20 = 0.8, CaO 2.0, Mg0 = 0.3, A1203 = 2.5, 3102 . 0.4, as well as traces of Ti02, Zr02 and V205. Since the reaction is exothermic reversible, it is essential to carry out the reaction in various type of autothermic reactors with external heat exchange and quench type cooling and/or internal heat exchange in the view of opposing reaction rate end equilibrium requirements. Analysis and simulation of ammonia synthesis rea-ctor is very important. 'or determining suitable conditions for its operation at high conversion. Van Heerden, and Baddour and co-workers have presented the stability analysis of simplified single bed models. Shah has used a two bed..............