Optimal Design of Ammonia Synthesis Reactor for a Process Industry

Abstract

Ammonia synthesis is a crucial section of ammonia and urea plant. Many industries are facing a challenge of efficient ammonia production every day. In this study, steady state one dimensional pseudo-homogeneous models of an axial flow industrial catalytic packed bed ammonia converter have been developed. The converter is a vertical two catalytic bed reactor with varying volumes of catalysts. Required industrial data for the design were collected from a fertilizer industry in Bangladesh - and the Halder Topsoe process was followed. Differential equations of the - mathematical model were solved using Runge-Kutta-Fehlberg (RKF45) method by Polymath solver software. For a 23.8% single-pass conversion and for a 3 m inside diameter vessel, a total of 22.5 (15 + 7.5) m catalyst bed was required. Pressure vessel wall and head thickness were found 112 mm and 62 mm respectively. Skirt support was selected and the thickness was calculated 12 mm. Pressure drop along the length of the bed was found 2.55 atm. Finally, parameters of the optimized model were compared with the real industrial data and found quite satisfactory.