Design and modelling of a novel dual-type reactor for ammonia production

The ammonia production is one of the most essential petrochemical processes. This article focuses on the heart of this process, the ammonia synthesis reactor. First, an industrial fixed bed reactor for ammonia production, designed by Kellogg's company, is modeled and simulated. Next, a dual-type reactor is proposed to overcome the equilibrium limitations of the exothermic ammonia synthesis reaction. The rules of similar industrial reactor design methodology and the Particle Swarm Optimization (PSO)- Differential evolution (DE) optimization method are used to obtain the reactors' best design parameters and operational conditions. The length of the reactors, the number of tubes in each reactor, the diameter of the gas-cooled reactor, and the cooling water temperature are considered decision variables for the optimization. These variables are optimized to maximize the ammonia yield. Furthermore, the effect of co-current and countercurrent flow patterns on the efficiency of the proposed reactor is investigated. A one-dimensional pseudo-heterogeneous model is applied to simulate the reactor at steady-state conditions. The governing differential equations form a boundary value problem and are solved by the shooting method. The results show that the developed dual-type reactor satisfies all the design limitations. Furthermore, this novel reactor increases the ammonia production capacity by 574 tons per day compared to the conventional Kellogg reactor.