A simplified computational approach to hydrodynamic behavior of an ammonia-phosphoric acid mixing system within a tubular reactor

This study employs a simplified computational approach to investigate the hydrodynamic behavior within tubular reactors for Monoammonium Phosphate (MAP) fertilizer production. The main objective is to understand the impact of key parameters, including volumetric flow rates, fluid properties, reactor geometry, operating conditions, and distinct inlet configurations, on reactant distribution and mixing efficiency. Two primary cases were investigated: Case 1, where ammonia was injected coaxially with phosphoric acid introduced via a side inlet; and Case 2, where phosphoric acid was injected coaxially with ammonia entering through a side inlet. A significant effect of the reactant dosing location into the reactor was observed and was more effective in Case 2 with respect to the MAP formation reaction. High ammonia and acid velocities were obtained at the constriction (nozzle) in the reactor tube. The nozzle design caused a uniform discharge of the reactants to the further part of the reactor, where there was good mixing of the components, comparable to Cases 1 and 2. These simulations provide a practical tool for engineers to adjust design parameters, optimize residence times, and ensure consistent product quality, facilitating both laboratory and industrial-scale applications. Future studies should incorporate chemical species transport and reaction kinetics to further enhance model accuracy and provide a more comprehensive understanding of the reaction process. Ultimately, this research offers valuable insights for informed decision-making in optimizing tubular reactor design and operation, leading to improved MAP production efficiency and product quality.