Hydrodynamics and mass transfer simulation of wastewater treatment in membrane reactors Original Research Article

This work presents CFD simulation of hollow-fiber membrane reactors (HFMRs) for separation of ammonia from aqueous solutions. Simulations are carried out to predict ammonia transport in a membrane reactor. Mass transfer and hydrodynamics of the system were investigated through solving conservation equations. The conservation equations solved here were the Navier–Stokes and continuity equations. Finite element analysis was applied for numerical solution of the system equations. UMFPACK was chosen as linear solver and showed good convergence. The influence of effective parameters on the mass transfer and hydrodynamics of the ammonia removal was investigated. Simulation results showed that total flux of ammonia decreases sharply in the region near the membrane inlet. Hydrodynamic investigations also revealed that velocity reached fully developed after a short distance from the reactor entrance. The results of this work confirmed that feed and solvent velocities are the most important parameters in the removal of ammonia. It is also indicated that the numerical procedure is useful and capable to predict the performance of hollow-fiber membrane reactors for separation of ammonia from aqueous solutions.