Numerical simulation and experimental studies on the ammonia absorption process by water injection in reaction effluent air cooler system

Abstract

Water injection to dissolve ammonium salts and absorb crystallized gas components is an essential method to protect hydrogenation equipment against corrosion in refineries. The complex water-injected absorption process of NH3 is achieved by the Euler-Lagrange method, and in-situ experiments conducted under various operating conditions are utilized to validate it. The results indicate that the increase in velocity will raise the mass transfer coefficient slightly, however, the contact time between gas and liquid is shortened and decrease the efficiency of ammonia absorption. The area of gas–liquid contact increases as water flow rate rises, increasing the efficiency of ammonia absorption. The ammonia absorption efficiency initially increases and subsequently decreases when the water temperature rises from 290 K to 310 K. In addition, the ammonia absorption efficiency for the forward injection way is 10 %-15 % higher than that of the backward injection way at the same inlet velocity. The results of this work can provide theoretical guidance for the design optimization of the water injection process in refineries.