The mixing characteristics of the urea reactor of Chungju Fertilizer Plant was studied by the instant injection of C¹⁴O₂ radioactive tracer at the feed and analyzing the radioactivity at the outlet.
The experimental results were compared with that of theoretical models and the results were agreed well with the model of 90 % complete mixing succeeded by 10 % plug flow with diffusion and 30 % recirculation. The average residence time obtained is 33.0 minutes.
The rates of reactions, NH₃ + CO₂ to carbamate and carbamate to urea, were compared by analyzing the radioactivities of carbamate and urea, separately. The reaction time obtained by this method agrees well with the previous study.