Ammonia absorption in a vertical contact spray tower at low ammonia partial pressures

Ammonia emission from livestock buildings has been one of the major environmental concerns. Alternative methods for emission reduction are needed. The use of a diffusion-coagulation-separation (DCS) system as an air-cleaning method has shown promising results in reducing dust emission from livestock facilities. The NH ₃ removal efficiency of a DCS system with a wet scrubber section measuring 32 cm in diameter x 132 cm in height was evaluated. The NH ₃ mass transfer was calculated from the NH ₃ concentrations measured from both air and water streams. The effects of number of nozzles (1, 2, and 3 in series), retention time (0.8, 1.1, 1.7, 2.8, and 8.1 sec), and NH ₃ inlet concentration (5, 15, and 50 ppm in volume) on performance were determined. The DCS system was found to effectively remove as high as 90% of NH ₃ from the air stream when three nozzles were used in series and when the retention time of the air was 8.1 sec. Both increasing the number of operating nozzles and increasing retention time improved NH ₃ removal efficiency. The NH ₃ inlet concentration was found to have an effect on removal efficiency. The removal efficiency was highest when inlet concentration was 5 ppm.