The absorption of dilute nitrogen oxides into aqueous media using a structured packing

Pilot-plant experiments on the aqueous scrubbing of dilute NO_x gas mixtures at atmospheric pressure have been conducted using an absorber filled with high efficiency packing. NO_x removal efficiencies of 10 to 70% were obtained for gas mixtures of 125 to 2500 ppm N _x; the NO_x species were predominantly NO₂* (NO₂ and N₂O₄). The 0.102-m-id absorber was packed with Koch Sulzer packing (Type BX) to a depth of 0.8 m.

The experimental results are in good agreement with a model based on the absorption/hydrolysis of N₂O₄ and NO₂. A liquid phase mass transfer coefficient of - 4 4.982 X 10^-4 m/s was calculated by data analysis. The value of this coefficient is reasonable compared to mass transfer coefficients of other packings. The gas-liquid interfacial area of the packing was determined to be 690. M^-1. This interfacial area was found to be inde pendent of the liquid rate which is in agreement with other studies.