Mass transfer coefficient of ammonia in liquid swine manure and aqueous solutions

Correlations for the overall mass transfer coefficient of ammonia with liquid properties and environmental conditions were developed for ammonia volatilizing from aqueous solutions as well as from liquid manure in a convective emission chamber where the air velocity, temperature, turbulence, and relative humidity were precisely controlled. The mass transfer coefficient was observed to increase with increasing air velocity and liquid temperature but decreased with increasing air temperature. Analysis of air-liquid temperature combinations on the influence of mass transfer coefficient using the correlation equations showed that a lower air temperature (15 degrees C) and higher liquid temperature (35 degrees C) combination is more likely to result in higher ammonia volatilization rates compared to other temperature combinations. On the other hand, a higher air temperature (35 degrees C) and lower liquid temperature (15 degrees C) combination would result in lower ammonia volatilization rates for different air velocities. The mass transfer coefficient for ammonia was muchmore sensitive to changes in air velocity at lower compared to higher velocity ranges. Similar sensitivity responses were obtained for both air and liquid temperature ranges. (C) 1999 Silsoe Research Institute.