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Title: Semi-mechanistic modelling of ammonia absorption in an acid spray wet scrubber based on mass balance

Author
item HADLOCON, LARA - The Ohio State University
item ZHAO, LINGYING - The Ohio State University
item WYSLOUZIL, BARBARA - The Ohio State University
item Zhu, Heping

Submitted to: Biosystems Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2015
Publication Date: 12/26/2015
Publication URL: http://handle.nal.usda.gov/10113/61864
Citation: Hadlocon, L., Zhao, L., Wyslouzil, B., Zhu, H. 2015. Semi-mechanistic modelling of ammonia absorption in an acid spray wet scrubber based on mass balance. Biosystems Engineering. 136:14-24.

Interpretive Summary: High levels of anthropogenic ammonia (NH3) emission to the atmosphere from animal feeding operations have been linked to respiratory and cardiovascular health issues in humans and reduced productivity levels of farm animals. The negative impacts of NH3 emission urge the need for effective and economically feasible control technologies for animal feeding operations. In this research, a semi-mechanistic model was developed to correlate NH3 absorption performance of counter-current acid spray scrubbers with their primary operation parameters. Test results demonstrated the use of this semi-mechanistic modeling approach optimized the acid spray scrubber design to further increase the ammonia absorption efficiency, and also helped predict the absorption efficiency of the optimized acid spray scrubbers operated under different conditions. Thus, this research has provided an innovative approach to improve spray scrubber design and operation for mitigation of NH3 emissions from mechanically-ventilated animal facilities.

Technical Abstract: A model to describe reactive absorption of ammonia (NH3) in an acid spray scrubber was developed as a function of the combined overall mass transfer coefficient K. An experimental study of NH3 absorption using 1% dilute sulphuric acid was carried out under different operating conditions. An empirical correlation for K with respect to droplet Sauter mean diameter, liquid flow rate, and inlet NH3 concentration was developed with an R2=97.12%. Air velocity positively correlated with K at 30 ppmv, but did not exhibit an effect at higher concentrations (165-300 ppmv), while liquid flow rate showed the greatest effect on K. The K correlation was incorporated in the performance model to construct a semi-mechanistic model with high prediction accuracy (R2=97.60%, MSE=0, RMSE=0.03, MAPE=5.24%). This generalized performance model can be used to predict NH3 removal efficiencies of our optimized acid spray scrubber under various operating conditions at animal facilities.