Statistical modelling of ammonia absorption in an acid spray scrubber

• Simplified models aid in scrubber design and operation at animal facilities.
• A model to predict ammonia removal efficiency of an acid spray scrubber was set up.
• Inlet NH3 concentration and droplet size have greatest effect on efficiency.
• Increased retention time and liquid flow rate have positive effect on efficiency.
• Models showed good predictive ability based on residual and power analysis.

The use of acid spray wet scrubbers for recovering ammonia (NH3) emissions is promising due to its high NH3 removal efficiency, simplicity in design, and minimal pressure drop contribution on fans. An experimental study was conducted to evaluate the performance of a lab-optimised acid spray scrubber using simple modelling tools. Important parameters that significantly affect scrubber efficiency were identified as inlet NH3 concentration, air retention time, Sauter mean diameter of spray droplets, and liquid flow rate. Two statistical models (additive and multiplicative models) were developed from the experimental data using regression analysis of scrubber efficiency as a function of the significant operating parameters. The additive model had better performance accuracy with an R2 value of 0.93, MSE of 0, RMSE of 0.06, and MAPE of 8.89%. Both models have good predictive ability based on residual analysis, power analysis, and cross-evaluation. This study was able to develop simplified models to aid in predicting NH3 removal efficiency of an acid spray scrubber, which can be installed at animal facilities for NH3 abatement.