Optimization of a wet scrubber with electrolyzed water spray—Part I: Ammonia removal

Abstract

Electrolyzed water (EW) is an effective disinfectant with a wide range of pH. EW in acid range was proved to be an ammonia absorbent which make it valuable for wet scrubbers used in animal feeding operations (AFOs). This study aimed to optimize the design and operating parameters of a wet scrubber with EW spray for ammonia removal, based on the size distribution of droplets, the property of EW and the reduction efficiency of ammonia. The optimized parameters included droplet size, nozzle flow rates, pH and available chlorine concentration (ACC) of EW, nozzle number at single stage, stage number, initial ammonia concentration and air speed in the duct. The ammonia removal efficiency increased with the decrease of droplet size and the increase of flow rate. The pH values of EW showed significant influence on ammonia removal efficiency (P ˂ 0.05), while ACC of the EW showed no significant influence (P > 0.05). For inlet ammonia concentration of 70 ppm with one and three spray stages, the wet scrubber with EW (pH = 1.35) spray was able to reduce 55.8 ± 4.3 % and 97.2 ± 3.0 % of ammonia, respectively, when the nozzles with 0.9 mm orifice diameter operated at a flow rate of 1.20 L min-1. Response surface analysis showed that orifice diameter, nozzle flow rate, and their combination were all significant factors impacting ammonia removal efficiency for both pH =1.35 and 5.50 at a 95% confidence level. Optimal ammonia removal efficiency was obtained at orifice diameter 0.9 mm and flow rate 1.20 L min-1 within the selected range. The results of this study demonstrated that wet scrubber with EW spray could be a very effective and feasible ammonia mitigation technology for animal feeding operation. Implications: It is difficult to effectively reduce ammonia emitted from the animal feeding operations (AFOs). Both the acidity and disinfection effects of electrolyzed water (EW) make it a potential absorbent used for spray in wet scrubber to reduce the ammonia and microorganisms. Based on some preliminary field test results, lab tests were conducted to optimize the design and operation parameters of a wet scrubber with EW spray to improve the ammonia removal efficiency. A better understanding of the application and influence factors of the wet scrubber with EW spray can contribute to effective mitigation of ammonia emission from animal houses and improve the atmosphere air quality.

Optimization of a wet scrubber with electrolyzed water spray—Part II: Airborne culturable bacteria removal

“…A laboratory-scale wet scrubber was designed, and its detailed description was given in the companion paper by Li et al (2019). Full-cone nozzle with orifice diameter of 0.9 mm at flow rate 1.2 L min −1 was chosen in this study according to the finding of Zheng et al (2016b) that sprayed SAEW aerosols with Dv(50) (the diameter smaller than which are the diameters of 50% of spray droplets present in volume) of 60-90 μm could achieve high efficiency of airborne CB reduction in animal houses.…”

Technical and economic assessment of bio-syngas production from biomass and its application in natural gas pipelines

“…The company SULFURIX TM manufactures an industrial two-stage water scrubber that can easily reduce the sulphur content of the syngas to 1 part per million (ppm). Furthermore, the water scrubber also meets the industrial level requirements for ammonia absorption, with a removal e ciency of up to 99.9% [17]. The water scrubber can even remove 100% of the small amount of solid particles [18].…”