科研之友
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摘要
Ammonia (NH3) emissions from animal facilities represent a significant health and environmental concern. Acid spray scrubbers are promising for the recovery of NH3 emissions from animal facilities due to their low pressure drop and additional benefit of fertilizer production through NH3 absorption by the dilute acid scrubbing solution. A spray scrubber for deep-pit swine finishing facilities was developed based on an optimized spray scrubber module with a round geometry and a diameter of 35.56 cm. A hollow-cone AAP01 nozzle with a larger orifice diameter of 200 mu m was used to spray I% (w/v) sulfuric acid solution into the scrubber. The use of this nozzle required three stages of spray, which reduced NH3 by 82% to 99% for inlet NH3 concentrations of 30 and 20 ppm(v), respectively. The scrubber was evaluated in four seasons at a commercial swine-finishing barn with deep-pit manure storage in Raymond, Ohio. An average NH3 removal efficiency of 88% was observed. The seasonal evaluations showed the lowest NH3 concentration (5.4 ppm(v)) occurred during spring when mixed natural ventilation and pit fan ventilation were used, while the highest NH3 concentration (25.4 ppm(v)) was observed during winter when minimal ventilation was used. It was observed that inlet NH3 concentrations negatively affected the scrubber efficiency. Water and acid consumption rates were considerably low for all seasons, with an average of 2.5 and 0.17 L d(-1), respectively. Energy consumption, mainly by the pump, averaged 0.56 kWh per day. A preliminary economic analysis estimated a five-year break-even period for operation of spray scrubbers at six pit exhaust fans, assuming minimal maintenance, low depreciation, and no significant additional energy cost for the ventilation fans.
- 出版日期2014-6
