Research On Application Of Long Path Differential Optical Absorption Spectroscopy For Online Monitoring Of Ammonia Emissions

Nowadays, many harmful gas such as ammonia and so on have become a main source of atmosphere pollution in pharmaceutical, chemical and electric power industry.Water pollution and solid pollution, etc have emerged with the snow and rainfall under the influence of air pollution, which make us face a serious global environmental problem. In recent years, the haze has become a hot issue of public concern, While the "ammonia" that has already reached a consensus in the scientific community has not been included in the emission monitoring. After controlling sulfide and nitrogen oxide emissions, the effectiveness of governance haze will be greatly reduced, if ammonia emissions have been perfectly controlled. At present, an experiment of a single and real-time monitoring for ammonia emissions has been carried out to improve the effectiveness of governance haze, the role of ammonia is further comprehended in the formation of haze through data obtained from experiments.In this paper, differential optical absorption spectroscopy was used for the on-line monitoring of ammonia. Firstly, the background of the research and the related technologies of the ammonia concentration measurement in the domestic and overseas were analyzed and introduced; Secondly, the basic principle and difficulties of differential optical absorption spectroscopy were analyzed and researched. Then the gas absorption of long path ammonia emissions monitoring was designed and manufactured to build experimental system. The various components of the experimental system including optical systems, long path gas absorption pool, gas distribution systems, data processing and acquisition systems were detailly introduced. And then, the absorption band of ammonia was determined according to the absorption characteristics of ammonia gas and the experimental conditions in the laboratory; The least square was applied to analyze the experimental data without any processing, the error between the inversion ammonia concentration and the standard concentration was calculated; Wavelet transform were adopted to make the experiment denoise, the error between the inversion ammonia concentration obtained by new data and the standard concentration was calculated, inversion results were compared to gain the wavelet of closer to the standard value and smaller error; Comparing two results of the inversion ammonia concentration,we can draw a conclusion that the wavelet processing result is better. Finally, the researchresults show the design of gas absorption pool and experimental system can meet the long path of ammonia absorption characteristics of the study and obtain a better experimental effect, and experimental methods have the site operational.