Basic Research For Improved Jet Technology On The Selective Non-catalytic Reduction

The energy consumption of China is increasing nowadays, and the problem of air pollution which caused by nitrogen oxides release is becoming more and more serious, especially the problem of acid rain is still deteriorating. Developing with the latest environmental requirements, NOx control technologies are imminent. Selective Non-Catalytic Reduction (SNCR) of NOx is suitable for China’s national conditions because of its low cost. So far the main reason for lower NOx removal efficiency in the SNCR applications of large boiler is the limit of mixing factor.In this paper, the mixing factor of SNCR technology was in-depth analysis, then proposed a denitration program which about the improved jet technology, and the basic research which corresponds to the content was studied in order for the implement of this program. Response to this improved jet technology, the flow and evaporation characteristics of droplet were mainly analysis in this paper.First, this paper studied the formation law of jet droplet. Then it was compared by changing the aperture of nozzle, the ejection speed and direction. Meanwhile, both the size and speed of droplet were also analysis at different falling distance, and then their trends and relationships were summarized. In addition, the interaction between the size and limiting speed of droplet which was under high temperature gas stream was calculated by using the model of falling droplet.Then, the study of deformation characteristics of suspended droplet was done with organic glass tube and blower. The relationship between the size and the speed of droplet was obtained under forced airflow. And also the deformation law was found during the experiment. These results can provide a reliable experimental data for the research of numerical simulation.Finally, the evaporation characteristics of droplets were compared under various ambient temperatures, initial droplet diameters, quality concentration of urea aqueous solution and forced airflow in a quartz tube reactor. Results show that the urea aqueous solution droplet revealed different evaporation behaviors when compared with water droplet. The microexplosion phenomenon will be occurred during the evaporation of urea aqueous solution droplet. Most of all, this phenomenon will bring significance to improve the mixing condition of droplet in the boiler.