选择性非催化脱硝反应非等温过程的实验研究

Experimental Study on NO_x Removal With Selective Non-catalytic Reduction in Non-Isothermal Process

建立了完善的选择性非催化脱硝(selective noncatalytic reduction,SNCR)反应的非等温实验系统,探讨了初始反应温度、氧气含量和还原剂与烟气流速比对非等温SNCR过程的影响,随初始反应温度升高,脱硝效率先升高再减小,在1 273~1 323K范围内,脱硝效率达到最大70%以上;氧气含量的增加在温度低于1 250 K时可以提高脱硝效率,在温度高于1 250 K时会导致脱硝效率降低,氧气浓度为2.5%时,最大脱硝效率可以达到85.4%;在温度低于1250 K时,反应处于动力控制区,还原剂与烟气流速比的增加使脱硝效率降低,在温度高于1 250 K时,反应处于混合控制区,流速比的增加使脱硝效率升高,流速比为5.0时最大脱硝效率可以达到79%;文中非等温SNCR的实验结论有助于工程实际中的选择性非催化法脱硝系统的优化。

In order to study the influence of initial temperature, oxygen content, and flow ratio of reductant and flue gas on selective non-catalytic reduction denitration (SNCR) systematically, a non-isothermal SNCR system was constructed. With a peak value of 70% in temperature range of 1273 and 1323K, the NOxreduction efficiency goes up and then down with temperature increasing. When the temperature is lower than 1250K, NOxreduction efficiency increases with the oxygen content increasing. However, when the temperature is higher than 1250K, NOxreduction efficiency decreases with the oxygen content increasing. When the oxygen content is 2.5%, the maximum denitration efficiency is approximate 85.4%; When the temperature is lower than 1 250 K, the denitration reaction is located in the temperature control zone, and the NOxreduction efficiency decreases with the increase of flow ratio of reductant and flue gas. However, when the temperature is higher than 1 250 K, the denitration reaction is located in the diffusion control zone, and the NOxreduction efficiency increases with the flow ratio increasing. When the flow ratio is 5.0, the maximum denitration efficiency is about 79%; The research results is beneficial to the system optimization of SNCR in practice. © 2016 Chin. Soc. for Elec. Eng.