介质阻挡放电脱硫脱硝过程特性

Characteristics of NO and SO_2 removal in dielectric barrier discharge plasma process

氮氧化物和硫氧化物在介质阻挡放电(DBD)反应器中的脱除率与很多因素有关,如氧气含量、相对湿度和烟气中SO_2的初始浓度等。本文通过改变SO_2初始浓度、氧气含量和相对湿度来研究脱除氮氧化物和硫氧化物过程中的反应机理。结果发现,在N_2/SO_2/NO体系中SO_2初始浓度在较大范围内变化对NO和SO_2的脱除率影响很小;而N_2/NO/SO_2/H_2O体系中相对湿度的增加对SO_2的脱除的影响较NO的影响大,增加烟气中相对湿度能明显减少SO_2在烟气中的浓度;N_2/NO/SO_2/O_2体系中氧气的增加对SO_2的脱除效率影响不明显,但能促进NO氧化成NO_2或者其他的氮氧化物,同时,在一定的条件下,也能加速NO的生成。探讨NO和SO_2的反应机理,发现SO_2的反应主要与OH和水合电子有关,而NO的反应与O、N等活性基相关。

There are many factors which affect the removal rate of nitrogen oxides and sulfur oxides in the reactor energized by dielectric barrier discharge （DBD）, such as oxygen content, relative humidity and SO2 initial concentration in the flue gas. In this paper, SO2 initial concentration, oxygen content and relative humidity in the flue gas were changed to study the reaction mechanism of NO and SO2 in the dielectric barrier discharge plasma process. The results showed that the initial concentration of SO2 varying even in a larger range had little effect on the removal rate of NO and SO2 in the N2/SO2/NO system. Increasing the relative humidity in the N2/NO/SOe/H2O system could reduce the concentration of SO2 significantly in the flue gas, and its influence on SO2 is more obvious than that on NO. In the system of N2/NO/SO2/O2, the influence of oxygen content on the removal rate of SO2 was not obvious, but more obvious on the reaction of NO in the DBD process. Adding O2 could promote the conversion of NO into NO2and other nitrogen oxides. On the other hand, the generation of NO was also accelerated under some circumstances. Analysis of the reaction mechanism based on the experiment demonstrated that the SO2 reaction was mainly related to the active free radicals produced in the DBD process, OH and eaq, while the NO reaction was related to O and N.