A great deal of attention has been focused on discharge plasma as it can rapidly decompose N_2O without additives,which is not only a kind of greenhouse gas but also a kind of damages to the ozone layer.The thermal equilibrium plasma is chosen to combine with catalysts to decompose N_2O,and its characteristics are analyzed in the present paper.The results indicate that NO and NO_2 were formed besides N_2 and O_2 during N_2O decomposition when N_2O was treated merely by discharge plasma.Concentration of NO declined greatly when the discharge plasma was combined with catalysts.Results of Raman spectra analysis on CeO_2,Ce_(0.75)Zr_(0.25)O_2and Ce_(0.5)Zr_(0.5)O_2 imply that the products selectivity has been obviously improved in discharge plasma decomposing N_2O because of the existence of massive oxygen vacancies over the composite oxide catalysts.
By adopting the optical multi-channel analyzer combined with fourier transform infrared（FTIR） spectrometer,the dominant free radicals and products generated by arc discharge were measured and studied,and the main plasma chemical reaction process in the nitric oxide production by arc discharge was identified.Plasma chemical kinetic curves of O,O2,N2,N and NO were simulated by using CHEMKIN and MATLAB.The results show that the main plasma chemical reaction process of nitric oxide production by arc discharge is a replacement reaction between O and N2,where NO can be generated instantaneously when discharging reaches stable.
This study conducted experiments on producing inhaled medical nitric oxide(iNO) by pulsed arc discharge in dry and clean air under different discharge current.The concentration of NO and NO 2 produced by air discharge,as well as the change of the ratio of NO 2 /NO under different discharge current were investigated.Through the analysis of plasma emission spectrum,the relationship between discharge current and arc plasma temperature was studied.The results indicate that,as discharge current increases,the arc plasma temperature increases,which then leads to the increase of NO concentration,the decrease of NO 2 concentration,and the rapid decrease of the ratio of NO 2 /NO.When the plasma temperature is 9000 K,the ratio of NO 2 /NO is approximately 60%,while when the plasma temperature varies between 10550 K and 11300 K,the NO 2 /NO ratio is within the range of 4.2% to 4.6%.
一氧化氮(NO)是燃煤锅炉烟气中的主要污染物,因其是酸雨和光化学烟雾的前体物而受到广泛关注。采用作为氧化剂开展了其对模拟烟气中NO的氧化去除研究,并分析了氧化脱硝反应的热力学过程以及NO从气相主体到液相主体的传质过程。结果显示:以为氧化剂氧化NO的总反应吉布斯自由能为-659.69 k J·mol^(-1),小于零,说明该反应是自发过程;气液传质分析表明NO气体的吸收传质速率主要由液膜控制。实验采用添加Fe(Ⅱ)ED-TA的方法增大化学反应对液相传质速率的放大系数,致使液膜传质阻力减小,从而使NO的去除率从30%提高至91.6%。该结果为湿法氧化脱硝工艺的后续研究和应用提供了理论参考和技术支持。
