燃煤烟气中氮氧化物以NO为主，其大量排放对自然环境和人类健康危害极大。针对低温等离子体（Nonthermal plasmas,NTPs）技术脱除NO效率低、能耗高的问题，系统研究不同气体流量、O2含量和NO初始浓度等因素对低温等离子体过程中NO去除效果的影响。结果表明，在N2/NO混合气体条件下，NO脱除率为90%、气体流量为5 L/min对应的单位能耗NO处理量最高，为4.17 g/kWh〖JP〗。O2的存在对于NO转化具有一定抑制作用，且在高O2含量下，升高电源的输出功率反而不利于NO脱除。研究发现，O2体积分数6%条件下，NO脱除率低于46%，对应单位能耗NO处理量仅为2.29 g/kWh。为实现有氧条件下NO的低能耗高效脱除，在低温等离子体反应段前添加活性炭吸附氧化工艺。首先利用活性炭对高浓度NO进行吸附氧化预处理，降低进入低温等离子体反应器中的NO浓度；随后，采用低温等离子体技术对剩余NO进行深度氧化处理，实现NO的低能耗高效脱除。结果表明，采用该耦合工艺，活性炭吸附氧化NO去除率达55%以上，控制低温等离子过程输出功率为9.66 W，NO整体脱除率达90.5%，单位能耗NO处理量达13.58 g/kWh。与仅采用低温等离子体过程相比，该耦合工艺对应的单位能耗NO处理量提升了近5倍，具有良好的应用前景和社会经济价值。

NO is the nitrogen oxide in coal-fired flue gas,of which the tremendous emission generates great damage on natural environment as well as human health. To overcome the problems of low efficiency and high energy consumption of NO removal by Nonthermal plasma (NTP) technology,the influences of different gas flow rate,O2 content,and initial NO concentration on the NO removal in the low-temperature plasma process were systematically investigated. The results show that the highest NO treatment capacity of per unit energy consumption is 4.17 g/kWh,corresponding to the NO removal rate of 90% and the gas flow rate of 5 L/min under the N2/NO gas mixture. The presence of O2 has an inhibitory effect on the conversion of NO. Moreover,improving the output power is disadvantageous to NO removal conversely at high O2 concentration. It is found that under the 6% O2 concentration condition,the NO removal rate is less than 46%,the corresponding treatment capacity of NO per unit energy consumption is only 2.29 g/kWh. To achieve high efficiency and low energy consume of NO removal at oxygen atmosphere,the activated carbon adsorption and oxidation process was added before the NTP process. Firstly,activated carbon was used to adsorb and oxidize NO,reducing the high NO concentration entering into the NTP reactor. Then,the residual NO was deeply oxidized by low-temperature plasma technology to achieve the efficient removal of NO with low energy consumption. The results show that the removal rate of NO by activated carbon adsorption and oxidation is more than 55% using coupled process. Controlling the NTP output power to be 9.66 W,the overall removal rate and treatment capacity of NO for coupled technique can be reached as high as 90.5% and 13.58 g/kWh,respectively. Compared with individual NTP process,the treatment capacity of NO per unit energy consumption corresponding to this coupling process has been increased by nearly five times,which has a good application prospects and socio-economic value.

0 引言

1 试验

   1.1 试验系统

   1.2 计算方法

2 试验结果与讨论

   2.1 气体流量对NO去除率及单位能耗处理量的影响

   2.2 氧体积分数对NO去除率的影响

   2.3 N2/O2条件下氧体积分数及功率对产物组成的影响

   2.4 不同初始NO体积分数对其去除率的影响

   2.5 活性炭对NO吸附氧化效果的影响

   2.6 低温等离子体前置活性炭吸附氧化耦合工艺对NO去除效果

3 结论