Simultaneous Removal of Extremely High or Low Concentration NOx, SOx and Particulate Using Plasma Emission Treatment Combined Concentrating Technology

针对电厂和锅炉排放的低浓度(30~200ppm)废气，在前人研究的低温等离子体化学复合法的基础上，开发了同时脱除颗粒物、NOx和SOx的新技术。该系统由两级干法等离子体氧化工艺和湿法化学氧化工艺组成。另外，在300℃的高温气体中注入活化空气，将NO氧化为NO2的间接等离子体法非常有效，需要等离子体处理的气体流量降至一次气体流量的1/5以下。这种间接等离子体技术进一步从实验室实验扩展到中试规模的NOx和SOx处理系统，锅炉排放的NOx和SOx处理速度为450~1,470 Nm~3/h，适用于城市燃气和重油燃烧。气体燃烧的NOx脱除效率超过90%，但由于缺乏臭氧c…，石油燃烧的NOx脱除效率略低。与目前的脉冲电源相比更加集中。SO2的脱除效率在85~90%之间。对洗涤器出水水质进行了调查，证明其已处理完毕。此外，发展了等离子体浓缩技术，将低浓度气体的大流量转化为高浓度的小流量。也就是说，低浓度烟气首先在分子筛13X颗粒或疏水分子筛蜂窝等吸附材料上长时间吸附，然后在吸附材料上施加脉冲等离子体，在几分钟内将吸附的NO解吸。然后，采用等离子体-化学复合法对低流量高浓度NO进行处理，减小了等离子体反应器的体积。经鉴定，反应副产物含量低。此外，还开发了一种处理2,500ppm以上NOx的新工艺，利用氮等离子体干法一步法将NO直接还原为N_2。氮氧化物浓缩技术和氮等离子体的结合能够实现非常经济和有吸引力的系统，并可用于许多工业应用。较少

Based on nonthermal plasma chemical hybrid process developed previously, simultaneous removal of particulates, NOx and SOx was developed for treating the low concentration (30〜200 ppm) emission from the power plant and the boiler application. This system consists of two-stage dry plasma oxidation process and wet chemical process. In addition, the indirect plasma method which NO can be oxidized to NO_2 extremely effective by injecting the activated air into the high temperature gas in the range of 300℃, which the required gas flow rate to be treated by the plasma was reduced to less than 1/5 of the primary gas flow rate. This indirect plasma technique was further expanded from the laboratory experiment to the pilot-scale NOx and SOx treatment system from the boiler emission in the range of 450〜1,470 Nm^3/hr for both city gas and heavy oil firings. The NOx removal efficiency for gas firing exceeds 90% but NOx removal efficiency for oil firing was somewhat lower due to the lack of ozone c … More oncentration with the present pulse power supply. The removal efficiency of SO_2 was in the range of 85〜90%. The quality of treated water from the scrubber was investigated and proved to be disposed. Moreover, the plasma concentration technique was developed to convert the large flow rate with low concentration gas to small flow rate with high concentration. That is, the low concentration flue gas was first adsorbed on the adsorbent materials such as molecular sieve 13X pellets or hydrophobic zeolite honeycomb for a long time and the pulsed plasma was applied to the adsorbent material to desorb the adsorbed NO within few minutes. Then, the high concentration NO with low flow rate was treated by the plasma-chemical hybrid process, which was able to reduce the size of the plasma reactor. Reaction byproducts were identified to be low. Moreover, a new technology for treating more than 2,500 ppm NOx was developed to reduce NO directly to N_2 using the nitrogen plasma in dry one-step process. The combination of NOx concentration technique and nitrogen plasma is able to achieve an extremely economical and attractive system and can be used for many industrial applications. Less