| Nitrogen oxides (NO_x) as an important cause of air pollution are taking more attention. At the same time, along with the rapid development of chemical, paper production, paint, textile and other industries, volatile organic compounds (VOCs) is getting worse at environmental pollution. Non-thermal plasma technology as an emerging contaminant removal technique has many advantages: a small footprint, fast response and no secondary pollution etc. This paper is composed by several parts: literature review, reactor system design, experimental discussion, conclusions. The literature review describes the application and research status of several VOCs and nitrogen oxides removal technology and non-thermal plasma, detailing the development and inadequate of non-thermal plasma technology in the field of environmental protection. The part of reactor system designs the line-board and board-plate dielectric barrier discharge reactor based on the extensive research literature, improving the traditional small reactors, create a larger reactor that can handle a large number of polluting gas. Take the experiment under laboratory conditions to remove the nitrogen oxides and volatile organic compounds evaluating the reactor on the base of energy cost.By the experiments, we find:(1) when little oxygen contented in the flue gas (oxygen content less than 10%), the oxygen will inhibit the removal of NO in line-board reactors, when the oxygen content continues to rise, it will facilitate the removal of NO; In the board-plate reactors, due to higher operating voltage, the presence of oxygen has been promoting the removal of NO. In higher oxygen content conditions, high energy electrons collide with oxygen molecules and form the O,03 ion that take predominant role in the removal of NO. (2) Operating voltage has a significant impact on the efficiency of removal of pollutants in the same reactor. Because the reactor has a certain discharge voltage, as the increase of the applied voltage, it will increase the efficiency of contaminant removal. Increasing the voltage has little effect on the removal of NO in energy consumption. In the removal of VOCs, the higher voltage will increase the energy consumption, because the VOCs and generate could reactive group of CO, CO2, H2O and other molecules that can react with energetic electrons increasing energy consumption. (3)An increase of line-board type reactor pole spacing will reduce the NO conversion rate, increase energy consumption, in a parallel plate reactor, pole spacing increases will correspondingly reduce NO conversion. When the pole spacing is 10mm, the conversion rate is 92％, and the conversion rate is reduced to 62％when it is 20 mm, but the energy consumption is different with line-board type reactor, it will decrease if the pole spacing increased, because the board-plate reactor need higher voltage to discharge, minimum voltage is 23.17 kV, maximum discharge voltage is up to 32.19 kV (line-board type reactor maximum voltage is only 26.4 kV). In VOCs treatment experiment, there is no oxygen presented, the two type reactors showed the same law: with the increase of pole spacing the removal efficiency increases, energy consumption increases. (4) With the increases of relative humidity,the NO removal efficiency increases in the experiment reducing the generation rate of NO2, That illustrated that small amount of water steam in the flue gas could increase the conversion rate of NO place and decrease the generation rate of NO2. (5) In the experiments, two dielectric barrier discharge reactor has been compared, line-board reactor has high energy efficiency, and the board-plate reactor could remove more NO and VOCs. The improved reactor has better removal efficiency and lower power consumption. Improving the electrode geometry could increase reactor performance. |
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