Treatment of NOx by Discharge Plasma

设计了三种NOx处理反应器模型，并对其基本放电特性、臭氧生成和NOx去除进行了研究。所制备反应器的放电应用：1)水面电晕放电，2)两级电晕放电，3)多板电极阻挡放电。在水面电晕放电中，锯边型放电电极在自由基生成和柴油机尾气NOx处理试验中表现出较好的特性。设计了带水放电电极的电除尘器作为同时除硝和除尘的反应器。电晕空间产生的离子、臭氧和OH自由基对电除尘器除尘和除硝等离子体化学反应有较好的促进作用。为了得到水面电晕放电的基本数据，采用多径i针和锯齿型放电电极，测量了水面电晕放电的正、负V-I特性和臭氧生成。在不同的脉冲电压波形下，测量了脉冲电晕特性。实验在常压和室温下进行。直流电和脉冲电晕对水面均表现出稳定的V-I特性，但水面受电晕风的影响较大。在直流和脉冲日冕中，正流光日冕比负流光日冕产生更多的臭氧。利用模型电潜泵反应器对柴油机尾气进行了粉尘和氮氧化物的处理试验。在除硝过程中，电晕向水面放电可诱导较好的条件进行NO氧化和NO_2溶解到水中，并可捕集粉尘。设计了用于汽车隧道或地下停车场污染空气净化的ESP模型。采用该模型进行的粉尘和NOx处理试验结果表明，负电荷除尘效果较好，但NOx处理效果较差。设计了用于NOx处理的屏障放电反应器，并在各种条件下进行了试验。结果表明，对于NOx处理性能而言，存在最大臭氧产量和最低排放功率的合适频率。少

Three types of NOx treatment reactor model were designed and investigated on the basic discharge characteristics, ozone generation and NOx, removal. The prepared reactors were application of discharge : 1)Corona discharge over water surface, 2)DC corona in the two-stage ESP model, 3)Barrier discharge by multi plate electrodes.In corona discharge over water surface, the discharge electrodes of saw-edge type showed better characteristics on radical production and NOx treatment test with diesel engine exhaust gas. The ESP with the discharge electrode over water was designed as the reactor for removal of dust and NOx simultaneously. The ESP was expected to make the better proceeding of dust collection and the plasma chemical reactions for NOx removal by the ions, ozone and OH radical produced in the corona space. In order to get the fundamental data of the corona discharge over the water surface, positive and negative V-I characteristics and the ozone production were measured with the mult … More i needle and the saw-edge type of the discharge electrodes. The pulse corona characteristics were also measured with some different waveforms of the applied pulse voltage. The experiments were carried out under the atmospheric pressure and room temperature. Both DC and the pulse corona to the water surface showed the stable V-I characteristics though the surface of water was waved by the corona wind. The positive streamer corona showed the more ozone production than the negative one both in the DC and in the pulse corona. Some dust and NOx treatment tests by the model ESP reactor were carried out with diesel engine exhaust gas. The corona discharge to the water surface was confirmed to induce the better conditions for the proceeding of the NO oxidation and the NO_2 dissolution into water in the NOx removal processes as well as dust catching. An ESP model was designed for the contaminated air cleaning in the automobile tunnel or in the underground parking space. The results of dust and NOx treatment tests by the model showed good dust removal rates in negative charging but less removal rate for NOx treatment. Barrier discharge reactor for NOx treatment was also designed and tested under various conditions. They showed there was the fitting frequency for maximum ozone production and the lowest discharge power for NOx treatment performance. Less