等离子体辅助选择性催化还原技术是脱除汽车尾气中NOx的有效途径,不同的还原剂影响着最终的处理效果,为此通过填充床式反应器产生等离子体,处理分别添加甲烷和乙烯作还原剂的模拟汽车尾气,对不同电压等级、电源频率、填料粒径条件下的NO脱除率、NO2体积分数、NOx总体积分数变化、CO体积分数等进行研究,对比甲烷和乙烯的处理效果。试验结果表明,两种还原剂的脱除效果随电压等级变化趋势一致,乙烯的脱除效果要好于甲烷,源于二者的预处理产物不同,且不同的电源频率下还原剂的脱除效果不同,高频的处理效果要优于工频。此外,在同一电压等级下向反应器内填充不同粒径的玻璃球处理效果会有所差别,多数情况下,填充玻璃球的处理效果要优于未填充的情况,而当工频电压等级〉20kV,乙烯作用下未填充的NO脱除效果优于填充的情况。在实际应用中,应根据还原剂选择恰当的电压等级、电源频率、填充球粒径等参数,使得等离子体预处理NO的效果最好。
PF-SCR(plasma-facilitated selective catalytic reduction) technology is an effective way to remove nitric oxide in vehicle exhaust gas,of which the effect depends partly on the reducing agent.Consequently,plasma was generated in packed-bed reactor,while vehicle exhaust gas was imitated by mixing nitric oxide,oxygen and nitrogen in certain proportion.Methane and ethylene were added in the exhaust gas as reducing agent,respectively,to survey the variation of nitric oxide,nitrogen dioxide and carbon monoxide with different loaded voltage,frequency and particle size.Results show that the loaded voltage has the same influence on nitric oxide removal rate,while effect of ethylene is better than that of methane.Different contents of carbon monoxide supplies pretreatment of the plasma have different intermediate products.In addition,frequency and particle size also affect the nitric oxide removal rate and nitrogen dioxide generation.It is necessary to choose the suitable condition according to the practical application.