Control of Bad Emissions from Flames by Corona Discharges

对碳氢化合物扩散火焰的排放控制进行了实验研究。在本研究中，在丙烷火焰射流的轴线上施加了两根导线相对尖端之间产生的小电晕放电。得到了以下结果：1。在火焰外部施加电晕放电可显著减少火焰产生的烟尘，而在火焰内部富燃料区域直接施加电晕放电则增加了烟尘。对于层流扩散火焰和湍流扩散火焰，在火焰下部施加1 W量级的直流电电晕放电时，其烟尘排放量约为层流火焰的1/20，可降低到3%左右。经证实，对于煤烟的抑制存在以下原因。(1)电晕风的曝气效应；(2)电场和电晕风引起的火焰形状和湍流的变化；(3)放电对烟尘核的形成和生长的直接影响；(4)放电对火焰上部产生的烟尘颗粒燃烧的影响。在层流和湍流扩散火焰中，几瓦量级的电晕放电对NO_x的生成速率没有影响。

An experimental study on the emission control of hydrocarbon diffusion flames were conducted. In this study corona discharges of small electrical power produced between opposed tips of two wires were applied across the axis of propane flame jets.Following results were obtained :1. The soot produced from the flames can be decreased remarkably by applying corona discharges from the outside of flames, while the soot was increased when the discharges were applied directly to the fuel rich region inside the flames.2. The soot emission can be decreased to the order of 3%, for a laminar diffusion flame and for a turbulent diffusion flame of which soot emission without corona discharges was about 1/20 of the former laminar flame, when direct current corona discharges of the order of 1 W were applied the lower part of the flames.3. It was confirmed, for the supression of the soot following causes exist. (1) Aeration effect of corona winds, (2) The variation of flame shape and turbulence, caused by electric fields and corona winds, (3) Direct effect of electric discharges for the formation and growth of nuclear of soot, (4) the effect of discharges for the combustion of soot particles produced in the upper part of the flames.4. The corona discharges of the order of few watt do not influence on the rate of NO_x production, in both laminar and turbulent diffusion flames.