Overall Evaluation of Plasma Exhaust Gas Cleaning Method for Diesel Engine Generator

柴油发电机等离子废气净化方法的总体评价

基本信息

批准号：
17560270
负责人：
YOSHIOKA Yoshio
金额：
$ 2.18万
依托单位：
KANAZAWA INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560270/
关键词：
Barrier discharge NOx removal Diesel engine Exhaust gas recirculation (EGR)Urea Automatic control Catalysis Discharge mode バリヤ放電発電設

项目摘要

Based on the original scheme of research, various NOx removal experiments were carried out, and analyzed the results. The followings are the principal conclusion of this work.(1)Barrier discharge usually has a filamentary micro-discharge mode. As the radical formation by high energy electrons occur only in the thin micro-discharge channels, we considered that to make such micro-discharge as small as possible and to increase the number of micro-discharges would be better for NO removal performance. We found that by increasing the temperature of barrier materials or by using acrylic barrier, the barrier discharge mode changed from filamentary mode to glow like mode. The glow like discharge mode was confirmed to increase the NO removal efficiency by 170%.(2)The reason why the temperature of barrier material changes the discharge mode was investigated using very simple needle to plane discharge device. We found that the surface discharge changes with temperature and at the top of surface d … More ischarge, some glow like discharge mode appears. This phenomenon is considered to be a cause of the change of discharge mode.(3)As a new method, we made an experimental system, with which we can test the effect of a combination of discharge, catalysis and ammonia. Ammonia is generated from urea resolved in water by heating it over 160℃. Various experiments were carried out, and we had a conclusion that a combination of ammonia, discharge and catalysis directly can reduce NOx from exhaust gas at relatively lower temperature such as 200℃, although the catalysis used work at the temperature more than 400℃ without discharge. Even if we added ammonia in exhaust gas and plasma treatment was done, the NOx removal performance is not improved.(4)The exhaust gas recirculation (EGR) reduces the emission of NOx from engine considerably. Therefore, if we apply EGR before the plasma treatment, the load of the plasma process will be lightened. It was demonstrated that EGR of 10% could decrease the energy for plasma process to 1/4 of the case without EGR application. The automatic control of NOx removal apparatus using EGR was developed. By controlling the discharge power of discharge device and EGR rate, we can keep the outlet NO concentration to a low constant level.(5)As for over all evaluation of the plasma process, we concluded that a combination of EGR and ozone injection would be the best. It can reduce the plasma energy to minimum, and meets the industrial demand of energy consumption. It can achieve much lower NOx level control than conventional ways. A combination of ammonia generated from urea, discharge and SCR has a merit that the water scrubber is not necessary. Plasma can lower the operating temperature of SCR considerably. However, the higher temperature operation of discharge device is not so stable, and there need another cost for urea for ammonia source. Less

在原研究方案的基础上，进行了各种NOx去除实验，并对实验结果进行了分析，得出以下结论：(1)阻挡放电通常具有丝状微放电模式。高能电子仅发生在薄的微放电通道中，我们认为使这种微放电尽可能小并增加微放电的数量会更好地去除NO。我们发现通过提高温度来去除NO。阻隔材料或通过使用丙烯酸屏障，屏障放电模式从丝状模式变为类辉光模式，证实类辉光放电模式将NO去除效率提高了170%。（2）屏障材料的温度改变放电模式的原因是。使用非常简单的针面放电装置进行研究，我们发现表面放电随温度变化，并且在表面放电的顶部出现一些辉光放电模式，这种现象被认为是放电变化的原因。 (3)作为新方法，我们制作了一个实验系统，通过将尿素加热到160℃以上，可以测试放电、催化和氨的组合效果，并进行了各种实验。结论是氨、排放和催化的组合可以在相对较低的温度如200℃下直接还原废气中的NOx，尽管所使用的催化剂在超过400℃的温度下工作而不排放。我们在废气中添加氨并进行等离子体处理，但NOx去除性能并没有提高。（4）废气再循环（EGR）大大减少了发动机NOx的排放，因此，如果我们在等离子体处理之前应用EGR，事实证明，10%的EGR可以将等离子体处理的能量减少到不应用EGR的情况的1/4。通过控制，开发了利用EGR的自动控制装置。放电放电装置的功率和EGR率，可以将出口NO浓度保持在较低的恒定水平。(5)对于等离子体过程的总体评价，我们得出结论，EGR和臭氧喷射的组合是最好的。将等离子能量降至最低，满足工业能耗需求，可以实现比传统方式更低的NOx水平控制。尿素产生的氨、排放物和SCR的结合具有不需要水洗涤器的优点。可以降低操作SCR的温度显着降低，但排放装置在较高温度下运行不太稳定，并且需要额外的尿素作为氨源成本。