INVESTIGATION OF THE FACTORS AFFECTING NOx REMOVAL PERFORMANCE FOR DIESEL ENGINE EXHAUST GASES BY SILENT DISCHARGE

柴油机废气无声排放脱氮效果影响因素研究

基本信息

批准号：
12650294
负责人：
YOSHIOKA Yoshio
金额：
$ 2.3万
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：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650294/
关键词：
NOx Diesel Engine Silent Discharge NO Removal Efficiency Exhaust Gases Discharge Power Residence Time Ozone NOx除去除去効率オゾン添加剤電極構造

项目摘要

In the first year, the experimental system was set up in the laboratory. As the first experiment, the effect of electrode of silent discharge was investigated. It was found that NO removal efficiency using flat type electrode is better than various meshed electrodes and electrode area has almost no effect on the efficiency. Next, influence of discharge power density, discharge energy density and gas residence time of the discharge device were investigated. It was found that the first two factors have almost no influence, however the gas residence time shows considerable influence to the efficiency. The optimum residence time was in between 50 to 150ms. Hydrocarbon (HC) addition into exhaust gases showed big effect on the efficiency and the HCs with big molecular size were found to be better. During the experiments, the phenomenon that NO removal performance becomes very poor was found. The reason was analyzed and found that it came from the moisture condensation on the dielectric plate of discharge device.In the second year, the photo-catalyst was investigated. Ti0_2 coated filter activated by ultraviolet ray was found to be effective if it was placed down stream of discharge device. Multi-stage arrangement showed better performance. As an alternative technology of direct discharge method, ozone injection into exhaust gases was investigated. It was found that the ozone injection method has many advantages to the direct discharge method, such as high NO removal rates and contamination free process by soot and moisture in exhaust gases. However the HC addition has no or even bad effect for efficiency improvement. Oxygen enhancement was found to be good method for efficiency improvement.The application and a way of comparison method of non-thermal plasmas to NOx removal were proposed as a final achievement of this investigation.

第一年，在实验室搭建了实验系统。作为第一个实验，研究了无声放电电极的效果。结果发现，使用扁平型电极的NO去除效率优于各种网状电极，并且电极面积对效率几乎没有影响。接下来，研究放电装置的放电功率密度、放电能量密度和气体停留时间的影响。研究发现，前两个因素几乎没有影响，但气体停留时间对效率有相当大的影响。最佳停留时间在 50 至 150 毫秒之间。在废气中添加碳氢化合物 (HC) 对效率有很大影响，并且发现分子尺寸较大的 HC 效果更好。在实验过程中，发现NO去除性能变得很差的现象。分析原因，发现是放电装置介质板上的水分凝结所致。第二年，研究光触媒。发现由紫外线激活的TiO_2涂层过滤器如果放置在放电装置的下游是有效的。多级布置表现出更好的性能。作为直接排放法的替代技术，对废气中注入臭氧进行了研究。结果发现，臭氧喷射法比直接排放法具有许多优点，例如高NO去除率以及不受废气中烟灰和水分污染的过程。但HC的添加对于效率的提高没有任何作用，甚至有不良作用。发现增氧是提高效率的好方法。作为本研究的最终成果，提出了低温等离子体去除NOx的应用和比较方法。