Continuous reduction of cyclic adsorbed and desorbed NO(x) in diesel emission using nonthermal plasma

Takuya Kuwahara; Harunobu Nakaguchi; Tomoyuki Kuroki; Masaaki Okubo

doi:10.1016/j.jhazmat.2016.01.034

Continuous reduction of cyclic adsorbed and desorbed NO(x) in diesel emission using nonthermal plasma

J Hazard Mater. 2016 May 5:308:216-24. doi: 10.1016/j.jhazmat.2016.01.034. Epub 2016 Jan 19.

Authors

Takuya Kuwahara¹, Harunobu Nakaguchi², Tomoyuki Kuroki², Masaaki Okubo³

Affiliations

¹ Department of Products Engineering and Environmental Management, Nippon Institute of Technology, 4-1 Gakuendai, Miyashiro-machi, Minamisaitama, Saitama 345-8501, Japan.
² Department of Mechanical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531, Japan.
³ Department of Mechanical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531, Japan. Electronic address: mokubo@me.osakafu-u.ac.jp.

PMID: 26844402
DOI: 10.1016/j.jhazmat.2016.01.034

Abstract

Considering the recent stringent regulations governing diesel NO(x) emission, an aftertreatment system for the reduction of NO(x) in the exhaust gas has been proposed and studied. The proposed system is a hybrid method combining nonthermal plasma and NOx adsorbent. The system does not require precious metal catalysts or harmful chemicals such as urea and ammonia. In the present system, NO(x) in diesel emission is treated by adsorption and desorption by adsorbent as well as nonthermal plasma reduction. In addition, the remaining NO(x) in the adsorbent is desorbed again in the supplied air by residual heat. The desorbed NO(x) in air recirculates into the intake of the engine, and this process, i.e., exhaust gas components' recirculation (EGCR) achieves NO(x) reduction. Alternate utilization of two adsorption chambers in the system can achieve high-efficiency NO(x) removal continuously. An experiment with a stationary diesel engine for electric power generation demonstrates an energy efficiency of 154 g(NO2)/kWh for NO(x) removal and continuous NO(x) reduction of 70.3%. Considering the regulation against diesel emission in Japan, i.e., the new regulation to be imposed on vehicles of 3.5-7.5 ton since 2016, the present aftertreatment system fulfills the requirement with only 1.0% of engine power.

Keywords: Adsorption; Diesel engine; Exhaust gas recirculation; NO(x) reduction; Nonthermal plasma.

Publication types

Research Support, Non-U.S. Gov't