Kinetic Modeling of Ammonia-SCR and Experimental Studies over Monolithic Cu-ZSM-5 Catalyst

Wataru Eijima*, Gen Shibata, Yoshimitsu Kobashi, Ryutaro Koiwai, Hideyuki Ogawa, Kenichi Shimizu, Jin Kusaka


研究成果: Conference article査読

2 被引用数 (Scopus)


Ammonia-selective catalytic reduction (SCR) systems have been introduced commercially in diesel vehicles, however catalyst systems with higher conversion efficiency and better control characteristics are required to know the actual emissions during operation and the emissions in random test cycles. Computational fluid dynamics (CFD) is an effective approach when applied to SCR catalyst development, and many models have been proposed, but these models need experimental verification and are limited in the situations they apply to. Further, taking account of redox cycle is important to have better accuracy in transient operation, however there are few models considering the cycle. Model development considering the redox reactions in a zeolite catalyst, Cu-ZSM-5, is the object of the research here, and the effects of exhaust gas composition on the SCR reaction and NH3 oxidation at high temperatures are investigated. The simulations are compared with the experimental results of a surrogate gas, a mixture of nitrogen monoxide (NO), oxygen (O2), water vapor (H2O), and nitrogen (N2), and the accuracy of the developed model is validated. To investigate the effects of O2 concentration on standard SCR and NH3 oxidation, the experiments are conducted with the surrogate gas. The results suggest that the O2 has a larger reaction order (1.25-1.51) to NH3 oxidation than that to the standard SCR (0.73-0.75). The model considering these reaction orders of O2 predicts the effect of O2 on NOx and NH3 conversions well. A transient operation experiment is also conducted with the Cu-ZSM-5 catalyst. The experiment consists of NH3 adsorption part and NO reduction part, where the re-oxidizing of copper does not occur. The results clearly show that Cu+ does not contribute to the SCR reaction. Further, the NH3-SCR simulation model was greatly improved by considering the redox reaction cycle and the concentrations of oxygen.

ジャーナルSAE Technical Papers
出版ステータスPublished - 2019 1月 15
イベントSAE 2019 International Powertrains, Fuels and Lubricants Meeting, FFL 2019 - San Antonio, United States
継続期間: 2019 1月 222019 1月 24

ASJC Scopus subject areas

  • 自動車工学
  • 安全性、リスク、信頼性、品質管理
  • 汚染
  • 産業および生産工学


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