Appraisal of a De-NOx System Based on H2 for Light-Duty Diesel Engine Vehicles

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• 作者：Samir Bensaid ; Edoardo Merlone Borla ; Nunzio Russo ; Debora Fino ; Vito Specchia
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2010
• 出版时间：November 3, 2010
• 年：2010
• 卷：49
• 期：21
• 页码：10323-10333
• 全文大小：566K
• 年卷期：v.49,no.21(November 3, 2010)
• ISSN：1520-5045

文摘

The present paper describes a novel, fully integrated after-treatment system based on the use of hydrogen for de-NO_x purposes, designed for light-duty diesel engine applications. Hydrogen is generated by an autothermal reformer, placed as a bypass unit of the close-coupled DOC and DPF, and it promotes an NO_x reduction in a specific catalytic converter in the under-floor position. The results of the tests on commercial reforming catalysts and on H₂-selected catalytic reductions (SCR) perovskite catalysts that were synthesized by our group are presented. The best catalyst, on the basis of TPRe activity tests, was La_0.8Sr_0.2Fe_0.9Pd_0.1O₃. At a lab-scale, the fuel penalty of the system is around 4% for an NO_x to N₂ conversion of 60%, under the best operating conditions. T₅₀ is very low (150 °C) compared to other de-NO_x strategies. The system was then integrated on board a vehicle, and several testing protocols were performed (NEDC2000 cycle, stationary driving conditions on the roller test bench, and real driving conditions on the road). It has been demonstrated that the system is able to work independently in many driving conditions and that the reforming reaction can be effectively controlled and maintained. The NO_x emissions were kept below Euro 6 levels, even though undesired CO and HC secondary emissions were produced. This performance was reached with a fuel penalty of 10%. Although this value is presently too high to envisage direct application on the market, it has been demonstrated that this technology is already fully functional on board a real vehicle, which encourages further refining research activity.