物理化学学报 >> 2015, Vol. 31 >> Issue (4): 750-756.doi: 10.3866/PKU.WHXB201502051

催化和表面科学 上一篇    下一篇

理论空燃比天然气汽车尾气中H2O和O2对CH4与NO反应的影响

尚鸿燕1, 胡伟1, 王云2, 任成军3, 龚茂初3, 陈耀强1,3   

  1. 1 四川大学化学工程学院, 成都610065;
    2 四川省中自尾气净化有限公司, 成都611731;
    3 四川大学化学学院, 教育部绿色化学与技术重点实验室, 成都610064
  • 收稿日期:2014-11-02 修回日期:2015-02-04 发布日期:2015-04-03
  • 通讯作者: 陈耀强 E-mail:nic7501@scu.edu.cn
  • 基金资助:

    国家自然科学基金(21173153), 四川省环境保护厅项目(2011HB002)及四川省科技厅科技支撑项目(2012FZ0008)资助

Effects of H2O and O2 on the Reaction of NO Reduction by CH4 under Stoichiometric Natural Gas Vehicles

SHANG Hong-Yan1, HU Wei1, WANG Yun2, REN Cheng-Jun3, GONG Mao-Chu3, CHEN Yao-Qiang1,3   

  1. 1 College of Chemical Engineering, Sichuan University, Chengdu 610065, P. R. China;
    2 Sichuan Zhongzi Exhaust Gas Cleaning Co., Ltd., Chengdu 611731, P. R. China;
    3 Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
  • Received:2014-11-02 Revised:2015-02-04 Published:2015-04-03
  • Contact: CHEN Yao-Qiang E-mail:nic7501@scu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21173153), Project from Sichuan Provincial Environment Office, China (2011HB002), and Science and Technology Support Project of Science and Technology Department of Sichuan Province, China (2012FZ0008).

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摘要：

共沉淀法制备CeZrYLa+LaAl 复合氧化物载体, 等体积浸渍法制备了Pt 催化剂, 用于研究理论空燃比天然气汽车(NGVs)尾气净化反应中CH4与NO的反应规律. 并考察了10% (体积分数, φ)H2O和计量比O2对CO2存在时的CH4+NO反应的影响. 结果表明: 对于不同条件下的NO+CH4反应, 主要生成N2和CO2, 高温区有CO生成. 低温区无O2时可以生成N2O, 有O2时可以生成NO2; 添加10% (φ)的H2O后, CH4 转化活性降低, NO转化活性基本不变, 这是由于H2O减弱了CH4与CO2的重整反应, 但是对CH4与NO的反应基本没有影响; 添加计量比的O2后, CH4转化活性提高, 而NO转化活性降低, 这是由于O2和NO之间存在竞争吸附, CH4被O2氧化为主要反应, 从而减弱了NO的转化; 同时添加计量比的O2和10% (φ) H2O, CH4与CO2的重整反应受到抑制,CH4与NO的反应、甲烷蒸汽重整反应和甲烷被O2氧化反应同时发生, CH4和NO的转化活性均提高.

关键词: Pt, CeZrYLa+LaAl, 尾气组分, CH4对NO的还原, 天然气汽车尾气净化

Abstract:

Composite support CeZrYLa + LaAl was prepared by co-precipitation, and platinum catalyst supported on the composite support was prepared by impregnation. The behavior of the Pt catalyst for the reaction of NO reduction by CH4 from the exhausts of natural gas vehicles (NGVs) was studied under stoichiometric conditions. Additionally, the effects of 10% (volume fraction, φ) H2O and stoichiometric O2 on the reaction in the presence of CO2 were also investigated. Results show that N2 and CO2 were the main products for the different reactions, CO was detected under high temperature, and NOx was detected under low temperature (in the presence of O2, the NOx was NO2, whereas the NOx was N2O when no O2 was present). In the presence of 10% (φ) H2O, the conversion of CH4 noticeably decreased and NO conversion remained unchanged, possibly because the presence of H2O weakens the reforming reaction of CH4 with CO2, but does not affect the activity of NO reduction by CH4. In the presence of stoichiometric O2, there was an obvious increase of CH4 conversion and a decrease of NO conversion. These could be explained by the competition between NO and O2, where the oxidation of methane by O2 is the main reaction, limiting the reaction of NO reduction by CH4. Moreover, in the presence of 10% (φ) H2O and stoichiometric O2, CO2 reforming of CH4 was negligible. Numerous reactions were detected simultaneously, such as the oxidation of CH4 by NO, steam reforming of CH4, and the reduction of NO by CH4, thus improving the conversions of CH4 and NO.

Key words: Pt, CeZrYLa+LaAl, Gas composition, Reduction of NO by CH4, Natural gas vehicle exhaust purification