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首页> 外文期刊>Environmental Science & Technology >Propene Poisoning on Three Typical Fe-zeolites for SCR of NO_X with NH_3: From Mechanism Study to Coating Modified Architecture
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Propene Poisoning on Three Typical Fe-zeolites for SCR of NO_X with NH_3: From Mechanism Study to Coating Modified Architecture

机译：NH_3与NO_X SCR的三种典型铁分子筛上的丙烯中毒：从机理研究到涂层改性体系结构

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摘要

Application of Fe-zeolites for urea-SCR of NO* in diesel engine is limited by catalyst deactivation with hydrocarbons (HCs). In this work, a series of Fe-zeolite catalysts (Fe-MOR, Fe-ZSM-5, and Fe-BEA) was prepared by ion exchange method, and their catalytic activity with or without propene for selective catalytic reduction of NO_x. with ammonia (NH_3-SCR) was investigated. Results showed that these Fe-zeolites were relatively active without propene in the test temperature range (150-550 ℃); however, all of the catalytic activity was suppressed in the presence of propene. Fe-MOR kept relatively higher activity with almost 80% NO_x conversion even after propene coking at 350 ℃, and 38% for Fe-BEA and 24% for Fe-ZSM-5 at 350 ℃, respectively. It was found that the pore structures of Fe-zeolite catalysts were one of the main factors for coke formation. As compared to ZSM-5 and HBEA, MOR zeolite has a one-dimensional structure for propene diffusion, relatively lower acidity, and is not susceptible to deactivation. Nitrogenated organic compounds (e.g., isocyanate) were observed on the Fe-zeolite catalyst surface. The site blockage was mainly on Fe~(3+) sites, on which NO was activated and oxidized. Furthermore, a novel fully formulated Fe-BEA monolith catalyst coating modified with MOR was designed and tested, the deactivation due to propene poisoning was clearly reduced, and the NO_x conversion reached 90% after 700 ppm C_3H_6 exposure at 500 ℃.
机译：Fe沸石在柴油发动机中用于NO *的尿素-SCR的应用受到碳氢化合物（HCs）催化剂失活的限制。本文通过离子交换法制备了一系列铁沸石催化剂（Fe-MOR，Fe-ZSM-5和Fe-BEA），并在有或没有丙烯的条件下选择性催化还原NO_x。用氨气（NH_3-SCR）进行了研究。结果表明，在测试温度范围（150-550℃）下，这些铁沸石在没有丙烯的情况下具有较高的活性。然而，在丙烯的存在下所有的催化活性均被抑制。即使在350℃下丙烯焦化后，Fe-MOR仍保持较高的活性，NO_x转化率接近80％；在350℃下，Fe-BEA和Fe-ZSM-5分别达到38％和24％。发现Fe-沸石催化剂的孔结构是形成焦炭的主要因素之一。与ZSM-5和HBEA相比，MOR沸石具有一维结构用于丙烯扩散，相对较低的酸度，并且不易失活。在Fe-沸石催化剂表面上观察到氮化的有机化合物（例如异氰酸酯）。该位阻主要在Fe〜（3+）位上，NO被激活并被氧化。此外，设计和测试了一种新型的，完全改性的经MOR改性的Fe-BEA整体催化剂涂层，明显减少了丙烯中毒引起的失活，在500 ppm C_3H_6暴露于700 ppm后NO_x转化率达到90％。

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  • 来源
    《Environmental Science & Technology》 |2012年第3期|p.1747-1754|共8页
  • 作者

    Lei Ma; Junhua Li; Yisun Cheng; Christine K. Lambert; Lixin Fu;

  • 作者单位

    State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China;

    State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China;

    Research and Innovation Center, Ford Motor Company, Dearborn, Michigan 48121, United States;

    Research and Innovation Center, Ford Motor Company, Dearborn, Michigan 48121, United States;

    State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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