Effect of Support Materials on Pd Methane Oxidation Catalyst Using Dynamic Estimation Method
Effect of Support Materials on Pd Methane Oxidation Catalyst Using Dynamic Estimation Method
复制标题
采用动态估算法研究载体材料对 Pd 甲烷氧化催化剂的影响
DOI：
10.1115/icef2020-2930
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Yamasaki Yudai
中科院分区：
文献类型：
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作者：
Nitta Yoshifuru;Yamasaki Yudai
在海运业中，期望稀燃燃气发动机减少诸如NOx、SOx和CO2的排放。另一方面，作为从稀燃燃气发动机排放的未燃烧甲烷（CH 4）的逃逸甲烷具有对全球变暖的影响的担忧。因此，开展稀燃发动机排气后处理技术的研究具有重要意义。钯（Pd）催化剂具有较低的活化温度，有望成为解决甲烷逃逸问题的最佳方法之一。但近年来的研究表明，水蒸气（H2O）的可逆吸附抑制了催化剂上CH 4的氧化，使其氧化能力降低，可见Pd催化剂上的活性位对CH 4氧化性能有影响。本文提出了一种利用饱和化学吸附CO与脉冲诱导H_2O之间的水煤气变换反应动态估算Pd催化剂上有效活性中心数量的方法。以前的研究阐明了吸附CO体积和Pd负载在燃气发动机排气温度之间的关系，并揭示了流动条件对吸附CO体积的估计的影响。为了提高Pd催化剂在废气条件下的CH 4氧化性能，必须弄清载体材料对活性中心的影响，本文介绍了用动态评价法估算不同载体材料Pd催化剂上CO吸附量的实验结果。实验结果表明，在250-450 °C范围内，Pd/Al 2 O3催化剂上的CO化学吸附量高于Pd/SiO2和Pd/Al 2 O3-SiO2催化剂。这些结果可为Pd催化剂在稀燃发动机排气中的应用提供部分依据。
In the maritime industry, lean burn gas engines have been expected to reduce emissions such as NOx, SOx and CO2. On the other hand, the slipped methane, which is the unburned methane (CH4) emitted from lean burn gas engines have a concern for impact on global warming. It is therefore important to make a progress on the exhaust aftertreatment technologies for lean burn gas engines. As a countermeasure for the slipped methane, Palladium (Pd) catalyst for CH4oxidation can be expected to provide one of the most feasible methods because Palladium (Pd) catalyst for CH4oxidation can activate in the lower temperature. However, recent studies have shown that the reversible adsorption by water vapor (H2O) inhibits CH4oxidation on the catalyst and deactivates its CH4oxidation capacity.It can be known that the CH4oxidation performance is influenced by active sites on the Pd catalyst. However, measuring methods for active sites on Pd catalyst under exhaust gas conditions could not be found. Authors thus proposed a dynamic estimation method for the quantity of effective active sites on Pd catalyst in exhaust gas temperature using water-gas shift reaction between the saturated chemisorbed CO and the pulse induced H2O. The previous study clarified the relationship between adsorbed CO volume and Pd loading in gas engine exhaust gas temperature and revealed the effects of flow conditions on the estimation of adsorbed CO volume. However, in order to improve CH4oxidation performance on Pd catalyst under exhaust gas conditions, it is important that effects of support materials on active sites should clarify.This paper introduced experimental results of estimation of absorbed CO volume on different support materials of Pd catalysts by using the dynamic evaluation method. Experimental results show that chemisorbed CO volume on Pd/Al2O3catalyst exhibits higher chemisorbed CO volume than that of Pd/SiO2and Pd/Al2O3-SiO2catalyst in 250–450 °C. These results can provide a part of the criteria for the application of Pd catalyst for reducing the slipped methane in exhaust gas of lean burn gas engines.