On the Nature of Nitrogen-Containing Carbonaceous Deposits on Coked Fluid Catalytic Cracking Catalysts
On the Nature of Nitrogen-Containing Carbonaceous Deposits on Coked Fluid Catalytic Cracking Catalysts
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DOI：
10.1021/ie034163i
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发表时间：
2004-04
影响因子：
4.2
通讯作者：
J. Barth;A. Jentys;J. Lercher
中科院分区：
文献类型：
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作者：
J. Barth;A. Jentys;J. Lercher
FCC催化剂的再生导致显著的NOx排放。因此，表面沉积物和反应中间体的识别对于理解含氮物质转化为NOx或N2的机制是重要的。通过IR和NMR光谱以及（MA）LDI-TOF质谱对进料和废FCC催化剂上的碳质沉积物的表征表明，多芳族吡咯衍生物（烷基咔唑、烷基苯并咔唑、烷基吲哚）是FCC装置进料中氮的主要来源。因此，咔唑、喹啉衍生物等（多）芳香族化合物（m/z = 350 - 850）是焦炭中的主要含氮成分。在氧化再生过程中，这些预石墨物质被转化为类似于原料中最初存在的氮分子的较小的芳族化合物。随着温度的升高，含氮焦炭物种在催化剂表面积累，只能通过催化剂表面的氧化作用去除。
The regeneration of FCC catalysts leads to significant NOx emissions. Hence, the identification of surface deposits and reaction intermediates is important for understanding the mechanisms by which nitrogen-containing species are converted into NOx or N2. Characterization of the feed and of carbonaceous deposits on spent FCC catalysts by IR and NMR spectroscopy as well as by (MA)LDI-TOF mass spectrometry showed that polyaromatic pyrrole derivatives (alkylcarbazoles, alkylbenzocarbazoles, alkylindoles) are the main source of nitrogen in the feed of FCC units. Consequently, (poly-)aromatic compounds (m/z = 350−850) such as carbazole and quinoline derivatives are the main nitrogen-containing components in the coke. During oxidative regeneration, these pregraphitic species are converted into smaller aromatic compounds similar to the nitrogen molecules originally present in the feedstock. With increasing temperature, nitrogen-containing coke species accumulate on the catalyst surface and can only be removed by...