Insights into the coke deposited on HZSM-5, Hβ and HY zeolites during the cracking of polyethylene
Insights into the coke deposited on HZSM-5, Hβ and HY zeolites during the cracking of polyethylene
复制标题
DOI：
10.1016/j.apcatb.2011.02.024
复制
发表时间：
2011-04-27
影响因子：
22.1
通讯作者：
Bilbao, Javier
中科院分区：
文献类型：
--
作者：
Castano, Pedro;Elordi, Gorka;Bilbao, Javier
通过结合多种光谱和分析技术的结果，研究了沸石结构（HZSM-5、H beta 和 HY）对高密度聚乙烯裂解过程中焦炭沉积的影响：FTIR、拉曼、UV-vis、C-13 NMR 和焦炭萃取，然后进行 GC-MS 和 H-1 NMR 分析。此外，通过结合 FTIR 和程序升温氧化 (TPO) 分析，我们获得了有关焦炭的信息：性质、烧尽以及催化剂再生过程中的成分变化。废催化剂样品是在最先进的中试装置（锥形喷动床反应器）中使用 30 克催化剂在 500 摄氏度下连续处理 900 克（1 克·分钟（-1），15 小时）高密度聚乙烯后获得的。结果表明，随着沸石孔径的增大，双分子反应（氢转移和低聚）、缩合和环化反应增强，产生更多的芳香焦。此外，HZSM-5 沸石的孔隙拓扑结构改善了焦炭前体（也受到 N-2 的高流速的影响）到催化剂外部的流动：即。 HZSM-5催化剂可更长时间地保持其活性。 (C) 2011 Elsevier B.V. 保留所有权利。
The effect of the zeolite structure (HZSM-5, H beta and HY) on coke deposition during the cracking of high-density polyethylene has been studied by combining the results of multiple spectroscopic and analytical techniques: FTIR, Raman, UV-vis, C-13 NMR and coke extraction, followed by GC-MS and H-1 NMR analysis. In addition, by combining FTIR and temperature programmed oxidation (TPO) analysis we obtained information on the coke: properties, burn-off, and changes in composition during catalyst regeneration. Samples of the spent catalysts were obtained in a state-of-the-art pilot plant (conical spouted bed reactor) after the continuous treatment of 900 g (1 g min(-1), 15 h) of high-density polyethylene at 500 degrees C, using 30 g of catalyst. The results show that as the pore diameter of the zeolite is increased, bimolecular reactions (hydrogen transfer and oligomerizations), condensations and cyclizations are enhanced, yielding more aromatic coke. Furthermore, the pore topology of the HZSM-5 zeolite improves the flow of coke precursors (also favored by the high flow rate of N-2) to the outside of the catalyst: viz. HZSM-5 catalyst preserves its activity for longer. (C) 2011 Elsevier B.V. All rights reserved.