Effects of post treatment of HZSM-5 zeolites on catalytic cracking of butene

doi:10.11949/j.issn.0438-1157.20150645

Abstract

Abstract:

The structure and acidity of HZSM-5 zeolites were modified using different post treatment methods: alkaline treatment, steam treatment, and alkaline-steaming treatment. The catalytic performances of modified zeolites were tested in 1-butene catalytic cracking. Their physicochemical properties were characterized by N₂adsorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), and infrared spectroscopy with pyridine adsorption (Py-IR). The acidities of zeolites increased after the alkaline treatment, and as a result, the activity of butene cracking increased and the selectivity of propylene decreased. However, the deactivation rate of alkaline-treated zeolites had no significant change. There was a pronounced development of mesopores (5—20 nm) with a broad pore-size distribution in alkaline-treated ZSM-5 zeolites. Mesopores (2—4 nm) with a narrow distribution is observed after steaming treatment, while the mesopore volume is low. Zeolites after alkaline-and steaming-treatment showed two kinds of mesopore distributions, 2—4 nm (narrow) and 5—20 nm (broad). Due to the decrease of Brønsted acidic sites, the selectivity of propylene increased over ZSM-5 zeolites with any of the post treatments; a relatively stable propylene yield was obtained after the reaction of 2.5 h (except for zeolites treated with high concentration of alkaline followed by steaming treatment).

Key words: zeolite, catalyst, reaction, alkaline treatment, hierarchical pores

摘要：

采用不同后处理手段(碱处理、水汽处理以及碱处理-水汽处理)对HZSM-5沸石的孔结构和酸性质进行了调变,并对其丁烯裂解性能进行了研究。运用N₂吸脱附、扫描电镜(SEM)、X射线衍射(XRD)以及吡啶吸附红外(Py-IR)对后处理改性前后的沸石样品的物理化学性质进行了表征。碱处理后HZSM-5的质子酸量增加,在5～20 nm处具有分布较宽的介孔,其反应活性升高,丙烯选择性下降,但失活速率没有加快。单独水汽处理在2～4 nm处产生介孔,但介孔体积较小。碱处理-水汽处理在2～4和5～20 nm处具有双分布介孔,前者分布较集中,后者分布较宽。单独水汽处理和碱处理-水汽处理的样品可以提高HZSM-5的丙烯选择性,主要归功于酸量的降低;反应2.5 h后具有较稳定的丙烯收率(高碱浓度处理-水汽处理的样品除外)。

关键词: 沸石, 催化剂, 反应, 碱处理, 多级孔

CLC Number:

TQ032

ZHANG Rongrong, WANG Zhengbao. Effects of post treatment of HZSM-5 zeolites on catalytic cracking of butene[J]. CIESC Journal, 2015, 66(8): 3098-3105.

张荣荣, 王正宝. 后处理改性对HZSM-5沸石丁烯裂解性能的影响[J]. 化工学报, 2015, 66(8): 3098-3105.

References 22

[1]	Na K, Choi M, Ryoo R. Recent advances in the synthesis of hierarchically nanoporous zeolites [J]. Microporous Mesoporous Mater., 2013, 166 (15): 3-19.
[2]	Chal R, Gérardin C, Bulut M, Donk S. Overview and industrial assessment of synthesis strategies towards zeolites with mesopores [J]. ChemCatChem, 2011, 3 (1): 67-81.
[3]	Verboekend V, Pérez-Ramírez J. Design of hierarchical zeolite catalysts by desilication [J]. Catal. Sci. Technol., 2011, 1: 879-890.
[4]	Pérez-Ramírez J, Verboekend D, Bonilla A, Abello S. Zeolite catalysts with tunable hierarchy factor by pore-growth moderators [J]. Adv. Funct. Mater., 2009, 19 (24): 3972-3979.
[5]	Möller K, Bein T. Mesoporosity—a new dimension for zeolites [J]. Chem. Soc. Rev., 2013, 42: 3689-3707.
[6]	Jacobsen C J H, Madsen C, Houzvicka J, Schmidt I, Carlsson A. Mesoporous zeolite single crystals [J]. J. Am. Chem. Soc., 2000, 122: 7116-7117.
[7]	Park D H, Kim S S, Wang H, Pinnavaia T J, Papapetrou M C. Selective petroleum refining over a zeolite catalyst with small intracrystal mesopores [J]. Angew. Chem. Int. Ed., 2009, 48 (41): 7645-7648.
[8]	Tosheva L, Valtchev V, Sterte J. Silicalite-1 containing microspheres prepared using shape-directing macro-templates [J]. Microporous Mesoporous Mater., 2000, 35/36: 621-629.
[9]	Choi M, Cho H S, Srivastava R, Venkatesan C, Choi D H, Ryoo R. Amphiphilic organosilane-directed synthesis of crystalline zeolite with tunable mesoporosity [J]. Nat. Mater., 2006, 5: 718-723.
[10]	Müller M, Harvey G, Prins R. Comparison of the dealumination of zeolites beta, mordenite, ZSM-5 and ferrierite by thermal treatment, leaching with oxalic acid and treatment with SiCl4 by 1H, 29Si and 27Al MAS NMR [J]. Microporous Mesoporous Mater., 2000, 34 (2): 135-147.
[11]	Triantafillidis C S, Vlessidis A G, Nalbandian L, Evmiridis N P. Effect of the degree and type of the dealumination method on the structural, compositional and acidic characteristics of H-ZSM-5 zeolites [J]. Microporous Mesoporous Mater., 2001, 47 (2/3): 369-388.
[12]	Ong L H, Dömök M, Olindo R, André C, Lercher J A. Dealumination of HZSM-5 via steam-treatment [J]. Microporous Mesoporous Mater., 2012, 164 (1): 9-20.
[13]	Groen J C, Peffer L A A, Moulijn J A, Pérez-Ramírez J. Mesopore development in ZSM-5 zeolite upon optimized desilication condition in alkaline medium [J]. Colloids Surf. A, 2004, 241 (1-3): 53-58.
[14]	Jin Wenqing(金文清), Zhao Guoliang(赵国良), Teng Jiawei(滕加伟), Xie Zaiku(谢在库). Catalytic performance of ZSM-5 catalyst modified by sodium hydroxide for C4-olefin cracking [J]. Chemical Reacion Engineering and Technology(化学反应工程与工艺), 2007, 23 (3): 193-199.
[15]	Groen J C, Jansen J C, Moulijn J A, Pérez-Ramírez J. Optimal aluminum-assisted mesoporosity in MFI zeolite by desilication [J]. J. Phys. Chem. B, 2004, 108 (35): 13062-13065.
[16]	Lietz G, Schnabel K H, Peuker C, Gross T, Storek W, Volter J. Modifications of HZSM-5 catalysts by NaOH treatment [J]. J. Catal., 1994, 148(2): 562-568.
[17]	Zhang R R, Wang Z B. Catalytic cracking 1-butene to propylene over Ag modified HZSM-5 [J]. Chin. J. Chem. Eng., 2015, 23 (7): 1131-1137. DOI: 10.1016/j.cjche.2015.01.008
[18]	Yang X, Shang Y, Yang P. Catalytic cracking of 1-butene to propene and ethane on HMCM-49 zeolite [J]. Reac. Kinet. Cat., 2010, 100: 399-405.
[19]	Zhu X X, Liu S L, Song Y Q, Xu L Y. Catalytic cracking of C4 alkenes to propene and ethene: influences of zeolites pore structures and Si/Al2 ratios [J]. Appl. Catal. A: Gen., 2005, 288 (1/2): 134-142.
[20]	Milina M, Mitchell S, Crivelli P, Cooke D, Pérez-Ramírez J. Mesopore quality determines the life time of hierarchically structured zeolite catalysts [J]. Nat. Comm., 2014, (5): 1-20.
[21]	Cerqueira H S, Caeiro G, Costa L, Ramôa Ribeiro F. Deactivation of FCC catalysts [J]. J. Mol. Catal. A, 2008, 92 (1/2): 1-13.
[22]	Guisnet M, Magnoux P. Coking and deactivation of zeolites: influence of the pore structure [J]. Appl. Catal., 1989, 54 (1): 1-27.