Effect of hierarchical ZSM-5 zeolite crystal size on diffusion and catalytic performance of n-heptane cracking

Abstract

Hierarchical ZSM-5 zeolite aggregates with different sizes of nanocrystals were synthesized using different amounts of the mesoporogen 3-aminopropyltriethoxysilane. The effect of the crystal size on the catalytic cracking of n-heptane was investigated and the Thiele modulus and effectiveness factor were used to determine the reaction rate-limiting step. The crystal size affected the textual properties of the catalysts but not the acidic properties of the catalysts. The reaction rate was first order with respect to the n-heptane concentration. Cracking over hierarchical zeolites with nanocrystal sizes larger than about 50 nm took place under transition-limiting conditions, whereas the reaction over hierarchical zeolites with nanocrystal sizes of 15 or 30 nm proceeded under reaction control conditions. Hierarchical ZSM-5 zeolite aggregates with smaller nanocrystals had better selectivity for light olefins which can be ascribed to the shorter diffusion path lengths and lower diffusion resistance in these catalysts. Furthermore, these catalysts had lower coking levels which can be attributed to the substantial number of mesopores which prevent the formation of coke precursors.

Key words： hierarchical ZSM-5; crystal size; catalytic cracking; Thiele modulus; effectiveness factor

Acknowledgements

The support from the National Key R & D Program of China (2016YFA0202900), the National Natural Science Foundation of China (91434123, 21622606), the Zhejiang Provincial Natural Science Foundation of China (LR18B060001) and the Fundamental Research Fund for Central Universities is greatly appreciated. Xiaohong Ren acknowledges financial support from the State Key Laboratory of Fine Chemicals (KF1516).

References

1 Sadrameli S M. Thermal/catalytic cracking of hydrocarbons for the production of olefins: A state-of-the-art review I: Thermal cracking review. Fuel, 2015, 140: 102–115

2 Sadrameli S M. Thermal/catalytic cracking of liquid hydrocarbons for the production of olefins: A state-of-the-art review II: Catalytic cracking review. Fuel, 2016, 173: 285–297

3 Yoshimura Y, Kijima N, Hayakawa T, Murata K, Suzuki K, Mizukami F, Matano K, Konishi T, Oikawa T, Saito M, et al. Catalytic cracking of naphtha to light olefins. Catalysis Surveys from Japan, 2001, 4(2): 157–167

4 Wang G, Xu C M, Gao J S. Study of cracking FCC naphtha in a secondary riser of the FCC unit for maximum propylene production. Fuel Processing Technology, 2008, 89(9): 864–873

5 Plotkin J S. The changing dynamics of olefin supply/demand. Catalysis Today, 2008, 106(1): 10–14

6 Jung J S, Park J W, Seo G. Catalytic cracking of n-octane over alkali-treated MFI zeolites. Applied Catalysis A: General, 2005, 288(1–2): 149–157

7 Alipour S M. Recent advances in naphtha catalytic cracking by nano ZSM-5: A review. Chinese Journal of Catalysis, 2016, 37(5): 671–680

8 Liu D, Choi W C, Kang N Y, Lee Y J, Park H S, Shin C H, Park Y K. Inter-conversion of light olefins on ZSM-5 in catalytic naphtha cracking condition. Catalysis Today, 2014, 226: 52–66

9 Rahimi N, Karimzadeh R. Catalytic cracking of hydrocarbons over modified ZSM-5 zeolites to produce light olefins: A review. Applied Catalysis A: General, 2011, 398(1-2): 1–17

10 Borm R V, Reyniers M F, Martens J A, Marin G B. Catalytic cracking of methylcyclohexane on FAU, MFI, and bimodal porous materials: Influence of acid properties and pore topology. Industrial & Engineering Chemistry Research, 2010, 49(21): 10486–10495

11 Bari Siddiqui M A, Aitani A M, Saeed M R, Al-Khattaf S. Enhancing the production of light olefins by catalytic cracking of FCC naphtha over mesoporous ZSM-5 catalyst. Topics in Catalysis, 2010, 53(19–20): 1387–1393

12 Wakui K, Satoh K, Sawada G, Shiozawa K, Matano K, Suzuki K, Hayakawa T, Yoshimura Y, Murata K, Mizukami F. Dehydrogenative cracking of n-butane over modified HZSM-5 catalysts. Catalysis Letters, 2002, 81(1–2): 83–88

13 Magnoux P, Cartraud P, Mignard S, Guisnet M. Coking, aging, and regeneration of zeolites: III. Comparison of the deactivation modes of H-mordenite, HZSM-5, and HY during n-heptane cracking. Journal of Catalysis, 1987, 106(1): 242–250

14 Kokotailo G T, Lawton S L, Olson D H, Meier W M. Structure of synthetic zeolite ZSM-5. Nature, 1978, 272(5652): 437–438

15 Konno H, Ohnaka R, Nishimura J, Tago T, Nakasaka Y, Masuda T. Kinetics of the catalytic cracking of naphtha over ZSM-5 zeolite: Effect of reduced crystal size on the reaction of naphthenes. Catalysis Science & Technology, 2014, 4(12): 4265–4273

16 Konno H, Tago T, Nakasaka Y, Ohnaka R, Nishimura J I, Masuda T. Effectiveness of nano-scale ZSM-5 zeolite and its deactivation mechanism on catalytic cracking of representative hydrocarbons of naphtha. Microporous and Mesoporous Materials, 2013, 175(13): 25–33

17 Konno H, Okamura T, Kawahara T, Nakasaka Y, Tago T, Masuda T. Kinetics of n-hexane cracking over ZSM-5 zeolites-effect of crystal size on effectiveness factor and catalyst lifetime. Chemical Engineering Journal, 2012, 207–208(10): 490–496

18 Tago T, Konno H, Nakasaka Y, Masuda T. Size-controlled synthesis of nano-zeolites and their application to light olefin synthesis. Catalysis Surveys from Asia, 2012, 16(3): 148–163

19 Rownaghi A A, Rezaei F, Hedlund J. Selective formation of light olefin by n-hexane cracking over HZSM-5: Influence of crystal size and acid sites of nano- and micrometer-sized crystals. Chemical Engineering Journal, 2012, 191(19): 528–533

20 Mochizuki H, Yokoi T, Imai H, Watanabe R, Namba S, Kondo J N, Tatsumi T. Facile control of crystallite size of ZSM-5 catalyst for cracking of hexane. Microporous and Mesoporous Materials, 2011, 145(1–3): 165–171

21 Tago T, Konno H, Sakamoto M, Nakasaka Y, Masuda T. Selective synthesis for light olefins from acetone over ZSM-5 zeolites with nano- and macro-crystal sizes. Applied Catalysis A: General, 2011, 403(1–2): 183–191

22 Zhang X X, Cheng D G, Chen F Q, Zhan X L. n-Heptane catalytic cracking on hierarchical ZSM-5 zeolite: The effect of mesopores. Chemical Engineering Science, 2017, 168: 352–359

23 Yang L, Liu Z, Liu Z, Peng W Y, Liu Y Q, Liu C G. Correlation between H-ZSM-5 crystal size and catalytic performance in the methanol-to-aromatics reaction. Chinese Journal of Catalysis, 2017, 38(4): 683–690

24 Zhou J, Liu Z, Li L, Wang Y G, Gao H X, Yang W M, Tang Y. Hierarchical mesoporous ZSM-5 zeolite with increased external surface acid sites and high catalytic performance in o-xylene isomerization. Chinese Journal of Catalysis, 2013, 34(7): 1429–1433

25 Jin H L, Ansari M B, Jeong E Y, Park S E. Effect of mesoporosity on selective benzylation of aromatics with benzyl alcohol over mesoporous ZSM-5. Journal of Catalysis, 2012, 291(7): 55–62

26 Gao X H, Tang Z C, Lu G X, Cao G Z, Li D, Tan Z G. Butene catalytic cracking to ethylene and propylene on mesoporous ZSM-5 by desilication. Solid State Sciences, 2010, 12(7): 1278–1282

27 Deng Q, Zhang X W, Wang L, Zou J J. Catalytic isomerization and oligomerization of endo-dicyclopentadiene using alkali-treated hierarchical porous HZSM-5. Chemical Engineering Science, 2015, 135(2): 540–546

28 Groen J C, Jansen J C, Moulijn J A, Perez-Ramirez J. Optimal aluminum-assisted mesoporosity development in MFI Zeolites by desilication. ChemInform, 2004, 35(45): 13062–13065

29 Cho H S, Ryoo R. Synthesis of ordered mesoporous MFI zeolite using CMK carbon templates. Microporous and Mesoporous Materials, 2012, 151(11): 107–112

30 Wang L F, Zhang Z, Yin C Y, Shan Z C, Xiao F S. Hierarchical mesoporous zeolites with controllable mesoporosity templated from cationic polymers. Microporous and Mesoporous Materials, 2010, 131(1–3): 58–67

31 Choi M, Cho H S, Srivastava R, Venkatesan C, Choi D H, Ryoo R. Amphiphilic organosilane-directed synthesis of crystalline zeolite with tunable mesoporosity. Nature Materials, 2006, 5(9): 718–723

32 Xiao Q, Yao Q S, Zhuang J, Liu G, Zhong Y J, Zhu W D. A localized crystallization to hierarchical ZSM-5 microspheres aided by silane coupling agent. Journal of Colloid and Interface Science, 2013, 394(1): 604–610

33 Serrano D P, Aguado J, Morales G, Rodríguez J M, Peral A, Thommes M, Epping J D, Chmelka B F. Molecular and meso- and macroscopic properties of hierarchical nanocrystalline ZSM-5 zeolite prepared by seed silanization. Chemistry of Materials, 2009, 21(4): 641–654

34 Serrano D P, Aguado J, Escola J M, Rodriguez J M, Peral A. Effect of the organic moiety nature on the synthesis of hierarchical ZSM-5 from silanized protozeolitic units. Journal of Materials Chemistry, 2008, 18(35): 4210–4218

35 Treacy M M J, Higgins J B. Collection of Simulated XRD Powder Patterns for Zeolites.Amsterdam: Elsevier, 2001, 21: 388–389

36 Serrano D P, Aguado J, Escola J M, Rodriguez J M, Peral A. Hierarchical zeolites with enhanced textural and catalytic properties synthesized from organofunctionalized seeds. Chemistry of Materials, 2006, 18(10): 2462–2464

37 Koohsaryan E, Anbia M. Nanosized and hierarchical zeolites: A short review. Chinese Journal of Catalysis, 2016, 37(4): 447–467

38 Jacobsen C J H, Madsen C, Houzvicka J, Schmidt I, Carlsson A. Mesoporous zeolite single crystals. Journal of the American Chemical Society, 2000, 122(29): 7116–7117

39 Miar Alipour S, Halladj R, Askari S, BagheriSereshki E. Low cost rapid route for hydrothermal synthesis of nano ZSM-5 with mixture of two, three and four structure directing agents. Journal of Porous Materials, 2016, 23(1): 145–155

40 Thommes M, Kaneko K, Neimark A V, Olivier J P, Rodriguez-Reinoso F, Rouquerol J, Sing K S W. Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IUPAC Technical Report). Pure and Applied Chemistry, 2015, 87(9–10): 1051–1069

41 Cychosz K A, Guillet-Nicolas R, García-Martínez J, Thommes M. Recent advances in the textural characterization of hierarchically structured nanoporous materials. Chemical Society Reviews, 2017, 46(2): 389–414

42 Christensen C H, Johannsen K, Törnqvist E, Schmidt I, Topsøe H, Christensen C H. Mesoporous zeolite single crystal catalysts: Diffusion and catalysis in hierarchical zeolites. Catalysis Today, 2007, 128(3–4): 117–122

43 Masuda T. Diffusion mechanisms of zeolite catalysts. ChemInform, 2004, 35(6): 133–144

44 Masuda T, Fujikata Y, Nishida T, Hashimoto K. The influence of acid sites on intracrystalline diffusivities within MFI-type zeolites. Microporous and Mesoporous Materials, 1998, 23(3): 157–167

45 Meunier F C, Verboekend D, Gilson J P, Groen J C, Pérez-Ramírez J. Influence of crystal size and probe molecule on diffusion in hierarchical ZSM-5 zeolites prepared by desilication. Microporous and Mesoporous Materials, 2012, 148(1): 115–121

46 Zhao H, Ma J H, Zhang Q Q, Liu Z P, Li R F. Adsorption and diffusion of n-heptane and toluene over mesoporous ZSM-5 zeolites. Industrial & Engineering Chemistry Research, 2014, 53(35): 13810–13819

47 Shetti V N, Kim J, Srivastava R, Choi M, Ryoo R. Assessment of the mesopore wall catalytic activities of MFI zeolite with mesoporous/microporous hierarchical structures. Journal of Catalysis, 2008, 254(2): 296–303

48 Javaid R, Urata K, Furukawa S, Komatsu T. Factors affecting coke formation on H-ZSM-5 in naphtha cracking. Applied Catalysis A: General, 2015, 491: 100–105

49 Kim J, Choi M, Ryoo R. Effect of mesoporosity against the deactivation of MFI zeolite catalyst during the methanol-to-hydrocarbon conversion process. Journal of Catalysis, 2010, 269(1): 219–228