Contributions of acid and metal sites fo propane aromatisation over fresh Ga, H-ZSM-5 catalyst
Abstract
A kinetic modelling has been developed to describe the aromatisation of propane over fresh H-ZSM-5 and Ga, H-ZSM-S5 catalysts at 500°C. It was shown that the introduction of metal into H-ZSM-5 has enhanced both the yield and selectivity of aromatics and that the conversion of propane is mainly due to the dehydrogenation step over metal sites. Over Ga, H-ZSM-5 catalyst, the contribution of hydrogen transfer steps (between the feed alkane and alkenes adsorbed over acid sites) to the conversion of alkane is reduced considerably.
On the other hand, the formation of aromatics is mainly from aromatisation steps over metal sites. As a result of the alkane dehydrogenation and alkene aromatisation steps over metal sites, the hydrogen yield is observed to increase in comparison with the hydrogen yield for the transformation over H-ZSM-5.
References
2. Kwak, B. S., Sachtler, W. M. H. and Hagg, W. О. Catalytic conversion of propane to aromatics: Effects of adding Ga and/or to HZSM-5. J. Catal. 1994; 149: p. 465 - 473.
3. Biscardi, J.A., and Iglesia, E. Reaction pathways and rate-determining steps in reactions of alkanes on HZSM-5 and Zn/HZSM-5 catalysts. J. Catal. 1999; 182: p. 117 - 128.
4. El-Malki, El-M., van Santen, R. A. and Sachtler, W. M. H., 1999. Introduction of Zn, Ga, and Fe into HZSM-5 cavities by sublimation: Identification of acid sites. J. Phys. Chem. B 103, p.4611 - 4622.
5. Lukyanov, D. B. Development of kinetic models for reactions of light hydrocarbons over ZSM-5 catalysts. experimental studies and kinetic modelling of ethane transformation and deactivation of HZSM-5 catalyst, in: Froment, G.F., and Waugh, K. C. (Eds.). Reaction kinetics and the development of catalytic process, Stud. Surf. Sci. Catal. 1999; 122: p. 299 - 306.
6. Nguyen, L. H., Vazhnova, T., Kolaczkowski, S. T., and Lukyanov, D. B. Combined experimental and kinetic modelling studies of the pathways of propane and n-Butane aromatization over H-ZSM-5 catalyst. Chemical engineering science. 2006; 61: p. 5881 - 5894.
7. Turner, J. CE30062 Research project report, department of chemical engineering. University of Bath 2003.
8. Berger, R.J., Stitt, E.H., Marin, G. B., Kapteijn, F, and Moulijn, J. A. Chemical reaction kinetics in practice. 2001; cattech 5 (1): p. 30 - 60.
9. Nguyen Huu Luong and Dmitry B. Lukyanov. Development of a kinetic model for the aromatization of propane and propene over H-ZSM-5 catalyst under deactivating conditions. Petrovietnam Journal. 2011; Vol. 6: р.74 - 78.
1. The Author assigns all copyright in and to the article (the Work) to the Petrovietnam Journal, including the right to publish, republish, transmit, sell and distribute the Work in whole or in part in electronic and print editions of the Journal, in all media of expression now known or later developed.
2. By this assignment of copyright to the Petrovietnam Journal, reproduction, posting, transmission, distribution or other use of the Work in whole or in part in any medium by the Author requires a full citation to the Journal, suitable in form and content as follows: title of article, authors’ names, journal title, volume, issue, year, copyright owner as specified in the Journal, DOI number. Links to the final article published on the website of the Journal are encouraged.
