H2-poor bio-syngas in Fischer-Tropsch synthesis over un-promoted and rhenium promoted alumina-supported cobalt catalysts: Effect of water addition

  • Dewi Tristantini Department of Chemical Engineering, University of Indonesia, Depok, INDONESIA
  • Borje Gevert Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, SWEDEN
Keywords: Adsorption H2-poor bio-syngas, Fischer-Tropsch Synthesis, Water-Gas Shift, Cobalt, Rhenium-Cobalt Alumina, molar H2/CO-ratios

Abstract

The effect of water addition on Fischer-Tropsch synthesis (FTS) over 12%Co/Al2O3 and 12%Co-0.5%Re/Al2O3 catalysts was investigated in a fixed bed reactor with model mixtures of biomass-derived syngas (bio-syngas). The bio-syngas model mixtures consist of H2 and CO of different molar H2/CO-ratios (1.0, 1.5 and 2.1). The FT-reaction requires a H2/CO molar ratio of approximately 2.1 above the catalyst surface. For the ratios lower than 2.1, an in situ water-gas shift (WGS) activity is desired in order to increase the H2/CO-ratio. However, the studied catalysts had quite low WGS activities. The addition of water slightly increased the WGS activity for all types of bio-syngases and for both catalysts. The highest WGS activity was found for the un-promoted Co-catalyst at the inlet H2/CO-ratio = 1.0. Water addition also results in an increase in selectivity to C5+ and a decrease in selectivity to CH4 . Interestingly, for both of catalysts the selectivity to C5+ and CH4 were rather similar for inlet H2/CO-ratios of 2.1 and 1.5, while the highest selectivity to C5+ and the lowest selectivity to CH4 were also found for the inlet ratio = 1.0. All catalysts were deactivated by water addition but the catalyst activity is partly recovered in H2/CO-ratio inlets = 1.0 and 1.5. The Co/Al2O3 was affected by water more severely in H2/CO ratios = 2.1. The Re-promoted Co catalyst was considerably more active and selective to longer hydrocarbons than the un- promoted one. The conclusion of this study is that in order to utilize the advantages of a bio-syngas with a low H2 content (higher selectivity to C5+ , lower selectivity to CH4, no WGS-unit needed prior to FT-reactor), the catalyst must possess a much higher WGS activity than the ones studied.

References

1. Aaserud, C. , Hilmen, A.M. , Bergene, E., Eri, S. , Schanke, D,. Holmen,A. (2004) Catal. Lett. 94, 171.
2. Bertole, C.J. , Mims, C.A. , Kiss, G. (2002) J. Catal. 213, 84.
3. Ekstrom, A. and Lapszewicz, J. (1986) Appl. Cat. 21, 111.
4. Hilmen, A.M., Lindvåg, O.A., Bergene, E., Schanke, D., Eri, S., Holmen, A. (2001) Stud. Surf. Sci. Catal. 106, 295.
5. Hilmen, A.M., Schanke, D., Hanssen, K.F., Holmen, A. (1999) Appl. Catal. A 186, 169.
6. Huber, G.W., Guymon, C.G., Conrad, T.L., Stephenson, B.C., Bartholomew, C.H. (2001) Stud. Surf. Sci. Catal. 109, 423.
7. Iglesia, E. (1997) Appl. Catal. A 161, 59.
8. Jacobs, G., Patterson, P.M., Zhang, Y., Das, T., Li, J., Davis, B.H. (2002) Appl. Catal. 233, 215.
9. Kim, C.J. (1993) US patent 5, 227, 407.
10. Krishnamoorthy, S., Tu, M., Ojeda, M.P., Pinna, D., Iglesia, E. (2002) J. Catal. 211, 422.
11. Li, J., Jacobs, G., Das, T., Davis, B.H. (2002) Appl. Cat. A, 233, 255.
12. Li, J., Jacobs, G., Zhang, Y., Das, T., Davis, B.H. (2002) Appl. Catal. A 236, 67.
13. Minderhoud, J.K. , Post, M.F.M. , Sie, S.T. (1984) Eur. Past. Appl.
14. Rofer-de-Poorter, C.K. (1984) in Catalytic Conversion of Synthesis Gas and Alcohols Chemicals (R.G. Herman, ed.), Plenum Press, New York.
15. Schanke, D., Hilmen, A.M., Bergene, E., Kinnari, K., Rytter, E. Ådnanes, E., Holmen, A. (1995) Catal. Lett. 34, 269
16. Schulz, H., van Steen, E., Claes, M. (1994) Stud. Surf. Sci. Catal. 8, 445.
17. Storsæter, S., Borg, Ø., Blekkan, E.A., Tøtdal, B., 405. Storsæter, S., Borg, Ø., Blekkan, E.A.,
18. Tøtdal, B., Holmen, A. (2005), Catal. Today 130, 343.
19. Tristantini, D., Lögdberg, S., Gevert, B., Borg, Ø., Holmen, A. 2006 Proceeding of 231st ACSNational Meeting, Atlanta, GA, USA, March 26-30.
20. Van Der Laan, G.P. and Beenackers, A.A.C.M. (1999) Catal. Rev.-Sci. Eng. 41, 255.
21. Yates, I.C. and Satterfield, C. N. (1991) Energy& Fuels, 5, 168.
22. Zhang, Y., Wei, D., Hammache, S. and Goodwin, J.G. Jr. (1999) J. Catal. 188, 281.
23. Zowtiak, J.M. , Weatherbee, G.D. , Bartholomew, C.H. (1983)J. Catal. 82, 230.
Published
2009-12-31
How to Cite
Tristantini, D., & Gevert, B. (2009). H2-poor bio-syngas in Fischer-Tropsch synthesis over un-promoted and rhenium promoted alumina-supported cobalt catalysts: Effect of water addition. ASEAN Journal of Chemical Engineering, 9(1), 1-10. Retrieved from https://jurnal.ugm.ac.id/v3/AJChE/article/view/7704
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Articles