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Operando magnetic resonance imaging of product distributions within the pores of catalyst pellets during Fischer–Tropsch synthesis

Nature Catalysis volume 6, pages 185–195 (2023)Cite this article

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Abstract

The optimization of a heterogeneous catalytic process requires characterization of the catalyst at industrially relevant conditions and length scales. Here we use magnetic resonance imaging to gain insight into the Fischer–Tropsch synthesis occurring in a pilot-scale fixed-bed reactor operating at 220 °C and 37 bar, for three H2/CO feed ratios. The molecular diffusion and carbon number of the hydrocarbon products are spatially resolved within both the reactor and individual 1 wt% Ru/TiO2 catalyst pellets. These data highlight the importance of mass transfer, in addition to the nanoscale catalyst activity, on catalyst performance. In particular, a start-up time of up to three weeks is required for the steady state to be achieved in the catalyst pores. Further, the average carbon number present in the pores can be as much as double that in the product wax. The operando characterization of water and oxygenates present in the pores is also achieved. The presence of a water-rich liquid at the pore surface is confirmed.

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Fig. 1: Schematic of the reactor and reaction data.
Fig. 2: Imaging catalyst bed structure and liquid distribution within the reactor.
Fig. 3: Effect of pore filling and mass transfer processes on catalyst selectivity.
Fig. 4: 2D maps of the average diffusion coefficient of intra-pellet products.
Fig. 5: Average carbon numbers of intra-pellet products.
Fig. 6: Carbon number distributions within an individual catalyst pellet.
Fig. 7: Comparison between the intra-pellet liquid products and collected wax.
Fig. 8: Operando characterization of water in catalyst pores.

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Data availability

The data that are used to produce the main text figures are available at https://doi.org/10.17863/CAM.92264. All data in the study are available from the corresponding author upon reasonable request.

References

  1. Grunwaldt, J. D., Hannemann, S., Schroer, C. G. & Baiker, A. 2D-mapping of the catalyst structure inside a catalytic microreactor at work: partial oxidation of methane over Rh/Al2O3. J. Phys. Chem. B 110, 8674–8680 (2006).

    Article  CAS  PubMed  Google Scholar 

  2. de Smit, E. et al. Nanoscale chemical imaging of a working catalyst by scanning transmission X-ray microscopy. Nature 456, 222–225 (2008).

    Article  PubMed  Google Scholar 

  3. Nijhuis, T. A., Tinnemans, S. J., Visser, T. & Weckhuysen, B. M. Towards real-time spectroscopic process control for the dehydrogenation of propane over supported chromium oxide catalysts. Chem. Eng. Sci. 59, 5487–5492 (2004).

    Article  CAS  Google Scholar 

  4. Urakawa, A., Maeda, N. & Baiker, A. Space- and time-resolved combined DRIFT and Raman spectroscopy: monitoring dynamic surface and bulk processes during NOx storage reduction. Angew. Chem. Int. Ed. 47, 9256–9259 (2008).

    Article  CAS  Google Scholar 

  5. Stavitski, E., Kox, M. H. F., Swart, I., de Groot, F. M. F. & Weckhuysen, B. M. In situ synchrotron-based IR microspectroscopy to study catalytic reactions in zeolite crystals. Angew. Chem. Int. Ed. 47, 3543–3547 (2008).

    Article  CAS  Google Scholar 

  6. Ulpts, J., Dreher, W., Klink, M. & Thoming, J. NMR imaging of gas phase hydrogenation in a packed bed flow reactor. Appl. Catal. A Gen. 502, 340–349 (2015).

    Article  CAS  Google Scholar 

  7. Baker, L. et al. Operando magnetic resonance studies of phase behaviour and oligomer accumulation within catalyst pores during heterogeneous catalytic ethene oligomerization. Appl. Catal. A Gen. 557, 125–134 (2018).

    Article  CAS  Google Scholar 

  8. Weckhuysen, B. M. Chemical imaging of spatial heterogeneities in catalytic solids at different length and time scales. Angew. Chem. Int. Ed. 48, 4910–4943 (2009).

    Article  CAS  Google Scholar 

  9. Meirer, F. & Weckhuysen, B. M. Spatial and temporal exploration of heterogeneous catalysts with synchrotron radiation. Nat. Rev. Mater. 3, 324–340 (2018).

    Article  Google Scholar 

  10. Weber, D., Holland, D. J. & Gladden, L. F. Spatially and chemically resolved measurement of intra- and inter-particle molecular diffusion in a fixed-bed reactor. Appl. Catal. A Gen. 392, 192–198 (2011).

    Article  CAS  Google Scholar 

  11. Bouchard, L. S. et al. NMR imaging of catalytic hydrogenation in microreactors with the use of para-hydrogen. Science 319, 442–445 (2008).

    Article  CAS  PubMed  Google Scholar 

  12. Jarenwattananon, N. N. et al. Thermal maps of gases in heterogeneous reactions. Nature 502, 537–540 (2013).

    Article  CAS  PubMed  Google Scholar 

  13. Burueva, D. B. et al. In situ monitoring of heterogeneous catalytic hydrogenation via 129Xe NMR spectroscopy and proton MRI. ACS Catal. 10, 1417–1422 (2020).

    Article  CAS  Google Scholar 

  14. Kuppers, M., Heine, C., Han, S., Stapf, S. & Blumich, B. In situ observation of diffusion and reaction dynamics in gel microreactors by chemically resolved NMR microscopy. Appl. Magn. Reson. 22, 235–246 (2002).

    Article  Google Scholar 

  15. Nicholas, C. P. Applications of light olefin oligomerization to the production of fuels and chemicals. Appl. Catal. A Gen. 543, 82–97 (2017).

    Article  CAS  Google Scholar 

  16. James, O. O., Chowdhury, B., Mesubi, M. A. & Maity, S. Reflections on the chemistry of the Fischer–Tropsch synthesis. RSC Adv. 2, 7347–7366 (2012).

    Article  CAS  Google Scholar 

  17. Wood, D. A., Nwaoha, C. & Towler, B. F. Gas-to-liquids (GTL): a review of an industry offering several routes for monetizing natural gas. J. Nat. Gas. Sci. Eng. 9, 196–208 (2012).

    Article  CAS  Google Scholar 

  18. Ail, S. S. & Dasappa, S. Biomass to liquid transportation fuel via Fischer Tropsch synthesis – technology review and current scenario. Renew. Sust. Energ. Rev. 58, 267–286 (2016).

    Article  CAS  Google Scholar 

  19. Gao, R. X. et al. Green liquid fuel and synthetic natural gas production via CO2 hydrogenation combined with reverse water-gas-shift and Co-based Fischer-Tropsch synthesis. J. CO2 Util. 51, 101619 (2021).

  20. Iglesia, E. Design, synthesis, and use of cobalt-based Fischer-Tropsch synthesis catalysts. Appl. Catal. A Gen. 161, 59–78 (1997).

    Article  CAS  Google Scholar 

  21. Pohlmann, F. & Jess, A. Interplay of reaction and pore diffusion during cobalt-catalyzed Fischer–Tropsch synthesis with CO2-rich syngas. Catal. Today 275, 172–182 (2016).

    Article  Google Scholar 

  22. Papavasileiou, K. D. et al. Molecular dynamics simulation of the n-octacosane-water mixture confined in hydrophilic and hydrophobic mesopores: the effect of oxygenates. Fluid Phase Equilib. 526, 112816 (2020).

  23. Williams, J. et al. In situ determination of carbon number distributions of mixtures of linear hydrocarbons confined within porous media using pulsed field gradient NMR. Anal. Chem. 92, 5125–5133 (2020).

    Article  CAS  PubMed  Google Scholar 

  24. Freed, D. E., Burcaw, L. & Song, Y. Q. Scaling laws for diffusion coefficients in mixtures of alkanes. Phys. Rev. Lett. 94, 067602 (2005).

  25. Madon, R. J. & Iglesia, E. The importance of olefin readsorption and H2/CO reactant ratio for hydrocarbon chain growth on ruthenium catalysts. J. Catal. 139, 576–590 (1993).

    Article  CAS  Google Scholar 

  26. Kuipers, E. W., Vinkenburg, I. H. & Oosterbeek, H. Chain-length dependence of α-olefin readsorption in Fischer-Tropsch synthesis. J. Catal. 152, 137–146 (1995).

    Article  CAS  Google Scholar 

  27. Lillebo, A., Rytter, E., Blekkan, E. A. & Holmen, A. Fischer–Tropsch synthesis at high conversions on Al2O3-supported Co catalysts with different H2/CO levels. Ind. Eng. Chem. Res. 56, 13282–13287 (2017).

    Article  Google Scholar 

  28. Schurm, L., Kern, C. & Jess, A. Accumulation and distribution of higher hydrocarbons in the pores of a cobalt catalyst during low-temperature Fischer–Tropsch fixed-bed synthesis. Catal. Sci. Technol. 11, 6143–6154 (2021).

    Article  CAS  Google Scholar 

  29. Pinard, L. et al. Identification of the carbonaceous compounds present on a deactivated cobalt based Fischer–Trospch catalyst resistant to “rejuvenation treatment”. Appl. Catal. A Gen. 406, 73–80 (2011).

    Article  CAS  Google Scholar 

  30. Bukur, D. B., Mandic, M., Todic, B. & Nikacevic, N. Pore diffusion effects on catalyst effectiveness and selectivity of cobalt based Fischer-Tropsch catalyst. Catal. Today 343, 146–155 (2020).

    Article  CAS  Google Scholar 

  31. Krishnamoorthy, S., Tu, M., Ojeda, M. P., Pinna, D. & Iglesia, E. An investigation of the effects of water on rate and selectivity for the Fischer–Tropsch synthesis on cobalt-based catalysts. J. Catal. 211, 422–433 (2002).

    Article  CAS  Google Scholar 

  32. Terenzi, C., Sederman, A. J., Mantle, M. D. & Gladden, L. F. Enabling high spectral resolution of liquid mixtures in porous media by antidiagonal projections of two-dimensional 1H NMR COSY spectra. J. Phys. Chem. Lett. 10, 5781–5785 (2019).

    Article  CAS  PubMed  Google Scholar 

  33. Mandic, M., Todic, B., Zivanic, L., Nikacevic, N. & Bukur, D. B. Effects of catalyst activity, particle size and shape, and process conditions on catalyst effectiveness and methane selectivity for Fischer–Tropsch reaction: a modeling study. Ind. Eng. Chem. Res. 56, 2733–2745 (2017).

    Article  CAS  Google Scholar 

  34. Hubble, R., York, A. P. E. & Dennis, J. S. Modelling reaction and diffusion in a wax-filled hollow cylindrical pellet of Fischer Tropsch catalyst. Chem. Eng. Sci. 207, 958–969 (2019).

    Article  CAS  Google Scholar 

  35. Marano, J. J. & Holder, G. D. Characterization of Fischer-Tropsch liquids for vapor-liquid equilibria calculations. Fluid Phase Equilib. 138, 1–21 (1997).

    Article  CAS  Google Scholar 

  36. Pohlmann, F., Kern, C., Rossler, S. & Jess, A. Accumulation of liquid hydrocarbons in catalyst pores during cobalt-catalyzed Fischer–Tropsch synthesis. Catal. Sci. Technol. 6, 6593–6604 (2016).

    Article  Google Scholar 

  37. Bezemer, G. L., Remans, T. J., van Bavel, A. P. & Dugulan, A. I. Direct evidence of water-assisted sintering of cobalt on carbon nanofiber catalysts during simulated Fischer–Tropsch conditions revealed with in situ Mössbauer spectroscopy. J. Am. Chem. Soc. 132, 8540–8541 (2010).

    Article  CAS  PubMed  Google Scholar 

  38. Kliewer, C. E., Soled, S. L. & Kiss, G. Morphological transformations during Fischer-Tropsch synthesis on a titania-supported cobalt catalyst. Catal. Today 323, 233–256 (2019).

    Article  CAS  Google Scholar 

  39. Zheng, Q. et al. Water-wax behaviour in porous silica at low temperature Fischer–Tropsch conditions. Appl. Catal. A Gen. 572, 142–150 (2019).

    Article  CAS  Google Scholar 

  40. Liu, G., Li, Y. & Jonas, J. Confined geometry effects on reorientational dynamics of molecular liquids in porous silica glasses. J. Chem. Phys. 95, 6892–6901 (1991).

    Article  CAS  Google Scholar 

  41. Taylor, K. C. Determination of ruthenium surface areas by hydrogen and oxygen chemisorption. J. Catal. 38, 299–306 (1975).

    Article  CAS  Google Scholar 

  42. Hennig, J., Nauerth, A. & Friedburg, H. RARE imaging: a fast imaging method for clinical MR. Magn. Reson. Med. 3, 823–833 (1986).

    Article  CAS  PubMed  Google Scholar 

  43. Cotts, R. M., Hoch, M. J. R., Sun, T. & Markert, J. T. Pulsed field gradient stimulated echo methods for improved NMR diffusion measurements in heterogeneous systems. J. Magn. Reson. 83, 252–266 (1989).

    CAS  Google Scholar 

  44. Williams, J. Magnetic Resonance Studies of the Diffusion Dynamics of Molecular Systems Relevant to Fischer-Tropsch Catalysis. PhD thesis, Univ. of Cambridge (2020).

  45. Markley, J. L., Horsley, W. J. & Klein, M. P. Spin-lattice relaxation measurements in slowly relaxing complex spectra. J. Chem. Phys. 55, 3604–3605 (1971).

    Article  CAS  Google Scholar 

  46. Mitchell, J., Chandrasekera, T. C., Johns, M. L., Gladden, L. F. & Fordham, E. J. Nuclear magnetic resonance relaxation and diffusion in the presence of internal gradients: the effect of magnetic field strength. Phys. Rev. E 81, 026101 (2010).

  47. Mitchell, J., Chandrasekera, T. C. & Gladden, L. F. Numerical estimation of relaxation and diffusion distributions in two dimensions. Prog. Nucl. Magn. Reson. Spectrosc. 62, 34–50 (2012).

    Article  CAS  PubMed  Google Scholar 

  48. Zheng, Q. et al. Experimental determination of H2 and CO diffusion coefficients in a wax mixture confined in a porous titania catalyst support. J. Phys. Chem. B 124, 10971–10982 (2020).

    Article  CAS  PubMed  Google Scholar 

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Acknowledgements

We thank P. Munnik for catalyst synthesis and J. Chen for calculations and simulation studies supporting this work. This work was funded by Shell Global Solutions International B.V. Q.Z. thanks the IChemE Andrew Fellowship for additional financial support. For the purpose of open access, the authors have applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission.

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Authors and Affiliations

  1. Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK

    Qingyuan Zheng, Jack Williams, Léonard R. van Thiel, Scott V. Elgersma, Mick D. Mantle, Andrew J. Sederman & Lynn F. Gladden

  2. Shell Global Solutions International B.V., Amsterdam, Netherlands

    Timothy A. Baart, G. Leendert Bezemer & Constant M. Guédon

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Contributions

Q.Z. led the experimental design, the data acquisition and interpretation and the writing of the manuscript. J.W. was also involved in the data collection, and developed and applied the analysis for transforming the diffusion measurements into hydrocarbon chain length data. L.R.v.T. and S.V.E. contributed to the experimental design and data acquisition, and design of the reaction engineering set-up. T.A.B. and C.M.G. helped design the experiments and provided the catalyst materials. L.F.G., M.D.M. and A.J.S. oversaw the project and worked with the coauthors to analyse and interpret the data obtained. J.W., T.A.B., G.L.B., C.M.G., M.D.M., A.J.S. and L.F.G. edited and revised the manuscript.

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Correspondence to Lynn F. Gladden.

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Zheng, Q., Williams, J., van Thiel, L.R. et al. Operando magnetic resonance imaging of product distributions within the pores of catalyst pellets during Fischer–Tropsch synthesis. Nat Catal 6, 185–195 (2023). https://doi.org/10.1038/s41929-023-00913-8

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