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Vanadia Promoted Co-AI20 3 Fischer-Tropsch Catalysts
Bibliography: leaves 117-124.
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| Format: | Thesis |
| Language: | English |
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Department of Chemical Engineering
2014
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| _version_ | 1867613210854555648 |
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| access_status_str | Open Access |
| author | Zwane, Seneliso T |
| author2 | Van Steen, Eric |
| author_browse | Van Steen, Eric Zwane, Seneliso T |
| author_facet | Van Steen, Eric Zwane, Seneliso T |
| author_sort | Zwane, Seneliso T |
| collection | Thesis |
| description | Bibliography: leaves 117-124. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/6760 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:31.718Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2014 |
| publishDateRange | 2014 |
| publishDateSort | 2014 |
| publisher | Department of Chemical Engineering |
| publisherStr | Department of Chemical Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/6760 Vanadia Promoted Co-AI20 3 Fischer-Tropsch Catalysts Zwane, Seneliso T Van Steen, Eric Chemical Engineering Bibliography: leaves 117-124. The primary aim of this work was to study systematically V20 5 promotion on yAI203 supported cobalt-based Fischer-Tropsch catalysts. The y-Ah03 support was modified by addition of varying amounts of vanadia and was subsequently loaded with the same Co content (10 wt-%). The modified supports and catalysts were characterised using conventional characterisation methods. The physio-chemical properties of the vanadia promoted supports and catalysts were characterised using Atomic Adsorption Spectroscopy (AAS), zeta-potential measurements, and BET measurements, X-ray Diffraction (XRD), Temperature Programmed Reduction (TPR), Transmission Electron Microscopy (TEM), and CO chemisorption. Catalyst performance in the Fischer-Tropsch synthesis was tested in fixed bed reactor. A catalysts synthesised from plain y-A1203 was used as a base catalyst. Characterization results show that modification of y-Ab03 support to obtain V205 loadings beyond 1-monolayer vanadia coverage was difficult when using ion exchange. Ion-exchange equilibrium limitations might have caused the poor vanadia loadings beyond 1-monolayer coverage. The supports net surface charge as measured using zeta potential, was decreased by vanadia content in the supports. CO chemisorption results were complex and could only be modelled using dual site Langmuir model assuming the presence of two different sites absorbing CO on the Co-V-AI catalyst system. This made extraction of physical properties from this method rather difficult. Fischer Tropsch synthesis reaction was carried out at typical industrial conditions (T=220°C, P=20 bar (a), H2/CO=2 Xco-60 mol-%) for cobalt catalysts. Vanadia promoted catalysts showed a marked decrease in initial activity. However, the overall deactivation rate was lower with increasing vanadia content. The vanadia content did not affect the chain growth kinetic behavior of the catalyst in the Fischer-Tropsch synthesis hence C5+ selectivity in the Fischer-Tropsch synthesis was unperturbed by vanadia content. Increasing the vanadia content in the catalyst resulted in high n-olefin content and high 1-olefin content. The observed increase in olefin content might be due to the low catalytic activity observed for the catalysts with high vanadia loadings. The most pronounced effect of vanadia promotion on Fischer Tropsch synthesis was in the oxygenate content in the Fischer-Tropsch product. Catalysts with high vanadia loading yielded high amounts of oxygenate products; mainly alcohols and aldehydes. 2014-08-29T12:45:41Z 2014-08-29T12:45:41Z 2004 Master Thesis Masters MSc http://hdl.handle.net/11427/6760 eng application/pdf Department of Chemical Engineering Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Chemical Engineering Zwane, Seneliso T Vanadia Promoted Co-AI20 3 Fischer-Tropsch Catalysts |
| thesis_degree_str | Master's |
| title | Vanadia Promoted Co-AI20 3 Fischer-Tropsch Catalysts |
| title_full | Vanadia Promoted Co-AI20 3 Fischer-Tropsch Catalysts |
| title_fullStr | Vanadia Promoted Co-AI20 3 Fischer-Tropsch Catalysts |
| title_full_unstemmed | Vanadia Promoted Co-AI20 3 Fischer-Tropsch Catalysts |
| title_short | Vanadia Promoted Co-AI20 3 Fischer-Tropsch Catalysts |
| title_sort | vanadia promoted co ai20 3 fischer tropsch catalysts |
| topic | Chemical Engineering |
| url | http://hdl.handle.net/11427/6760 |
| work_keys_str_mv | AT zwanesenelisot vanadiapromotedcoai203fischertropschcatalysts |