Due to the combined heavy dependence on crude oil and the unpredictable nature of the associated markets, an alternative means to produce the required hydrocarbon based products is much desired. The Fischer-Tropsch synthesis provides a route to the production of synthetic crude oil by a catalytic reaction between carbon monoxide and hydrogen (collectively referred to as syngas) at moderate temperatures and pressures. First discovered in the early 1900's, the process results in a multitude of products which can supply a range of transportation fuels and petrochemicals. However, knowledge of the reaction process is still not completely understood due to the complex product distribution which is obtained. In order to gain better control over the process outputs, enhancing the understanding of the mechanistic routes which govern the overall reaction is key. A novel route was developed to monitor the number and length of hydrocarbon species which accumulate and grow on the catalyst surface during the reaction by implementing in situ quantitative FTIR spectroscopy. Initially molar absorption coefficients, required in order to quantify the adsorbed hydrocarbon species, were determined utilising a custom made thermogravimetric infrared cell. The resulting absorption coefficients values were then applied to data which was derived from infrared spectra collected for various catalysts during multiple Fischer-Tropsch reactions. The quantitative analysis of the catalyst surface was then compared with reaction data collected using gas chromatography (GC), in order to investigate if a link exists between the surface species and reaction products. Results showed that while no direct link was detected, the observed surface species could be attributed to oxygenate products of the Fischer-Tropsch reaction which are not produced in a detectable amount by GC. The species were shown to reside on both the metal and support material, with the transportation mechanism to the support also investigated.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:737942 |
| Date | January 2017 |
| Creators | McNab, Andrew Irvine |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=235995 |
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