Increasing energy demands in the transport sector, combined with the scarcity of fossil energy sources and the need for climate protection, illustrate the importance of finding alter-native and CO2-neutral sources of energy. This thesis presents the results of research concerning the behaviour of cracked vegetable oil (CVO) during hydroprocessing. The product “hydrogenated cracked vegetable oil” (HCVO) could be an alternative renewable diesel fuel. The experiments were conducted in a high pressure, high temperature reactor. The parameters of investigation under hydrogen atmosphere were: temperature (150-450 °C), initial hydrogen pressure (50-150 bar), and reaction time (1-20 h). These experiments were either thermal or catalytic, whereas the type (CoMo, NiMo and Pd+Pt on Al2O3, HZSM5, Pd and Pt on carbon) and quantity of the catalyst (0.5-5 wt.-%) were additional parameters. Furthermore the influence of an inert reaction atmosphere was investigated. The optimal reaction temperature regarding deoxygenation without coke formation during hydroprocessing was found to be 380 °C. An increase of reaction time, as well as higher initial hydrogen pressure led to increased energy density in the product – the only exceptions were the Pt catalyst and HZSM5, where the gross calorific value (gcv) remained constant with in-creased initial pressure from 100 to 150 bar. Density, viscosity, acid value, iodine number, energy density, chemical and elemental com-position of the HCVO were analysed and evaluated in relation to CVO and diesel fuel. The highest gcv was 46.1 MJ/kg using the Pt catalyst; CoMo, NiMo and Pd led to 44.8-45.1 MJ/kg. These are comparable to diesel fuel. A kinetic model was developed to estimate the thermal deoxygenation of CVO at different reaction temperatures. Absorption of hydrogen in the liquid phase was investigated in catalytic and non-catalytic processing. In the presence of precious metal catalysts, substantial absorption of hydrogen and therefore extensive deoxygenation and saturation of double bonds in CVO were observed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:627906 |
| Date | January 2013 |
| Creators | Sievers, Anika |
| Publisher | University of the West of Scotland |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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