Increasing environmental concerns coupled with increasing oil prices have led to bio- refmeries becoming attractive as a viable route for renewable energy from biowastes. This research focused on: three crucial steps in the production of value added intermediates in the biorefinery process: Hydrolysis of biomass waste producing sugars. Dehydration of sugar monomers producing furfural. Aldol condensation of furfural with acetone. The first step was concerned with the viability of the dilute acid hydrolysis of potato peel wastes to produce sugars. Acid concentrations and temperature were investigated to find optimum conditions. High phosphoric acid concentrations with low temperatures gave -the optimum yield of 55.2g sugars/lOOg of dry mass using 10% w/w phosphoric acid and a temperature of 408 K. The second step investigated the use of xylose for value added chemical production by catalytic dehydration to furfural, an aldehyde. To date, little was known about ." the exact reaction mechanism and kinetics involved. This work looked in detail at the reactions occurring within the liquid phase. A reaction mechanism was proposed and kinetic parameters estimated. The mechanism included isomerization of xylose to lyxose, dehydration of lyxose and xylose to furfural, fragmentation of furfural to organic acids, oligomerization of furfural to bi- and tridimensional furilic species, and complete dehydration of organic acids to carbonaceous deposits. Finally, the base catalysed aldol condensation of furfural with acetone was investigated. This reaction is a step in the production of bio-alkanes by lengthening the chain length so the resultant product is less volatile. Unlike sodium hydroxide used by comparative studies, charred dolomite as a novel solid base catalyst was employed. The properties of dolomite were studied using X-ray diffraction, scanning-electron-microscopy, thermo-gravimetric analysis, and were related to its catalytic activity. The reaction was found to be effectively catalysed by dolomite, attributed to the formation of hydroxyls within the catalyst when the charred dolomite is hydrated. ii
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:580169 |
| Date | January 2013 |
| Creators | O'Neill, R. E. |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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