This research investigates the influence of pyrolysis on the properties of several biomasses in the context of heating fuel production for the first time. Laboratory-scale torrefaction, pilot-scale pyrolysis and product development trials have been conducted. Laboratory-scale tests found that torrefaction at 350°C for 30 minutes results in a reduction in volatile content of all investigated biomasses (pine, eucalyptus, hardwood, PKS, almond shell and olive stone) from approximately 80% to 30% indicating suitability for inclusion in smokeless fuels. Meanwhile an increase in gross heating value from 18 MJ/kg up to 28 MJ/kg and a concentration in carbon content indicate a shift in properties towards those similar to medium-ranked coals. Pilot-scale investigations reveal PKS as the preferred biomass for inclusion in domestic heating fuels. Following pyrolysis at 700°C PKS was found to exhibit superior mass and energy yields of 27% and 41%, respectively, when compared to olive stone, almond shell and hardwood. Additionally, thermogravimetric techniques have shown PKS chars to be the least intrinsically reactive with burnout times of 160 minutes following pyrolysis at 700 °C compared to only 15 - 30 minutes for equivalent almond shell, olive stone and hardwood chars. Product development trials indicate that briquetted fuels containing PKS char produced at 500°C possess better physical properties at all bio-char inclusion rates (30 - 100 wt. %). Open fire tests demonstrate that intrinsic char reactivity provides a good indication of combustion behaviour with briquettes containing PKS-derived chars resulting in fires lasting up to 100 minutes longer than those containing almond shell and olive stone chars. Finally, NMR investigations have demonstrated that torrefaction at 350°C results in an increase in aromatic carbon content of biomasses of up to 56% and in-situ NMR techniques have been used for the first time to follow the real-time high-temperature curing process of molasses.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:727639 |
| Date | January 2015 |
| Creators | Lenthall, Joanna |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0019 seconds