Thermochemical characterisation of various biomass feedstock and bio-oil generated by fast pyrolysis

  • Charles Greenhalf

Student thesis: Doctoral ThesisDoctor of Philosophy


The projected decline in fossil fuel availability, environmental concerns, and security of supply attract increased interest in renewable energy derived from biomass. Fast pyrolysis is a possible
thermochemical conversion route for the production of bio-oil, with promising advantages. The purpose of the experiments reported in this thesis was to extend our understanding of the fast pyrolysis process for straw, perennial grasses and hardwoods, and the implications of selective
pyrolysis, crop harvest and storage on the thermal decomposition products. To this end, characterisation and laboratory-scale fast pyrolysis were conducted on the available feedstocks, and their products were compared. The variation in light and medium volatile decomposition products was investigated at different pyrolysis temperatures and heating rates, and a comparison of fast and
slow pyrolysis products was conducted. Feedstocks from different harvests, storage durations and locations were characterised and compared in terms of their fuel and chemical properties. A range of analytical (e.g. Py-GC-MS and TGA) and processing equipment (0.3 kg/h and 1.0 kg/h fast pyrolysis
reactors and 0.15 kg slow pyrolysis reactor) was used. Findings show that the high bio-oil and char heating value, and low water content of willow short rotation coppice (SRC) make this crop attractive for fast pyrolysis processing compared to the other
investigated feedstocks in this project. From the analytical sequential investigation of willow SRC, it was found that the volatile product distribution can be tailored to achieve a better final product, by a variation of the heating rate and temperature. Time of harvest was most influential on the fuel
properties of miscanthus; overall the late harvest produced the best fuel properties (high HHV, low
moisture content, high volatile content, low ash content), and storage of the feedstock reduced the moisture and acid content.
Date of Award8 Jan 2014
Original languageEnglish
SupervisorJames O Titiloye (Supervisor) & Tony Bridgwater (Supervisor)


  • sequential pyrolysis
  • selective pyrolysis
  • Py-GC-MS
  • thermogravimetric analysis
  • biomass storage

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