Fast Pyrolysis of Oil Mallees Woody Biomass
Covering 15 percent of pasture and cereal-growing fields with mallee alleys is a goal to alleviate the soil salinity problems in the Western Australian wheatbelt. The social and economic benefits of this practice are the main reasons for the birth of a new industry processing oil mallee woody biomass. This study aims to investigate the production of crude bio-oils from the pyrolysis of mallee woody biomass at fast heating rates and to explore the potentials of these liquids as a source of transportation fuels. The mallee feedstock was ground and sieved to several narrow particle size ranges prior to pyrolysis in a novel lab-scale fluidised-bed pyrolysis reactor. Pyrolysis tests were carried out at temperatures between 350 and 600 oC to study the effects of temperature on the yield and fuel properties of bio-oils. The effects of feedstock particle size on the fuel properties of bio-oils were also studied within a particle diameter range of 100 and 600 microns. The crude bio-oils thus produced were characterised using solvent extraction, thermogravimetric analysis, GC-MS, Karl Fisher titration and UV-fluorescence spectroscopy. Some other common fuel properties like density, viscosity and surface tension were also measured. Our results indicate that the crude bio-oils can potentially be refined to produce valuable liquid transportation fuels. An overview of the foreseeable technical problems in the use of crude bio-oils as transportation fuels as well as its potential as a feedstock for bio-refineries will also be presented.