Influence of storage temperature on stability of physicochemical properties of sawdust pyrolysis bio-oil

For the objective of understanding stability difference of physicochemical properties of bio-oil under different storage temperature, bio-oil from pine sawdust pyrolysis with a bubbling fluidized bed reactor was used as sample to investigate properties variation regulation of two groups of bio-oil (No 1 and No 2) stored in 35 days under different storage temperatures (4℃, 27℃, 40℃). FTIR and GC-MS analysis were also conducted pre and post storage under 40℃ on bio-oil No 2. The results indicated that low temperature (4℃) brought about the reduction of water content of bio-oil while normal and high temperature (27℃, 40℃) did the inverse effect. The increase of kinematical viscosity of bio-oil had a close relationship with storage temperature without the disturbance of water. Higher temperature caused greater increase of kinematical viscosity of bio-oil. pH value had a slight variation and no obvious regulation could be found under all three storage temperature. Frequency shifting and variation of light transmittance from FTIR analysis showed that the violent movement of electron on different functional groups intensified the interaction of molecular in bio-oil. GS-MS analysis demonstrated that the composition of bio-oil became more complex because some reactions were catalyzed after 35 days storage under high temperature. Therefore, low temperature has the best effect on controlling the stability of bio-oil