Characterisation of bio-oil from fast pyrolysis of rice husk in a fluidised bed reactor

Fast pyrolysis of rice husk was conducted to produce bio-oil. The physical–chemical properties of the bio-oil were analysed. The results show that bio-oil has relatively high water content (47·05%), high ash content (0·29%), high carbon residue (5·84%) and low higher heating value (16·42 MJ kg−1). The density, kinetic viscosity at room temperature and pH value of the bio-oil were 1100 kg m−3, 3·41 mm2 s−1 and 3·23 respectively. Simultaneously, the kinetic viscosity of the bio-oil decreases significantly with increasing measurement temperature from 25 to 100°C, and its prominent viscosity–temperature characteristics were proved. Analysis of chemical functional groups and chemical structure of the bio-oil through Fourier transformation infrared spectrometer and Fourier transformation nuclear magnetic resonance technologies demonstrated the complexity of chemical compositions of the rice husk bio-oil.