Development of bio oil and bio asphalt by hydrothermal liquefaction using lignocellulose

Bio asphalt is an organic polymer derived from biomass resources, which has the potential to partially or completely replace petroleum asphalt. This study used lignocellulose to prepare bio oil by hydrothermal liquefaction method. A mixed solvent of ethanol and ethylene glycol was introduced to increase the oil yield and decrease the reaction temperature. The oil yield reached the highest when solvent mixing ratio of 1:1, liquid-solid ratio of 6:1, catalyst dosage of 3%, and reaction temperature of 250 degrees C respectively. The bio oil and 50# asphalt were mixed in proportion sheared for 30 min (1000 rpm) under the condition of 135 degrees C to produce bio asphalt. The chemical structures and rheological properties of bio oil and bio asphalt were investigated and compared with petroleum asphalt. Fourier transform infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance analysis indicate that the bio oil expressed a lower H/C ratio, higher O content and more light components including liquid compounds comparing to the petroleum asphalt. The content of the polar group including O-H and C-O of bio oil was higher than that of petroleum asphalt. Gas Chromatography-Mass Spectrometry (GC-MS) was used to prove the presence of olefins and alcohols in bio oil. Thermogravimetric analysis showed that the bio oil expressed better thermal stability than that of petroleum asphalt, which expressed a potential of using as a pavement material. The dynamic shear rheometer (DSR) results showed that the complex shear modulus, G* decreased as the content of bio oil. The Glass transition temperature Tg indicated that the bio asphalt with 10% bio oil content showed similar performance with that of 70# asphalt. (C) 2020 Published by Elsevier Ltd.

Automated summary

This study used lignocellulose to prepare bio oil by hydrothermal liquefaction method and then mixed it with petroleum asphalt to produce bio asphalt, which showed better thermal stability and potential as a pavement material.