Effects of pyrolysis parameters on physicochemical properties of biochar and bio-oil and application in asphalt

Highlights: • Waste wood and pig manure were used as biomass for fast pyrolysis. • Pyrolysis temperature affects the pyrolysis yield and chemical properties of pyrolysis products. • Bio-oil can be used to replace partly or fully the petroleum asphalt. • Biochar and bio-oil can be co-used to asphalt modification and replacement. Adoption of renewable energy sources such as biomass has been increasing worldwide. In this study, fast pyrolysis as an acceptable and viable method to get renewable bio-oil and biochar is used. Different temperatures and N₂ flow velocities were used in the fast pyrolysis process to evaluate the pyrolysis yield of biochar and bio-oil. The waste wood and pig manure were utilized to prepare biochar and bio-oil. X-ray fluorescence, X-ray diffraction, high-pressure liquid chromatograph, Micro confocal laser Raman spectrometer, Fourier transform infrared spectrometer, and dynamic shear rheometer were used to measure the chemical compositions, structure, and pyrolysis yield of biochar and bio-oil. The obtained results indicate that pyrolysis temperature increases the purity of inorganic oxide in biochar and N₂ flow velocity promotes the yield of carbon in biochar. The increase of N₂ flow velocity would increase the acid property of bio-oil and damage the products yield of bio-oil. It was also observed that biochar could remarkably alter the fundamental performances of petroleum asphalt including penetration, softening point, ductility, viscosity, and complex modulus. The most important is that the upgraded bio-oil can be used to replace partly or fully the petroleum asphalt which is a promising biomass application.