Thermo‐physical properties of bio‐oil and its fractions: Measurement and analysis

Abstract

Thermo‐physical properties including densities and viscosities of bio‐oil itself and its two fractions (aqueous fraction and organic fraction) are important for practical utilization. In this study, the bio‐oil fractions were prepared in various weight ratios of 2:1, 1:1, and 1:2. Density and viscosity of a bio‐oil itself, and its aqueous and organic fractions were accurately measured at various temperatures varying from ambient to 343 K and pressures from ambient to 10 MPa. Increasing temperature decreased the density of bio‐oil itself and the two separated phases (aqueous and organic phases) by almost 2.5 %, and 0.3 to 0.4 %, respectively. Increasing the temperature also decreased the viscosity of the bio‐oil by almost 86 % and its aqueous and organic fractions by up to 68 % and 98 %, respectively. The density of the bio‐oil and its organic and aqueous fractions was enhanced by increasing the pressure, whereas increasing the pressure increased the viscosity of bio‐oil and the organic fraction, but not the viscosity of aqueous phase. The generated experimental density and viscosity data of bio‐oil and its aqueous and organic fractions were evaluated with existing models that account for the effects of temperature and pressure. The impacts of pressure and temperature on the density and viscosity were considered in the correlations and evaluated with the experimental results.