Study On The Solubilization Capacity Of Bio-oil In Diesel By Microemulsion Technology With Span80as Surfactant

The increasing demand for fossil fuel leads to the rapid development inalternative energy sources such as the biomass energy. Bio-oil, produced by fastpyrolysis or liquefaction of biomass, is a promising renewable energy source whichhas received extensive recognition around the world for its characteristics ascombustion fuels used in boiler, engines or gas turbines and resources in chemicalindustries.Bio-oils obtained from liquefaction/pyrolysis of biomass have undesiredproperties such as high water content (15-30wt%), high oxygen content (low heatingvalue), high corrosiveness (acidity) and instability. Therefore, they can’t be directlyadopted for fuel applications. Solubilizing bio-oil into diesel by microemulsiontechnology is one of the most convenient approaches for further upgrading bio-oil.In the present work, a synthetic bio-oil was prepared to overcome the seriouslimitation posed by the complex nature and instability of crude bio-oil. The effects ofseveral microemulsion parameters on the solubilization capacity of bio-oil in dieselwere evaluated, including the initial bio-oil/diesel volume ratio (B/D ratio), theconcentration of surfactant (Span80), the type of cosurfactant (n-butanol, n-pentanol,n-hexanol, n-heptanol and n-octanol) and the cosurfactant/surfactant mass ratio (C/Sratio). The optimum bio-oil/diesel volume ratio was5:5. The rational concentration ofSpan80was0.36mol/L. And n-octanol was certified as an ideal cosurfactant. Inaddition, the solubilization capacity of bio-oil in diesel increased with the increase ofcosurfactant/surfactant mass ratio, while the heating value decreased. A proper C/Sratio of0.40was suggested.Meanwhile, the fuel properties of bio-oil/diesel microemulsion were examined,including the heating value, density, kinematic viscosity, cloud point, pour point,water content, corrosivity and stability. And the ultimate and thermogravimetricanalyses of bio-oil/diesel microemulsion were conducted. Compared to the original bio-oil, the bio-oil/diesel microemulsion presented more desirable fuel propertiesclosed to diesel. But it still had some unsatisfactory features, such as viscosity andstability. Further upgrading of bio-oil was needed. In sum, the processing ofemulsifying bio-oil with diesel may be a promising method to extract some of the fuelfractions present in bio-oil for use as an additive to diesel.