Due to large amounts of oxygenated components present, the oil has a polar nature and does not mix readily with hydrocarbons. The degradation products from the biomass constituents include organic acids (like formic and acetic acid), giving the oil its low pH. Water is an integral part of the single-phase chemical solution. The (hydrophilic) bio-oils have water contents of typically 15 - 35 wt.%. Typically, phase separation does occur when the water content is higher than about 30 to 45 %. Below an example of properties from typical wood-derived pyrolysis oil is given. However, some of the properties may be strongly influenced by the biomass feedstock like e.g. the nitrogen content.
|Kinematic viscosity (40 °C)||cSt||30|