3.4.1 Product quality

The complex interaction of time and temperature on liquid product quality has not

been explored, at least partly because the characteristics of pyrolysis oil for different applications has not been defined and there is no "standard" pyrolysis liquid. It is this definition of oil quality that is a major uncertainty and requires to be defined by potential users and may differ by application. While there are set standards and methods of measurement for conventional fuels, analogous standards and methods have not yet been defined for biomass pyrolysis liquids. Density, viscosity, surface tension and heating value are known to be typical key properties for combustion applications in boilers, furnaces and engines; but other characteristics such as char level and particle size and ash content may have a major effect.

3.4.2 Unusual characteristics

Bio-fuel-oil has a number of special features and characteristics which require consideration in any application including production, storage, transport, upgrading and utilisation. These are summarised in Table 3.3 below. The conclusion is that some problems are soluble and some are more intractable but none are insoluble. Recognition of problems and awareness of potential difficulties is a major contribution to dealing with any of the above difficulties.