The crude primary liquid product from flash pyrolysis contains very high levels of oxygen which give the product some unusual characteristics including water miscibility and temperature sensitivity as described above. While the oil can be used directly in a number of thermal and power generation applications, this is considered to be unsuitable in some demanding applications such as turbines and engines and substitution for transport fuels, so upgrading to more conventional liquid hydrocarbon fuels has been examined.

There are currently two basic processes: modified conventional hydrotreating to a naphtha-like product can be characterised as CH2; or zeolite cracking and synthesis to a highly aromatic product which can be characterised as CH1.2 . Recent developments have been reviewed by Elliott et al. (3), Sharma and Bakshi (60) and Milne and Soltes (61) and future needs identified (62,63).