Flash pyrolysis involves heating of biomass rapidly to temperatures around 450-600°C at very high heating rates, in the absence of oxygen. The product obtained depends on the conditions of pyrolysis. Temperatures of around 500°C with high heating rates and short vapor residence times (1 s or 500 ms) maxi­mizes liquid yield at up to 80% on weight basis with minimum gas and char production, whereas very rapid heating to temperatures around 700°C and vapor residence times similar to the above maximize the gas yields (up to 80% on weight basis), with minimum liquid and char production. The liquid produced from the flash pyrolysis process has a relatively low viscosity (51 cp) and a high water miscibility capacity (up to 35-50% w/w water can be mixed). The char­acteristics of bio-oil obtained from flash pyrolysis process are given by Bridgewater [13]. The conversion efficiency of biomass conversion into crude oil in a flash pyrolysis process can reach up to 70%. However, the quality and stability of the oil produced as a result of pyrolysis is a major problem with the flash pyrolysis process as flash pyrolysis of biomass invariably results in the production of pyrolysis water [14]. The gaseous product obtained from flash pyrolysis has a low to medium heating value (5-15 MJ/Nm3). This gas has a relatively high oil content. It is either used as such for drying feedstock or as a fluidizing medium in fluid bed reactors (however, its specific energy content is somewhat low). The gas from high temperature flash pyrolysis can also give non­equilibrium products such as alkenes. However, the yields (of around 15%) are not very economical.