Pyrolysis is the thermal decomposition of organic compounds..
Pyrolysis can be either slow or fast..
Fast pyrolysis (FP) is pyrolysis, in which heat energy is supplied to the feedstock at high speed and without oxygen access.
Whereas slow pyrolysis can be assumed as the process of bringing water to a boil,
fast pyrolysis can be assumed as the process of a drop of water falling into hot oil ('explosive boiling').
The distinctive features of fast pyrolysis are: