Pyrolysis oil has attracted the attention of the renewable energy sector for quite some time, as it is being scientifically scrutinized as a viable option to conventional petroleum. It is synthetic oil that is being converted from biomass to liquid with the BTL technology.
Pyrolysis oil has traditionally been produced by heating biomass to temperatures of several hundred degrees Celsius in the absence of oxygen, a process which vaporizes the biomass and produces a complex chemical liquid with a heating value approximately equal to that of bunker oil, the bottom of the barrel residue gotten from oil refineries. More recently the flash pyrolysis production process has come to predominate. Here the biomass is heated to a considerably higher temperature for a very brief duration which results in higher production efficiencies and better yields
There are 3 primary products which are obtained from pyrolysis of biomass: charcoal, synthetic gases, and vapors; that at ambient temperature condense to a dark brown viscous liquid.
While pyrolysis of biomass has been practiced in some form for thousands of years, it wasn’t until recently that the relationship between heat transfer rates into the biomass and product distribution yields were well understood. The practice of charcoal manufacture from biomass is generally referred to as a slow pyrolysis process based on the rate in which heat is imparted to the biomass. Under a “fast pyrolysis” conditions the product distribution is dramatically altered and shifts the distribution primarily to a liquid bio-oil product.
This picture shows a rapid thermal processing plant from a Honeywell Corporation that is used to produce pyrolysis oil. Honeywell is one of the pioneer and leading in the field of fast pyrolysis to create bio fuel from woodchips.