Products formed under pressurized pyrolysis

Pressure is responsible for very high charcoal yields (varying from 40% to 48% depending on the raw material and process parameters). This high solid yield induces products quality changes. A primary goal of this ongoing research is to quantitatively measure the effect of process parameters (e.g., temperature, pressure) and feedstock composition (species, moisture) on the quality of pyrolysis products. Reaction pressure was achieved either by adding nitrogen into a sealed reactor or by self-increase due to gas formation during load heating. Charcoal proximate and ultimate analyses have been performed. Gas and vapour analyses by GC are not completed yet and will be discussed later. The experimental results on Brasilian tropical hardwoods show the influence of the initial pressure on product quality compared with atmospheric pressure reaction. The paper will then compare and discuss results on the role of water during the reaction. Temperature and pressure profiles suggest that water has no chemical action in the reaction but allows faster pressure increase when heated.