Pyrolysis is thermal decomposition occurring in the absence of oxygen. Lower process temperatures and longer vapour residence times favour the production of charcoal. High temperatures and longer residence times increase biomass conversion to gas, and moderate temperatures and short vapour residence time are optimum for producing liquids. Three products – gas, liquid and solid - are always produced, but the proportions can be varied over a wide range by adjustment of the process parameters as shown in the table below.
| Method | Conditions Wt % products | Liquid | Char | Gas |
| Intermediate | ~ 500ºC; short HVRT ~10-30 s; moderate solids RT | 50% in 2 phases | 25% | 25% |
| Fast | ~ 500ºC; very short Hot Vapour Residence Time (HVRT) ~1 s; short solids RT | 75% | 12% | 13% |
| Slow | ~ 400ºC; long HVRT; very long solids RT | 35% | 35% | 30% |
| Torrefaction | ~ 300ºC; long HVRT; long solids RT | Vapours | 85% solid | 15% vapours |
| Gasification | ~ 800-900ºC; short HVRT; short solids RT | 1-5% | <1% | 95-99% |
Pyrolysis research at EBRI
All types of pyrolysis are being researched and developed in EBRI and you can find out more using the links on the left hand side.
