Biomass Gasification for Industrial Production of Tar and Charcoal

Process conditions in a retort prototype plant for production of tar and charcoal is evaluated. Experiments were carried out with a batch load of 810 kg wet biomass. The biomass used in this production is resinous pine root with particle size similar to chunkwood. The total duration of the experiment was approximately 15 hours with a mean biomass conversion rate of 53 kg/hr. The retort had a transient period of approximately 2 hours with an increasing amount of tar production followed by an 11 hour period with a steady state production rate of tar in the order of 8 kg/hr. Test results show a tar yield of 0.21 kg/kg dry biomass and a charcoal yield of 0.08 kg/kg dry biomass. Temperature measurements in the retort indicate heating rate in the area of 6 °C/min in the temperature range of 200 °C – 300 °C, and a high temperature zone moving downward in the retort with an average speed of 0.2 m/hr.