Studies of biomass torrefaction and carbonization using rotary gasifier system

Torrefaction and carbonization test in a rotary gasifier system for nine different temperatures (450 – 600 ℉ by +25℉, 650℉, and 700℉), using almond shells and hulls mixture as feedstock, was developed in this work. The almond shells and hulls mixtures were evaluated before and after torrefaction and carbonization processes through HHV (High Heating Value) and proximate analysis to study the final product, solid fuels biomass, for torrefaction and carbonization processes. Torrefaction and carbonization are thermal processes performed in an inert atmosphere at temperatures between 200-300℃ and 300-800℃, respectively, with residence time less than 60 minutes and heating rates lower than 20℃/min. These processes aim to improve a biomass as a solid fuel. In this work, the processes were carried out at different temperatures in an inert atmosphere (syngas) in approximately 1 hour at a residence time of 12 minutes with the feeding rate of 50lb/h. As a result, it was found that the biggest mass loss rate happened in between 500℉ and 525℉, changing from 6.4% to 26.4% of mass loss as received. Also, the fixed carbon content started to increase at higher rate after being treated at 525℉ while the volatile content showed the opposite trend. The ash content was not significantly changed in this study.