Development of a bench scale biomass torrefier

Cofiring biomass with coal has become very popular with power utilities to reduce fossil fuel carbon dioxide (CO2) emission. It is relatively easy to implement on most common pulverised coal plants. However, raw biomass is difficult to utilise and requires upgrading to a higher quality fuel to substitute coal. Upgrading by torrefaction can improve the properties of biomass close to low rank coals suitable for cofiring. In this study, a bench scale torrefier was developed to produce torrefied biomass samples for further studies of its properties and combustion behaviour. The torrefier was developed from a domestic 1600W electric oven. Biomass pellets was then torrefied at 250 °C for 1 hour using this torrefier. Proximate analysis and gross calorific value (GCV) of the torrefied biomass were carried out. The results showed that GCV of the torrefied biomass had increased when compared to raw. The moisture content and volatile matter had decreased, and ash content and fixed carbon had increased as expected.