Torrefaction of waste biomass for application in energy production in South Africa

Abstract

Power producing plants are major emitters of greenhouse gases that lead to global warming and climate changes. In the past two to three decades, attention has been drawn to organizations such as these reduce their dependence on coal reserves which are depleting and focus on producing clean energy i.e. for every ton of fuel produced, 100 kg or more should be made from clean energy. This has made torrefaction to gain interest as it improves energy content of biomass, a renewable and clean energy source, to levels equal to and sometimes above that of coal. The benefit of this is that, torrefied biomass could be co-fired with coal thereby reducing greenhouse gases and global warming.In this study, the effect of different parameters were investigated on two abundant sources of biomass in South Africa. There parameters were temperature, oxygen content,heating rate and residence time. It was observed that a temperature range between 275 and 300 degrees celcius under inert conditions with a heating rate of 10 degrees celcius/min and residence time between 20 and 40 min were required to achieve the best biomass with properties comparable to those of coal. This made it possible to co-fire the biomass with coal for energy production at different proportions.