Investigation of torrefaction reaction on high moisture content biomass using dairy manure

Abstract. Torrefaction is a thermal treatment used to convert biomass into a solid fuel. It is generally performed in a temperature ranges from 200 °C to 300 °C in a limited oxygen condition. The torrefaction reaction involves a simultaneous process of drying and decomposition of biomass. However, the process reaction remains poorly understood, particularly for biomass containing high amount of moisture and at atmospheric condition. Therefore, this study investigates the isothermal degradation of high moisture content biomass using fresh dairy manure in aerobic condition. Mass reduction, gas production and sample temperature were the determinant parameters during the experiments at 250 °C, 270 °C and 290 °C. From the result of mass reduction profile, the graph trend of 250 °C shows a gradual decrease and a sharp peak, accordingly referred as drying and decomposition where both process had occurred simultaneously. As the temperature increase, time for drying and decomposition become shorter and more than one peak were observed. Multiple peaks suggest more distinct decomposition steps had occurred. The gas production and sample temperature are in agreement with mass reduction profile trend. However, the drying process is identified through a steady line but longer time until peak appeared was observed. For sample temperature, the peak reach maximally 700 °C. We believe these results can accommodate the underlying mechanism for high moisture content biomass for producing valuable bioenergy product.