Development and application of a detailed kinetic model to evaluate the torrefaction process of rice-based biomass.

Torrefaction techniques are often used to improve the properties of biomass fuels. This study developed a new detailed lumped model to investigate the reaction mechanism of rice husk (RH) and rice straw (RS) degradation during the torrefaction process. The validity of this model was confirmed by comparing it with the experimental result. The van Krevelen diagram and CHO index are obtained by the simulation. A new parameter (loss of O/loss of energy) was also defined to account for the energy efficiency of the torrefaction system. The calculation of the Chemkin model showed that 260 °C is relatively an optimum torrefaction temperature for rice husks, while for straw is 270 °C. Compared to rice husk, rice straw has a higher energy yield and more loss of oxygen after torrefaction. The simulation can provide information on the whole range of temperature, which makes up the experimental defects such as time consumption and high cost. Combining the van Krevelen diagram, CHO index and the new parameter (loss of O/loss of energy) could provide useful information that deepens the understanding of the biomass torrefaction process and the inherent connection between the different indexes. It is believed that the research result can provide some valuable insights and guidance for understanding and optimizing the torrefaction process. [ABSTRACT FROM AUTHOR]