Torrefaction of wood chips improves crushability, making it easier to apply to coal co-firing power generation. On the other hand, after torrefaction, the interaction between the coarsely ground particles is weak and pelletization is difficult. In this study, commercial cellulose powder was torrefied at 250-280 °C for 30 or 60 minutes in a small carbonization furnace in order to clarify the effect of torrefaction temperature and time on cellulose, which is the main component of wood. Subsequently, 0.2 g of the torrefied sample was pelletized by compression molding, and the relationship between the composition of the torrefied cellulose and the pellet strength was examined. Sugar composition analysis based on two-step sulfuric acid hydrolysis revealed that the amount of acid-insoluble components increased with the progress of torrefaction, and the corresponding pellet strength decreased significantly. It was also clarified that there is a strong correlation between the remaining amount of cellulose in the sample and the strength of the pellets. It was suggested that cellulose contributes to the bonding between the coarsely ground particles, and it was presumed that moderate torrefaction conditions of about 250 °C with little denaturation of cellulose would not adversely affect pelletization.

This study aims to analyze the potential emission reduction of cofiring 5% energy supplied from oil palm empty fruit bunch (EFB) pellets and to calculate the purchasing price by incorporating the carbon price. A life cycle assessment (LCA) is used with a functional unit of 1 kWh of electricity. The scope of this study comprises the material collection, pellet production, material transportation and power generation. The foreground inventories were gathered from pellet pilot plants in Cibinong, Indonesia, as a case study, supported by relevant background data from the literature. According to this study, utilization of oil palm biomass converted into pellet for cofiring offer a promising solution for global warming potential (GWP) mitigation, in which 0.1 kg CO₂eq/kWh or 8.57% CO₂eq emissions can be reduced in a power plant. At 5% cofiring, a typical 500 MW power plant can utilize 112,940 t EFB to substitute 87,118 t coal; therefore, utilizing EFB can reduce GHG emissions by 0.285 Mt CO2eq annually in the power plant. Furthermore, the carbon tax savings obtained from emission reduction can be utilized to elevate the purchasing price of pellets up to 65.34 USD/t (9.83% increase from current practice) to attain it more competitive.