Complementary effects of torrefaction and co-pelletization: Energy consumption and characteristics of pellets

• Caster bean cake improves the features of pellets produced from torrefied biomass.
• Grindability and lubricant are available to decrease the energy consumption.
• Complementary effect of protein and enlarged contact area improve pellet strength.
• Co-pelletizing biomass torrefied at 270 °C with 15% CAS are the optimal conditions.

In this study, complementary of torrefaction and co-pelletization for biomass pellets production was investigated. Two kinds of biomass materials were torrefied and mixed with oil cake for co-pelletization. The energy consumption during pelletization and pellet characteristics including moisture absorption, pellet density, pellet strength and combustion characteristic, were evaluated. It was shown that torrefaction improved the characteristics of pellets with high heating values, low moisture absorption and well combustion characteristic. Furthermore, co-pelletization between torrefied biomass and cater bean cake can reduce several negative effects of torrefaction such as high energy consumption, low pellet density and strength. The optimal conditions for energy consumption and pellet strength were torrefied at 270 °C and a blending with 15% castor bean cake for both biomass materials. The present study indicated that compelmentary performances of the torrefaction and co-pelletization with castor bean cake provide a promising alternative for fuel production from biomass and oil cake.