Optimization of drying conditions considering specific energy consumption and particle size: Application to post-drying comminution of eucalyptus chips

Low-temperature drying demonstrates potential in biomass pretreatment, mitigating thermal energy consumption and simplifying processing. The post-hammer-milling process of eucalyptus chips under low-temperature drying was investigated. It was found that drying conditions not only changed the moisture content but also resulted in different effective moisture diffusivities. Screen size increased from 1 mm to 2 mm, reducing moisture content and energy consumption influence by 75 %, and D90 multiplied by 2.03-3.17 times. The impact of drying conditions on particle size was primarily manifested in the reduction of D90. The transformation of the grinding mechanism after drying resulted in large-particle thinning. Based on Rittinger's theory, a model of moisture content, particle size and specific energy consumption was developed with an error of +/- 12.5 %. The mapping analysis revealed that the optimal drying condition for milling, in terms of drying time, temperature, D90 and total energy consumption, was 80 degrees C-15 min.