Characterization of woody biomass comminution based on entrained flow gasification

Efficient dense-phase pneumatic conveying in entrained-flow gasification, processes requires biomass feedstocks to be comminuted to millimeter-scale particles. This study investigates the comminution characteristics of four typical woody biomasses sycamore, metasequoia, birch, and pine using a hammer mill with various screen sizes and moisture contents ranging from 0.5 to 16 wt%. The results reveal that the moisture content significantly effects energy demand and particle size distribution, depending on the biomass composition. For a screen size of 1.0 mm, materials with comparable lignin content (sycamore, metasequoia, and birch) at 0.5 wt% moisture exhibited energy demand and D-90 values of 39.4 kWh/t and 605.5 mu m, respectively. For higher lignin content (pine), the energy demands and D-90 values were 55.1 kWh/t and 732.6 mu m. The interplay between moisture and lignin significantly influenced mechanical properties such as bending stress, with pine (>30 % lignin) showing a 61 % reduction in bending stress as moisture increased. Consequently, a predictive model developed to relate energy demand and moisture content achieved a deviation of less than +/- 12 %.