100 Mass percentage (%) 80 60 40 20 0 Shavings Sawdust < 16 mm > 16 mm description and the composition of each category in the four pellet plants. Shav -ings and sawdust fractions were common among all four plants. PARTICLE SIZE Hog Bush grind Wood chips Infeed mix Figure 1 -Particle size classification of the tested infeed materials (separation using 16 mm sieve). versity of British Columbia collabo-rated with the Wood Pellet Association of Canada to analyze and report infeed biomass properties. Nine pellet plants in B.C. and Alberta provided infeed sam -ples for analysis. Several plants provided the flowsheet they follow to process their infeed mate-rial. Several magnetic rolls and air densi -ty separators are used to remove foreign objects such as metals and rocks. Prior to drying, the infeed materials are ground on a hammermill to meet the size specified by the dryer manufacturer. BBRG researchers classified 30 batches of infeed biomass received from the nine pellet plants into six categories of shavings, sawdust, hog, bush grind, wood chips, and infeed mix. Additional -ly, four out of nine plants provided data on the fraction of each category of in-feed in their operation. Table 1 lists the Particle size influences the bulk density and handling properties, flow of materi -al in dryers, drying uniformity and size distribution of ground samples. For ex -ample, based on information from dryer manufacturers, Stela and Prodesa, the op-timum size of particles in belt dryers is 8-10 mm with the minimum and maximum allowable sizes between 0.5 mm and 50 mm, respectively. Particles less than 0.5 mm are not desired because these par-ticles are easily entrained in the drying air and tend to fall through the dryer belt perforations. The maximum size limit of 50 mm is set to avoid clogging the dryer screw conveyor and uneven drying. The size analysis of received samples showed that 98 per cent of the received sawdust Canadian BIOMASS CB_ConceptAir_Summer23_CSA.indd 1 2023-06-07 7:47 AM 13
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