Biomass Research was smaller than 16 mm, while 80 per cent of the infeed mix was smaller than 16 mm. Shavings had 47 per cent of par -ticles smaller than 16 mm. The hog sam -ples from the sawmill operations were smaller than 16 mm, likely because of the size reductions that occurred during debarking, end-cutting, and trimming op-erations. Seventy-four per cent of bush grind and 65 per cent of wood chips were larger than 16 mm. MOISTURE CONTENT the plant identified as “legacy hog” had up to 60 per cent wb (wet mass basis) moisture content. The moisture content of sawdust and wood chips ranged from 30 per cent to 55 per cent wb depending on the pile being under the shed or in open. ASH CONTENT BULK DENSITY The moisture content of each type of woody infeed varied substantially from around 10 per cent for shavings to over 50 per cent for hog samples. The variabil -ity within the individual type of infeed material was substantial, too. The hog’s moisture content varied by its bark con-tent and the age of the hog. Because bark contains higher nitrogen content, it was infested by fungi quicker and therefore accumulated moisture. Older hog, which Bush grind and hog had the largest ash content at 1.7 per cent and 2.8 per cent, respectively. Their ash contents were significantly higher than clean shavings (0.4 per cent). The international quali -ty standard for industrial wood pellets, ISO 17225-2 specifies that the maximum moisture content and maximum ash con-tent of I2 industrial pellets are 10 per cent and 1.5 per cent, respectively. The analysis of samples received from plants indicated that deep drying and careful blending of infeed material are essential for meeting the maximum allowable level for the industrial grade. Bulk density varied from 73 kg/m3 (4.6 lb/ft3) to 279 kg/m3 (17 lb/ft3). The wide range of bulk density shows the chal-lenge to feed a calculated mass ratio of a blend based on a fixed-volume loader that would be used to blend the infeed for drying and pelletization. Bulk density is an important factor when blending the in-feed biomass. The blending ratio of two or more fractions is based on the desired mass fractions but the blending operation at the plant site often takes place by pre-scribing volumes. For example, the buck -et of a front-end loader is used to blend different masses of feedstock types. SMOKING TEMPERATURE The onset of smoking temperature of 158-172 C was lower than the ignition tempera-tures for woody materials measured using test standard ASTM E2021-06 at 285-315 C. The lowest smoking temperature was 158 C for hog. The smoking temperature TSI BUILDS MACHINERY FOR THE BIOMASS INDUSTRY Complete Dryer and Torrefaction systems including Heat Energy and Pollution Control equipment in one integrated solution for plants from 50,000 tons/year to 500,000 + tons/year. (425) 771-1190 • www.tsi-inc.net 14 CB_TSI_HP_Spring23_MLD.indd 1 Canadian BIOMASS 2023-05-02 11:36 AM SUMMER 2023
Canadian Biomass Summer 2023: Page 14
