2019 Volume 36 Pages 241-251
Briquetting tests were conducted on lodgepole pine, switchgrass, and corn stover biomass. Three moisture levels (12, 15, and 18 % [w.b.]) and three-hammer mill screen sizes (4.8, 12.7, and 19.05 mm) were used to understand the impact of these variables on briquette-quality attributes such as unit and bulk density, durability rating, and briquetting energy consumption. A pilot-scale hydraulic continuous briquetting system was used in the present study. The briquette-quality attributes were measured after five days of storage. The hammer mill screen size of 4.8 and 12.7 mm and biomass moisture content of 12 and 15 % (w.b.) resulted in a higher unit and bulk density and durability rating. For the three biomasses tested, corn stover and lodgepole pine resulted in briquettes with bulk density > 480 kg/m3 whereas durability rating of corn stover was > 97.5 and lodgepole pine was about 92–93 %. A larger screen size of the hammer mill (12.7 mm) and higher moisture content of 18 % (w.b.) increased the briquetting energy consumption for both the woody and herbaceous biomass. Larger hammer mill screen size (19.05 mm) and moisture content of 15 % (w.b.) resulted in lower density and durability rating of the briquettes produced.