Densification Characteristics of Corn Stover and Switchgrass

Abstract

Densification characteristics of corn stover and switchgrass were studied under uniaxialcompression. The effects of pressure (100 to 150 MPa), moisture content (10 to 15%), particle size(0.56 to 0.80 mm), and preheating temperature (75 to 150oC) on the densification characteristics ofcorn stover and switchgrass were studied. Under room temperature (about 25oC), corn stoverbriquettes (about 19.2 mm diameter) with relaxed densities of 830 to 1000 kg m-3, and switchgrassbriquettes (about 19.4 mm diameter) with relaxed densities of 420 to 690 kg m-3 were produced.Densification at 25oC resulted in briquette durability of 50 to 84% for corn stover, and zero percent forswitchgrass. Preheating corn stover and switchgrass to 75, 100 or 150oC increased the densityfurther, and resulted in briquettes with maximum durability of 97% for corn stover and 67% forswitchgrass. Specific energy required for densification including the preheating energy for bothbiomass materials was about 0.7 to 1.7% of the energy content of the biomass material. This studysuggests that more research is required to improve the durability of switchgrass briquettes.