Artificial drying of corn stover in mid-size bales

摘要

A pilot-scale bi-directional batch dryer was used to dry either nine com stover bales (0.89 m high by a horizontal section of 0.81 m by 1.52 m per bale) on one layer or 18 bales on two layers. Corn stover bales had an average initial moisture contentof 56% (range of 49 to 66%) and an average dry matter (DM) density of 117 kg/m~3 (range of 87 to 144 kg DM/m~3). One layer of com stover bales dried during 40 h with air at 40/C, without recirculation, followed by 12 h with air at 67/C, with 89% recirculation of exhaust air. Airflow direction was alternated every 8 h up to 40 h. The final average moisture content was 19%, with a range of 7 to 30%. Two layers of corn stover bales dried during 90 h with air at 61/C (89% recirculation continuously). The final average moisture content was 18% (range of 8 to 38%). After a one-week period for transport, storage, and handling, six selected bales sampled at 75 locations indicated some re-hydration (4% units in the one-layer batch; 1% unit in the two-layer batch). Drying increased moisture content variation within bales (average SD of 13,2% after drying; 43% prior to drying). Estimated energy cost for drying from 55 to 12% moisture content ranged between 56 dollar and 98 dollar /t DM depending on the type of dryer and the source of energy. Reducing the energy cost below 10 dollar /t DM would require field drying com stover below 20% moisture prior to baling. Weather constraints and the cost of artificial drying are likely to limit the use of corn stover as adry feedstock for future biomass applications in eastern Canada.