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Oral
Presentation 1-06 Physical Separation of Straw Stem Components to Reduce Silica
J. Richard Hessa, David N. Thompsona,
Reed L. Hoskinsona, Peter G. Shawa,
and Duane R. Grantb
aIdaho National Engineering
and Environmental Laboratory, P. O. Box 1625, 2525 Fremont
Avenue, Idaho Falls, ID 83415-2210
bGrant 4-D Farms, Rupert, ID Telephone: (208) 526-0115; Fax: (208) 526-0690; Email:
jrh@inel.gov
The
current paradigm for biomass and crop residue utilization in industrial
products is to process the “whole” of the harvested biomass material (i.e.,
stems, leaves, sheaths, nodes, awns, etc.).
However, not all parts of the biomass crop and/or harvested crop residue
are equally valuable given an intended end-use. For example, the former physiologically active straw tissues of
leaves, sheaths and awns are heavily impregnated with minerals. Because of this, these non-stem tissues
could be more valuable if directed to other applications (i.e., cattle feed,
left in the field as a soil amendment, etc.).
Using mechanical separation, straw was
re-threshed and separated into two fractions, which we classified as the
“stem” and “chaff” fractions. The ash content of the whole straw before mechanical
separations was 11.2 wt%, of which 12% was silica or 1.3 wt% silica in the
whole straw. The ash content of the
mechanically separated stems was 8.8 wt%, of which 8.3% was silica or 0.73 wt%
silica in mechanically separated stems. Thus, the mechanical separation reduced
ash content by 23% and silica content by 44%.
These results indicate that mechanical separation is capable of
reducing the silica content of the straw by selectively harvesting
predominantly straw stems.
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