Final Report - Ohio Department of Transportation

CWRU’s carbonization reactors fall in the midrange on this continuum of sophistication. One
is a benchtop unit developed by modifying a muffle furnace to house a 1 liter pyrolysis chamber.
This is used to study reactor operating conditions and product yields. The second was developed
from an industrial annealing oven to house pyrolysis chambers of up to 40 liters and is used for
larger volume production. Both can operate at T> 500 o C, have digital controllers that allow for
ramped temperature profiles, and have off gas condensers for byproducts recovery (see Fig. 4).
Fig. 4 - CWRU Bench and Pilot-Scale Carbonization Research Reactors
These reactors are adequate for the production of biochar, and to produce enough material to
support plant growth studies conducted in biochar amended soils. However, because of
export/import difficulties with oil palm crop residues, researchers began examining other
feedstocks. CWRU is adjacent to urban areas with high yard waste generation rates, so
researchers began examining yard waste as a carbonization feed stock. This led to the evaluation
of yard waste components (see Fig. 5 and Table 3) and to plant growth studies conducted in
CWRU’s research greenhouse. The growth studies (see Fig. 6 and 7) were not intended to
duplicate the worldwide effort to evaluate the agricultural benefits of biochar, but to determine if
there was anything unusual about yard waste biochar that would inhibit its use. Results have
been promising and show no evidence of growth inhibition. The work proposed here grew out of
an observation made during the effort to manufacture sufficient biochar to support growth
studies.
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