NC State
Pilon, G., and Lavoi, J.-M. (2011). "Characterization of switchgrass char produced in torrefaction and pyrolysis conditions," BioRes. 6(4), 4824-4839.


In this research, char was prepared from Switchgrass (Panicum virgatum) cave-in-rock species and characterized from the perspective of value addition either as a soil amendment or as a feedstock for energy production. Char from torrefaction/pyrolysis was produced in a fixed bed lab-scale reactor, using a N2 flow at three temperatures (300, 400, and 500°C) and for two residency times (2.5 and 5 minutes). Proximate and ultimate analyses as well as calorific value tests were done on each of the chars obtained. Chars scanning electron microscopy (SEM) pictures were taken. Organic composition of char leachates was characterized using gas chromatography-mass spectrometry (GC-MS) following a Soxhlet extraction with dichloromethane. Char was analyzed using FTIR-ATR. No significant difference was observed in most char characteristics between 2.5 and 5 min residency times, for each temperature studied. Among the compounds identified, two may be of particular interest with respect to the biochar domain. 1-undecanol, a compound commonly used as a growth regulator in agriculture, was observed in 300 and 400°C chars for 5 and 2.5 min residence time, respectively. Naphthalene, commonly used as an ingredient in pesticide products, was the only polycyclic aromatic hydrocarbon (PAH) observed in chars and was found solely in the extracts obtained from the char produced at 500 °C (for both residency times).
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