TY - JOUR
T1 - Changes of chemical and mechanical behavior of torrefied wheat straw
AU - Shang, Lei
AU - Ahrenfeldt, Jesper
AU - Holm, Jens Kai
AU - Sanadi, Anand Ramesh
AU - Barsberg, Søren Talbro
AU - Thomsen, Tobias
AU - Stelte, Wolfgang
AU - Henriksen, Ulrik Birk
PY - 2012/5
Y1 - 2012/5
N2 - The purpose of the study was to investigate the influence of torrefaction on the grindability of wheat straw. Straw samples were torrefied at temperatures between 200 °C and 300 °C and with residence times between 0.5 and 3 h. Spectroscopic information obtained from ATR-FTIR indicated that below 200 °C there was no obvious structural change of the wheat straw. At 200-250 °C hemicelluloses started to decompose and were totally degraded when torrefied at 300 °C for 2 h, while cellulose and lignin began to decompose at about 270-300 °C. Tensile failure strength and strain energy of oven dried wheat straw and torrefied wheat straw showed a clear reduction with increasing torrefaction temperature. In addition, Hardgrove Grindability Index (HGI) of wheat straw torrefied at different conditions was determined on a standard Hardgrove grinder. Both results showed an improvement of grindability in the torrefaction temperature range 250-300 °C, which can be well explained by the findings from FTIR analysis. At a torrefaction temperature of 260 °C and with a residence time of 2 h, wheat straw samples produced similar HGI values as coal (RUKUZN) with 0% moisture content. Under this condition, the Anhydrous Weight Loss (AWL%) of the wheat straw sample was 30% on dry and ash free basis (daf), and the higher heating value of the torrefied wheat straw was 24.2 MJ kg -1 (daf). The energy loss compared to the original material was 15% (daf).
AB - The purpose of the study was to investigate the influence of torrefaction on the grindability of wheat straw. Straw samples were torrefied at temperatures between 200 °C and 300 °C and with residence times between 0.5 and 3 h. Spectroscopic information obtained from ATR-FTIR indicated that below 200 °C there was no obvious structural change of the wheat straw. At 200-250 °C hemicelluloses started to decompose and were totally degraded when torrefied at 300 °C for 2 h, while cellulose and lignin began to decompose at about 270-300 °C. Tensile failure strength and strain energy of oven dried wheat straw and torrefied wheat straw showed a clear reduction with increasing torrefaction temperature. In addition, Hardgrove Grindability Index (HGI) of wheat straw torrefied at different conditions was determined on a standard Hardgrove grinder. Both results showed an improvement of grindability in the torrefaction temperature range 250-300 °C, which can be well explained by the findings from FTIR analysis. At a torrefaction temperature of 260 °C and with a residence time of 2 h, wheat straw samples produced similar HGI values as coal (RUKUZN) with 0% moisture content. Under this condition, the Anhydrous Weight Loss (AWL%) of the wheat straw sample was 30% on dry and ash free basis (daf), and the higher heating value of the torrefied wheat straw was 24.2 MJ kg -1 (daf). The energy loss compared to the original material was 15% (daf).
U2 - 10.1016/j.biombioe.2012.01.049
DO - 10.1016/j.biombioe.2012.01.049
M3 - Journal article
SN - 0961-9534
VL - 40
SP - 63
EP - 70
JO - Biomass & Bioenergy
JF - Biomass & Bioenergy
ER -