Fast Pyrolysis of Short Rotation Coppice Poplar: An Investigation in Thermochemical Conversion of a Realistic Feedstock for the Biorefinery

Short rotation coppice (SRC) is a promising plantation system because it provides inexpensive feedstock for biorefineries. This study investigated the conversion of 2-year-old first rotation SRC poplar into bio-oil via fast pyrolysis. The impact of leaf removal was studied by comparing the yields and compositions of bio-oil from no-leaf coppice (NLC) and whole tree coppice (WTC). Leaf removal did not affect the bio-oil yield of SRC poplar samples (∼55%) but lowered the char yield from 19.7% to 13.6% and increased the gas yield from 14.3% to 17.7%. The chemical compositions of bio-oils, char, and noncondensable gases obtained from WTC and NLC were different. Leaf removal changed the elemental composition of the bio-oil. The bio-oil from WTC had higher H (9.1%) and O (64.8%) but lower C (25.3%) than that from NLC. Consequently, leaf removal increased the higher heating value (HHV) of bio-oil by 2.1 MJ/kg (16.0%). On the basis of the results of the current research and our previous study, the energy recovery rate for producing liquid fuel via fast pyrolysis of SRC poplar samples (29.4–34.2%) is markedly higher than that obtained by biochemical conversion (15.6–25.5%)