A comparative life cycle assessment of different pyrolysis-pretreatment pathways of wood biomass for levoglucosan production.

In order to identify the most environmental-friendly pretreatment for pyrolsis of wood residue to levoglucosan (LG), for the first time a comparative life cycle assessment (LCA) was carried out for hot water treatment (HWT), torrefaction, acid pretreatment (AP) and salt pretreatment (SP) pathways. Since LG production can facilitate both resource recovery (RR) and wood residue handling (WRH), two different functional units (FUs), i.e., 1 kg LG production and 1 kg wood residue handling were considered. AP was found to generate the least global warming potential of 134.60 kg CO ₂ -eq and human carcinogenic toxicity of 0.59 kg 1,4-dichlorobenzene-eq. for RR perspective. However, for WRH perspective, HWT was found to be the best pretreatment (6.39 kg CO ₂ -eq; 0.03 kg 1,4-dichlorobenzene-eq.). Sensitivity analysis revealed that a reduction in electricity consumption by 15% could reduce the overall impacts by 14.00-14.82 %. This study also highlights the impact of goal and FU selection on LCA.
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