A Life Cycle Greenhouse Gas Model of a Yellow Poplar Forest Residue Reductive Catalytic Fractionation Biorefinery

Abstract

The incentive to reduce greenhouse gas (GHG) emissions has motivated the development of lignocellulosic biomass conversion technologies, especially those associated with the carbohydrate fraction. However, improving the overall biomass valorization necessitates using lignin and understanding the impact of different tree parts (leaves, bark, twigs/branchlets) on the deconstruction of lignin, cellulose, and hemicellulose toward value-added products. In this work, we explore the production of chemicals from a yellow poplar-based integrated biorefinery. Yellow poplar (Liriodendron tulipifera L.) is an ideal candidate as a second-generation biomass feedstock, given that it is relatively widespread in the eastern United States. Herein, we evaluate and compare how the different proportions of cellulose, hemicellulose (xylan), and lignin among leaves, bark, and twigs/branchlets of yellow poplar, both individually and as a composite mix, influence the life-cycle GHG model of a yellow poplar biorefinery. For example, the processing GHG emissions were reduced by 1,110 kg carbon dioxide (CO₂)-eq, 654 kg CO₂-eq, and 849 kg CO₂-eq per metric ton of twigs/branchlets, leaves, and bark, respectively. Finally, a sensitivity analysis illustrates the robustness of this biorefinery to uncertainties of the feedstock xylan/glucan ratio and carbon content.