Techno-economic analysis and life cycle assessment of hydrogenation upgrading and supercritical ethanol upgrading processes based on fast pyrolysis of cornstalk for biofuel

In this study, the techno-economic analysis (TEA) and life cycle assessment (LCA) were used to make a comprehensive comparison from the perspectives of economic and environment between the hydrogenation upgrading process and the supercritical ethanol upgrading process based on fast pyrolysis of cornstalk for liquid biofuel. The whole processes of fast pyrolysis and hydrogenation upgrading (FP-HU), fast pyrolysis, and supercritical ethanol upgrading (FP-SU) were simulated by aspen plus software. The mass flow and energy flow of these two processes were calculated according to the simulation results. The TEA results showed that the minimum fuel selling prices (MFSP) of FP-HU and FP-SU were 0.0417 $/MJ and 0.0383 $/MJ. The largest contribution to the MFSPs of FP-HU and FP-SU were the cornstalk cost (0.0084 $/MJ) and the ethanol input cost (0.012 $/MJ), accounting for 18.8% and 31.3% of their MFSP, respectively. The LCA results showed that the abiotic depletion potential (ADP), chemical oxygen demand (COD), and global warming potential (GWP) values of FP-HU were lower compared with FP-SU. The eco-points representing the combined environmental impact of FP-HU and FP-SU were 4.5E - 12 and 5.2E - 12, respectively. Compared to conventional diesel, the ADP, GWP, and respiratory inorganics (RI) of FP-HU and FP-SU decreased by 25.1% and 8.6%, 66.8% and 51.9%, and 95.7% and 96.6%, respectively. The sub-process contribution analysis suggested that the electricity consumption of bio-oil production sub-process and the ethanol consumption of bio-oil upgrading sub-process contributed the most to the eco-points of FP-HU and FP-SU.

Automated summary

This study conducted a comprehensive comparison between the hydrogenation upgrading process and the supercritical ethanol upgrading process for liquid biofuel based on fast pyrolysis of cornstalk, using techno-economic analysis (TEA) and life cycle assessment (LCA) from the perspectives of economic and environment. The TEA results showed that the minimum fuel selling prices (MFSP) of FP-HU and FP-SU were 0.0417 $/MJ and 0.0383 $/MJ. The LCA results showed that the ADP, COD, and GWP values of FP-HU were lower compared with FP-SU. Compared to conventional diesel, the ADP, GWP, and RI of FP-HU and FP-SU decreased significantly.