Technologies for upgrading fast pyrolysis bio‐oil to drop‐in fuels and coproducts are under development and show promise for decarbonizing energy supply for transportation and chemicals markets. The successful commercialization of these fuels and the technologies deployed to produce them depend on production costs, scalability, and yield. To meet environmental regulations, pyrolysis‐based biofuels need to adhere to life cycle greenhouse gas intensity standards relative to their petroleum‐based counterparts. We review literature on fast pyrolysis bio‐oil upgrading and explore key metrics that influence their commercial viability through life cycle assessment (LCA) and techno‐economic analysis (TEA) methods together with technology readiness level (TRL) evaluation. We investigate the trade‐offs among economic, environmental, and technological metrics derived from these methods for individual technologies as a means of understanding their nearness to commercialization. Although the technologies reviewed have not attained commercial investment, some have been pilot tested. Predicting the projected performance at scale‐up through models can, with industrial experience, guide decision‐making to competitively meet energy policy goals. LCA and TEA methods that ensure consistent and reproducible models at a given TRL are needed to compare alternative technologies. This study highlights the importance of integrated analysis of multiple economic, environmental, and technological metrics for understanding performance prospects and barriers among early stage technologies.

Horse manure, the improper disposal of which, imposes considerable environmental costs, constitutes an apt feedstock for conversion to renewable fuels and chemicals when tail gas reactive pyrolysis (TGRP) is employed. TGRP is a modification of fast pyrolysis that recycles its noncondensable gases and produces a bio-oil low in oxygen concentration and rich in naphthalene. Herein, we evaluate the coproduction of phenol as a value-added renewable chemical, alongside jet-range fuels within distributed TGRP systems using techno-economic analysis and life cycle assessment. We investigate the metrics global warming potential (GWP), cumulative exergy demand (CExD), and cost for the conversion of 200 dry metric tons per day of horse manure to bio-oil and its subsequent upgrade to hydrocarbon fuel and phenolic chemicals. Assigning credits for the offset of the coproducts, the net GWP and CExD of TGRP jet fuel are 10 g of CO 2 eq and 0.4 MJ per passenger kilometer distance traveled, respectively. These values are considerably lower than the GWP and CExD of petroleum-based aviation fuel. The minimum fuel selling price of the TGRP jet fuel

Understanding spatially and temporally explicit life cycle environmental impacts is critical for designing sustainable supply chains for biofuel and animal sectors. However, annual life cycle environmental impacts of crop production at county scale across mutiple years are lacking. To address this knowledge gap, this study used a combination of Environmental Policy Integrated Climate and process-based life cycle assessment models to quantify life cycle global warming (GWP), eutrophication (EU) and acidification (AD) impacts of soybean production in nearly 1000 Midwest counties yr −1 over 9 years. Sequentially, a machine learning approach was applied to identify the top influential factors among soil, climate, and farming practices, which drive the spatial and temporal heterogeneity of life cycle environmental impacts. The results indicated that significant variations existed in life cycle GWP, EU, and AD among counties and across years. Life cycle GWP impacts ranged from −11.4 to 22.0 kg CO 2 -eq kg soybean −1 , whereas life cycle EU and AD impacts varied by factors of 302 and 44, respectively. Nitrogen application rates, temperature in March and soil texture were the top influencing factors for life cycle GWP impacts. In contrast, soil organic content and nitrogen application rate were the top influencing factors for life cycle EU and AD impacts.

Bio-oil produced from fast pyrolysis of biomass is a promising substitute for crude oil that can meet climate change mitigation goals, but due to its high oxygen content, it requires upgrading to remove oxygen in order to be used as a transportation fuel. Hydrodeoxygenation (HDO) is one means of upgrading fast pyrolysis oil; however, its main limitation is its large hydrogen requirement. We evaluate an alternative electrochemical deoxygenation (EDOx) method that uses catalytic electrode membranes on a ceramic, oxygen-permeable support to generate hydrogen in situ for deoxygenation at the cathode and oxygen removal at the anode. We analyze the life-cycle greenhouse gas (GHG) emissions and scale effects of gas-phase upgrading of pyrolysis oil [300 t/day (MTPD)] using different configurations of EDOx and compare it with the large-scale HDO process (2000 MTPD). We observe that the EDOx configurations have lower total GHG emissions of 5–8.4 and 7.4–11 g of CO2 equiv/MJ for vehicles operated with diesel and gasoline, respectively, compared to HDO (39 g of CO2 equiv/MJ). Furthermore, the EDOx processes offers potentially 10 times more small-scale pyrolysis upgrading facilities in the United States compared to HDO, suggesting that small-scale on-site EDOx processes can reach more inaccessible forest biomass resources.

No abstract