Life Cycle Environmental and Economic Evaluation of Pyrolysis Oil Upgrade Technologies
Authors:   , Sorunmu Yetunde Elizabeth , Spatari Sabrina 
Published: July 2021

Greenhouse gases are the leading contributors of climate change. The global rise of CO₂ over the years, has urged an interest in government and researchers to find means of CO₂ mitigation. Research has found that advanced biofuels can reduce CO₂ emissions by up to 90%. Advanced biofuels can be produced from various routes, such as pyrolysis, gasification and torrefaction - with each route having limitations that hinder commercialization. A major limitation of pyrolysis-based advanced fuels also known as pyrolysis fuels, is their excessive cost of production due to their oxygenated structure; hence, their inability to be an infrastructure compatible market-ready fuel. In order to overcome this limitation, there is the need to deoxygenate the pyrolysis fuel. This thesis evaluates the environmental and economic sustainability of alternative pyrolysis oil upgrade technologies using life cycle assessment (LCA) and techno-economic analysis (TEA). The objective of this thesis is realized by completing three tasks: (1) examining the environmental and cost tradeoffs of the isolation and extraction of value added chemicals from tail gas reactive pyrolysis oil upgrade in comparison to the conventional hydrodeoxygenation upgrade (2) evaluating the implications of configuration, scale and hydrogen supply in alternative pyrolysis upgrade systems using life cycle assessment and (3) evaluating environmental, economic and technological aspects of alternative pyrolysis oil upgrading strategies Herein, we evaluate two emerging pyrolysis oil upgrade technologies; isolation and distillation of tail gas reactive pyrolysis (TGRP) oil and electrochemical deoxygenation (EDOx), and compare them to widely cited alternative technologies such as hydrodeoxygenation (HDO) and catalytic fast pyrolysis. We capitalize on some of the benefits of these emerging technologies; such as, the value-added coproducts in the TGRP process as well as the oxygen coproduced and the limited use of hydrogen in the EDOx process. Another main factor that sets these emerging technologies apart from the existing technologies is the smaller scale of 200MTPD in the TGRP process and 300 MTPD in the EDOx process compared to the larger scale (2000 MTPD) of the HDO process. In this thesis, we treat these co-products using system expansion in LCA and weigh in their value in the overall economics through measures like minimum fuel selling price (MFSP). The life cycle GHG emissions from the TGRP and EDOx processes, indicate reductions of 88% to 95% of emissions from petroleum-based fuels compared to 53% to 75% GHG reduction from the HDO processes and 89% to 90% from the catalytic pyrolysis processes. Also, The TEA results reveal that, even though the emerging technologies have a high minimum fuel selling price (MFSP) of $1.8 L⁻¹ compared to the existing technologies of ($0.54 L⁻¹ to $1.65 L⁻¹), if the social cost of carbon is credited as a revenue, the TGRP of upgraded fuel cost can be reduced to $0.65 L⁻¹, a price that is close to being economically competitive to petroleum-based fuels ($0.47 L-1 to $0.48 L⁻¹).