Bio-oil co-processing can substantially contribute to renewable fuel production potential and meet air quality standards

Co-processing raw bio-oil derived from lignocellulosic biomass in existing petroleum refineries represents a nearterm greenhouse gas mitigation strategy by producing partially renewable and infrastructure-compatible hydrocarbon fuel with minimal capital requirements. One deterrent for risk-averse refinery owners is that a modification to their air permit may be required prior to any changes to refinery operations due to potential air emission changes. However, a lack of information on potential air emission changes resulting from bio-oil coprocessing yields uncertainty, which could cause delay in obtaining required permit. To address this concern, we perform a quantitative evaluation of air emission changes across a range of bio-oil co-processing fractions in refineries' fluid catalytic cracking units. We find that 92% of U.S. petroleum refineries could co-process 5% or more (up to 20%, by weight) raw bio-oil without triggering major permitting requirements. We then develop an upper bound estimate of the potential for co-processing bio-oil considering permitting and technical limits; our results suggest that U.S. refineries could co-process 573,000 barrels per day (0.79 cubic meter per second) of raw bio-oil, implying similar to 1.92 billion gallons gasoline equivalent of renewable fuel per year (0.23 cubic meter per second), equivalent to 1.4% of U.S. gasoline consumption or 18% of ethanol production in 2018. This first-of-itskind analysis integrates process and environmental engineering with air permitting analysis and demonstrates the importance of coupling regulatory considerations with engineering analysis to guide informed decisionmaking to minimize investment risks while fully leveraging refinery infrastructure. This novel approach is also applicable to refineries in other jurisdictions.