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 near-term 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 co-processing 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 ~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-its-kind analysis integrates process and environmental engineering with air permitting analysis and demonstrates the importance of coupling regulatory considerations with engineering analysis to guide informed decision-making to minimize investment risks while fully leveraging refinery infrastructure. This novel approach is also applicable to refineries in other jurisdictions.