Catalysis 2025 Issue

250

Direct LCA Indirect emissions

Petroleum baseline Total

200

150

100

-50

HEFA

ATJ

-100

Figure 2 Well-to-wake GHG emissions for SAFs made from non-crop feedstocks relative to petroleum jet fuel baseline.⁴ The error bars on this figure reflect the range of possible displacement emissions considering the low and high ends of the ranges estimated from literature

supported Co catalysts operating in the low-temperature FT regime (200-250°C) are preferred since they have a good selectivity to long-chain paraffins, low selectivity to oxygenates and olefins, and are resistant to deactivation. However, the FT Schulz-Flory product distribution results in higher carbon number waxy molecules that must be hydrocracked and hydroisomerised to maximise SAF prod - uct with the appropriate cold flow properties. With some 420,000 bbl/day of FT commercial capacity used for gas-to-liquids (GTL) production from natural gas ranging from 2,500 to 140,000 bbl/day units, technology providers offer large scalable options based upon several reactor design schemes. These include the following: • Slurry bed reactors – Sasol, Axens. • Shell and tube reactors – Shell Global Solutions. • Short path radial flow reactors – Johnson Matthey (JM)/bp CANS reactors. Considering the gasification, syngas purification, WGS-FT, and hydrocracking/hydroisomerisation infra - structure needed for FT-SPK processes, the capital is significant. Some potential to mitigate Capex is possible if integration into existing refining or petrochemical com - plexes is possible. Fulcrum BioEnergy licensed technology and built a facility near Reno, Nevada to process some 175,000 tons/year of MSW to 42 million litres/year (11 million gal/year or 725 bbl/day) of fuel that was sent to Marathon Refining for final processing. The JM/bp FT C ANS technology was employed. Early in 2024, DG Fuels announced a $4 billion FT-SPK project in Louisiana to produce 600,000 metric tons of SAF (200 million gal/year or 13,000 bbl/day) from 1.0 million tons per year of bagasse, sugar cane pulp, and MSW. The FT technology employed is JM/bp FT CANS and NextChem MyRechemical NX Circular for biomass gasifi - cation and purification. This would be the largest FT SAF plant announced as of mid-2024. Production is targeted to begin in 2028. Offtake agreements have been secured

with Delta Airlines and Air France-KLM. DG Fuels has also announced a 193 million gal/year (730 million litres/year or 13,000 bbl/day) biomass-to-SAF project in Nebraska. No technology selections have been announced. Carbon intensity and regulatory complexity In the final analysis, it is expected that the lowest carbon intensity SAFs – those exhibiting the lowest life cycle anal - ysis (LCA) for emissions (also referred to as well-to-wake or WtW emissions) – will be subject to the lowest tax pen - alties or highest incentives for use. It is appropriate that reported LCA value ranges for the processes described be reviewed: • Base case petroleum jet fuel: 89g CO₂ e/MJ (US RFS, FT-SPK processes are noticeably favoured, but the eco - nomics of greenfield or brownfield investments compared to HEFA synergies with existing refining assets are a clear inhibition in the near term. 3,4 Feedstock sources play a key role in GHG emissions sav- ings in SAF processes. Figure 2 provides a succinct example for the processes discussed here. For HEFA processes, used cooking oil (UCO) is clearly advantageous. For reference, both US soybean and EU rapeseed feeds yield about 70g CO₂ e/MJ LCA values. FT-SPK processes benefit greatly from non-biological MSW feeds.⁴ Regulatory requirements and incentives are region- ally specific. In the EU, ReFuelEU Aviation promotes the increased use of SAF as the single most powerful tool to decrease aviation CO₂ emissions. The measure is part of the Fit for 55 package to meet the emissions reduction target of 55% by 2030. It sets requirements for aviation fuel suppli - ers to gradually increase the share of SAF blended into the conventional aviation fuel supplied at EU airports to a 2% ICAO), 87g CO₂ e/MJ (California LCFS). • HEFA processes: 13.9-60.0g CO₂ e/MJ. • ATJ processes: 23.8-65.7g CO₂ e/MJ. • FT-SPK processes: 7.7-12.2g CO₂ e/MJ.

Catalysis 2025