Utilizing various feedstocks to progress SAF production
Story by: Tyler Campbell, Managing Editor, H2Tech
To decarbonize the aviation sector, sustainable aviation fuel (SAF) is becoming increasingly popular. According to Honeywell UOP, industrial, buildings and aerospace account for approximately 50% of greenhouse gas (GHG) emissions. At Honeywell Users Group 2023, Naved Reza, Director, Business Development Sustainable Technology Solutions for Honeywell UOP, delivered a presentation titled "Increasing SAF feedstocks to scale production and decarbonize aviation.”
Honeywell UOP has been involved in SAF since 2009 and led the ASTM D7566 SAF initiative. In 2013, the company installed a commercial renewable jet fuel production unit in California. In 2021, United Airlines used UOP’s technology to fly with 100% SAF in one of the engines. Today, UOP is utilizing its eFiningTM technology to progress sustainable aviation.
UOP’s eFining technology uses methanol as a feedstock for SAF. The process utilizes green hydrogen (H2)—H2 produced in electrolyzers with renewable energy—and captured biogenic carbon dioxide (CO2) to produce eMethanol. The eMethanol then goes through a methanol-to-olefins (MTO) process to create light olefins, then oligomerized and hydrogenated to create SAF.
In the presentation, Reza displayed several airlines’ commitment to decarbonization by showing their net-zero plans. Their net-zero target years differed, but all companies shown had SAF as a key part of their decarbonization strategies. Reza went on to note several countries’ SAF production goals and incentives. The U.S. Department of Energy is targeting 3 billion gallons per year (Bgy) gallons of SAF by 2030 and 35 Bgy by 2050. The U.S. Inflation Reduction Act offers a blender tax and clean fuel production credit of up to $1.75/gallon through 2027. The ReFuelEU Aviation, as part of the “Fit for 55” proposal in the EU, requires 5% eSAF by 2035 and 35% by 2050. The focus on SAF is due to it being a drop-in fuel, requiring no change to aircraft technology.
According to Reza, SAF forecast ranges up to 3.5 MMbpd by 2050. UOP’s technology is well-positioned to assist with this production capacity. In addition to eFining, UOP developed an ethanol-to-jet fuel process. In this process, low carbon ethanol (e.g. corn-based, cellulosic, or sugar-based) is catalytically converted to SAF through a series of unit operations—Dehydration, Oligomerization, and Hydrogenation. The SAF is blended with traditional jet fuel and loaded onto the aircraft.
The maximum blend allowed, as per ASTM 7566 requirements, is 50% for most SAF technology pathways. “The 50% limit is related to aromatics,” Reza said. “When you blend too much or too little, the seals inside the engine will swell or shrink. If you blend too much SAF leading to lack of aromatics, the seals shrink. Companies like Boeing are working on building engines capable of operating with 100% SAF, and I think they will have them commercially running by 2030.”
The third process UOP highlighted in the presentation is EcofiningTM, which uses vegetable oils, fats, algal oils or greases as feedstock to produce renewable diesel and SAF. UOP has seven operating Ecofining plants, three of which are expanding their capacity. The technology was first licensed in 2013 but has since been refined to reduce capital costs. For renewable diesel, the feedstock goes through a deoxygenation and isomerization reactor, using highly selective catalysts to minimize cracking and increase isomerization, then the product is separated. The process is similar to produce SAF, putting the feedstock through deoxygenation, hydrocracking and isomerization, followed by product separation.
“Honeywell has all the technologies needed to convert different types of feedstocks to sustainable aviation fuel,” Reza said. “We are investing, developing and commercializing technologies related to ethanol-to-jet, biomass-to-jet and the CO2-to-jet or methanol-to-jet.”
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