Co-processing: A fast-track to SAF
Brought to you by Topsoe
Introduction
Ignacio Costa
Licencing Manager for HP, eFuel, TiGAS and GTL
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Topsoe
The aviation industry is on a mission to decarbonize, and Sustainable Aviation Fuel (SAF) is at the forefront of this transformation. As the first commercial units producing SAF emerge, the industry is looking for the most efficient and straightforward solution to meet the ambitious SAF mandates that are being set by governments globally. One solution that offers a fast-track to SAF production is co-processing.
Co-processing involves the use of renewable feedstock in conventional fossil fuel units. This method allows existing refineries to seamlessly integrate renewable feedstocks into their production processes without the need for extensive infrastructural changes.
Why co-processing?
Co-processing is gaining popularity as it meets the growing demand for SAF in a shorter timeframe and with lowest capital expenditures (CAPEX). It allows fuel producers to introduce SAF to the market while plans for constructing new specialized processing units, that require significant investments and long schedules, materialize.
The advantages of co-processing for refineries are manifold. For instance, it offers economic competitiveness by leveraging existing production facilities, it ensures rapid availability of SAF and it has the lowest investment cost.
An ASTM-approved pathway to SAF
For aviation fuel, ASTM serves as the international standard for jet fuel quality, ensuring safety, quality, and dependability of SAF. Co-processing of SAF is permitted under the ASTM D1655 standard, which provides guidelines for producing aviation fuels. The standard outlines three types of co-processing:
1) 5 vol% co-processing of mono-, di-, and triglycerides, free fatty acids, and fatty acid esters.
2) 5 vol% co-processing of hydrocarbons derived from synthesis gas via the Fischer-Tropsch process using iron or cobalt catalyst.
3) co-processing (incl. co-fractionation) of hydrocarbons derived from hydroprocessed mono-, di-tryglycerides, free fatty acids, and fatty acid esters (max. 24 vol% of the feed and 10 vol% of the product).
These provisions ensure that SAF production via co-processing adheres to established standards for quality and safety.
Challenges of co-processing
While co-processing renewable feedstocks to produce SAF is a promising approach, it's not without its technical challenges. The introduction of renewable feedstocks into a hydroprocessing unit even in very small quantities results in the liberation of linear paraffins from fatty acids, which can significantly deteriorate the cold flow properties (freeze point in the case of jet fuels).
Safety and performance at high altitudes and low temperatures are paramount in aviation. Therefore, the ASTM mandates a minimum freeze point of -40ºC for jet fuels. As mentioned above, even small quantities of hydrotreated renewable feedstocks in a jet fuel has shown to significantly impact the freeze point of the product, requiring the dewaxing of these renewable paraffins into iso-paraffins. This process can be facilitated by a dewaxing catalyst.
Dewaxing catalysts have been used for years to improve the cold flow properties of fuels, but their application in kerosene hydrotreaters is not common. Introducing a dewaxing catalyst to a conventional fossil kerosene hydrotreater can result in challenges. This is due to several factors, including typically limited catalyst volumes, low operating pressures, and restricted maximum operating temperatures.
Therefore, selecting the right dewaxing catalyst is the golden ticket to unlocking the potential of SAF production through co-processing, and Topsoe has the solution to it.
Topsoe's solution for co-processing SAF
Thanks to a long history of research and development in dewaxing catalysts and in-depth understanding of renewable fuels, Topsoe has a valuable solution for customers seeking to produce SAF via co-processing.
The solution is a dewaxing catalyst that can operate at the demanding conditions of a kerosene hydrotreater while avoiding renewable carbon yield loss and ensuring stable operation. The dewaxing catalyst has been successfully applied in many of Topsoe’s renewable industrial references and it has shown impressive results in our testing for co-processing under typical kerosene hydrotreating conditions.
Want to know more?
As a leading provider of technology for the energy transition and solutions for the decarbonization of fuels, Topsoe is at the forefront of understanding the challenges and solution of co-processing in kerosene hydrotreaters. We understand how co-processing can be a fast-track to SAF for conventional fuel producers and we are ready to help.
Or chat with us at the Topsoe booth at Sustainable Aviation Futures Congress
Topsoe A/S is a world leader in electrolyzers, catalysts, and energy transition technology. The company develops solutions for decarbonizing hard-to-abate sectors such as steel, cement, chemicals, shipping and aviation. Renewable energy carriers, fuels, and chemicals, e.g. green hydrogen, green ammonia and eMethanol are among the solutions. Headquartered in Denmark, Topsoe A/S serves customers globally.