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How can the refining industry supply the aviation industry’s growing demand for sustainable aviation fuel (SAF)? What are the most efficient pathways?

Feb-2023

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Marcio Wagner da Silva, Petrobras, marciows@petrobras.com.br

This is one of the hot points of the downstream industry nowadays. The biofuels and renewables co-processing have a fundamental role in the energy transition and decarbonisation of refining industry and we are seeing attractive processing routes capable to reduce the carbon intensity of the fossil fuels like the co-processing of renewable raw materials in hydrotreating units to produce less carbon intensive diesel and jet fuel, for example. In the petrochemical industry, the ethanol to olefins route is another promising route which already presents commercial production plants.

The use of total renewable feedstock can be attractive under specific scenarios, but it's always important to consider the source of the renewable raw materials in order to avoid the competition with food industry as well as the pressure over the agribusiness especially in regions with restrictions of available arable lands. These restrictions can be also related to the biofuels production through esterification which are normally blended with the fossil fuels before commercialization.

Another interesting processing route is the Gas to Liquid (GTL) hydrocarbons production route applying biomass as feedstock, again it's necessary to consider the availability of the renewable raw material and the politician and social impact of this alternative. In the technical point of view, this alternative can produce high quality and low contaminants liquid hydrocarbons.

Lastly, but not less important, any effort to energy transition of the downstream industry needs to consider the hydrogen source applied to the process. We are seeing an increasing pressure in the last decades to reduce the environmental footprint of the fossil fuels and great part of the obtained results was achieved through the hydrorefining, leading to a growing dependence of hydrogen which, until this moment, is industrially produced through natural gas reforming process that produce great amount of carbon dioxide (CO2) emissions. The processing of renewable raw material requires even more hydrogen to achieve the goal of high quality and less contaminant fuels production, in other words, the sustainability cycle only will be closed if the hydrogen applied to the process is renewable or there is efficient carbon capture technologies which are still incipient in the market.

In summary, there are available processing routes and technologies capable of supplying the market of renewable fuels, but it's necessary to consider all impacts of the production chain as well as if the sustainability cycle is really closed.

Feb-2023
Yvon Bernard, Axens, Yvon.BERNARD@axens.net

Today, governmental authorities, refining companies, and the aviation industry are collectively exploring different technology pathways to substitute fossil-based jet fuels with SAF. A single solution will not fulfil future SAF demand. Rather, a combination of different technologies for every available feedstock around the world is required.

Among the seven pathways currently certified under the ASTM D-7566 specification for synthetic kerosene to be blended into Jet A1 pool, Axens provides mature technology for three main pathways (HEFA-SPK, FT-SPK, ATJ-SPK) via the following solutions:
-   Vegan, the hydroprocessed esters and fatty acids (HEFA-SPK) pathway. This is a flexible solution to produce renewable diesel and SAF through the hydrotreatment of a wide range of lipids (renewable vegetable oils and animal fats).
-   Gasel, the Fischer-Tropsch (FT-SPK) pathway, converts synthesis gas (Hâ‚‚+CO) from various origins into a flexible slate of lower carbon fuels, including SAF. To provide renewable synthetic gases from biomass, Axens developed BioTfueL, which unlocks SAF and advanced biofuels production from energy crops and agricultural and forestry residues via a thermochemical and Fischer-Tropsch pathway.
-   Jetanol, the ethanol-to-jet pathway (ATJ-SPK), is the process by which low-carbon ethanol is converted to SAF via different steps: dehydration, oligomerisation, hydrogenation, and fractionation.

Axens also provides a solution combining Futurol and Jetanol to produce renewable fuels. Futurol uses enzymatic conversion to produce advanced ethanol (2G) from lignocellulosic biomass (energy crops, agricultural and forestry residues).

The common threads running through these technologies are flexibility, reliability, and the realisation of decades of technology development, demonstrating that Axens is ready to meet the challenges of scaling up SAF capacity in the coming years to provide low-carbon fuels into the market.

Feb-2023