Question
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What are some of the optimal strategies for processing (or co-processing) second- and third-generation renewable feedstocks?
Mar-2023
Answers
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Joris Mertens, KBC (A Yokogawa Company), joris.mertens@kbc.global
Renewable feeds are either lipids (vegetable oils and animal fats) or lignocellulosic material. The main strategic challenge around processing these renewable feeds is feed procurement.
The first HVO/HEFA plants were mainly processing palm oil. However, the EU and, to a lesser extent, the US are narrowing the possibility to process such controversial feeds that pose substantial land-change issues. At the same time, REDIII, ReFuelEU legislation in Europe, and similar initiatives in the US and elsewhere have further incentivised the demand for lipid-based mid-distillate production from HEFA technology, and specifically SAF. In about five years, only a limited amount of waste oils and fats is expected to be available for new projects.
Despite its attractive lower cost and fewer feed supply challenges, co-processing in existing units does not address the long-term (post-2030) decarbonisation challenge, which will require a deeper cut in the carbon intensity of fuel than co-processing can deliver.
Theoretically, technologies using lignocellulosic wastes should pose less of a concern with feed availability. However, raw lignocellulosic stock is much less energy dense. Therefore, they must be sourced from shorter distances, typically less than 200km, which brings feed supply assurance to the forefront of strategic considerations. Pre-processing lignocellulosic material, for example pelletising or pyrolysis, can largely address the energy density issues but may add complexity to the feed supply chain. In addition, technological maturity and required capital cost are more challenging for processes using lignocellulosic feeds.
In addition to feed and technology readiness and cost, an optimised strategy needs to consider the product yield structure, which varies widely depending on feed type and technology, including catalyst technology. While the catalyst type impacts HVO yields significantly, with potential differences up to 5%, unit configuration and catalyst type will dramatically affect the SAF yield of Fischer-Tropsch complexes.
Mar-2023
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