Decarbonisation Technology August 2022 issue

Co-processing of bio-based feedstocks in the FCC unit Using bio-based feedstocks as a decarbonisation lever is one of the most effective methods to address Scope 3 downstream emissions

Bob Riley, Stefan Brandt and Kenneth Bryden W. R. Grace & Co.

W hile the landscape varies around created a driving force for the decarbonisation of the refining system. When the potential for systematic changes to refining was recognised decades ago, W. R. Grace & Co. began research activities to support refiners as the energy transition unfolds. One of the areas of particular interest for many refiners has been the processing of bio-based feedstocks in existing operating units, including the fluid catalytic cracker (FCC). Processing bio-based feedstock is a particularly interesting option for many refiners, as it is one of the few viable options to address the largest part of the refining system’s emissions – Scope 3 downstream emissions. For refiners, Scope 3 downstream emissions are those created from the products in use – which in many cases are combustion emissions associated with various forms of transportation. By far, this emissions scope represents the largest share of emissions in a life cycle assessment of petroleum refining. the world, factors including societal, regulatory, and investor pressures have What are bio-based feedstocks? While many often refer to bio-based feedstocks in tandem or in conjunction with other renewable resources, there are important differences to note. The carbon in bio-based feedstocks is sourced from the environment as part of the biogenic carbon cycle (International Energy Association, 2022). Compared to carbon from traditional fossil-based sources, carbon from biogenic feedstocks is not accretive to global atmospheric carbon inventories. This way, when fuels based on biogenic carbon feedstocks

Atmosphere

Non-biogenic CO

Biogenic CO

Bio - based feedstocks

Fossil fuel

Figure 1 Biogenic and fossil-based carbon emissions

are produced and consumed, global CO₂ inventories are not increased. Figure 1 illustrates the difference between biogenic carbon cycle sources and fossil-based sources. A large variety of materials can be used to create sustainable and renewable feedstocks for refinery application. To support our refining customers, Grace has evaluated many possible feedstocks for their suitability in existing refining processes as either a feed blend component (co- processing) or, in some cases, a pure feedstock stream. Although the most popular feedstocks for refinery use include lipid-based seed oils and animal fats, many alternate feedstocks sourced from materials listed in Table 1 , and converted through a variety of processes, have been considered by refiners. Motivation for processing bio-based feedstocks is largely driven by ambitions to control global CO₂ inventories. These ambitions can be embodied in regulatory frameworks (such as the European Renewable Energy