(111d) Towards Developing a Pathway for Efficient Conversion of Syngas-Derived Olefins to Sustainable Aviation Fuel in High Yield and Selectivity

Rapid efforts towards decarbonizing the aviation sector call for developing low-risk technologies that can easily be adapted to existing industrial processes, thereby improving the potential to be successfully commercialized. Though predominantly derived from fossil sources, syngas makes an attractive renewable feedstock to produce sustainable aviation fuel (SAF) from municipal solid waste (MSW) or any biomass via gasification that significantly reduces the carbon footprint ^{1, 2}. Various syngas-based pathways exist to produce aviation fuel, but bottlenecks such as low selectivity and/or yield to desired products and extensive downstream processing hinder these technologies. Syngas to methanol and methanol to olefins (MTO)³ are current commercial processes with high process yields of 99% and 92%, respectively. Therefore, developing a concerted single-reactor process to integrate with MTO plays a crucial role in producing SAF from syngas using the olefins derived from the MTO process as intermediates.

Oligomerization of olefins, C₂ (ethylene), C₃ (propylene), C₄ (butene) and C₅ (pentene) have been investigated in the literature using heterogenous catalysis to produce fuel range hydrocarbons. However, there is a wide technological gap in the co-oligomerization of these olefins (specifically C2 and C3+ olefins), which typically is the makeup of the MTO process-derived olefins. The primary challenge is the difference in their reactivity and the corresponding oligomerization reactions between C₂ and C₃₊ olefins. Tuning different process parameters and catalyst composition has allowed us to obtain >90% conversion of C₂ and C₃₊ with about 80% selectivity to jet-fuel range hydrocarbons (C₈-C₁₆). We also tested the process at varied compositions of the olefin feedstock, which further helped us investigate the technology for adapting to various upstream processes that produce olefins. Most importantly, the catalyst developed here demonstrated ~150 hours of stable performance without deactivating.

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2. Centi, G.; Perathoner, S., Chemistry and energy beyond fossil fuels. A perspective view on the role of syngas from waste sources. Today, 2020, 342, 4.
3. Tian, P.; Wei, Y.; Ye, M.; Liu, Z. Methanol to Olefins (MTO): From Fundamentals to Commercialization. ACS Catalysis 2015, 5 (3), 1922-1938. DOI: 10.1021/acscatal.5b00007.