GREEN-B2B-2

1,3-Butadiene (BD) is an important bulk chemical for the polymer industry with a global annual production amounting to 15 million ton and applications in, e.g., rubber production. Biomass, a resource resulting from CO₂ uptake from the atmosphere, represents an interesting alternative feedstock for the sustainable production of chemicals, such as BD, replacing the present, fossil ones. More specifically, renewable BD can be produced via catalytic conversion from butanediols (BDO) obtained by fermentation of carbohydrates as contained in (waste) biomass. Acid-catalyzed conversion routes are appealing for this transformation of BDO into BD. Yet, a better, quantified understanding of these consecutive dehydration reactions is required to bring true innovation within reach. An overall potential CO₂ emission reduction is estimated at 25 million tons per year when replacing fossil BD by green BD. 

GREEN-B2B, which started in March 2021 and which will end in the spring of 2022, brought together expert teams from Ghent University (Thybaut – coordinator, Verberckmoes, Soetaert) and KU Leuven (Sels, Dusselier) complemented by Bio-Base Europe Pilot Plant to establish an innovative acid catalysed 2-step dehydration process for butadiene production from biomass-derived butane diols by fermentation. Multi-scale modelling has been the key to reliably extrapolate laboratory-scale results to realistic performances at a relevant production scale.  

The envisioned continuation project GREEN-B2B-2 will bring these results further towards real-life application (lifting the technology from TRL3 to 4 to at least TRL5) by: 

• ‘Engineering’ the C. necator strain to also grow with high productivity (>0.1g/L/h) on carbon sources such as xylose and arabinose in addition to glucose and CO₂ in combined liquid and gas fermentation. 

• Designing scalable, beyond the state-of-the-art hybrid catalyst nanostructures that are mainly based on, but not limited to, MFI. Indeed, also FER, MWW zeolites and core-shell structures will be developed targeting long term catalyst stability and optimal mass transfer for high production capacity. 

• Designing an integrated process scheme from first principles, including biochemical kinetics, chemo-catalytic kinetics and, more specifically for the continuation project, reactive extraction (separation) and solvent selection. 

The demonstrated CO₂ incorporation by the C. necator strain in BDO production will lead to a CO₂ capture of 400 kT/year, not counting yet the CO₂ emission reduction in Flanders, which will be a multiple of that number by avoiding fossil BD production.