Techno-economic analysis of furfural derivatives in integrated sugarcane biorefineries

Global efforts to decarbonise chemical supply chains have increased interest in sugarcane biorefineries for producing value-added, bio-based chemicals. This study integrated techno-economic analyses (TEA) and cradle-to-gate greenhouse gas (GHG) assessments of five furfural-derived products: tetrahydrofuran (THF), 2-methyltetrahydrofuran (MTHF), maleic anhydride (MAH), 2,5-dimethylfuran (DMF), and gamma-valerolactone (GVL) from sugarcane. Conventional second-generation (2G) routes, based on furfural production from sugarcane bagasse and harvest residues, were compared with first-generation (1G) routes that convert sugarcane A-molasses into intermediates such as 5-hydroxymethylfurfural (HMF), levulinic acid (LA), and 1,4-butanediol (1,4-BDO). Process simulations were developed to generate mass and energy balances, which were used to estimate the capital and operating expenses of each biorefinery. The minimum selling price (MSP) required for each biorefinery to achieve a 20% internal rate of return (IRR) was determined using discounted cash flow analysis. Lifecycle GHG emissions were calculated for each biorefinery using two South African sugarcane cultivation datasets to capture variability in biogenic carbon accounting. Results revealed a clear trade-off between economic and environmental performance. 1G routes required significantly lower MSPs than 2G routes, with the 1G-THF pathway achieving the lowest MSP at US$2.47/kg, about 14% below its fossil-based market price. The 1G-MAH pathway achieved the second lowest premium of 57.6%, which lies towards the upper end of what consumers are typically willing to pay for biobased products (20% – 60%). In contrast, the 1G-MTHF pathway required the highest MSP among 1G scenarios,reflecting a 285% premium due to elevated hydrogen and energy demands. All 2G routesrequired MSPs exceeding US$10/kg, driven by low biomass-to-furfural yields, energy-intensive furfural conversion, and high capital costs, resulting in price premiumsbetween 315.5% and 463.5%. The MSPs of 2G biorefineries were two to three timeshigher than those reported for biorefineries annexed to existing furfural plants,highlighting the high capital cost of furfural production and the benefit of leveragingexisting furfural equipment. However, the 1G-THF scenario achieved a 50.1% lower MSPcompared to THF production attached to an existing furfural plant, showcasing thesuperior economic performance of THF derived from A-molasses via 1,4-BDO comparedto conventional 2G biobased pathways through furfural. Environmentally, 2G pathways yielded the lowest GHG impacts, with global warming potentials (GWP) between 0.68 and 1.76 kg CO₂-eq/kg product, equivalent to 26%–88% reductions relative to their fossil equivalents when the University of Cape Town (UCT) cultivation dataset, which incorporated CO2 uptake during cane growth, was applied. Conversely, 1G scenarios exhibited higher and more variable emissions, with the MAH scenario exceeding fossil benchmarks by 11%, demonstrating that MSP alone was insufficient for determining overall desirability. The choice of cultivation dataset substantially affected GHG estimates: The use of the Stellenbosch University (SU) dataset, which excluded CO2 uptake during cane growth, increased GHG impacts by 30%–76%. This discrepancy was especially evident in the 1G-MTHF scenario, where SU data produced the highest emissions among 1G routes at 4.68 kg CO₂-eq/kg, while UCT data rendered it the least emissive at 1.11 kg CO₂-eq/kg, underscoring the need for more accurate and standardised inventories for sugarcane cultivation in South Africa. Taken together, the economic and environmental results indicated that although furfural derivatives offered meaningful GHG reductions compared to fossil-based alternatives, these benefits did not automatically translate into economic viability. Except for 1G-THF, which achieved an MSP below its fossil market price even without carbon credits, the minimum carbon price (MCP) required to justify the green premiums of biobased furfural products far exceeded current South African and European carbon prices. In practice, no buyers would be willing to pay the green premiums on these products, as the MCP values exceed current and projected carbon credit prices by orders of magnitude, making them prohibitively expensive even under ambitious decarbonisation targets, unless further policy incentives or support mechanisms are implemented.

Grantor dc:publisher

Stellenbosch : Stellenbosch University

Year dc:date.issued

2026

Author dc:creator

• Machuwaire, Kudzai

Advisors dc:contributor.advisor

• Gorgens, Johann Ferdinand
• Louw, Janus

Language dc:language.iso

en

Repository record dc:identifier.uri

https://scholar.sun.ac.za/handle/10019.1/136274

OAI identifier oai:identifier

oai:scholar.sun.ac.za:10019.1/136274