Greening two chemicals with one bio-alcohol: environmental and economic potential of dehydrogenation to hydrogen and acids†

Abstract

Biomass is a promising feedstock for reducing greenhouse gas emissions in the chemical industry. Biomass availability, however, is limited. Still, many bio-based processes focus on producing a single product. Thereby, valuable feedstock potential is often lost with undesired co-products. In this study, we assess the environmental and economic potential of bio-based multi-product systems and provide insights on the sustainability benefits of co-producing hydrogen and high-value acids from bio-alcohols compared to fossil and green alternatives. We select dehydrogenation as a promising early-stage technology for producing hydrogen and four co-product candidates: formic acid, acetic acid, lactic acid, and succinic acid. All investigated dehydrogenation multi-product systems show the potential to reduce climate impacts and to become profitable. A higher carbon tax can improve the economic potential. Acetic acid is the most promising co-product compared to both fossil and green benchmarks with potential benefits in various environmental impact categories. In contrast, co-producing lactic acid shows substantial trade-offs compared to the benchmark technologies. Expected eutrophication impacts associated with biomass use occur in all dehydrogenation routes. Our analysis highlights that multi-product systems can increase benefits compared to single-product systems from both environmental and economic perspectives.