Comparative economic and environmental assessment of four beech wood based biorefinery concepts.

The aim of this study was to analyze four conceptual beech wood based biorefineries generated during process design in terms of environmental and economic criteria. Biorefinery 1 annually converts 400,000 dry metric tons of beech wood into the primary products 41,600t/yr polymer-grade ethylene and 58,520tDM/yr organosolv lignin and the fuels 90,800tDM/yr hydrolysis lignin and 38,400t/yr biomethane. Biorefinery 2 is extended by the product of 58,400t/yr liquid "food-grade" carbon dioxide. Biorefinery 3 produces 69,600t/yr anhydrous ethanol instead of ethylene. Compared to biorefinery 3, biorefinery 4 additionally provides carbon dioxide as product. Biorefinery 3 and 4 seem most promising, since under basic assumptions both criteria, (i) economic effectiveness and (ii) reduction of potential environmental impacts, can be fulfilled. All four alternatives may reduce potential environmental impacts compared to reference systems using the ReCiPe methodology. Economic feasibilities of the analyzed biorefineries are highly sensitive.