The environmental impacts of emerging lignin-first biorefineries: A consequential life cycle assessment approach

The innovative reductive catalytic fractionation (RCF) and its lignin-first valorization strategy aim to entirely valorize wood into high-value end products. Although the RCF process has already proved its novel high-value applications among many innovative approaches, the extent of environmental impacts and consequences of the RCF process implementation and its lignin-first valorization strategy is not fully known.
Therefore, a demand-driven consequential life cycle assessment is conducted to study the expected environmental changes as a consequence of a change in demand for the RCF products – pulp, monomer, and oligomer – using Belgian long-term electricity and heat mixes. The RCF products are compared to their alternative counterparts (unbleached sulfate pulp, fossil oil-based phenol, and bisphenol A).
Under the current assumptions, RCF products have higher carbon emissions (kg CO2-eq./kg) than their alternative counterparts. The contribution analysis shows that the high-polluting H2 gas bypass waste stream causes underperformance. Other highly contributing activities are RCF’s by-products that replace high-polluting alternative counterparts on the market and give (positive or negative) credit to the RCF process. Next, an additional RCF configuration (with higher processed end products) is assessed, showing that the higher-processed RCF products have lower carbon emissions than the lower-processed RCF products in this study but are still slightly higher than the alternative counterparts. It shows that carbon emissions are highly dependent on the RCF process configurations and the targeted alternative products that are potentially replaced by the RCF products on the market. Hence, a reorientation of the product development and the targeted markets is discussed. Next, the impact of the transportation distance and different transportation options are analyzed, showing that with increasing distances, sea shipping should be considered. Besides, the lack of (-direct) land-use change and the exclusion of the usage and disposal stage are discussed, implying a potential increase in carbon emissions of the RCF process. A more global environmental view shows that RCF products can outperform their alternative counterparts in several other characterization indicators (e.g. land occupation). Overall, the study shows that the RCF process can be environmentally desirable if the appropriate RCF configuration and products are chosen.