Mapping the feasibility of lignocellulosic biorefinery routes: the relevance of system modelling in life cycle assessment

The defossilization of the chemical industry, together with negative emission technologies like carbon capture and storage and carbon capture and utilization have been defined as essential contributors to curb the climate crisis. To reach climate goals, it will also be necessary to support the sustainable development of biorefining pathways. The objective of this thesis is to determine the environmental weaknesses and strengths of second generation biorefineries. The analysis of different renewable carbon opportunities to reach climate neutrality goals and objectives beyond decarbonization was achieved though the life cycle assessment methodology. Studying different modelling systems allowed to support the consistent development of recommendations and best practices in regulations and standards of biorefineries

Towards improving the sustainability of bioplastics: Process modelling and life cycle assessment of two separation routes for 2,5-furandicarboxylic acid

Within the framework of an economy excessively dependent on fossil resources, the concept of sustainable development, aimed at obtaining environmentally friendly consumer goods, has given rise to the development of biorefineries. These facilities are based on the production of biofuels and platform chemicals from the most abundant raw material on the planet: biomass. The use of biomass such as wood or lignocellulosic residues makes it possible to seize opportunities offered by the implementation of renewable feedstocks, which in many cases can be embedded within the perspective of circular economy, through the exploitation of residual fractions. Among the multiple basic chemicals that can be obtained from biomass, 2,5-furandicarboxylic acid (FDCA) has a great potential, as it is the precursor of poly(ethylene furanoate) (PEF) polymer, which is considered a feasible substitute for poly(ethylene terephthalate) (PET). The purpose of this study is the simulation and environmental analysis of two separation routes for FDCA production with the objective of identifying the environmental hotspots at an early stage of the process design. The present study addresses the modelling of FDCA production from hydroxymethyl furfural (HMF) by heterogeneous catalysis using commercial Aspen Plus® V9 software. Two different downstream separation options resulting in purified FDCA were simulated: crystallization (Scenario A) and distillation (Scenario B). The estimation of the mass and energy balances were considered in the development of the data inventories required to conduct Life Cycle Assessment (LCA). LCA-assisted decision making identifies the conceptual configuration that would eventually lead to the least environmental burden. In the case of Scenario A, the stage with the highest environmental burden was the reaction unit, due to the use of HMF. In Scenario B, on the other hand, the separation stages contributed most to the impact due to their high energy demand. The combination of process simulation and LCA allowed acquiring a detailed vision of the process, through the analysis of the sensitivity of the environmental profile to different process parameters. The operating pressure in flash and distillation units for both scenarios affects plant operation by influencing total energy consumption and FDCA production. The sensitivity of environmental outcomes to these parameters was also studied, resulting in small variations. Thus, the results of this assessment provide strategic information of the early decision-making process on potential configurations for industrial-scale FDCA productionThis research was supported by EnzOx2 BBI JU-Project [grant agreement No 720297]. The authors belong to the Galician Competitive Research Group GRC ED431C 2017/29 and to the CRETUS Strategic Partnership [ED431E 2018/01]. All these programs are co-funded by FEDER (EU)S

BECCS based on bioethanol from wood residues: Potential towards a carbon-negative transport and side-effects

Bioenergy with carbon capture and storage (BECCS) is gaining broad interest as an effective strategy to go beyond carbon neutrality. So far, most of the work on BECCS focused on power systems, while its application to the transport sector has received much less attention. To contribute to filling this gap, this work investigates the potential of BECCS as a carbon-negative strategy in the transport sector by applying process modelling and life cycle assessment (LCA) to bioethanol production from lignocellulosic waste. The process was analyzed following a cradle-to-wheel approach, i.e., from biomass growth to the combustion of biofuel in the cars, assuming that the CO2 emitted in the fermentation and cogeneration units is captured, compressed and transported to be stored permanently in geological sites. Several scenarios differing in the bioethanol-gasoline blends (10–85% bioethanol) were considered for a functional unit of 1 km of distance travelled, comparing with fossil-based gasoline. Our results show that blends above 85% (ethanol/gasoline) could have the potential to deliver a net-negative emissions balance of −2.74 kg CO2 eq per 100 km travelled and up to −5.05 kg CO2 eq per 100 km using a low carbon electricity source. The final amount of net CO2 removal is highly dependent on the carbon intensity of the electricity and the heating utilities. Biofuels blends could, however, lead to burden-shifting in eutrophication, ozone depletion and formation, toxicity, land use, and water consumption. This work highlights the potential of BECCS in the transport sector, and the need to analyze impacts beyond climate change in future studies to avoid shifting burdens to other categoriesThis contribution was supported by the European project iFermenter (Grant Agreement 790507). S. Bello, G. Feijoo and M.T. Moreira belong to the Galician Competitive Research Group GRC ED431C 2017/29 and to the CRETUS Strategic Partnership (ED431E 2018/01). All these programs are co-funded by FEDER (EU)S