| Abstract [eng] |
As anthropogenic CO₂ emissions drive the urgent need for carbon capture, utilisation, and storage, mineral carbonation has emerged as a potential permanent storage solution. However, the technology is challenged by high energy intensity and a lack of standardised environmental assessments. This study addresses this gap by comparing life cycle assessments of serpentine- and phlogopite-based mineral carbonation routes in the Finnish context. Using unified functional unit and system boundaries, both conventional and integrated process routes are evaluated, incorporating chemical recovery to improve system realism. This study uses SimaPro 9.0 software and Ecoinvent 3.5 database to perform life cycle assessment according to standarts ISO 14044:2006 and 14044:2006. Following life cycle assessment structure, this study has established goal and scope, analysed the inventory, evaluated impacts and followed with interpretation. The functional unit was set as one kilogramme of CO₂ captured. System boundaries chosen were gate-to-gate focusing primarily on the mineral carbonation processes in Åbo Akademi University, Turku, Finland where this study partially took place under Magnex project funding. IMPACT 2002+ was chosen as life cycle impact assessment calculation methodology. Implementation of this calculation method has allowed to annalyse scenarios based on four damage impacts such as human health, ecosystem quality, climate change and resources. Electricity parameter was used to perform sensitivity analysis. During the research, three scenarios were established based on different mineral carbonation routes implementing dry/wet magnesium sulfate extraction and wet carbonation principles. While scenario 1 and 2 use serpentine as their feedstock, scenario 3 implements phlogopite. Life cycle assessment results show that, despite its higher magnesium content, phlogopite does not achieve greater CO₂ capture efficiency than serpentine, disproving the hypothesis. While all three scenarios show similar environmental performance, scenario 1 exhibits lowest environmental burdens due to smaller electricity demands during magnesium sulfate extraction phase. Calculations resulted in CO2 estimations of -0.383, -0.329, -0.278 kg of CO2 emitted per functional unit across scenarios one, two and three respectively. During this study, importance was placed on establishing the use of chemical recycling to minimise environmental burdens and after ectablishing fourth scenario, it was concluded that chemical recovery and reuse is crucial to keep environmental burdens low in mineral carbonation process. Sensitivity analysis indicates that energy use is the primary driver of environmental impact. The findings demonstrate that process configurations relying on heat as the main energy input yield the most favourable outcomes, and that mineralogical composition alone does not ensure improved capture efficiency. |
