| Popis: |
Due to the continuous increase in Earth's atmosphere of carbon dioxide, under the threat of climate change, green processes based on chemical fixation of CO2 have recently attracted much attention. A systematic and standardized methodology to evaluate environmental impacts of products is life-cycle assessment (LCA). Along the entire life cycle, all material and energy flows are collected. These flows are linked to potential environmental impacts such as global warming and resource depletion, among many others. The approach of LCA allows understanding the different life-cycle stages of our processes and their environmental impacts. Therefore, LCA seems a suitable methodology for evaluating the environmental impacts of CO2. The aim of this TOTAL study is to investigate and to qualify the environmental performance of bio diethyl carbonate (bioDEC) as compared to a fossil fuel in terms of greenhouse gas emissions by means of a Life Cycle Assessment (LCA). The bioDEC synthesis process, from CO2, used as raw material, and bioethanol is studied, where bioethanol is used from three different biomass feedstocks, namely sugar cane, sugar beet and corn. These different biomass feedstocks will give different diethyl carbonate (DEC) synthesis routes. The results were compared to a fossil fuel (gasoline) and ethanol. To facilitate this goal, the study intends to consider the bioDEC molecule as a whole, taking into account the part of its origin from the CO2 raw material. For this purpose, different system boundaries were considered, showing that the CO2 raw material flow can be considered as neutral throughout the system considered, whatever its origin (CO2 raw material input is equal to related CO2 emissions released during combustion of final fuel). In summary, it can be stated in this study that all investigated bioDEC cases are alternatives to fossil gasoline as they emit less GHGs. When comparing bioDEC and ethanol as final fuels, one observes that ethanol has the better environmental performance of both fuels when considering the same feedstock. That means that for improving the environmental performance, from a GHG emissions perspective regarding bioDEC, we have to consider the following points: * Utilization of ethanol as final fuel without further processing to bioDEC, * Production of bioDEC from another ethanol feedstock, * Utilization of bioDEC as a structural molecule (example plastics) and not as a fuel. We report here the description of the bioDEC product and its pathways, the GHG emissions calculation, the life cycle inventory and the results of life cycle impact assessment. |
