Life Cycle Assessment of "100% Dutch grown" Polylactic Acid (PLA)

Abstract

In the last years the manufacture of bio-based chemicals and plastics has attracted a lot of attention as alternative to the fossil-based materials. Significant progress has been made leading to the competitive production of some bio-based compounds. This is the case of poly-lactic acid (PLA). In the coming five years, the Dutch company Synbra plans to build a 50/70kt or 35/70 kt PLA plant in the Netherlands ultimately using the syrup from sugar beets. This project is performed in collaboration with Purac and Suiker Unie. The aim of this Master thesis is to perform an environmental assessment based on detail information of “100% Dutch grown” PLA from sugar beet. This analysis is based on the principles of environmental Life Cycle Assessment (LCA), complying with ISO standards 14040-14043, for the system cradle-to-factory gate. The analysed process includes the growing of sugar beets, and the subsequent production of sugar, lactic acid and lactide, as well as the lactide polymerization into PLA. The required information was obtained by literature review and from the three companies involved, via interviews and visits to the plants. Gathered and calculated data were combined with the EcoInvent information to determine the environmental impacts, i.e. Non-Renewable Energy Use (NREU) and Greenhouse Gas emissions (GHG). For this study, the used functional unit is 1 tonne of PLA. Energy and GHG results for PLA production from sugar beet in The Netherlands were compared to those from sugarcane in sugarcane in Thailand. As a result, the PLA made of sugar beet showed higher impacts, surpassing the NREU of the PLA from sugarcane by 24% and the GHG by 6%. Compared to the PLA made from corn and other type of petrochemical polymers, the “100% Dutch grown” PLA performs better in environmental terms. Observed improvements year-by-year and foreseen developments in the near future suggest that the production of PLA from sugar beet can decrease its environmental impacts, and could even have a lower GHG emission profile than the PLA currently produced from sugarcane in Thailand.