preliminary LCA case study: comparison of different pathways to produce purified terephthalic acid suitable for synthesis of 100 % bio-based PET

• Published in: The international journal of life cycle assessment Vol. 19; no. 6; pp. 1238 - 1246
• Main Authors: Akanuma, Yasuhiko, Selke, Susan E. M, Auras, Rafael
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.06.2014; Springer Berlin Heidelberg; Springer Nature B.V
• Subjects: Acids; attributional life cycle assessment; Benzene; bioinformatics; biomass; Case studies; Chemical synthesis; chemistry; Climate change; Comparative studies; computer software; corn; Earth and Environmental Science; Environment; Environmental Chemistry; Environmental Economics; Environmental Engineering/Biotechnology; Environmental impact; ethylene; Global warming; Impact analysis; inventories; Lca for Agricultural Practices and Biobased Industrial Products; Life cycle analysis; life cycle impact assessment; Life cycles; Monte Carlo method; Monte Carlo simulation; Muconic acid; Stover; Terephthalic acid; Toluene; Triticum aestivum; wheat; Xylene; Polyethylene terephthalate; Toluene and xylene; Isobutanol; Bio-based; Muconic acid; Terephthalic acid
• ISSN: 0948-3349; 1614-7502
• DOI: 10.1007/s11367-014-0725-2

PURPOSE: This study provides a preliminary comparison of the environmental burdens of three different pathways for production of bio-based purified terephthalic acid (PTA), suitable for the production of 100 % bio-based poly(ethylene terephthalate), PET. These pathways are through (1) muconic acid originating in wheat stover; (2) isobutanol originating in corn; and (3) benzene, toluene, and xylene (BTX) originating in poplar. The goal is to point out what areas of these processes are the largest environmental contributors and hence are the most critical for development of accurate primary data, as well as to indicate which of these pathways looks most promising, from an environmental viewpoint, for production of 100 % bio-based PET. METHODS: Because much of the needed life cycle information to produce PTA is currently not available, inventory data for each scenario for the production of PTA were estimated based on the chemistry involved. In the impact analysis stage, the inventory data were classified and characterized with a focus on several environmental midpoint categories. SimaPro 7.3.3 software was used as the main computational software and Impact 2002+ v2.1 was used as the life cycle impact assessment methodology in this attributional life cycle assessment. RESULTS AND DISCUSSION: Valuable preliminary environmental impact data including identification of critical steps in the process were obtained. The global warming value of PET synthesized through the muconic acid scenario was 1.6 times larger than that of the scenario of PET synthesized through BTX even after a limited Monte Carlo simulation of 1,000 runs. CONCLUSIONS: Among the three scenarios for producing PET, PET synthesized through BTX looked the most promising to pursue for production of bio-based PET with lower environmental burdens. This work also indicated that the first production steps of producing PET through any of the evaluated scenarios (from biomass to the first intermediate) are responsible for the largest environmental burden and should be further characterized since they were the dominant processes in many impact categories.