2023 AIChE Annual Meeting

(339e) Techno-Economic Analysis and Life Cycle Assessment for Production of Biodegradable Polyesters

Authors

Wang, B. X. - Presenter, University of Wisconsin-Madison
Grady, B., University of Oklahoma
Huber, G., University of Wisconsin-Madison
Zavala, V., University of Wisconsin-Madison
Plastics in the ocean water pose a significant threat to marine animals, causing entanglement or being eaten mistakenly. Most plastic waste enters rivers and the ocean because of the inappropriate disposal. In 2010, 8 million tonnes of plastic leaked into the ocean, which accounts for 3% of global annual plastic waste [1]. One possibility to reduce or eliminate this problem is to use biodegradable plastics (BPs). Biodegradable plastics can be decomposed to innocuous substances in the natural environments through chemical hydrolysis or enzymatic action [2]. In this way, the plastic marine pollution problem can be mitigated as more plastics are replaced by BPs.

As people are more aware of plastic marine pollution, the global consumption of BPs has increased rapidly since their first introduction in 1980s [3]. BPs can be applied in many different fields such as medicine, packaging, and agriculture [4–6]. Among various types of BPs, aliphatic polyesters are studied extensively due to their highly hydrolysable ester bonds. They are synthesized through polycondensation between diols and dicarboxylic acids under high vacuum and high temperature condition. However, aliphatic polyesters suffer from poor mechanical and thermal properties compared to fossil-fuel based LDPE and LLDPE [7]. To tackle this problem, an aromatic diacid is selected and added as co-monomer into the process. The aromatic parts in polyester can enhance mechanical and thermal properties, but also decrease the biodegradability of polymer [8]. Among aliphatic-aromatic copolyesters, poly(butylene adipate-co-terephthalate) (PBAT) is currently one of the most promising polymers for applications due to its good flexibility and biodegradability [9]. PBAT has been applied in a wide range of packaging applications, and PBAT is commercially known as Ecoflexâ and was first prepared by BASF in the 1990s.

In this work, we propose new polyesters that are promising to replace the conventional biodegradable polyester, PBAT. Since to our knowledge there is no comprehensive technoeconomic analysis (TEA) or life-cycle assessment (LCA) on the production of PBAT in the open literature, TEA and LCA for the targeted polyesters have been conducted as well. The minimum selling price (MSP) for the new polyester containing furan-dicarboxylic acid and 1,5-pentanediol as monomers is determined to be $2.02/kg, which is 20% lower than that for PBAT ($2.52/kg). The sensitivity analysis of MSPs for the polyesters are performed by changing the various factors that can impact process economy, including production scale, feedstock prices, and financial parameters. In addition, we conduct the LCA on the production of the targeted polyesters, selecting global warming, energy consumption, and fossil resource depletion as representative indicators. Our analysis shows that the biomass-derived polyesters can have about 50% lower of carbon footprint and fossil resource depletion compared to the petroleum-derived polyesters. The production for 1 kg of biomass-derived poly(pentylene adipate-co-furandicarboxylate) will cause 3.05 kg CO2-equivalent of GHG emission.

References:

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