(160g) Trojan Horse Strategy for Sustainable PET Plastics: A Comparative Evaluation of Techno-Economic and Lifecycle Impacts

The recycling of Polyethylene Terephthalate (PET) is essential for achieving a circular economy. PET, derived from petroleum, necessitates recycling to promote sustainability and resource efficiency. Various recycling technologies, including mechanical and chemical processes, are crucial for establishing a circular economy for PET products, leading to reduced greenhouse gas emissions compared to linear production systems. The concept of chemically recyclable polymers underscores the importance of developing materials that can be efficiently recycled, contributing to supporting circular economy initiatives.

To overcome these challenges, a novel solution employing Trojan Horse units in PET is proposed. These units, integrated into the PET chain, facilitate targeted recycling processes, thereby conserving energy and preserving the physical and chemical properties of recycled PET akin to virgin counterparts. This research focuses on optimizing the implementation of Trojan Horse units and explores sustainable methods for producing Bio-PET. This paper underscores the significance of producing bio-based Polyethylene Terephthalate (PET) as a sustainable alternative to traditional petrochemical-derived PET. By utilizing biomass sources, bio-based PET reduces reliance on fossil fuels. It offers potential for a circular economy approach, especially with the development of bio-based PET products from recycled PET degradation products.

Assessing the scaling effects of circular economy strategies, particularly in the PET market, provides insights into the potential benefits of closed-loop recycling systems. The mature mechanisms of PET decomposition and recycling make it a suitable example for understanding the principles of recycling and depolymerization in the context of a circular economy. Recycling trojan horse incorporated PET and other plastic wastes on an industrial scale offers environmental benefits and aligns with the goals of a circular plastic economy.

Using the Techno-Economic Analysis (TEA) framework, this study compares the Trojan Horse approach with enzyme-based PET depolymerization technology. By employing a chemical process model based on the National Renewable Energy Laboratory (NREL) biorefinery design, the analysis evaluates capital and operational expenditures, energy consumption, potential product yields, and market viability. Initial findings indicate promising results for the Trojan Horse technology, sensitivity analysis is conducted to determine optimal Trojan Horse ratios and PET compositions for cost-effectiveness. The minimum selling price (MSP) of recycled PET is about $1.98/kg, whereas the price of the Trojan Horse incorporated PET is about $6.75/kg. This PET polymer consists of 5% Trojan horse, 25% bio-based TPA, and 70% recycled fossil TPA, thus naming it Bio-rPETTH. The TEA assessed the capital expenditure (CapEx) of $128 million, operational expenditure (OpEx) of $6,450 for Bio-rPETTH, and $2,180 for rPET.

Furthermore, a comprehensive Life Cycle Assessment (LCA) will be conducted to assess the environmental and socioeconomic impacts of both recycling methods. Considering the entire lifecycle of PET plastic using cradle to cradle approach. The LCA aims to inform decision-making towards the most sustainable PET waste management approach.