Economic and Environmental Benefits of Modular Microwave-Assisted Polyethylene Terephthalate Depolymerization

Abstract

The growing amount of plastic waste endangers the environment. Polyethylene terephthalate (PET) is among the most widespread plastics due to its extensive use in fibers and packaging. Recently, chemical recycling and upcycling approaches have been proposed to produce valuable products from bale PET feedstocks. This work performs techno-economic analysis and life cycle assessment to evaluate the environmental and economic performances of various technologies, including electrification via microwaves over a heterogeneous catalyst. We demonstrate that using a microwave-assisted heterogeneous glycolysis process to produce bis(2-hydroxyethyl) terephthalate (BHET) could have lower production costs and emissions than the traditional dimethyl terephthalate (DMT) route due to the high reactivity and excellent reusability of the catalyst. The fast reaction rate and high selectivity render this process ideal for handling spatially distributed PET waste effectively.

Circularizing PET-G Multimaterials: Life Cycle Assessment and Techno-Economic Analysis

“…BHET of higher purity can be obtained by increasing the amount of water used, albeit at the expense of more energy consumption in the evaporation stage. However, the environmental consequences of this sensitivity analysis have been largely overlooked in most studies, with a few exceptions. , …”

“…However, the environmental consequences of this sensitivity analysis have been largely overlooked in most studies, with a few exceptions. 36,38 To assess the sensitivity of the results to water usage, we increased this parameter in the model for S1 from our previous value of 3 tonnes (i.e., 3 times the mass of PET-G cards) to 5 tonnes. Literature data were used to predict the effect of this change on purity and yield.…”

“…The nonrandom two-liquid Redlich–Kwong (NRTL-RK) method was utilized to calculate the thermodynamic properties of the multicomponent system. Missing physical properties were obtained from either the NIST Thermo Data Engine (TDE) or estimated using the Aspen Plus Property Constant Estimation System (PCES) . As the conversion rate of the polymer had been determined previously through experiments, the scope of this simulation was limited to separation and purification (i.e., postdepolymerization processes).…”

Depolymerization within a Circular Plastics System

“…Pairing the best performing glycolysis systems with rigorous analyses like LCA and TEA would be invaluable for identifying optimal systems and environmental hotspots requiring improvement. Luo et al used TEA and LCA to analyze the potential benefits of microwave heating to glycolysis . Using microwaves was shown to be economically and environmentally advantageous compared to traditional heating methods during glycolysis.…”

β-Ketoadipic acid production from poly(ethylene terephthalate) waste via chemobiological upcycling

“…Suggesting further development in cost reduction. 3,4 To address the problem, several upcycling methods have been suggested, including chemical, biological, and chemobiological upcycling. While enzymatic hydrolysis offers a promising biotechnological approach to PET degradation under mild conditions, but it has serious limitations, such as the prerequisite for amorphous or low-crystallinity PET necessary for the proper enzyme activity.…”