In a world grappling with the detrimental effects of plastic pollution and climate change, finding sustainable alternatives to fossil-based plastic production is more crucial than ever. The U.S. Department of Energy’s (DOE) Argonne National Laboratory presents a groundbreaking solution in their research – the advanced recycling of post-use plastic (PUP). This innovative process not only reduces greenhouse gas emissions but also promises to significantly increase the U.S. recycling rate. Their comprehensive life cycle analysis study, published in the Journal of Cleaner Production in November 2023, sheds light on the potential of producing new plastic from PUP using pyrolysis as a recycling technique.
Pyrolysis, a process involving the heating of plastics to high temperatures in an oxygen-free environment, lies at the core of this transformative recycling method. By subjecting PUP to pyrolysis, the resulting product is pyrolysis oil – a versatile liquid mixture of compounds that can be used as an ingredient in manufacturing new plastic. The utiliztion of pyrolysis oil enables the replacement of fossil-based ingredients like naphtha and gases in the production of essential monomers such as ethylene and propylene – fundamental building blocks for plastic manufacturing.
To assess the environmental advantages of PUP-based plastic production, the study incorporated data from eight different companies with varying pyrolysis oil production processes spanning from 2017 to 2021. The findings revealed a significant 18% to 23% decrease in greenhouse gas (GHG) emissions when producing plastic with just 5% pyrolysis oil from PUP, in comparison to the traditional crude oil-derived low-density and high-density polyethylene (LDPE and HDPE, respectively). Furthermore, when considering the current end-of-life practices for plastic in the U.S., such as incineration, the reduction in GHG emissions amplifies to an impressive 40% to 50% when manufacturing pyrolysis-based LDPE and HDPE. These reductions are even more substantial in the European Union, where a larger portion of PUP is currently incinerated, leading to reductions of up to 131%.
The Role of Advanced Recycling in Achieving Sustainability Goals
As advanced recycling techniques continue to evolve and become increasingly efficient, they hold immense potential in addressing global sustainability goals, particularly in waste management and GHG emissions reduction. According to Benavides, a research scientist involved in the study, advanced recycling has the capacity to transform traditionally hard-to-recycle plastics into an array of high-value raw materials. By decreasing reliance on fossil resources, it has the power to significantly minimize the environmental impact associated with waste management practices. Furthermore, the ability to produce valuable industrial chemicals and develop markets for recycled plastic materials adds further value to the adoption of advanced recycling methodologies.
In addition to the reduction in GHG emissions, the Argonne research team expanded their assessment to include other critical metrics such as fossil energy consumption, water use, and solid waste generation. The comparison between the most-likely scenario of utilizing 5% recycled materials and virgin plastic production showcased compelling outcomes. The study demonstrated a staggering 65% to 70% reduction in fossil energy use, a 48% to 55% reduction in water consumption, and a remarkable 116% to 118% reduction in solid waste generation when recycling PUP instead of resorting to virgin plastic production. These findings highlight the multifaceted environmental benefits associated with embracing advanced recycling technologies.
The study employed Argonne’s widely acclaimed Greenhouse Gases Regulated Emissions and Energy use in Technologies (GREET) model, a tool that boasts over 55,000 users worldwide. This comprehensive model, extensively utilized by the DOE and other notable agencies like the U.S. Environmental Protection Agency, allows for a meticulous analysis of the environmental impacts of various technologies. By leveraging the power of GREET, the researchers could effectively evaluate the advantages of PUP-based plastic production and quantify its positive contributions to sustainability targets.
The research conducted by the U.S. Department of Energy’s Argonne National Laboratory underscores the promising potential of advanced recycling via pyrolysis as a viable solution to alleviate the environmental toll of plastic production and waste management. By significantly reducing GHG emissions and offering substantial environmental benefits in terms of energy use, water consumption, and solid waste generation, PUP-based plastic production represents a significant step towards achieving global sustainability goals. As advanced recycling techniques continue to advance and garner momentum, they hold the key to a more sustainable and resilient future where plastic waste is transformed into valuable resources, mitigating the adverse effects of plastic pollution on our planet.
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