Plastic's durability that was once considered a boon is now viewed as a bane. When we hear the word plastics today, one of the lasting images in our minds is that of a plastic bag floating in the ocean. This is largely because of the unprecedented rise in single-use applications and a mindset as consumers to just use and throw.
What are the advantages and disadvantages of plastics?
It is critical to not lose sight of the value plastics bring and the various industries that depend on this important material. Plastics have proven their merit in terms of mechanical properties, performance, versatility, cost, etc. For example, plastics are a key material of choice in the fight against the COVID-19 pandemic across the world. The health risk, especially for the medical professionals and frontline workers, would be higher without plastics in PPE kits, masks and gloves.
The way plastics are currently produced, consumed and managed at the end-of-life, however, is not completely sustainable. Talks of replacing plastics with other recyclable materials, such as paper, especially in packaging applications, have gathered pace due to the negative environmental impacts of linear plastics production, the high volume of single-use applications, and the mismanagement of waste over the years. Plastics circularity and waste valorization are the need of the hour and chemical recycling technologies can play a vital role in achieving the same.
Clearly, it is not possible to continue with business as usual, and all those across the plastics value chain must adopt circular principles.
One part of the solution to achieve plastic circularity is the recycling of plastics but the current recycling rates are far from ideal levels. The following table features 2018 data published by PlasticsEurope.
The European Commission echoes the need for higher recycling rates in its newly adopted Circular Economy Action Plan as part of the European Green Deal.
The member states must meet the following targets:
- 55% recycling of plastic packaging waste by 2030;
- reducing consumption to 40 bags per person by 2026;
- improving product design to address durability, reparability and recyclability;
- monitoring and reducing marine litter.
- the use of sustainable raw materials;
- reuse, recycling and recovery;
- extending useful life.
To further support plastic circularity and boost recycling rates, Versalis initiated Project Hoop® in February 2020. The project focuses on developing new technology to chemically recycle plastic waste. Together with Servizi di Ricerche e Sviluppo (S.R.S.), Eni’s chemical company is developing a cost-effective valorization process of mixed plastic waste that cannot be mechanically recycled.
What is chemical recycling of plastics?
Chemical recycling, an umbrella term for several advanced technologies, can convert plastic waste into raw materials that re-enter the value chain to produce new polymers. CEFIC, the European Chemical Industry Council, has broadly categorized these technologies into three types.
|Dissolution: Waste Plastic to Polymer||Depolymerization: Waste Plastic to Monomer||Conversion: Waste Plastic to Feedstock|
|The process involves extracting the polymer by dissolving the sorted-plastic waste using a solvent and/or heat. This also separates additives from polymers. Further, the extracted polymer can be processed with new additives to make new plastics.||In this method, sorted plastic waste is broken down into its constituent monomers using various chemical reactions. The purified monomers can then be used to manufacture new polymers. Typical polymers that are suited for this technique include Polyethyleneterephtalate (PET), Polystyrene (PS), Poly (methyl methacrylate) (PMMA), etc.||Using these techniques, mixed plastic waste is converted into an hydrocarbon mixture that can be used as raw materials/feedstock for new plastics. This oil- or gas-like feedstock can replace newly extracted fossil feedstock in chemical plants. The two main process types are pyrolysis and gasification.|
Pyrolysis is one of the leading processes being explored today to meet the challenging recycling targets and address the need for plastic circularity. The process occurs at high temperatures (in the absence of oxygen) and converts plastic waste into feedstock that is further used in manufacturing new chemicals.
Versalis is advancing the development of pyrolysis technology via Project Hoop® and to understand more about the mission and vision, I spoke to Fabio Assandri, Research and Innovation Technology Director at Versalis.
Q: Could you explain Project Hoop® and why Eni is investing in it?
Assandri: Plastic waste is a challenging issue we all face today. Europe collects close to 30 million tonnes of post-consumer plastic waste and recycles only one-third of it as of now. Mechanical recycling is the primary method used and it efficiently manages pre-sorted waste streams (e.g., mono-material, less contaminated, etc.). A good example is PET water bottles.
However, mechanical recycling has certain limitations. Reprocessing steps lead to degradation in material properties and may lead to downcycling. It also puts a cap on the number of times the plastic gets recycled. And, perhaps the biggest drawback is the inability to manage more complex and mixed plastic waste streams, which currently are either incinerated or landfilled.
This led us to invest in Project Hoop® which focuses on chemical recycling as an alternative solution to the problem, thereby advancing plastic circularity.
Q: How does Hoop® work?
Assandri: Hoop, the name of the project, represents a complete circle and aptly symbolizes the support for circularity. We've worked on a new process based on pyrolysis technology from S.R.S. that transforms polymers into smaller molecules and building blocks. This conversion is analogous to dismantling a lego set into individual blocks.
We have completed pilot-level testing and also the design of the demonstration plant with a capacity of 6,000 tonnes per year at the Mantova’s site. Our goal is to scale up and have the technology ready for application on a large scale.
Q: What is plasmix? And what are the advantages of pyrolysis technology?
Assandri: Plasmix is the mixed plastic waste that is not suitable for an effective mechanical recycling and accounts for a significant amount of plastic waste that currently doesn't get recycled.
Pyrolysis is ideal for such waste streams and it allows for the materials to stay in use longer, which aligns with circular economy principles. Because the quality is same as virgin plastics, chemically recycled grades can find use in high-value applications, including food-contact applications.
The process we've developed offers added benefits like flexibility, energy efficiency, quality of products, and large saving of greenhouse gas (GHG) emissions. Material recovery of all the streams resulting from the pyrolysis process (liquid, gas, and solid) is a high priority for us.
Q: Can chemical recycling reduce fossil fuel dependency and lower CO2 emissions?
Assandri: Overall, the carbon footprint of chemical recycling is lower than the upstream and downstream emissions in the current linear system (raw material extraction, plastic production, and end-of-life waste management). Currently, mixed plastic waste is either incinerated or landfilled and both have a negative environmental impact.
Incineration leads to an increase in the emissions of CO2 and other pollutants, while landfilling causes plastic waste to further leach into the environment. Chemical recycling avoids these issues and since it converts the waste back into raw materials, it helps reduce the dependence on fossil reserves.
Q: Will mechanical recycling fade with the development of chemical recycling plants?
Assandri: Not at all. Mechanical recycling is already a sizable business with a well-developed ecosystem for polymer streams like PET, HDPE, PP, etc. There is no point in replacing existing systems that work well.
The aim of the project is to complement mechanical recycling and drastically improve the circularity of plastic products by widening the scope of recyclable waste streams. In fact, I believe that mechanical recycling will benefit from the development of chemical recycling technologies as the targets and assessments would be more spread out between the two.
Q: Is the Hoop® process the solution to the plastic waste issue?
Assandri: The issue of plastic waste is complex and requires a multi-level approach to find effective solutions. Projects like Hoop® are taking steps in the right direction and are an important part of the solution. Whether or not chemical recycling, together with mechanical recycling, will succeed in addressing plastic waste issues depends on several factors:
- all actors across the value chain, including brand owners, need to get involved and collaborate;
- consumers must also play an important role in supporting the proper waste collection and in increasing the demand for recycled products;
- standardized certifications that are internationally recognized are a necessity. Because chemical recycling generates virgin-equivalent feedstock, the materials will get blended in chemical plants and make it difficult to physically track the recycled feedstock. Experts, therefore, suggest using the mass-balance approach to accurately trace the flow of the recycled material around industrial plants in order to allocate the correct value of recycled content to a product.
Last but not least, the industry will also need political and regulatory support. More clarity on sustainable plastics manufacturing should come in early 2021 once the European Commission completes its review of the EU's Taxonomy Regulation.
The author: Sreeparna Das
An independent consultant and published writer with a Master’s degree in Chemistry and 12 years of experience in the specialty chemicals industry. She specializes in mapping innovative solutions that support circular economy principles.
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