In many regions of the world, especially in European Union, legislation is setting aggressive targets, driving recycling efforts. The technical limitations in mechanical recycling to meet those goals, leads to the view that chemical recycling should play a role in future recycling strategies. This should be an opportunity for chemical recycling in the GCC and wider Middle East region for chemical recycling.

It is important to put the role of plastics recycling into the wider movement for establishing a circular economy and displacing linear economic thinking. The latter takes hydrocarbon and other raw materials through various conversion processes to provide solutions for end-users and consumers, e.g. food packaging, but directing post-consumer waste to landfill and/or incineration. The circular economy seeks to recover as much of the waste material and return it to viable use as a polymer and/or feedstock back in the petrochemical supply chain.

Recycling approaches

Cost and complexity are challenges to establishing a widespread chemical recycling infrastructure, compared to mechanical recycling.  Opinions differ regarding carbon lifecycle assessment (LCA) footprints cost and LCA optimization dependent on how projects are structured, linking municipal waste collection with sorting, recycling methods and integration with chemical conversion operations.

In recent consulting work, IHS Markit has seen common themes emerge in plastics recycling, especially the circular economy, and how “circularity” is achieved can vary significantly. Many people will understand the basics of converting hydrocarbon feedstocks into petrochemical building blocks that can include olefins and aromatics or their derivatives, e.g. ethylene glycol. Most polymers made today are processed with additives, fillers, and fibers to meet specific end-use customer needs, ranging from barrier films to keep food fresh to rigid components in automobiles.

Many municipalities collect and sort plastics waste, often alongside paper, cardboard, and glass. Plastics must be sorted for subsequent processing. Techniques such as near-infrared systems that can “see” different plastics help with this. If manufacturers can be convinced to rethink the design of common household items – using a single polymer such as HDPE instead of a mix of polyethylene, ethylene-vinyl acetate (EVA) copolymers, or polyacetal – recycling could be simplified. This redesign process is ongoing, especially when it comes to labelling.

A simplistic view of the circular economy and its relation to plastics recycling leads to different re-entry points, depending on the polymer and recycling solution. Sadly, today in several parts of the developed world, although municipalities collect recycling, the plastics are often simply incinerated.

Once sorted, polymer articles can be cleaned and baled, ready for downstream use. Many polymers can be mechanically recycled and re-incorporated into select packaging solutions or made into fibers for fabrics. In this way the plastics are re-used. As mechanical recycling continues to grow and develop, one of the many concerns is the range of applications that can use plastics recycled in this way as quality and performance can deteriorate.

A key question for mechanical recycling is how many times articles can be recycled and reprocessed in this way? In order to meet legislation-mandated recycling targets, mechanical recycling alone is insufficient.

Chemical recycling can take different forms. Some technologies like the Vinylloop® process were developed to process PVC in a way that recovered a polymer for reprocessing. The technology had some challenges, e.g., entrained plasticizer, but the principle could be revisited and potentially improved providing polymers for reprocessing, possibly into pipe, etc.  Other technologies applied to polyesters and polystyrene can in effect “unzip” the polymer chains to recover monomers and intermediates that can, in turn, be purified for use in polymer production.

The processing of polyolefins and certain mixed plastic waste can include technologies like pyrolysis that generates a hydrocarbon oil. Different combinations of polymers, pyrolysis technologies and post-treatment can yield feedstocks that can feed a steam cracker, a refinery FFC unit, or even be treated as some form of “syncrude” for the refinery. In China, for example, pyrolysis products could be cofed into gasification units and at present IHS Markit is analyzing in detail direct polymer gasification/co-gasification with coal.

Pyrolysis – a simplified view

A simplified view of the pyrolysis (also referred to as “thermolysis”) process indicates the general principle of the anaerobic heating of plastic waste, e.g., mixed polyolefins, at medium temperature at circa 450ºC to 650ºC, with various approaches to water removal, removal of chlorinated polymers, solids separation, etc. Designs varies from maximum hydrocarbon liquid make, which IHS Markit refers to as “pyro-naphtha”, through to maximum gas productions for reforming.

For companies and municipalities in the GCC and the wider Middle East there are many opportunities to exploit different technology solutions for recycling plastics. Many processes are developmental at demonstrations scale. Some processes are already for license, particularly in the pyrolysis family. These are generally small scale today in the tens of thousands of metric tons per year range. Scale economies are challenging, but work is ongoing to improve scalability.

In addition, technology for the chemical recycling of plastics continues to evolve. Companies like Synova, for example, are developing technologies to convert waste plastics into olefins or aromatics. There is a worldwide effort to develop scalable processes to meet the plastics waste management challenges of the future.

The post-consumer supply chain

Although, legislation can place levies on stakeholders, plastics producers and processors, there needs to be a way in which all parties in the circular economy chain can thrive, not one party fairing at the cost of another.

A simple view of the value chain that links the municipality with plastics production suggests scope for partnerships between private industry and public bodies. Each has very different business models and funding approaches. There are therefore opportunities for public-private partnerships, but the cultures are different. Some challenging bridges need building, in a way that the “value” is shared.

If government-established recycling targets are to be achieved, the links between consumers, municipalities, and petrochemical production must be improved. After all, public opinion is moved by media images of a threatened planet and ecosystem. Only through the collaboration of people, municipalities, and industry – supported by improved technology along the recycled plastics supply chain – can we begin to find a cost-effective solution closing the gaps in the circular economy and reduce polymer-based pollution. Such opportunities exist in the GCC and wider Middle East region.