Plastics Recycling: Innovation and Automation Enable a Circular Economy

Recycling plastic began in the 1970s, 20 years after the material's ubiquitous acceptance into everyday life. But yesterday's recycling couldn't keep up with our plastic consumption then-and it can't keep pace with the fast-moving world of today.

In 1950, global plastic production was around 2 million metric tons. In 2020, according to Statista, total global plastic production was around 367 million metric tons-and that was a slight reduction from the previous years due to COVID-19's impact on the plastics industry.

With all that new plastic released into circulation, you'd think a lot of it would be recycled-but it's not. Only a fraction of all of the plastic created each year is collected for recycling in the first place, and most of what is isn't actually recycled. As a result, most plastics make their way into landfills and eventually into the environment-increasing global waste and pollution on both the land and in the sea.

Since 1992, more than half of the higher-income countries' plastic waste intended for recycling has been exported to hundreds of lower-income countries for processing, with the lion's share of that going to China. This provided an outlet for managing plastic waste, preventing it from going to landfill or incineration, according to the National Center for Biotechnology Information.

But China's 2018 National Sword policy is changing that. Before the policy, the country's Ministry of Ecology and Environment says that it imported 42.27 million metric tons of dirty and mixed recyclables at its peak in 2017-and most of that was too dirty to recycle. A 2018 report in Yale Environment 360 indicated that, even before the ban, less than 13% of plastics the country imported were recycled or burned. The rest went to landfills or ended up in rivers and oceans, and one of the main reasons that China implemented the new policy was to decrease the importation of these low-quality plastics that are hard to sort and recycle.

Plastic pollution is a growing threat to all ecosystems and-with China and other nations no longer taking in half of the world's refuse-the problem is now on a path to more than double by 2030, according to an October 2021 United Nations report. The United States has recycled less than a tenth of its plastic waste, with Europe doing better at about a third of theirs, but now all these countries will have more plastic that they can no longer export-and with that, the plastics situation is poised to get worse.

The Circle of Life

More recycling would seem like a logical solution to the problem. Unfortunately, not all plastics have traditionally been recyclable, nor can most be recycled many times over. Most post-consumer plastics-like the packages your takeaway food containers come in, or margarine and yogurt tubs-are considered "unrecyclable" using traditional mechanical recycling methods, with the vast majority of it getting incinerated or sent to landfills.

This plastic, polypropylene, is rarely recycled. Better known as "Resin Code #5," it is used in everything from shampoo bottles and plastic cups to automotive parts and medical devices. Removing contaminants, color and odor from these plastics to recycle them has traditionally been expensive and complicated, often yielding poor results.

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In fact, less than 1% of the 170 billion pounds of polypropylene plastic produced each year is reclaimed for recycling and reuse. That also means that there is a huge opportunity to give the world's most versatile and widely used plastic more and better recycling efforts to help it fit into a circular economy. By recovering resources at the end of a product's life and channeling them back into production, the circular economy minimizes the products' pressure on the environment. When it comes to recycling and reusing existing products, specifically, a major goal is also to reduce the introduction of more carbon to the environment.

Innovation to the Rescue

Widespread use of recycling innovation technologies could promote a closed-loop circular economy from material design, to separation, to reprocessing-and bring new life to old plastics. Chemical recycling technologies, for one, can enhance or replace the currently used mechanical processing. In this, high heat, chemical reactions or both are used to turn used plastics into new virgin-like plastics, fuel, or other new chemicals or products.

These technologies reduce the overwhelming amounts of unrecoverable plastics that could potentially leak into the environment. Advanced technology is needed to remove color, odors and other contaminants from the used plastic. In addition, automation-like those services provided by Emerson-can play an integral role in turning end-of-life plastics into new products to reduce waste and pollution and to lower plastic production costs.

Two companies exemplify the potential of plastics recycling by introducing new ways to work with polypropylene. PureCycle returns the plastics to pure, near-virgin polypropylene, reintroducing them to the plastics economy in like-new form, whereas ReNew ELP reduces mixed plastics down to high-grade chemicals and oils … feedstock for new use cases and applications.

New Polypropylene, Same as the Old Polypropylene

Orlando, Fla.-based PureCycle Technologies uses an innovative technology to turn waste into nearly new polypropylene that can be reintroduced back into the same use case. Developed by Procter & Gamble, the process removes color, odor and contaminants, turning the recycled material into ultra-pure recycled polypropylene resin with virgin-like properties that can be used to make new plastic products.

"Recycled plastics are typically gray in color, have a malodor and have contaminants that present regulatory concerns," says John Layman, senior R&D director of sustainable materials development at Procter & Gamble and inventor of the solvent purification process used by PureCycle.

According to Layman, this is currently the only technology able to meet the demand for better-recycled polypropylene, making it a win for both PureCycle and the environment. "Today, consumers are increasingly expecting that the products they buy are environmentally responsible," he says. "This new technology delivers a win-win-advancing our innovative capabilities while also providing an environmental benefit."

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PureCycle can create near-virgin polypropylene plastic feedstock, suitable for many applications including in its original use case in medical, cosmetic, food and beverage packaging, as well as for textiles and automotive parts. "This provides a pathway to reverse low rates of global polypropylene recycling and opens new opportunities for the plastics supply into all polypropylene applications," says Dustin Olson, chief manufacturing officer of PureCycle Technologies.

To produce this advanced polypropylene, PureCycle is partnering with Emerson to build new facilities using the company's Plantweb digital ecosystem with its intelligent sensors and control valves, operations software and cloud data management system.

Unlike traditional manufacturing facilities that need to cope with transforming legacy platforms to digital, these facilities will be "born digital," according to Olson. The company has rapid expansion plans to build 50 plants in the next 15 years, and Emerson's automation will help the company scale quickly. "With Emerson's help," he says, "each PureCycle facility is expected to start up with the most advanced digital automation technologies available, allowing for faster project completion, fully integrated systems, and world-class operating performance."

(Just Like) Starting Over

Taking the idea of recycling a step further, U.K.-based ReNew ELP's process returns polypropylene to its raw chemical compounds. The company uses supercritical steam, where water is heated and pressurized above its critical point so that it exhibits the properties of both a liquid and a gas. This supercritical steam breaks down the shredded material's polymeric structure of the plastic, converting the hard-to-recycle plastic into new hydrocarbon feedstocks that can be used to manufacture new plastics.

Many post-consumer plastics-such as contaminated items or flexible, multi-layer plastic packaging-are not recyclable via traditional mechanical recycling methods and would thus be good candidates for ReNew ELP's process. That's because the supercritical HydroPRS steaming and distillation system developed by Mura Technology returns plastics to the original chemicals and oils from which they were produced. In addition, there is no need to separate the feedstock-all plastics, contaminated or not, can be fed into the process together.

Reducing pollution produced by plastics on a global scale will require an accelerated transition to new processes, additional innovation and the ability to support ambitious sustainability goals.

These new processes rely on advanced automation technology and software to create scalable production models, and so ReNew ELP selected Emerson as its digital automation partner to ensure a safe, efficient and innovative process. In addition, the company will be providing ReNew ELP with the project and operational methodologies and a control and safety system to keep the plants running efficiently and the employees safe.

"By converting end-of-life plastics into fossil-replacement feedstocks, ReNew ELP has the potential to eliminate unnecessary single-use plastic and make the raw ingredients for a circular plastics economy, creating value instead of waste," says Richard Daley, managing director at ReNew ELP.

The company has initiated a life cycle assessment by the Warwick Manufacturing Group to determine its new recycling process's environmental impacts and Global Warming Potential (GWP). This evaluation will also determine what CO2 savings occur when plastic waste is diverted from incineration instead of advanced recycling. The initial findings are encouraging, indicating a significant reduction in GWP.

"Through collaborative project engineering, advanced digital solutions and life cycle services, Emerson will help ReNew ELP create a solution that supports sustainable practices and helps advance our goals to preserve resources," says Roel Van Doren, group president of global sales at Emerson.

Reducing pollution produced by plastics on a global scale will require an accelerated transition to new processes, additional innovation and the ability to support ambitious sustainability goals. Advanced digital automation technologies, like the solutions Emerson provides, coupled with innovative and collaborative project engineering can help companies like PureCycle and ReNew ELP create long-term solutions that are safe, reliable and productive, ensuring the output is good for the environment and the bottom line. The combination of a trusted digital partner and innovative technology will take a huge bite out of the 170 billion pounds of polypropylene plastic produced each year and help to put us on track for a better future.