Few plastics get recycled—only about 9% in the US and 15% in Europe. The mechanical recycling that dominates today is hampered by contamination and a high variety in plastic waste streams. And those plastics that are recycled usually get turned into less-valuable products. Chemical recycling might offer help. Depolymerization can break down polyester and polystyrene into their raw materials for conversion back into new polymers. And pyrolysis can turn mixed plastic waste into naphtha, which can be cracked into petrochemicals and plastics. But experts say chemical recycling won’t work unless it is deployed at large scale. Chemical makers are investing to do just that.
Business is taking off for Agilyx. Eighteen months ago, the small company opened a plant in Tigard, Oregon, that uses pyrolysis to break down about 10 metric tons (t) per day of polystyrene waste into its starting material, styrene.
Big chemical companies have since been beating a path to Agilyx’s door. Ineos Styrolution plans to use Agilyx’s technology to build a plant in Channahon, Illinois, that will process 100 t of polystyrene waste per day.
And the Tigard plant itself is now part of a joint venture with the polystyrene maker Americas Styrenics. The two firms are close to announcing a new plant, with 50 t per day of capacity, in the western US. Trinseo and Ineos Styrolution are planning yet another Agilyx depolymerization plant in Europe.
“This last year and a half has been very frenetic,” says Joseph Vaillancourt, Agilyx’s CEO. “Lots of opportunities; very exciting. There is still a lot coming that we haven’t disclosed yet.”
Agilyx, Vaillancourt says, is working with 30 companies in total on projects at various stages of development, including efforts in polyethylene terephthalate (PET) and acrylic depolymerization. He plans to unveil three new polystyrene depolymerization plants in the coming months.
Agilyx isn’t the only chemical recycling company on a steep growth trajectory. Plastic Energy, which uses pyrolysis to transform mixed plastics into diesel and naphtha, plans to build 10 plants in both Asia and Europe by 2023, including 1 at Sabic’s chemical complex in the Netherlands. Loop Industries is building a commercial plant to break down PET into its raw materials in Spartanburg, South Carolina, as part of a joint venture with the big polyester maker Indorama. And Loop aims to build three more plants by 2023.
The projects are signs that the plastics industry is placing a big bet on chemical recycling as it comes under intense pressure to do something about plastic waste.
Plastics are under assault as they haven’t been in a generation. Documentaries showing beaches covered in debris and sea turtles tangled in plastics have turned the public against the material.
Plastics are recycled less in the US than other common materials.
Sources: US Environmental Protection Agency.
Consumer product companies such as Coca-Cola, PepsiCo, and Unilever have made ambitious commitments to incorporate recycled material in their packaging, up to 50% in some cases. Governments are seeking bans on single-use plastics like straws and are mandating greater use of recycled content.
But brand owners don’t want to compromise on performance. And they would if they depended on traditional mechanical recycling processes, which merely wash the plastics and melt them down again. Chemical recycling methods that recover their original raw materials to be remade into high-quality resins offer a way out.
Plastics producers are eager to give chemical recycling a try, and dozens of start-ups are ready to help them. But they face challenges. To have a chance at making the technique profitable, they need to build big, expensive plants and aggregate a lot of plastic waste.
Critics say they will never be able to ramp up the technology fast enough to make a dent in the problem. Chemical makers say they can—and in the process establish a circular economy for plastics.
The dysfunction of plastics recycling
Plastics recycling, as it exists today, is a mess. In 2015, the US recycled only 9.1% of the 31 million t of plastics that consumers threw out, according to the Environmental Protection Agency. The vast majority ended up in either landfills or incinerators. In contrast, two-thirds of paper, a third of metals, and a quarter of glass were recycled that year. In the European Union, about 14.8% of the roughly 27 million t of plastic waste was recycled in 2016, according to the European Commission.
Plastics recycling is a battle against entropy. Consumers throw plastics of all sorts into curbside bins, where they get mixed with metal and glass. From this assorted waste, recycling facilities use optical sorters to pluck out only the most valuable plastics for reuse.
Recycling facilities are most interested in PET beverage bottles and high-density polyethylene containers like milk jugs—plastics numbers 1 and 2, respectively. They are relatively clean and homogeneous materials, and recyclers handle enough of them to make extraction worthwhile. Secondary processors wash, melt, and repelletize them for reuse.
Some of the other residual plastics—polypropylene yogurt cups and multilayer plastic pouches, for example—are baled and carted off to processors that attempt to extract additional plastics of some value. But most go to landfills.
Even desirable number 1s and 2s that are sorted out of curbside streams are difficult to recycle. They are contaminated with food and grime. Not all plastics with the same name and number are actually the same: the PET used in a takeout container is different from that used in a water bottle.
For all these reasons, plastics are usually downcycled into applications with less-exacting specifications than what the virgin materials were designed for. A soda bottle doesn’t become a soda bottle again; it is made into a carpet or a fleece vest. In its next incarnation, the milk jug becomes the inner layer of a detergent bottle.
The US polymer industry sees polyethylene terephthalate as its recycling North Star.
Sources: US Environmental Protection Agency.
a Recycling rate is negligible. b Other resins include commingled plastics and undefined recycling.
To Nina Bellucci Butler, CEO of the consulting firm More Recycling, the economics are stacked against building an adequate recycling infrastructure. “There are a lot of inefficiencies in the marketplace,” she says. “Even those companies that make major strides to reduce environmental impact don’t realize the reward or competitive advantage because not all claims of recycled content or recyclability have adequate oversight or transparency. Also there is a failure to incorporate the environmental cost and benefit in using virgin materials versus recycled or the full environmental impact of landfilling our resources.”
For instance, Butler says, tipping fees—the cost municipalities pay to landfill plastics and other trash—are too low, reducing the incentive to try to recover value from waste plastics.
So are the prices of virgin plastics that recycled materials are supposed to compete with. In the early 2010s, Butler says, companies were investing in, and plastic goods makers were increasingly using, recycled material. That faded when oil prices tumbled. Recycling isn’t attractive when oil is below $100 per barrel, she says. “Companies aren’t ready to pay 20% premiums for a product that is not at the same level of quality as virgin unless there is a marketplace incentive to producing a product with a lower carbon footprint.”
Chemical recycling could be a way around some of mechanical recycling’s shortcomings. Chemical processes are more tolerant of contamination, and they yield polymers that are identical to the originals, eliminating downcycling. Extracting more value from waste plastics this way, proponents say, could provide industry with the incentives and money it needs, perhaps creating a virtuous cycle.
“If Agilyx can source and treat the material so that it enables them to produce at low cost so it can actually compete one for one with virgin, that would be such a beautiful game changer,” Butler says.
The chemical option
Executives at companies developing depolymerization processes to break PET into raw materials are keen to talk up their advantages, such as being able to handle every bale of PET that lands on their loading docks.
One such executive is Martin Stephan, deputy CEO of the French start-up Carbios. The company is developing a process to break down PET into purified terephthalic acid (PTA) and ethylene glycol with an engineered enzyme. It is building a demonstration plant, which will cost around $10 million, near Lyon, France.
Mechanically recycling waste PET into new bottles requires pristine, transparent raw materials, Stephan explains. Moreover, PET degrades every time it is reprocessed; after about six cycles it’s no good.
Carbios is developing a process to break down polyethylene terephthalate into purified terephthalic acid and ethylene glycol using enzymes.
Carbios’s approach has no such limitations, Stephan says. “Conceptually, it is an infinite recycling process,” he says. “You can depolymerize any kind of PET waste and make any kind of PET product. You can make a black transparent bottle using a black T-shirt as a feedstock, or you can make a black T-shirt using a transparent bottle.”
Stephan says Carbios’s process can tolerate high levels of impurity. The enzyme just ignores the impurities as it finds the PET polymer in the reactor and breaks it down.
Loop Industries’ process is explicitly designed for flexibility. The firm was founded in 2014 to use hydrolysis to break down PET into PTA and ethylene glycol. It shifted to using methanolysis to make dimethyl terephthalate, an alternative PET raw material, because the purification is much easier, CEO Daniel Solomita says. “The drawback of PTA is that it is difficult to purify,” he says.
Plastic is still fantastic. But the end of life of plastic has not been thought through enough.
Martin Stephan, deputy CEO, Carbios
The change made it easier for the company to remove the dyes, pigments, foreign polymers, and even ketchup and mayonnaise that can end up in bales of waste PET. The material Loop will process will contain on average 15% contamination, Solomita says.
Loop’s Spartanburg joint venture with Indorama was initially proposed to process about 20,000 t of plastic per year. It will handle mostly materials that mechanical recyclers rarely touch, such as PET clamshells, microwave trays, and carpeting. “There is an abundance of material on the market that there is no solution except for Loop’s,” Solomita says.
Pyrolysis plants are even more omnivorous than depolymerization facilities. Pyrolysis cracks long polymer chains into short-chain hydrocarbons like diesel and naphtha under low-oxygen conditions and temperatures of more than 400 °C.
One polymer that pyrolysis plants don’t like is PET because it contains oxygen. Thus they have a symbiotic relationship with mechanical recyclers, which have a preference for PET soda and water bottles anyway.
Pyrolysis is best suited to handle a mixture of polyethylene and polypropylene. While pyrolysis today is focused mostly on fuels, chemical companies hope that more firms will use the process to make naphtha, which can be fed into petrochemical plants and become polyethylene and polypropylene again.
Brightmark Energy has one of the largest such projects. It has started construction on a $260 million plant in Ashley, Indiana, that will transform 100,000 t per year of plastic waste into 68 million L of diesel and naphtha, which it will sell to BP, and 22 million L of industrial wax.
The feedstock will be mixed plastic leftovers from recycling operations in Northeast Indiana, says Brightmark CEO Bob Powell. Brightmark will open the bales, remove contaminants such as aluminum cans, and then shred, dry, and pelletize the plastic before it is sent to the reactor.
Credit: Brightmark Energy
Brightmark Energy is spending $260 million to build this plastic pyrolysis plant in Ashley, Indiana.
Powell wants the company to evolve away from producing fuels for combustion and focus on naphtha for making plastics again. “Ultimately, the output of this process will be used to create a high proportion of plastic feedstock,” he says. “It is achievable; it can be done with this facility. It will really help with the circular economy.”
This is precisely the idea Dow has in mind for its partnership with the Dutch start-up Fuenix Ecogy. Dow plans to feed a naphtha-like oil from Fuenix’s pyrolysis process into Dow’s petrochemical plant in Terneuzen, the Netherlands.
“The beautiful thing about feedstock recycling is that you take waste plastic, you make a pyrolysis oil, and at the end of the day you make a virgin plastic,” says Carsten Larsen, who directs recycling in Europe and Asia for Dow’s plastics business. “You have a 100% normal grade of food-approved plastic, except instead of coming from fossil fuels, it comes from waste plastic.”
It is not clear yet how much naphtha Dow will be able to procure, but the company took its first delivery of raw material in August. The company’s goal for Europe is to incorporate 100,000 t of recycled plastic in its polymers by 2025, both through mechanical recycling and the partnership with Fuenix. “The challenge for us as a company is now going to be to scale this solution in quantities that are relevant for the industry,” Larsen says.
While chemical recycling appeals to manufacturers, it would ideally offer environmental benefits beyond waste reduction. Marco J. Castaldi, director of the Earth Engineering Center at the City College of New York, puts chemical recycling a rung below mechanical recycling in terms of greenhouse gas emissions efficiency because of the extra steps and heat involved in the process. On the other hand,“When you have recycling where you are decomposing, bringing it back to its monomers, and reconstructing it, that’s still good,” he says. “That’s obviously better than disposing of it.”
A 2017 study from Argonne National Laboratory found that producing low-sulfur diesel fuel via pyrolysis of waste plastics is up to 14% less greenhouse gas intensive than making the same fuel from crude oil.
Similarly, a study published last year by the Dutch think tank CE Delft estimated that widespread adoption of chemical recycling in the Netherlands would reduce greenhouse gas emissions by about 300,000 t per year. The researchers found that by avoiding production of virgin materials, depolymerization saves 1.5 t of CO2 per metric ton of plastic recycled. Mechanical recycling saves 2.3 t.
Although chemical recycling offers some environmental benefits, Neil Tangri, science and policy director for the environmental group Global Alliance for Incinerator Alternatives, is skeptical it will be a significant solution.
With global plastics production growing 3–4% per year, he thinks a cap on output is a better approach. “There is no way any downstream solution, no matter how good the technology is, is going to scale up and keep pace with that level of production,” he says.
Chemical recycling proponents would love to prove Tangri wrong. They want nothing more than to be able to scale up their processes, consume more waste, and survive economically.
“I have looked at the economics under a number of different conditions, and it is pretty scale dependent,” says Mark Morgan, vice president of chemical consulting at IHS Markit. For example, a pyrolysis plant with 15,000 t of annual capacity, processing polyolefins, could produce hydrocarbon oil at a cost of about $800 per metric ton in North America and $1,000 per metric ton in Europe. If the plant has a capacity of 55,000 t, costs drop to $500 and $600, respectively.
These larger plants should be close to large sources of feedstock, Morgan says. “I do not see a business case for very long-distance movement of plastic waste to do chemical recycling with,” he says.
Morgan has firsthand knowledge. In the early 1990s, he was with BP when the company was developing a pyrolysis-like process that would have supplied feedstock to its ethylene plant in Grangemouth, Scotland. Part of the problem was that the waste plastics had to be trucked in from a long distance.
The economics of procuring feedstocks depend on the product a company wants to make, Morgan says. A company depolymerizing PET will likely be able to pay more for its raw material and ship it longer distances than a company trying to break down mixed plastics into lower-value naphtha or synthetic fuel.
Cloé Ragot, head of policy and sustainability at Plastic Energy, says her firm has the fortune of being close to both raw materials and customers with its project in the Netherlands. It is building a waste plastic pyrolysis facility on Sabic’s site in Geleen and will supply the petrochemical giant the plant’s naphtha-like output as a raw material.
The plant will have about 20,000 t of annual capacity and run on waste acquired locally by the waste management firm Renewi. “Basically, it is the leftover from mechanical recyclers,” Ragot says. Most of the material, she says, will be low-density polyethylene, polypropylene, and some polystyrene that otherwise would have been incinerated.
The company has operated two plants in Spain for 3 years that supply diesel and naphtha to the Spanish oil company Repsol.
On its way to establishing 10 plants in Asia, Plastic Energy is planning a plant in Malaysia and 5 in Indonesia. Feedstock sourcing will be a challenge in a region where plastic is not yet separated from the rest of the trash, Ragot acknowledges. “There is very little sorting infrastructure, which means that the plastic is really contaminated, mainly by food waste,” she says.
The value in plastic waste
Economics has driven Agilyx to completely change its business model over the years. The company started by making fuels in its pyrolysis process in 2004. Agilyx transitioned last year to making styrene from polystyrene by modifying its pyrolysis process somewhat and also using polystyrene as a raw material. It made the change largely because styrene sells for more.
Green gold rush
Dozens of companies are developing technologies for pyrolysis and depolymerization of plastics.
Decomposition of mixed plastics into fuels, including naphtha, via pyrolysis and other processes
Depolymerization of single polymers into their monomers and raw materials
Decomposition of polymers into chemicals other than fuels or monomers
Sources: Closed Loop Partners, company documents.
“In the commodity market, you have a lower return on fuels; you will have a little bit better return on naphtha and some pretty interesting returns on discrete polymers,” Vaillancourt says.
Making a higher-value product allowed Agilyx to cast a wider geographical net for polystyrene waste. “It is much more financially attractive to build larger regional facilities” that are near contract customers, Vaillancourt says. This is as opposed to smaller, local facilities. “We found ways to be economical around aggregation of feedstock.”
Agilyx has built a network of 500 qualified feedstock suppliers. For the Tigard plant, the company accepts feedstock from as far away as a school lunch program in Florida. The company pays for the plastic, gets it for free, or in some cases, gets paid to take it. On balance, Vaillancourt says, Agilyx pays nothing.
Vaillancourt’s advice to other chemical recyclers is to align with a partner that will buy predictable volumes of a single product. “We won’t develop any project without a committed partner,” he says.
Agilyx has an enthusiastic partner in Ineos Styrolution, which hopes to open the Illinois plant in 2022. “I would like to have the plant tomorrow, to be honest with you,” says Ricardo Cuetos, the firm’s vice president of standard products.
Later this month, at the K plastics show in Düsseldorf, Germany, Ineos Styrolution will announce a new product line incorporating the recycled polystyrene resins. It will be geared toward food-contact use, an application that is not appropriate for polystyrene that is mechanically recycled.
Actually, very little polystyrene is recycled at all, Cuetos says, but he thinks chemical recycling will change that. “There was no end market for polystyrene. It was just benches and picture frames or things like that,” he says. “Now we are closing the loop in a true circular economy. We will be taking the styrene and producing virgin material that will go into any application: food, industrial, everything.”
At every stage of the process, Cuetos predicts, companies will profit and preserve the original value of the polymer. “I think it is really going to help boost the collection of polystyrene,” he says.
Single-use polystyrene foam products are a favorite target of politicians. New York City, for instance, banned polystyrene food-service clamshells this year. Cuetos wonders what will happen if polystyrene becomes 100% recyclable. “I hope that will change the public perception and mind-set,” he says.
In the hopes of reversing polystyrene’s fortunes, Ineos Styrolution is betting on a few approaches to polystyrene recycling. It is working with GreenMantra Technologies, which makes synthetic waxes and polymer additives from waste plastics. And it is in a partnership with Pyrowave, which uses microwave radiation to break down the polymers.
I would like to have the plant tomorrow, to be honest with you.
Ricardo Cuetos, vice president of standard products, Ineos Styrolution
Consumer product companies, many of which have big commitments to use recycled plastic, are lining up to buy chemically recycled material. Coca-Cola aims for 50% recycled content by 2030. Pepsi wants to average 33%, Nestlé Waters is shooting for 50%, and Unilever aims to achieve 25%, all by 2025.
Governments are also pushing companies to use more recycled plastic. California wants beverage containers to hit 50% recycled content by 2030. The European Union is pushing for 30% by the same date.
Pyrowave is testing a process that uses microwaves to break down polystyrene into styrene.
“If you look at the amount of recycled content in the plastic industry that companies are committing to, they are not going to be able to reach that with the mechanical technologies that exist today,” says Bridget Croke, vice president of external affairs at Closed Loop Partners, which studies and invests in recycling technologies. “They’re going to need new ways to be able to get that plastic back so that the quality of material is high enough to get into packaging again.”
Many of the companies in chemical recycling expect that consumer goods giants will be willing to pay a premium for their products so they can meet their recycling targets. Indeed, big customers are placing orders.
Loop Industries has supply agreements in place with Coca-Cola, Danone, and Pepsi. The material from the upcoming Spartanburg plant is spoken for, and the partnership is already considering doubling capacity to 40,000 t. “We are looking at potentially going bigger because demand is so overwhelming,” Solomita says. The company is also considering plants on the West Coast, in Canada, and in Europe.
Similarly, Tupperware and Unilever are beginning to use polymers resulting from Plastic Energy’s partnership with Sabic. For example, in August, Unilever launched ice cream tubs under its Magnum brand incorporating the material.
If you look at the amount of recycled content in the plastic industry that companies are committing to, they are not going to be able to reach that with the mechanical technologies that exist today.
Bridget Croke, vice president of external affairs, Closed Loop Partners
The commitments to use recycled material are a sign that consumer product makers realize they need real change to mitigate the backlash against plastic. Chemical recycling hasn’t proved it will be the means by which they will keep those promises, but companies of all types are betting that the technology will be a part of the solution.
“Plastic is still fantastic,” Carbios’s Stephan says. “But the end of life of plastic has not been thought through enough. We need to find solutions to continue to use plastic.”
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