INSIGHT: New chemical-recycling technologies proliferate
HOUSTON (ICIS)–Companies are developing several chemical recycling technologies as they face pressure from consumers, regulators and investors to keep plastic out of oceans and landfills.
Shoppers are actually willing to pay more for sustainable products, according to a survey released in 2019 by the consultancy Accenture.
“We are seeing a drive from consumers first and foremost,” said Jessica Long, managing director and lead for the Accenture’s North American Sustainability and Trust practice. She is one of the authors of The Circular Economy Handbook.
Not only are consumers demanding natural and healthier products, they want them sold in packaging that can be recycled and reused, she said. Companies that sell directly to consumers are feeling this pressure, and they are relying on chemical companies to provide them with materials to placate their customers.
Employees are also demanding that their employers do more to promote sustainability, Long said. The rise of environmental, social and governance (ESG) investing will create another sustainability front for chemical companies. Some lenders are even issuing loans whose interest rates are tied to borrowers meeting sustainability goals.
Chemical recycling is one way that companies can meet these demands from lenders, investors, employees and consumers.
ADVANTAGES OF CHEMICAL
Chemical recycling is the ultimate closed-loop system because it brings plastics back to feedstocks that can be used to make virgin resin, said Bob Kumpf, specialist executive at Deloitte Consulting.
It also avoids some of the problems with mechanical recycling. Under mechanical recycling, waste plastic is re-processed without being broken down chemically.
In mechanical recycling, plastics of different grades and with varying additives get mixed up, resulting in material that is heterogenous, he said. This compromises the qualities of the material. In addition, each time a plastic is re-heated and re-processed, it becomes degraded.
As the quality of the recycled plastic deteriorates, it goes into less demanding applications. Ultimately, it ends up in the trash.
Chemical recycling avoids this problem because it breaks down plastic into oils and monomers, which can be used to make virgin resins.
Typically, addition polymers such as polyethylene (PE) and polypropylene (PP) are chemically recycled through pyrolysis to produce oil, Kumpf said. Pyrolysis can tolerate different grades of plastic, but the end product is an oil, which often needs further refining before it can be converted into monomers and new polymers.
Condensation plastics such as polyethylene terephthalate (PET) can be chemically recycled into valuable monomers, which require little processing before they can be used to make new plastics, Kumpf said. The problem is that the waste condensation-plastics cannot tolerate much contamination before they can be recycled.
Polyvinyl chloride (PVC) presents its own problems since the chlorine in the polymer can react during chemical processes to produce harmful byproducts.
Given the challenges for chemical recycling, mechanical recycling can still play an important role. It doesn’t require the upfront capital costs involved with building chemical plants, said James Ray, ICIS vice president of consulting – Americas.
Ideally, mechanical and chemical recycling would work side by side with waste-to-energy operations at a recycling centre, Ray said.
Some of the output from chemical recycling could be refined to produce diesel for the centre’s trucks, he said. Waste-to-energy operations could produce power for the recycling centre. Excess power could be sold.
Sorting could be done by consumer, since this would require little effort on their parts, he said. Plastic deposit fees – similar to those for bottles or aluminium cans – could give consumers more incentive to separate and sort their plastic waste.
Kumpf said the logistics involved with collecting plastics is as much of a challenge as perfecting the technologies involved with recycling polymers, be it mechanically or chemically.
COMPANIES TURN TO CHEMICAL
So far, pyrolysis has been the most common form of chemical recycling. This process uses heat to break down the bonds within the plastic to produce synthetic oil. The oil is then used as a feedstock for crackers.
Since 2018, Agilyx has been recycling polystryene (PS) at its plant in Tigard, Oregon. It can convert up to 10 tonnes/day of polystyrene (PS) waste into styrene oil through pyrolysis.
Since starting up the plant, Agilyx has created the Regenyx joint venture with AmSty. It also has agreements to supply styrene oil to INEOS Styrolution.
Notably, Agylix has been combining PS recycling with data analytics. The company is determining how different bales of plastics produce different grades of oil. The insight that the company is learning from its data could give it control over the quality of its oil.
Agylix is now adapting its technology to produce a naphtha base-stock. The combination of technology with data analytics could allow Agylix to produce naphtha grades of high enough quality to be used in crackers without further refining.
Agylix could soon be joined by more pyrolysis plants.
Brightmark Energy plans to start up its 100,000 tonne/year chemical recycling plant in Indiana by the end of this year.
Plastic Energy still plans to build 20 chemical-recycling plants by 2025, each of which can produce about 20,000 tonnes/year of pyrolysis oil
The company relies on a pyrolysis process called thermal anaerobic conversion to produce the oil, which it markets as Tacoil.
Fuenix Ecogy Group to Dow to be used as feedstock to produce plastic at the company’s Terneuzen site in the Netherlands.
Other companies are adapting refining technologies to recycle waste plastics.
The UK-based Recycling Technologies relies on a modular fluid catalytic cracking (FCC) unit to convert plastic into wax and oil. The product, which the company markets as Plaxx, is then shipped to refineries, where it can be further processed into fuels and naphtha.
Recycling Technologies stands out because it is locating its plants within recycling centres, where plastic is already being sorted and separated by type.
Anellotech is also relying on FCC technology, which it initially designed to handle biomass. The company’s Plas-TCat process technology could be ready for commercialisation in two to three years.
Other companies are relying on gasification.
Under its Carbon Renewal Technology, Eastman is adding waste plastic in its coal gasification unit in Kingsport, Tennessee. The resulting synthesis gas (syngas) contains carbon monoxide (CO) and hydrogen gas, which Eastman uses to make acetic acid and other acetyls.
Eastman is already using the process to recycle carpet.
Other companies that developed gasification technology for municipal waste could be modified to handle varying amounts of plastic.
Among other processes, Eastman plans to revive its methanolysis technology to recycle polyethylene terephthalate (PET). Eastman once used the process to recycle the polyester used in photographic film.
This process, now called Advanced Circular Recycling Technology, will use methanol to break down waste PET into monoethylene glycol (MEG) and dimethyl terephthalate (DMT). Eastman will then use most of the output of the plant to produce specialty co-polyesters.
IBM’s VolCat process relies on a catalyst and ethylene glycol to break down PET into its monomers, said Terence Cooper, CEO of ARGO Group International, a consultancy.
Cooper summarised a host of chemical recycling technologies during a recent presentation at the SPE International Polyolefins Conference. These included Carbios, Ioniqa and GreenMantra Technologies.
Carbios developed a process that breaks down PET using enzymes.
Meanwhile, Ioniqa has started up a 10,000 tonne/year plant in the Netherlands that recycles PET.
Pyrowave is relying on microwaves and a silicon carbide catalyst to break down PS into monomers.
GreenMantra Technologies is producing polyolefin waxes from waste plastics by using a a thermo-catalytic process. It has also signed an agreement with INEOS Styrolution to recycle PS by using catalytic microwave depolymerisation.
Licella, a company based in Australia, is relying on supercritical water and catalysts to break apart the bonds in polymers.
Insight article by Al Greenwood