Pyrolysis offers hope to tackle the plastics crisis

Images of plastic mountains at landfills and islands of floating plastics in our oceans demonstrably show that we are living in an age of immense consumer consumption, said Recyclingtoday.

A rising worldwide population coupled with an increasing desire for goods mean that the global production of plastic is set to nearly triple in the coming decades from around 460 million metric tons in 2019 to 1,231 million metric tons in 2060, according to the Organization for Economic Co-operation and Development (OECD).

Despite international concern that more waste generated equals more harm to the environment, the problem continues to grow. Additionally, as increasing volumes of plastic enter the food chain via animals and fish feeding on discarded materials, the threat to public health increases. In short, we are in the middle of a plastics crisis.

Various international policies aimed at tackling the issues have been adopted or proposed, including the U.S. Environmental Protection Agency’s (EPA’s) draft National Strategy to Prevent Plastic Pollution, the European Commission’s ban on single use plastics and its commitment that 55 percent of end-of-life plastic be recycled by 2030 via the Packaging and Packaging Waste Directive. The U.K. government recently increased its Plastic Packaging Tax which is levied on components with less than 30 percent recycled plastic that are roduced in or imported into the U.K.

We must consider, though, whether these measures adequately deal with the issues. One of the main factors is that less than one-fifth of plastic is recycled. Households and businesses diligently might put out their refuse for recycling collections, but if the majority of this material is not converted into new products, environmental and health problems will increase exponentially.

Mechanical recycling has certainly been useful as the prevalent mechanism employed by municipal authorities to manage plastics in recent years. However, mechanical recycling technologies are facing challenges in treating plastic streams, limiting their scope. In contrast, chemical recycling technologies can have higher tolerances to treat contaminated and complex mixed plastics streams. Those highly contaminated mixed plastic streams are not recycled yet given the limitations of current mechanical recycling technologies.

Chemical recycling through pyrolysis (often referred to as “advanced recycling”) is gaining traction as an alternative to mechanical recycling and incineration because of the wider scope of what can be processed. Pyrolysis involves heating mixed plastics to temperatures of 400 to 600 C (750 to 1,110 F) in the absence of oxygen, with or without a catalyst, to convert polymers into a mixture of liquid hydrocarbons.

The initial steps are similar to mechanical recycling with sorting, pretreatment (acid washing) and shredding before the material is transferred to a reactor to be melted. The high temperatures cause the complex hydrocarbon chains to break into smaller molecules. The resulting oil-gas mixture is transferred to a condenser to be cooled into pyrolysis oil. This oil can be further refined to produce approximately 80 percent liquid, 15 percent gas and 5 percent carbon black (ash).

The resulting products from pyrolysis can be used in a number of ways. The gas can be fed back into the system to heat the reactor’s furnace, and the carbon black can be used for a variety of purposes, such as the production of rubber goods, automotive parts and coatings, batteries, cables and printer inks.

The oil, the majority product by volume, can be used as feedstock for the chemical and petrochemical industries to produce new plastics that have the same chemical structure as first-generation plastics with virgin quality. Moreover, research by the U.S. Department of Energy’s Argonne National Laboratory shows that production of plastic using just 5 percent pyrolysis oil reduces greenhouse gas emissions by up to 23 percent compared with plastic made using crude oil.

The pyrolysis process is not without its challenges, however. With respect to the pyrolysis technology and the plastic feedstock used, the concentration of downstream contamination and its nature can differ significantly. Numerous types of plastics and nonpolymeric sources are combined in mixed plastic feedstocks. Those feedstocks contain coarse to fine particles (e.g., filler, flame retardants, etc.) and other materials that are detected in the oil produced in the pyrolysis process (e.g., coke). Besides the particulate matter, a variety of additional contaminants, such as organic gels, dissolved metals and dispersed liquids, can be found in pyrolysis oil. This complex mixture of contaminants must be extracted from the oil.

Appropriate filtration media and coalescer technologies are key at various stages of the process to remove particles and separate water from pyrolysis oil or liquids from gas. The retention and separation of contaminants not only purifies the oil and gas, making them more suitable for downstream processing but also helps prevent fouling of equipment and unnecessary downtime for maintenance.

To refine the pyrolysis oil further for use as fuel or a feedstock for plastic production, it must be transferred to a steam cracker to convert the oil into lighter olefins. The presence of particles and metal contaminants in crude pyrolysis oils could have significant negative impacts on the steam cracker‘s furnace and recovery section such as furnace run-length reduction from the coking increase.

However, using depth filtration can be an effective method to remove harmful contaminants and reduce the contamination in pyrolysis oils to the thresholds accepted for crude naphtha feed in steam crackers. It is an efficient and cost-effective way to remove particle content from the oils.

Recently published work by Kevin M. van Geem (et. al., including me) highlights that when the filtered pyrolysis oils were subjected to steam cracking, radiant coil coke formation was reduced by 40 percent to 60 percent compared with unfiltered oil. Additionally, this reduction occurred without any changes in product selectivity, thus confirming the significant impact of particulate contamination on coke formation during steam cracking.

This filtration step can occur in the plastic oil production site, in a separated oil upgrade unit or directly in the steam cracker, before blending the oil with naphtha. This technology can accommodate different filtration grades to mitigate the potential evolution of the pyrolysis oil with an increase in solid contamination that could occur from degradation and polymerization.

We know that we need to minimize our use of the earth’s natural resources and reduce the amount of waste generated to prevent environmental damage. Recycling of mixed plastics via pyrolysis and subsequent steam cracking toward light olefins is a promising solution for the ever-growing plastic waste crisis. It can be understood as a substituent of crude fossil oil.

The more that plastics and other items are chemically recycled, the less pollution there will be in waterways and oceans. Consequently, this should reduce harm to wildlife and minimize the volume of microplastics entering the food chain that pose a threat to human health.

Universal collection, sorting, pretreatment and design of plastic products for recycling are keys to using mechanical recycling methods as the most established technology in industry. However, many end-of-life plastic streams remain unsuitable for mechanical recycling. To apply circularity to an increased share of end-of-life plastics, chemical recycling must be scaled up.

International government perspectives on the role of chemical recycling technology should be reviewed and acknowledged as being crucial to improve plastic circularity and recycling rates. Pyrolysis providers’ R&D also must clarify the role, performance and use of these technologies at an industrial scale.

If these elements are in place, the price of pyrolysis oil production could come down. If it falls to a level equal to the cost of current liquid fossil feedstocks, there will be less impetus to create first-generation plastics from fossil fuels. As such, chemical recycling could become the default option in the plastics value chain, waste and pollution would be reduced, and we would all be living in a more sustainable world.

Emmanuelle Biadi is a petrochemicals and recycling expert at Pall Corp., Port Washington, New York. She is a co-author of the scientific paper “Contaminant removal from plastic waste pyrolysis oil via depth filtration and the impact on chemical recycling: A simple solution with significant impact.”

We remind, Royal Dutch Shell, the Anglo-Dutch oil and gas giant, has officially lifted the force majeure on the supply of phenol and acetone to Deer Park, Texas, USA. According to market sources, the line, boasting a substantial capacity of 363,000 tonnes of phenol and 225,000 tonnes of acetone annually, has resumed full operational status. The declaration of force majeure, made in mid-October the previous year, had stemmed from a technical malfunction that temporarily disrupted the supply chain.

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Chris Jahn, president and CEO of the American Chemistry Council (ACC), has sent US President Joe Biden a letter aimed at shaping the US government’s stance in upcoming negotiations on an international, legally binding treaty on plastic pollution, said Plasticsnews.

The letter recommends a set of key elements for inclusion in the agreement and requests a meeting to discuss priority issues in advance of the fourth session of the Intergovernmental Negotiating Committee (INC-4), which meets on April 23 in Ottawa, Canada under the auspices of the United Nations Environmental Program.

“The agreement has an opportunity to advance common-sense solutions that preserve the irreplaceable value plastics provide the world, maintain US competitiveness and keep plastics out of the environment,” said Ross Eisenberg, president of America’s Plastic Makers, part of ACC. “We are concerned that the negotiations are moving away from the original intent of the [UN Environment Assembly] 5/14 resolution to end plastic pollution and instead turning into an activist wish list to end plastic. We’re asking President Biden to meet with us to discuss practical ways we can eliminate plastic pollution through an effective agreement all countries can join that doesn’t eliminate the massive societal benefits plastics provide.”

The letter from Jahn says that an effective global agreement should include a requirement for globally harmonized measures that promote effective implementation of the agreement while recognizing national and local circumstances, national assessments and progress reports on plastic waste reduction, and mechanisms to accelerate the use of recycled plastics through public-private partnerships and blended finance.

We remind, Armando Alvarez Group (AAG), a Spain-based global solutions provider with a focus on sectors including packaging, containers and agriculture, has collaborated with Irving, Texas-based ExxonMobil Corp. to develop silo bags primarily made with polyethylene (PE) resin the companies say improves their recyclability in locations where film is accepted.

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Armando Alvarez Group (AAG), a Spain-based global solutions provider with a focus on sectors including packaging, containers and agriculture, has collaborated with Irving, Texas-based ExxonMobil Corp. to develop silo bags primarily made with polyethylene (PE) resin the companies say improves their recyclability in locations where film is accepted, said Recyclingtoday.

AAG sought to develop silo bags with enhanced characteristics such as increased filling capacity, dart impact, tear and puncture resistance, and high resistance to slumping, while also offering recyclability. Managed by its Spain-based affiliate Sotrafa, AAG aimed to create a solution to meet the growing demand for silo bags, a sector in the agricultural films market known for its flexibility, reliability and cost-effectiveness.

A silo bag is a tube produced mostly out of PE resin, normally 5 to 12 feet in diameter and 200 to 400 feet in length, depending on the amount of material to be stored. They are designed to extend the preservation of agricultural products like silage and grains.

The bags feature a white external layer to reflect sunlight and a black internal layer to block it, maintaining a cool storage environment, and ExxonMobil says AAG’s initiative aligns with its commitment to a circular economy, aiming for resource conservation and reduced raw material use.

In the effort to replace its existing octene-based linear low-density polyethylene (LLDPE) product, AAG worked with ExxonMobil’s PE business to create a new silo bag film formulation, utilizing Exceed S 9272 performance PE. ExxonMobil says this formulation not only met the mechanical property requirements, but also facilitated the transition to a less complex monomaterial PE structure, enhancing recyclability.

“The integration of specifically developed technologies in the production and deployment process of the silo bags signifies a shift towards more sustainable agricultural practices," the company says in a news release.

The collaboration resulted in the launch of two silo bag brands, which ExxonMobil says showcase increased filling capacity, improved resistance to slumping and better recycling prospects.

“The enhanced film formulation including Exceed S has led to a first PE cobranding collaboration between ExxonMobil and AAG with the introduction of two premium silo bag brands,” says Jose Miguel Juarez, product manager of crop packaging films at AAG. “Both bags allow increased filling capacity, high slumping resistance and offer recycling opportunities. These bags help support AAG’s pursuit of circular plastic economy solutions. We are confident that these added value solutions for our global customers will help grow our business.”

ExxonMobil says its PE portfolio offers converters and brand owners an extensive range of performance polymers as well as specialty copolymers and additional PE grades for numerous applications. With properties such as strength, durability and toughness, ease of sealing and optics, the company says its PE formulations help create, protect and promote products throughout the packaging, agriculture, industrial, personal care and hygiene markets.

We remind, Pregis LLC, headquartered in Chicago and renowned for its innovative protective packaging solutions, has recently unveiled a groundbreaking foam packaging product. Developed in collaboration with ExxonMobil Corp, based in Irving, Texas, this new product is supported by certified-circular polyethylene (PE) resins, marking a significant stride towards sustainability in the packaging industry.

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MOL Group (Budapest, Hungary) said it plans to spend more than USD4 bn on green investments by 2030 and expand its waste management activities to potentially provide up to 1.5 million metric tons per year (MMt/y) of feedstock for its oil, chemicals and energy activities by the end of the decade, said the company.

To diversify away from fossil fuels, the company said on March 14 in a strategy update that it will invest USD1 bn in “waste integration, recycling and medium-scale chemical investments by 2030.”

MOL, which has a previously announced target to reach carbon neutrality by 2050, announced an updated long-term strategy that it said places “greater emphasis on renewable fuels, green hydrogen, biomethane and geothermal energy.”

In terms of circular waste management, MOL said it plans to hike its recycling rates to 65% by 2035, while reducing landfilling to 10%. The waste management business could potentially provide 1.5 MMt/y of feedstock to the regional oil, chemical and energy sector from 2030, it said.

We remind, Novoloop, an advanced recycling startup based in Menlo Park, California, announced that it has raised USD11 mln in Series A funding. The funding will be used to expand the company's plastic chemical recycling process, Accelerated Thermal Oxidative Decomposition (ATOD), and bring its production process to scale.

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Air Liquide announces the divestiture to Adenia Partners Ltd of the Group’s activities in twelve countries in Africa representing a total annual sales of about 60 million euros, said the company.

Air Liquide has signed an agreement with Adenia to sell its activities in the following twelve countries in Africa: Benin, Burkina Faso, Cameroon, Congo, Cote d'Ivoire, Gabon, Ghana, Madagascar, Mali, Democratic Republic of Congo, Senegal and Togo. These activities represent sales of about 60 million euros (less than 10% of the Group’s sales in Africa).

The proposed divestiture, which is subject to the usual regulatory and financial approvals, illustrates Air Liquide’s strategy to actively manage its portfolio. Adenia, a recognized investor in Africa for over 20 years, plans to invest up to 30 million euros to accelerate the development of these businesses.

With approximately 1,600 employees in the region and 700 million euros invested in the last 3 years, Air Liquide will remain a major industrial and medical gases player in Africa where it will continue to pursue development opportunities, particularly in the fields of energy transition, hydrogen and healthcare.

We remind, Industrial gas supplier Air Liquide and infrastructure provider Vopak have joined forces to look into the development and operation of infrastructure for ammonia import, cracking, and hydrogen distribution in Singapore.
The companies have formalized their intention through a memorandum of understanding (MoU) under which they will study and explore the joint development of low-carbon ammonia supply chains in Singapore.

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