Plastic pollution of the oceans, the resulting damage to wildlife, and the human
health risks from microplastic have ignited public concern and heated
discussions around plastic reduction. The decisions by
China,
Malaysia and soon Vietnam to stop imports of plastic
waste
— and growing public pressure — have prompted the realisation that exporting,
burning and burying are not the right solutions to the smouldering plastic
crisis. Global approaches are needed to deal with the predicted doubling of the
global production of plastic over the next 20 years fuelled by increasing
consumption, particularly in developing countries.
Under the New Plastics
Economy
global commitment initiated by the Ellen MacArthur Foundation, consumer
brands including Coca-Cola, Colgate, H&M,
PepsiCo, SC Johnson and
Unilever vowed to make all
their plastic packaging either reusable, recyclable or bio-degradable by 2025.
In January, the global Alliance to End Plastic
Waste
— featuring petrochemical and packaging giants including
BASF,
Braskem, DSM,
ExxonMobil, Henkel, Procter &
Gamble, Suez and
Veolia — committed to invest €1,3 billion over the next five years into
innovative technology to help recover and recycle plastics waste from the land
and the ocean.
The problem remains that so little of the collected plastic waste actually gets
turned into new material. This is a significant loss of valuable resources to
the economy, and a huge cost to the environment. In Europe, for example, of
the 30 percent of plastic waste that got collected in 2016, only 31.1 percent
actually got converted into new products. This is mainly because mechanical
recycling — shredding into resin pellets — only works for pure streams of
plastic types, such as PET bottles; composite, dirty materials usually get
incinerated. As a consequence, more than half of Europe’s plastic converters
are running
short
on suitable waste. Producers that want to use recycled material for their
products cannot rely on steady supply streams of quality feedstock.
A fresh look at chemical recycling
To tackle this situation, industry is taking a fresh look at chemical
recycling.
The technology is not new — it has been used to turn plastic into fuel for
decades. What is new is the growing market
demand
for high-quality plastic recyclates, due to significantly higher targets for
recycled plastic in packaging products and a heightened sense of corporate
responsibility.
For lawmakers, the concern is to avoid “waste-to-fuel lock-ins.” In Europe, the
revised EU waste
legislation
states that plastic waste can be considered as recycled only if it is not
subject to energy recovery and is reprocessed into new materials that are not to
be used as fuels. This definition is technology-neutral, but is complex when it
comes to transforming plastics back into basic chemicals. The ultimate goal is
nothing less than closing a gap in the waste-management process to seize the
benefits of a circular plastic economy.
There are four methods of chemical recycling, which are substantially different
in terms of waste input and obtained products:
-
Depolymerisation turns monoplastic (ex: PET bottles) back into monomers,
which can be re-polymerized into new PET-based products.
-
Solvolysis (dissolution) is used to break down certain plastics such as
expanded polystyrene (EPS) into monomers with the aid of solvents.
-
Pyrolysis converts mixed plastics into tar oil, which can be cracked down
and further refined for new plastics production.
-
Gasification is able to process unsorted, uncleaned plastic waste and turn
it into syngas, which can be used to build bigger building blocks for new
polymers.
The latter two — pyrolysis and gasification — transform plastics, and most of
their additives and contaminants, into basic chemicals; in theory, any kind of
plastic waste can be converted. To meet the same quality standards as primary
feedstock, some pre-sorting of non-organic waste or purification of the output
material may be necessary. If the resulting oil and gas are used for chemical
production, the final plastic products will be identical to those produced from
conventional feedstock.
To this end, Air Liquide, Nouryon (formerly AkzoNobel Specialty
Chemicals), Enerkem, Shell and the Port of Rotterdam are preparing
a commercial-scale gasification facility to be operational in 2020. The
objective is to produce syngas and methanol from organic waste that Nouryon
would turn into chemical products. In addition to mixed plastic waste, the pilot
plant will also be able to process biomass, diapers, rotten paper
and the like.
A hurdle race
Chemical recycling through gasification still has a number of hurdles to take
before crossing the finish line. Firstly, gasification plants are built at
larger scale than pyrolysis, which means that the initial hurdle for investment
is particularly high. Next is the dependency on waste streams that imply
logistical costs such as collection and transport, followed by the syngas’
fluctuating flowrates and varying compositions on the gas grid of a chemical
production complex.
Pyrolysis has its challenges, too, but due to their smaller scale, it has been
easier for companies to keep some pilot facilities running. Even though
pyrolysis is capable of handling any type of organic material, non-organic
materials such as metals, glass fibers, halogens and often PET need
to be removed from the input stream, ideally before the process or through
purification of the pyrolysis oil afterwards. Remaining non-organic pollutants
represent a cost factor, making ocean
litter
unviable as an input material, and adding problems such as massive water
consumption for rinsing.
Room for growth
But soon, even food-grade plastic could be commercially produced from pyrolysed
plastic waste. At the end of 2018, BASF with several partners announced the
development of refrigerator components, insulation panels and even mozzarella
packaging that consist of polymers generated from such pyrolysed plastic waste.
In this ChemCycling collaboration
project,
waste operators deliver mixed plastic to technology providers for the pyrolysis
procedure. BASF then uses the generated naphtha to produce high-quality plastic
material that downstream customers use in their final products.
BASF project lead Stefan Gräter states that chemical recycling provides a
valuable cleaning function in a circular economy resulting in secondary
materials with “virgin” properties. Even under the optimistic assumption that
packaging products could be re-designed to a large extent, mechanical recycling
would still struggle to meet the required quality standards. Contaminants and
additives could be accumulated in the material over several mechanical recycling
cycles and might lead to poor product performance or even health risks.
“From this perspective, chemical recycling is a complementary option to
established recycling and waste management processes,” Gräter argues. “The
objective is to find technology solutions for the type of waste that is not
suitable for mechanical recycling.”
To bring it to an industrial scale, chemical recycling needs to strike a balance
between economic viability, regulatory compliance and environmental impact. When
it comes to the latter, gasification of mixed plastic waste and pyrolysis of
sorted plastics yield superior CO2-reduction scores than incineration with
energy recovery, according to a recent study by Dutch independent research and
consultancy firm CE
Delft.
From a business point of view,
McKinsey
sees “opportunities to build a new and profitable branch of the industry based
on recycled plastics” that might represent a profit pool of nearly €50 billion
per year worldwide by 2030. Under a scenario where much larger quantities of
plastic waste are routed for reuse instead of going to landfill and
incineration, they see a “potential for chemical companies to transform two
areas: polymers produced from mechanical recycling, and the whole field of
pyrolysis and chemical recycling of used plastics Projecting a step further,
it’s possible to imagine a wholly new configuration of petrochemical and
plastics plants.”
The true potential for chemical recycling to become profitable depends on the
sufficient supply of suitable plastic feedstock, and the further development of
pyrolysis and gasification technologies to produce high volumes of recyclates
with consistent quality at a competitive price. But reaching that potential also
depends on conducive regulatory framework. At a policy briefing between
stakeholders and European policy makers, EU Environment Commissioner Karmenu
Vella emphasized the Commission’s intention to investigate further incentives
and regulatory measures to increase the recyclability of plastics and make it a
valuable resource. According to Vella, improved sorting and recycling techniques
can also contribute to this objective: “The Commission is eager to learn more
about chemical recycling.”
It is often said that circular approaches have to be systemic, and plastics are
no exception. Scaling a systemic solution towards a circular plastics economy
will require a combination of complementary technologies and collaboration
between the different parties of the value chain, without favoring one over
another. From this perspective, chemical recycling, despite its challenges,
seems to have an important role to play.
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Michael Laermann is an independent consultant, editor and founder of Reason & Rhyme Communications in Brussels, specialized in designing integrated communications and sustainability strategies.
Published Apr 10, 2019 2pm EDT / 11am PDT / 7pm BST / 8pm CEST