Chemical Engineering March 2019 - 16

BioCellection
and fed into a flow-through reactor,
where the microwaves, generated
by a standard magnetron, penetrate
the mixture to aid the reaction
and formation of MEG and PTA
products. The company has built a
demonstration-scale reactor and is
currently building a demonstration
plant in Italy that will process 1,000
ton/yr of PET feedstock. The demonstration
plant will be completed at
the end of 2019 or early 2020. The
company's vision is to build plants
close to cities to reduce the need to
transport waste PET feedstock. It is
going to partner with a mechanical
recycler to handle the waste PET
that is not used.
In yet another approach, Ioniqa
FIGURE 1. Several companies are developing chemical recycling approaches to handle low-value mixed
plastics. Among them is BioCellection, whose founders are shown here inspecting mixed plastic waste that
could be a feedstock for its process to make chemical intermediates from such plastic
high-purity monomers that can be
re-polymerized by PET producers
into high-quality PET with 100% recycled
material.
The enzymes are extracted from
naturally occurring bacteria that can
break down PET, explains Carbios
engineer Benjamin Audebert. " The
enzymes have been engineered and
optimized by our teams to be highly
selective for PET, so only the PET is
digested. In this way, the process
can handle mixed-plastic streams, "
he says. Because PET is broken
down selectively, other polymers are
alone and can be separated. " The
enzyme does the sorting for you, "
Audebert comments, " so you can
use low-value mixed plastics materials
as feedstock. "
The enzyme's active sites cleave
the ester bonds of PET. Carbios
generated detailed models of the
enzyme and its interaction with the
polymer chains. The company will
launch construction of a demonstration
plant for this biorecycling
technology in June 2019. It will be
operational by the Q4 2020, Audebert
says. Carbios will then license
its
technology
for a commercialscale
facility to be fully operational by
2023. They are enlisting the help of
the German division of Technip FMC,
16
which has expertise in PET plants.
Infinite recycling of PET is possible,
Audebert comments. Carbios is
working on enzymes for breaking
down other polymers, and is also
involved with technology for embedding
specialized enzymes into single-use
films of bio-based polylactic
acid, so the plastic breaks down in
an ecofriendly manner just after use.
In Switzerland, Gr3n Recycling
(Lugano, Switzerland; www.gr3nrecycling.com)
is also taking aim at
PET, but instead of biological aids,
they are using microwave technology
to assist the depolymerization
reactions of PET plastic into its
constituent monomers. Gr3n's process
uses a saponification reaction
with sodium hydroxide in water to
break down the polymer. The key
innovation is the application of microwaves
to the reaction to speed it
up. " The microwaves act like a catalyst, "
says Mauricio Crippa, CEO of
Gr3n. " The microwaves reduce the
reaction times from multiple hours
down to several minutes. Although
the mechanistic details of how the
microwaves catalyze the reaction at
the molecular level are not clear, the
process works on densified polyester
fibers and on PET plastic.
The recycled waste is ground up
Technologies (Eindhoven, the Netherlands;
www.ioniqa.com) is using
an iron-based ionic liquid in a proprietary
technology that is able to
convert any PET waste, including
colored packaging, back into transparent
virgin grade material. The
technology has successfully passed
its pilot stage and is now moving towards
testing at an industrial scale.
Ioniqa, a spin-off business from
the Eindhoven University of Technology,
has formed a partnership with
Unilever, and the largest global producer
of PET resin, Indorama Ventures,
to develop the new technology
which converts PET waste back
into virgin-grade material for use in
food packaging. Ioniqa's Magnetic
Smart Process is based on its proprietary
Magnetic Fluid Catalyst (an
iron-based ionic liquid). The platform
technology is also being used in
other applications beyond recycling.
In a process that was previously
this magazine (Chem.
reported in
Eng., November 2016, p. 8 and August
2018, p. 5), the BCD Group
(Cincinnati, Ohio; www.bcdinternational.com)
developed a modified
base-catalyzed decomposition process
for removing dyes from PET
fabrics, and separating cotton from
cotton-polyester blend textiles and
fabrics is now being applied to bottles
made from PET.
Making mixed streams work
One of the most difficult problems
in plastics recycling is multi-comCHEMICAL
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MARCH 2019

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Chemical Engineering March 2019

Table of Contents for the Digital Edition of Chemical Engineering March 2019