PET enzymatic depolymerization: towards a demo plant
For the development of CARBIOS’ Enzymatic Recycling Process, TechnipFMC will provide advisory, engineering, procurement and construction supervision services for the demonstration plant.
Present estimates suggest that of the 359 million tons of plastics produced annually worldwide, 150–200 million tons accumulate in landfill or in the natural environment. Polyethylene terephthalate (PET) is the most abundant polyester plastic, with almost 70 million tons manufactured annually worldwide.
The current main recycling process for PET, via thermomechanical means, results in a loss of plastic mechanical properties. PET waste needs an innovative technology to be recovered with the same properties as virgin petrochemical PET.
A sustainable process
CARBIOS developed a technology of plastic enzymatic depolymerization for conversion of the PET polymer back into its original pure monomers. This allows subsequent re-polymerization of the pure monomers to PET. The process used by CARBIOS is based on natural enzymes, which have been improved by enzymatic engineering, to fully break down the polymers that make up plastic materials. The enzymatic depolymerization allows the recycling of plastic waste according to circular economy principles and opens the path to infinite bottle-to-bottle bio-recycling. With a strengthened financial position following the recent capital increase, and an explicit timetable for the deployment of its technology, CARBIOS continues its transformation from a research body into a commercial enterprise.
As a result, TechnipFMC decided to assist this sustainable green chemistry firm as it builds a demonstration plant to enable the recycling of PET plastic wastes. The plant, which will be located in France, will demonstrate CARBIOS’ Enzymatic Recycling Process for depolymerizing PET waste into its monomers. The technology uses proprietary enzymes to recycle PET waste into monomers ready for repolymerization into PET exhibiting the same technical and physical properties as virgin PET.
From the laboratory, through pilot scale to the demonstration plant
CARBIOS’ Enzymatic Recycling Process implements an improved PET hydrolase that ultimately achieves, over 10 hours, a minimum of 90% PET depolymerization into monomers. The two companies believe that this highly efficient, optimized enzyme outperforms all PET hydrolases reported so far and have agreed to transpose CARBIOS’ process from the laboratory and pilot stages to a semi-industrial level with the construction of a demonstration plant. This assistance will further aim at supporting the development of the project and define the basis of the industrial process.
Through this contract, CARBIOS will benefit from TechnipFMC’s industrial know-how in sustainable chemistry and bio-based processes engineering and from the expertise of its German affiliate, Technip Zimmer, in PET polymerization technologies.
TechnipFMC has technological know-how and a leading-edge approach to commercializing new processes. In the case of CARBIOS’ Enzymatic Recycling Process, TechnipFMC will provide advisory, engineering, procurement and construction supervision services for the demonstration plant. The company added that construction has started this year, with operations projected to begin in 2021.
We asked some questions to Audrey Tardy, in charge of coordinating the technical development of this PET enzymatic depolymerization for TechnipFMC.
TechnipFMC has technological know-how and leading-edge approach to commercializing new processes. Why has the Company decided to work with CARBIOS to demonstrate their plastic recycling technology?
TechnipFMC continues to break boundaries and accelerate the journey to a low-carbon society. Energy transition is part of our core business which includes our 4-pillar framework:
- LNG,
- sustainable chemistry including the plastics’ circular economy,
- decarbonization,
- carbon-free energy solutions.
TechnipFMC’s Lyon office has the experience and expertise in bio-based technology and is able to assist start-up companies and technology providers in their early stage development. The Lyon office, with over 500 employees, including 130 process engineers, offers our clients an autonomous approach to tailoring projects and gives us the flexibility to adapt our global methods to match their specific needs. CARBIOS has developed a state-of-the-art PET enzymatic depolymerization technology. As TechnipFMC has been involved supporting the design development since 2017, it was a natural “win-win” outcome for both companies to continue to work together on the technology’s industrialization.
The technology development plan is ambitious and exciting, but the technology needs to be proven on a semi-industrial size through a demonstration plant. TechnipFMC is working with CARBIOS to have this demo-plant running in 2021, to prove the process and finalize the economics. This aims to envisage a first 50 to 100 kta commercial plant project from 2022.
CARBIOS and TechnipFMC have complementary skills to achieve this goal. Our collaboration to demonstrate the technology, build the demo-plant and implement a fast track process workflow is a natural outcome.
What should not be missed in a demonstration unit to be able to define the solid basis of the industrial process? What are the scale-up criteria? What are the critical aspects and technical characteristics to consider?
The key objectives of a demonstration unit are:
- to set the baseline for securing the technology and the economic viability of such a process,
- to prove that the unit can operate safely, continuously and reliably over a long period of time,
- the validation of all unitary operations selected at a lab and pilot stage,
- to move from a 100 percent batch approach at the lab and pilot scale to a continuous running philosophy closing the recycle loops,
- the optimization of the process operating parameters to increase monomers recovery yields and reduce the quantities of unwanted side streams and effluents,
- to define the core heat and mass balances,
- to set the core technology’s performance in view of future full-scale machine selection and performance process guarantees,
- to validate the final products through process qualifications and records,
- to obtain the technology labels for efficiency in the plastic’s circular economy.
To ensure the success of the final industrial size scale-up from the running demonstration plant, we designed the demo-unit with scale-up coefficients between 15 and 50.
The critical design aspects are driven by the future industrial constraints. We have to prove that the technology will be able to run safely on a continuous basis over 8000 h/year while producing pure terephthalic acid and mono-ethylene glycol on-specifications and meeting the process guarantees. The environmental and economic impact of by-products and waste emissions should be fully addressed and integrated.
The demo-plant design addresses the following constraints:
- the final selection of the equipment and associated technologies,
- the design and sizing of all single pieces of equipment,
- the operating flexibility to cope with the final optimizations and testing that will be done while running the demo-plant and the reliability required for an industrial unit,
- the implementation of operational needs for enzymes handling and process cleaning.
To ensure its implementation at large-scale, it is key for operators to gain insights into operational conditions. Which are the most critical aspects to evaluate under a plant engineer’s point of view?
The most critical aspects include:
- ensure a safe plant operation,
- ensure an environmentally friendly and sustainable plant design,
- have complete control of the plant operation (a plant with unfailing process and emergency control systems, an easy-to-operate plant),
- have well trained operators,
- deliver the market with on-spec products at the required capacity with the lowest cost of production and carbon footprint.
The demo-plant for the PET enzymatic technology supports these needs by allowing the future industrial operators to be trained and, the development of the operating and controls manual, the maintenance procedures, and the analytical manual.
Do you think that this technology is marketable? Is there a chance of it being commercialized in the future?
We are convinced of the technology’s potential for commercialization. The process works, and the final PTA and MEG are at the required specifications to be used to make PET plastic bottles.
This technology definitely addresses the needs of the circular economy. Under the impetus of the European Union (through the Circular Economy Directives), together with heightened consumer awareness and leadership from brand owners, the plastics recycling business is moving fast. The ban on waste plastic imports by China is bringing focus to the requirement to find near to mid-term solutions for our industry. As an example, it is mandatory for brand owners to have 25 percent of r-PET content in their plastic bottles by 2025.
The extended producer responsibility will shortly lead to the implementation of levies and taxes when recycling targets are not met. The overall recycling targets for plastics and packaging, will lead to about 220 MMt of worldwide polymer waste being recycled by 2030.
The market is definitely looking for solutions. Our short-term aim is to have the tool to convince ourselves and the market that the CARBIOS solution is technically and economically justifiable.
The images below show some particulars of laboratory and pilot plant facilities.
carbios.fr
