The plastic waste feedstock for chemical recycling varies immensely, from type of polymer to degree of contamination and type of format. Some chemical recyclers have developed their technology to process mixed waste, and this is often touted as a huge benefit of chemical recycling. In real-world conditions, however, processing mixed waste of different compositions and degrees of contamination can be very challenging, impacting efficiency, yield, and quality.
In February, Circular Polymer Resources (CPRI), a Texas-based pyrolysis feedstock provider, and AmSpec, a testing and certification company, signed a Memorandum of Understanding to collaborate on the development of a comprehensive testing and certification process for waste plastic feedstock used in chemical recycling and pyrolysis oil. The partnership plans to fully characterise waste plastic feedstock to give all processors a comprehensive, uniformed approach to evaluate feedstocks.
Sustainable Plastics spoke with Robert Schucker, CEO at CPRI about the testing and certification processes under development.
When are you planning to start developing the process?
Schucker: CPRI has access to multiple kinds of waste plastic, many of which are not currently used in advanced recycling, and a solid background in the chemistry of plastic pyrolysis; and AmSpec has an extensive array of analytical testing equipment already in use primarily for conventional petroleum analyses. We have begun scheduling visits with major pyrolysis companies who would be the end users of plastic waste to gauge their needs and acceptance criteria as well as coordinating efforts with them.
Questions we would like answers to include:
- Does a company’s particular pyrolysis process require a higher level of polyolefins to produce a quality pyoil (this relates to the reaction rates of various plastics in thermal and catalytic conversion processes)?
- How much pyoil product falling in the fuel oil or heavier boiling range is acceptable, as there are concerns regarding potential changes in the use of the current “mass balance” approach to product stewardship?
- What contaminants are of the most concern (halides, metals, moisture, organics) and what is the maximum acceptable limit of those contaminants?
- How are emissions that are regulated by the EPA under the Toxic Substances Control Act (TSCA) affected by contaminants in the feedstock and do they need to be quantified?
- Do they require a semi-quantitative composition of their plastic feedstock as part of the analysis (i.e. fraction of polyolefins, PET, PVC, Nylon, etc)? If so, what degree of accuracy do they need
We will then develop analytical procedures that will be used to create “grades” of certified plastic waste feedstocks which should command different prices.