Renewable products technology developer Encina will soon launch its first commercial plant that will leverage pyrolysis to convert waste polypropylene (PP) into end chemicals, and petrochemical giant and biopolymer producer Braskem will buy the output. Encina will invest hundreds of millions and has committed to deliver up to 30,000 tons a year to Braskem, for what will be the developer’s first venture working with this uncommonly-recycled plastic.
Encina’s output is refinery grade propylene (RGP), a commodities liquid that contains PP monomer, and Braskem will process it to make PP resins to go into varied manufacturers’ products.
“Technically, we make BTX/P [with the BTX being a usable byproduct of pyrolysis]. BTX/P is benzene, toluene, mixed xylenes, and propylene. These are chemicals used to create various products, including monomer plastic resins that go into commodities from packaging materials to laundry detergent to aspirin, as well as transportation fuels,” says David Schwedel, Encina executive director.
He describes his process as a BTX/P (propylene) train (a train is the processing unit that converts feedstock to end chemicals). Each train is designed to process 20 tons per hour of waste plastic and deliver about 90,000 tons per year of renewable chemicals, Schwedel says.
The roughly 30,000 tons to be delivered to Braskem will provide the corporation with what Schwedel calls a “fully closed loop PP solution.”
Each BTX/P train will cost about $310m. Schwedel envisions scaling to two trains at the first plant, to be located in the Northeast.
It’s a big investment for the developer who will be applying its proprietary process to PP for the first time. Though Encina has built facilities that process the same chemicals from other hydrocarbons, using the same technology.
“So, we are taking an existing technology revolving around pyrolysis, which has been used in the hydrocarbon space and applying it to plastics, when originally we used our technology to process oil and coal to make BTX that went into fuels and basic building blocks that can also be used in various products,” Schwedel says.
Encina will finance, engineer, and build the plant. Braskem is working alongside Encina to define product quality specifications of feedstock that can be accepted at Braskem’s PP production facilities.
“For the final product, the Braskem plants have very clear incoming PP feedstock specifications. Pretreatment of intermediate products will be done as part of the Encina project before being delivered to Braskem facilities,” says Geoffrey Inch, Circular Economy & Sustainability director, Braskem, North America.
The overall plan is for the PP (or RGP) to get to Braskem via pipeline or chemical rail cars.
The BTX will be delivered via chemical rail cars to a national buyer to make basic chemicals and fuels. Schwedel cannot name the customer yet due to a nondisclosure agreement.
Encina is pursuing long-term contracts to secure feedstock from materials recovery facilities (MRFs) who often have a hard time dealing with PP, and it will look for more feedstock from other sources.
“There is ample polypropylene going to landfill, and we are seeking to focus on those opportunities,” Schwedel says.
While Braskem is currently the only offtake client for the PP-derived product, Encina is looking to others in the monomer/basic chemicals supply chain who want plastic resin from a renewable source.
Schwedel explains the relevance of working with monomers:
“They are the basic building blocks that make everything from consumer packaging materials and laundry detergent, to aspirin.
“Often at the start of plastic resin processing, manufacturers produce these building blocks in large quantities that are then transformed into plastic resins, intermediate chemicals, specialty chemicals, and many other industrial uses,” he says.
Encina is targeting PP, specifically, because its melt point and strength make it very versatile, so it’s widely used, yet it’s one of the least recovered plastics, meaning there’s plenty to be recovered, and a high, underserved demand.
But recovery comes with challenges, with the two big ones being poor collection infrastructure and sortation limitations.
Most MRF resin sorting is focused on polyethylene terephthalate (PET) and high-density polyethylene (HDPE) and not PP, as the latter’s varying sizes, shapes, and applications can make sorting and processing the material more challenging than PET and HDPE.
Currently, PP is sorted either into mixed bales of #3-#7 plastics, or, less frequently, full bales of #5, according to Schwedel.
“But Encina’s process can utilize either #3-#7 or polypropylene sorted materials, as well as even lower-end streams. So, we are able to work with MRFs however they need,” he says.
Meanwhile, PP is getting some attention from elsewhere. There are programs, such as one launched by the Recycling Partnership, to help increase recovery at MRFs. The Recycling Partnership/Polypropylene Coalition has earmarked monies specifically for collecting and sorting this material.
Schwedel sees his agreement with Braskem as one more step in a good direction.
The corporation serves the automotive, household appliances, medical and hygiene, and packaging markets, among others and has a PP capacity in the U.S. of 4.5 billion pounds.
“Braskem is a global company, and an excellent partner. Wherever there are opportunities to enable a circular polypropylene supply chain, we will look to be of benefit to them,” Schwedel says.
This agreement is an important step in Braskem’s next phase of growth, says Inch, commenting that the company’s aim is “realizing our vision of a carbon neutral circular economy and helping our clients meet their aggressive recycled content goals.
“Encina’s model includes an economic and scalable technical solution to address the plastic waste problem, a robust business plan, strong strategic partners, and an experienced senior management team. In addition, Encina is targeting initial U.S. projects in the Northeast USA where Braskem can leverage our unique industrial footprint and PP plants located in the same region,” Inch says.
The Encina plant lease has been signed and the groundbreaking is slated for Q4 2021.