When San Francisco-based Brightmark was looking for shredding equipment to use in its feedstock preparation system at its Ashley, Indiana, plant, the company prioritized consistency of particle size at the throughput rate required for commercial operation. Its turnkey system provides that consistency despite variable feedstock as well as redundancy, says Mike Dungan, the company’s feedstock development director.
Mixed plastics to fuel
In the late 2020 profile that appears in Plastics Recycling, a supplement to Waste Today’s sister publication Recycling Today, Brightmark CEO Bob Powell says the company is developing “holistic solutions that are closed-loop and tackle the most pressing environmental challenges.”
Those solutions include Brightmark’s $260 million “plastics renewal facility” in Ashley. That plant, which is ramping up operations as of early 2021, will recycle 100,000 tons of mixed plastics annually into ultra-low-sulfur diesel, naphtha and wax using a form of pyrolysis invented by RES Polyflow, which Brightmark acquired in late 2018.
“Brightmark was attracted to the flexibility of the technology” RES Polyflow had developed, says Jay Schabel, president of Brightmark’s Plastics Division and the founder of RES Polyflow.
Unlike similar technology, Brightmark’s can accommodate up to 3 percent polyvinyl chloride (PVC) by weight in its mixed plastics feedstock.
But before the mixed plastics can head to Brightmark’s plastic conversion units (PCUs), first they must be processed by the company’s feedstock preparation system, which was supplied by Vecoplan LLC, Archdale, North Carolina.
All in the prep
Mixed plastics bales that enter Brightmark’s Indiana facility are dewired and audited, with the baling wire and the obvious contaminants removed while the material is still on the tipping floor, Dungan says. The material is then blended and loaded onto a conveyor, where sorters further remove obvious contaminants by hand. The material then passes through optical and magnetic sorting technology. At this point, the mixed plastics encounter the first of two shredders manufactured by Vecoplan.
Dungan says the VAZ 2000 MFTV preshredder achieves a homogenous particle size before magnetic separation is employed for a second time.
“The first shredder is a little more robust,” Dungan says.
After the metals liberated by the preshredder are removed, the plastics are fed to the second shredder, a Vecoplan VEZ 2500T, where they are reduced to a 2-inch-minus particle size.
Additional system components include drying, pelletizing and material handling equipment that was integrated by Vecoplan, as well as an optical sorter to identify and remove PVC.
Dungan says the systems’ fluidized bed drier removes excess moisture from the plastics before a pelletizing system reduces the bulk density of the material.
“Drying is the final step before we pelletize,” he says. “High-moisture material is run through there,” he says of the fluidized bed drier, “and we can turn the heat up or down based on the condition of the material.”
Dungan says Brightmark’s minimum processing requirement for the system is 6 tons per hour of throughput with continual operation. However, the system is rated for 12 tons per hour, meaning it can produce up to 280 tons in a 24-hour shift. The finished pellets can be bunkered and stored, he adds, “so that we always have a raw material hedge operationally,” or they can be surged directly to the PCUs.
The facility is permitted to hold days of pellet inventory on-site, Dungan says.
Brightmark began shopping for the feedstock preparation system five or six years ago. The company issued a request for proposals but received few offers that proposed turnkey solutions, he says. The company tested equipment from four shredder manufacturers, running material in a series of trial shredding campaigns. Brightmark assessed the machines’ performance, ease of operability, construction and maintenance.
“The turnkey aspect of the system was the most appealing, but it was supported by good equipment,” Dungan says of the company’s decision to hire Vecoplan for the project. He adds that the equipment met Brightmark’s requirements from a throughput and robustness standpoint and features an “operator-friendly” design.
While Dungan says all the shredders Brightmark looked at during its comprehensive search were “good” and all the companies that supplied them were “solid,” the turnkey aspect of Vecoplan’s system as well as the equipment stood out.
“The reason we selected a turnkey system provider is, based on their experience and installations around the world, we figured they were domain experts, so we didn’t have to become domain experts initially,” Dungan explains.
While Brightmark is still commissioning the equipment, installation was substantially completed as of the start of the year. The system will be tasked with creating the final specification for the pellets, including their “size, shape, bulk density and moisture level that will be used in Brightmark’s PCUs,” Dungan says. These pellets will be derived from an ever-changing stream of incoming material that includes mixed plastics from material recovery facilities as well as postindustrial plastics, plastics from electronic scrap, car seats and boat wrap.
He says the feedstock preparation system is broken into two lines to create redundancy.
“In the event one machine failed completely, we’d still be able to operate at 50 percent capacity on the other line.”
Brightmark can “turn up” the system following planned downtime to produce more pellets during a shift to “catch up quickly,” he adds.
The resulting pellets are placed in the PCUs, which are heated stainless steel vessels that measure 8 feet in diameter and 60 feet long. The vapor produced in the heating process is captured and cooled, creating fuels and the building blocks for future plastic products.
The ultra-low-sulfur diesel and naphtha the plant produces will be supplied to BP, which has a refinery nearby. The naphtha the plant produces can be blended into gasoline or even used to make new plastics. The waxes generated in the process will be marketed by Am Wax, headquartered in La Mirada, California.
In Ashley, the company will consume 100,000 tons of plastic per year and will create 18 million gallons of diesel or naphtha and 6 million gallons of wax. And its feedstock preparation system will play a key role in the overall efficiency of the process.