A wet granulation solution has helped KW Plastics process high volumes of postconsumer plastics.

Troy, Alabama-based KW Plastics is a large recycler of postconsumer high-density polyethylene (HDPE), polypropylene (PP) and other scrap materials. The company also produces products made of 100-percent-recycled postconsumer resin, such as paint containers, through its KW Container Division.

Over the years, KW Plastics needed to find a way to process scrap materials without damaging its machinery. The company also wanted to offset global warming potential (GWP) by recycling postconsumer packaging.

KW Plastics worked with Cumberland (ACS Group), New Berlin, Wisconsin, to pioneer a wet granulation process for high volumes of postconsumer PP and HDPE. To reinforce the environmental benefits of recycling, Cumberland says it helped KW Plastics identify the average reduction of GWP achieved through the recycling process when compared with manufacturing virgin resins. The manufacturer says the net benefit of this wet-grinding process indicated a reduction of CO2 released into the environment.

For more than 30 years, KW Plastics has partnered with Cumberland and used the company’s granulators to recycle postconsumer HDPE, PP and other plastics.

Recycling postconsumer scrap can be challenging and presents a harsh environment for the machinery. Scott Saunders, general manager at KW Plastics, says dry granulation technology tends to add additional heat and strain on granulating equipment. The extra heat can damage bearings on the granulator, which eventually reduces the machine’s life.

As an alternative to dry granulation, KW Plastics decided to approach Cumberland about applying wet granulation technology at its Troy facility. Saunders says wet granulation uses water under pressure to force material into the granulator’s cutting chamber.

“Postconsumer plastics have a lot of dirt and contaminants in the material,” he says. “With Cumberland’s help, we pioneered wet granulation, which enhanced the process to help us successfully recycle high volumes of materials.”

Saunders says 13 Cumberland Model 62B heavy-duty granulators are used to support its operations, and the facility features a proprietary, continuous-wash process in which the granulators are in line and used at two locations.

He adds that the company also has worked with Cumberland on several modifications to its wet-granulation equipment over the years.

In addition to Cumberland’s granulators, Saunders says KW Plastics uses shredders manufactured by Wilsonville, Oregon-based SSI Shredding Systems for initial size reduction.

Throughout its history, KW Plastics has processed billions of pounds of plastic scrap. Saunders says the company currently processes about 500 million pounds of HDPE and PP annually. He notes that KW Plastics is installing an additional 100 million pounds of annual capacity that is expected to come online in the first quarter of 2023.

According to Cumberland, KW Plastics is maximizing pounds per hour of throughput for each of its processing lines. The company operates seven wash lines at its facility in Troy, including one each for spent PP battery cases, natural HDPE containers, mixed-color HDPE containers, bulky rigid HDPE containers, PP tubs and lids and PP and HDPE purge and regrind. KW Plastics relies on its wet granulation process to provide consistent, reliable output.

“Cumberland has been a true partner in helping us build our recycling business to where we are today,” Saunders says. “We started out just trying to show that recycling plastics was a viable business. Once we perfected the process, we set out to expand, and Cumberland has been with us every step of the way.”

Today, business is strong for KW Plastics. “We are encouraged with the growth of plastics recycling, and we believe that more recycling is a big part of the solution to the planet’s solid waste management problem,” Saunders says.

KW Plastics initially produced recycled PP from products such as automotive battery casings. As the market for recycled content grew, the company moved into producing recycled resins from postconsumer HDPE containers as well, selling its pellets to other consumers in addition to consuming its recycled PP internally.

In 1998, KW Plastics entered the packaging industry by introducing a plastic and metal hybrid 1-gallon paint can made of recycled materials. KW Container was established as an injection molding company that molded 100-percent-recycled and 100-percent-recyclable paint containers.

“Becoming a molder of recycled products completed the circular nature of recycling for us as we brought used products in, recycled them into reusable resins and molded finished products from them,” Saunders says.

In 2016, KW Container launched TruSnap, a resealable paint can made from recycled plastic and a proprietary resin. More than 100 million pounds of recycled material are used annually to produce these paint containers, and Cumberland granulators are used in the process to support that production.

Recycled HDPE and PP require less energy to produce when compared with their virgin counterparts, and those lower energy requirements equate to lower greenhouse gas (GHG) emissions. Having lower GHG emissions and GWP is of interest to KW Plastics’ consumers, Saunders says.

“Many of our customers purchase recycled resin as a way to lower their environmental footprint,” he adds.

To help KW Plastics with its mission to promote the benefits of recycling plastics, Cumberland developed a method to estimate the reduction of GWP achieved through recycling. According to Cumberland, the net benefit of the process indicates a reduction of CO2 released into the environment. Cumberland says it was determined that it would be possible to approximate net GHG emissions reductions at KW Plastics’ operation, specifically how many tons of CO2 equivalent can be avoided by recycling plastics instead of manufacturing virgin resins.

Andre Adams, senior product manager at Cumberland, constructed a simplified model for KW Plastics that included 1.9 kilograms of CO2 equivalent generated per kilogram of virgin HDPE manufactured, 0.67 kilograms of CO2 equivalent generated per kilogram of HDPE recycled, 1.24 average net kilograms of CO2 reduction per kilogram of HDPE recycled and KW operating 24/7.

According to Cumberland, on a single production line, KW Plastics has mitigated its CO2 equivalent potential by more than 75,000 tons per year on average, which equals eliminating about 15,000 passenger vehicles per year.

“KW Plastics already knew that the process of recycling plastics was better for the environment than producing virgin resins,” Adams says. “This analysis showed their reduction in GWP was even greater than anticipated. Recycling plastics truly supports circular economy initiatives.”

Cumberland (ACS Group), headquartered in New Berlin, Wisconsin, submitted this article. Visit www.cumberlandplastics.com for more information.