Collective idea

Flexible plastic packaging material, while tough to recycle, can be recovered for energy value, and it’s feasible to do so.

Those are the findings of a recent research project co-sponsored by the Dow Chemical Co. in collaboration with pyrolysis provider Agilyx Corp. and other interested stakeholders.

At the core of the 2014 Energy Bag Pilot Program was the fact that difficult-to-recycle plastics can be collected using existing collections infrastructures and then converted to fuel. It’s good timing for such a program too. Midland, Michigan-based Dow reports that despite expanded recycling programs, more than half of all U.S. trash, to the tune of around 135 million tons, still ends up in landfills. The Energy Bag project was designed to test the feasibility and workability of implementing a waste-to-energy solution for some of these materials.

The three-month Energy Bag program was launched in the summer of 2014, co-sponsored by Dow and collaborators The Flexible Packaging Association (FPA), Annapolis, Maryland; Republic Services, Pheonix; Agilyx Corp., Beverton, Oregon; Reynolds Consumer Products, Lake Forest, Illinois; and the city of Citrus Heights, California.

“Our goal was to develop a system where we could create alternative energy that was economically self-sustaining,” says Jeff Wooster, global sustainability director for Dow Packaging and Specialty Plastics.

For the program, the 26,000 households of Citrus Heights were provided with purple Energy Bags, in which they were asked to collect plastic items not eligible for recycling in the community, during the months of June, July and August. Residents were asked to place these filled bags in their 96-gallon lidded recycling containers for collection on the community’s every-other-week schedule.

“We used the motto, ‘if you don’t bin it, bag it,’” Wooster shares. Residents were told to bag such items as snack bags, salad bags, meat and cheese wrappers, foam serving containers, toothpaste tubes, drink pouches and plastic utensils. The company says that around 58 percent of what was received were flexible packaging materials, some of which could have been made by Dow.

The purple bags were removed from the stream of recyclables at Republic’s Newby Island Resource Recovery Park in Milpitas, California. The translucent bags, manufactured by Reynolds, were designed to be easy for material recovery facility (MRF) operators to sort from incoming recyclables. The bags were then sent to Agilyx. The company specializes in converting nonrecyclable and low-value waste plastics into synthetic crude oil through a patented pyrolysis system. Processing took place at Agilyx’s Tigard, Oregon, demonstration facility.
 

Interested parties

Wooster says Dow developed the Energy Bag concept for close to two years ahead of its June 2014 launch, in part looking for project partners. Each of the collaborators funded its own part of the project: Agilyx handled the pyrolysis, Republic Services managed the collections; Dow and FPA managed the communications efforts; and Reynolds provided the purple bags.

All of the partners, Wooster says, were interested in furthering their existing recycling services. The community of Citrus Heights, for instance, already has a comprehensive collections program, accepting such things as clean pizza boxes, Nos. 1 through 7 plastic containers and plastic bags.

“We were very proud to be the first community in America to participate in the Energy Bag initiative,” said Sue Frost, mayor of Citrus Heights, after the close of the program. “The program demonstrated how communities nationwide can benefit by diverting typically nonrecycled plastics from landfills and give them new life as an energy resource.”

Wooster says Republic, which services households in Citrus Heights from its Sacramento-area facilities, also was interested in partnering in the program. And Agilyx was identified as the closest pyrolysis facility able to handle the mix of plastics.

According to Wooster, Agilyx is one of a handful of U.S. companies with a suitable pyrolysis technology.

“They were willing to participate and were geographically in the right location,” Wooster says.

Program benefits

Jeff Wooster, global sustainability director for Dow Packaging and Specialty Plastics, says the company had a few reasons for entering into the Energy Bag project.

“One reason was to keep plastics out of landfills. Two was to provide a usable source of energy, which we need, and third is to meet the needs of markets and ultimately consumers of our products who want to keep that material out of landfills,” Wooster observes.

Some of that material, Wooster acknowledges, is packaging made by Dow for a host of consumer goods and food items.

“We recognize that we sell plastic material to companies that make packaging for products,” he says, noting that increasingly, consumers don’t want these materials buried in landfills,” he says. “We’re always trying to find outlets and uses for our material once it’s done packing products.”

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The three-month Energy Bag program was launched in the summer of 2014, co-sponsored by Dow and collaborators The Flexible Packaging Association, Republic Services, Agilyx Corporation, Reynolds Consumer Products and the city of Citrus Heights, California.

Wooster explains that the project was intended to help educate the entities on how to implement a feasible, full-scale program to deal materials like potato chip bags, deli pouches, meat trays and plastic utensils.

“Our goal was to develop a system where we could create alternative energy that was economically self-sustaining,” Wooster says. And one of the key elements of such a system, he adds, was being able to leverage the existing collections infrastructure for recyclables.

“By leveraging the existing infrastructure, the incremental cost is very low,” Wooster says. This makes such a system financially viable for the long term, he adds.

For the program, the 26,000 households of Citrus Heights were asked to collect their nonrecyclable plastics in special purple “Energy Bags,” that were in turn delivered to Agilyx Corp., Beaverton, Oregon, for processing into synthetic crude oil.

Wooster says polyethylene (PE) and polypropylene (PP) films, among the most widely used flexible packaging materials, proved to be ideal feedstocks for the pyrolysis process.

Some 8,000 bags were collected through the program, representing about 3 tons of waste materials diverted from landfills and yielding 512 gallons of synthetic crude oil.

Ross Patten, CEO of Agilyx, says the 10-ton-per-day development and demonstration facility can process materials at a rate of about 16 pounds per minute. Agilyx sells the resulting synthetic crude oil to refineries.

This Generation 6 continuous-feed, automated technology, as the company calls it, has replaced an earlier batch process that was used in a North Portland facility that has since been closed. With the newer process, Patten says it takes about an hour for material to be converted into synthetic crude, and the system runs 24/7.

“When we need material, we source it from generators in the area,” Patten explains, referring to local MRFs in the region. The company tests samples of material to determine the type of oil that the mix of material can be expected to produce, explains Mark Rumford, vice president of engineering for Agilyx.

Tests of Energy Bag materials indicated they were suitable for the company’s process. Even polystyrene, often shunned by MRFs, can be part of the mix. “It actually makes an extremely good oil when we put it in our system,” Rumford observes.

Patten points out that Agilyx’s process also can handle the No. 3 through 7 plastics that are sometimes relegated to MRF residue streams. Since the community of Citrus Heights accepts these materials for recycling, those materials weren’t a focus of the Energy Bag program.

Patten says Agilyx was pleased with the materials that ended up in the purple bags. Having residents in effect presort the materials meant that further sorting did not need to occur at Newby Island.

“We didn’t have to worry about the contents at all because they were still putting all of their normal recyclables into the bin,” he observes.

For the process, Rumford explains, the Energy Bags were shredded to a 2-inch minus size before heading to pyrolysis. The material was fed to a premelter to drive off the water and which created a black, toothpaste-like mixture. Next, the system’s reactor, utilizing two interwoven, self-cleaning shafts, boiled off the usable plastic which was then condensed into oil, Rumford explains, leaving a char byproduct.

“The whole thing is done in the absence of air, so there’s no combustion,” Rumford explains. “We are adding heat to boil the plastic to get the vapors, which rise out of the reactor, break down, are recombined and are condensed back into a liquid which then is cleaned and conditioned.”

Agilyx holds an exclusive worldwide license to use technology from California-based Therma-Flite for its plastic pyrolysis, Patten says.

While Rumford says the pyrolysis process is relatively simple, adding to its complexity are the challenges of dealing with feedstocks that can vary daily and from source to source.

Earlier in the company’s history, he says, “We erroneously thought we could process any plastic. Now we’ve learned that is not the case.”

Even so, Rumford and Patten say the facility can accept most types of nonrecyclable plastics, with the exception of polyvinyl chloride (PVC). Furthermore, the mix of plastics must be free of other contaminants.

“We want a material that has been preprocessed at the MRF and which meets a specification for our process.,” says Rumford.

The company has developed a specification that Rumford says limits the amount of dirt and moisture that can be included. The specification calls for a minimum of 90 percent plastic, no organic wastes and minimal PET and HDPE plastics.

Those two grades make a lower quality oil, Rumford explains, adding “they have a higher value as a recycled feedstock.” The specification also sets a limit on the amount of PVC that can be included in the feedstock. However he notes that PVC has become less common in today’s postconsumer streams.

The company is marketing its system to waste and recycling companies and regional authorities, but its first commercial installation will be its own. Patten says the company is in the final stages of permitting for its first commercial-scale facility, to be located on the U.S. East Coast.
 

Program results

A limitation of the program was communicating the project thoroughly enough to the community’s households, Wooster says.

Information was shared through flyers sent with garbage and recycling statements. However certain residents, such as those on auto-pay programs or those living in rental units, didn’t necessarily receive the information.

Dow says the program reached a 30 percent participation rate, with 78 percent of residents reporting they would participate if given another opportunity.

Wooster says future programs will use additional communications channels, such as school campaigns and mass media, in an attempt to reach a participation rate that matches recycling. Even so, Wooster describes the program as a success.

“We were very pleased,” Wooster says. “We proved that each of the major steps was workable and feasible and could work with existing infrastructure.”

The author is an editor with the Recycling Today Media Group and can be reached at lmckenna@gie.net.