Companies focus on technology at symposium

NIAGARA FALLS, Ontario—Pyrolysis and devulcanization—two technologies that rubber recyclers have striven to make commercially viable for decades—were major topics at the 2016 Rubber Recycling Symposium held in Niagara Falls Oct. 5-7.

Executives of several recycling companies discussed their firms' proprietary technologies at the conference, telling the audience that significant advances in pyrolysis and devulcanization technology have made their companies into reliable producers of high-quality recycled products.

The theme of the conference was “Driving Towards the Circular Economy,” and the recycling executives said their technologies would help manufacturers and government officials achieve their goal of converting waste tires into value-added new products.

Eliot Sorella, chairman and CEO of Ecolomondo Corp. Inc., said his company has spent more than 25 years and more than $30 million Canadian developing its thermal decomposition process.

Ecolomondo has dedicated technical teams who have overcome critical operational challenges to offer customers a sustainable way of recycling hydrocarbon waste into high-quality, ready-for-use recovered resources, according to Sorella.

Unlike many competing technologies, Economondo has achieved industrial-scale output and can deliver consistent products that meet custom specifications, he said.

Achieving a circular economy worldwide has become crucial, according to Sorella.

“Today, 1.3 billion tons of solid waste are generated per year globally,” he said. “In spite of recycling efforts such as zero waste programs, solid waste is expected to increase to 2.2 billion tons per year by 2025.

“Even though some countries have begun to divert certain waste streams to recycling, waste disposal by burning and landfilling are extremely widespread,” Sorella said. “It is time to move forward and stop these practices altogether.”

Stakeholders need to play role

Business, government and the public all have a role in promoting the circular economy, according to Sorella.

“It is necessary for big business to get involved and take the lead,” he said. “After all, it has the most to lose if the circular economy fails.”

Big business has the ability to influence upstream decisions, such as whether to use recycled materials in manufacturing their products, Sorella said. Small and medium-sized businesses, just because of their number, also can play a major role in promoting recycled materials, he said.

Government must support waste-to-resources technology by making subsidies, grants, financing and comprehensive programs available to them, Sorella said.

The public, meanwhile, must show it supports recycling programs by accepting tipping and environmental fees and giving preference to consumer products manufactured with recycled materials, he said.

“They must make recycling part of their everyday lives,” he said.

The benefits of a circular economic model are obvious everywhere, according to Sorella.

“Nature is circular in itself,” he said. “It reinvents and repeats itself, season after season.

“Similar to nature, the circular economy will ensure its own sustainability,” Sorella said. “Recycling waste over and over will achieve that goal and evolve into a permanent solution.”

Among the other speakers at the Rubber Recycling Conference were Sam Visaisouk, CEO of Tyromer Inc., and Graham Choonoo, technical director at AirBoss Rubber Compounding Inc.

Visaisouk and Choonoo spoke of the collaboration between Tyromer and AirBoss in attempting to commercialize the devulcanization process created by Prof. Costas Tzoganakis of the Department of Chemical Engineering at the University of Waterloo, Ontario.

Tyromer opened a plant at AirBoss' facility in Kitchener, Ontario, in September 2015, dedicated to the production of Tyromer-TDP, a devulcanized rubber product made using Tzoganakis' technology.

Devulcanization is a crucial technology in developing a circular economy for tires, according to Visaisouk.

“Fifty percent of the world's rubber goes into tires, and yet only a very small quantity of end-of-life tires make it back into new tire production,” he said.

Devulcanization is a very different process from rubber reclaiming, Visaisouk said. Devulcanization seeks only to break the sulfur bonds of vulcanization in rubber, whereas reclaiming destroys polymeric links as well.

“Reclaimed rubber is degraded and cannot be used as tire rubber,” he said. “Reclaiming is down-cycling.”

China is the world's largest market for reclaimed rubber, producing about 4.5 million metric tons annually. The Chinese government encourages reclaim production through tax incentives and other market intervention, according to Visaisouk.

On the other hand, reclaimed rubber is virtually unknown in the U.S., whereas 48.6 percent of U.S. scrap tires go to tire-derived fuel, he said.

“China does not have a scrap tire problem but pays a high environmental price,” Visaisouk said. “We do not have a scrap tire problem if, as a society, we accept burning 50 percent.

“The sheer volume of scrap tires dictates that any effort to recycle scrap tire rubber must target the tire industry,” he said.

Devulcanization vs. reclaiming

However, tire industry veterans tend to confuse devulcanization with reclaiming, and also remember all the previous devulcanization projects that failed, according to Visaisouk.

“There is a high degree of skepticism among rubber veterans,” he said. “Their usual reaction is, "Heard it, never seen it, won't work.' Introducing another rubber devulcanization technology becomes a venture that begins at below ground zero.”

However, the Tzoganakis devulcanization method does not use any chemicals, which tend to break polymer chains as well as sulfur chains, Visaisouk said.

The Tzoganakis method uses inert supercritical carbon dioxide to expand the crosslinked rubber network rapidly, followed by controlled mechanical shear in an extruder to preferentially break the sulfur links over the rubber network bonds, he said.

AirBoss' tests on Tyromer TDP show the material disperses better in off-the-road tire compounds than crumb rubber and has much less effect on the Mooney viscosity and other physical properties of OTR tire compounds than treated crumb or reclaim, Choonoo said.

Tyromer TDP also revulcanizes well, depending on crumb source, rubber mixing sequence, loading level and compound polymer type, he said.

“No matter what, we have achieved fairly consistent physical property results,” he said. “Using any rubber recycled material is never easy and presents certain challenges. But we are selling Tyromer TDP to OTR customers today.”

The next challenges for Tyromer and AirBoss, according to Choonoo, are:

• Increasing the percentage of TDP used in NR3p.595-based OTR recipes;
• Expanding TDP into other NR applications; and
• Devulcanizing other elastomers, including SBR, EPDM and NR from non-TDP sources.