Tech

Recycling through pyrolysis: oil, gas and carbon from old tires

It all started 14 years ago in a garden shed with an idea. Today it is ready for the market and arouses the interest of large companies: A new process for recycling old tires in which old tires are completely broken down into their raw materials. “Everything can be completely recycled”, says the chairman of the board of Pyrum Innovations AG, Pascal Klein, in Dillingen in Saarland in front of mountains made from old tires.

This is made possible by the decomposition of the previously shredded old tires at a constant 650 to 700 degrees in a specially built reactor – in a vacuum, without oxygen. The so-called thermolysis. In the end, what comes out is oil, carbon and gas. “It’s like getting eggs, milk and flour back out of a cake,” says the 34-year-old.

“The tires are sweated out and decompose,” says Klein and explains: You let the rubber granulate “rain” on 150 electric heating plates from above in a 25-meter-high reactor. When the granules fall on the hot plates, the carbon and steam are created, which are sucked off. The steam condenses and oil plus gas is produced, which is used to generate electricity for the entire system. 2500 old tires a day are processed on the company premises.

“There has never been a pyrolysis process like this before,” says Klein. Big players noticed that too. Like the chemical company BASF, which invested 16 million euros in Pyrum last autumn after carefully examining its patents and systems. “We are thus supporting the expansion of the existing pyrolysis plant in Dillingen to a total capacity of 20,000 tons of tires per year by the end of 2022 and the further market launch of the technology,” says a company spokeswoman in Ludwigshafen.

BASF has assured Pyrum that it will purchase up to 100,000 tons of oil per year. It is of high quality. “We can easily use it as a raw material in our production and thus save fossil raw materials.” For example in the manufacture of plastics. BASF speaks of a “unique pyrolysis technology for recycling old tires” at Pyrum.

The entry of BASF was “the breakthrough”, says Klein. Before that, they were often smiled at as “Saarland boys”. Now everything has changed. “I used to ask tire manufacturers for an appointment. And now they call us.”

A tower (PDF file) is generated about 2500 tons of carbon, 500 tons of gas and – 2000 tons of oil a year. In order to be able to supply BASF with 100,000 tons of oil, Pyrum will build 50 additional towers, Klein reckons. Two are being built in Dillingen, the others across Europe. There are preliminary contracts for plants in Ireland and Belgium. The number of employees has risen from 20 to 60 in one year alone, says Klein.

According to the trade association of the German rubber industry, around 571,000 tons of old tires were generated in Germany in 2019. Two thirds would be retreaded or recycled as granulate in the construction industry or for other rubber products. A third is burned for use in the cement industry. This creates a lot of carbon dioxide: one tonne of old tires produces 2.6 tons of CO2.

The expert for circular economy, Henning Wilts, from the Wuppertal Institute for Climate, Environment and Energy thinks it is fundamentally sensible to break down and reuse raw materials: “That makes sense from a resource perspective, that makes sense from a climate protection point of view, that makes economic sense.” You save disposal costs and money if you think about possible future oil prices.

And in contrast to mechanical recycling with the shredding of a product into its individual parts, pyrolysis, i.e. chemical recycling, means that in the end you get a significantly higher quality from the raw materials. “At the same time, the energy consumption is significantly higher.”

But it is important that the industry is not only working on recycling technologies, says Wilts. “Instead, we have to ask ourselves right from the start: How should the product be designed from the start so that it can be easily recycled?” In view of the goals for CO2-Reduction intensively discussed whether and how the recovery of raw materials can be recognized as recycling.

In tire recycling in Saarland, after the tires have been shredded, steel wire that is sorted out is sent to steelworks, and textile fibers are turned into insulating material. The company is now also in the focus of the Saar Ministry of Economic Affairs: “Pyrum Innovations has exciting innovations in store that can be very valuable, especially in terms of a circular economy and with a view to finite resources,” says Minister Anke Rehlinger (SPD).


(tiw)

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