End-of-life bicycle tyres have so far ended up in landfill or at waste incineration plants and are dumped in the form of incineration ash. In a research project at TH Köln on the “Innovative raw material recycling concept for old bicycle tyres in the sense of a closed cycle economy”, a team from the TH Köln is working with two cooperation partners on how new bicycle tyres can be made from old tyres.
Pyrum Innovations Cooperates with TH Köln
“Currently, bicycle tyres are mostly incinerated as residual waste. This process does not make sense from an ecological point of view,” says project manager Prof. Dr. Danka Katrakova-Krüger from the Institute for General Mechanical Engineering at the TH Köln. Together with the cooperation partners Ralf Bohle GmbH and Pyrum Innovations AG, it is pursuing the goal of recycling old bicycle tyres as raw materials and producing functional new bicycle tyres from some of the raw materials.
Pyrolysis is to be Used in the Recycling Process
In the pyrolysis plant, the old tires are thermally treated at temperatures between 550 and 750 degrees with exclusion of oxygen. As a result, bicycle tyres are broken down into the following three components: pyrolysis gas, oil, and coke. The process is particularly environmentally friendly: the pyrolysis gas is converted into electricity in two combined heat and power plants, each with 250 kilowatts of electrical output, and used to operate the system. The system can thus be operated completely self-sufficient in terms of energy.
The second pyrolysis product is a high-quality oil that is obtained by condensing the pyrolysis vapor. It can be processed into valuable fine chemicals for the chemical industry. The pyrolysis coke – also known as recovered Carbon Black – is to be reintroduced into the new bicycle tyre compounds and replace fossil-based industrial soot.
The project is under the direction of Prof. Dr. Danka Katrakova-Krüger from the Laboratory for Materials at the Institute for General Mechanical Engineering in cooperation with Ralf Bohle GmbH from Reichshof, which includes the bicycle tire brand “Schwalbe“, and the company Pyrum Innovations AG from Dillingen. The Federal Ministry for Economic Affairs and Energy is funding the project as part of the “Central Innovation Program for SMEs” (ZIM).