Valuable resources: recycling through pyrolysis creates new markets and protects the environment

Scarcity of resources, rising raw material prices and the move away from fossil fuels: in view of these challenges, innovative recycling concepts for the recovery of resources and the simultaneous generation of environmentally friendly energies are in demand. One of them used to be considered cost-inefficient, but is now increasingly becoming the focus of companies: the recycling of discarded materials or residual materials by means of pyrolysis. According to the coalition agreement of the German government, coal burning is to be phased out before 2038 if possible. Instead of coal from open-cast mines, the energy sources of the future could be obtained, for example, from the combustion of wood pellets or other organic residues.

Pyrolysis also produces gas. What happens with it? Strict regulations stipulate thermal post-combustion or further use in order to avoid environmental and health damage. The gas can be used in the following ways, for example:

1. Pyrolysis gas can be used to heat the kiln. This creates a green and cost-effective process that does not require external energy sources.

2. Pyrolysis gas can be condensed into pyrolysis oil, which can be sold and used as a new feedstock for various industries.

3. Pyrolysis gas can be purified into biomethane, which can also be sold as a new raw material.

From used tyres to organic residues from the food industry

Pyrolysis is not only used to recover resources from organic waste – the areas of application are far more diverse. Used tyres, for example, can be shredded and turned into recovered carbon black (rCB) in a pyrolysis process. Carbon black is a high-tech industrial material that is contained in almost every black rubber or plastic product. The tyre and plastics industries have already expressed interest in rCB. Conventionally, it takes about 1.5 tonnes of fossil raw materials as well as large amounts of water to produce carbon black – all the better to recover it through pyrolysis.

Worldwide, about 1.8 billion used tyres are produced every year, which makes it clear that there is enormous potential here. Pyrolysis can be used to recover rCB from them, which can be recycled as a raw material in industry. Another example is battery recycling. Here, valuable metals can be recovered through pyrolysis, among other things.

Conclusion and outlook

The energy transition is forcing us to rethink. How can a maximum of resources be recovered from supposed waste? Pyrolysis is a recycling trend whose potential is far from exhausted. Areas of application such as used tyre recycling, battery recycling and especially the recycling of organic residues show that it is a possible approach to reduce the CO2 footprint and further advance the energy transition.

Sources:

https://www.bundesregierung.de/breg-de/themen/klimaschutz/kohleausstieg-1664496
https://www.chemie.de/lexikon/Pyrolyse.html
https://recovered-carbon-black.com/