The Swedish forest has potential to replace fossil content in tires

Renewable-based carbon black has been produced at RISE ETC in Piteå using pyrolysis oil derived from pine and spruce stem wood as feedstock. Preliminary results also indicate that the production of bio-based carbon black can be economically feasible even compared to conventional production using fossil-based feedstocks. 

Carbon black is one of the world’s most used carbon-based chemicals. The material is a fine powder of carbon that is forms during the incomplete combustion of organic materials. Carbon black is commonly used in paint and ink, but most of it ends up as additive in tires.

Today, carbon black is produced by the incomplete combustion of heavy, fossil-based fuels, such as coal tar, leading to a high emission of greenhouse gases. Approximately 11 million tons of carbon black is used every year, of which 90% are used as fillers and enhancers in tires and other rubber products. Carbon black gives the black color of tires.

Researchers at RISE ETC have succeeded in producing renewable-based carbon black (”green carbon black”). This was done by first extracting pyrolysis oil from sawdust of a mixture of 80% pine and 20% spruce, and then using the pyrolysis oil to produce carbon black. The discovery replaces the fossil-based feedstock with a bio-based one, making the process carbon-neutral. The process appears flexible and scalable. The discovery was made in 2018 by Dr. Pál Tóth, Therese Vikström, Roger Molinder and Prof. Henrik Wiinikka at RISE ETC.

- The process has great potential because the yield of green carbon black is relatively good even on a small scale, and is expected to increase when scaling up. Our preliminary techno-economic study suggests that the green carbon black can be competitive with fossil-based, commercial carbon black - says researcher Pál Tóth.

Research is now underway to ensure that the process can be scaled up to pilot scale and that the quality of the products meets the applicable standards and requirements.

Pyrolysis oil is produced by rapidly heating an organic material (e.g., sawdust) to approximately 500 degrees Celsius in the absence of oxygen. After about 2 seconds, the run-off stream of volatiles cools and forms a viscous dark brown liquid called pyrolysis oil, solid coke and non-condensable gas.