Smithers study details sustainability paths for carbon black

Leatherhead, UK – Technologies supporting the production of sustainable carbon black are increasingly in demand and are estimated to contribute just under 2 million tonnes to the global supply of the material by 2041, according to a recent report by UK consulting firm Smithers.

The figure is the equivalent of 20 conventional carbon black furnace lines, said Smithers in its “impact of sustainability on carbon black to 2041” published late last month.

According to Smithers, four leading technologies are expected to evolve over the next two decades to meet growing demand for more environmentally friendly alternative materials to fossil fuel-based carbon lack.

The technologies include methane pyrolysis, which is an alternative to furnace black manufacturing and less energy-intensive comparatively.

Existing pilot lines for the technology are currently using natural gas but Smithers said there was potential to evolve the technology to also work with bio-gas or bio-methane.

For end-users, the report said, the main requirement beyond scale up is for refinements to produce “harder, more durable carbon black grades.”

Another technology with high potentials is the production of recovered carbon black (rCB) from waste tires.

The end-of-life tire (ELT) pyrolysis process, Smithers said, is “an increasingly popular option” as rCB is the preferred sustainability option for 65% of tire OEMs for the future.

The recovered material, said the report, can be up to 85% less carbon intensive than furnace black to manufacture, and does not require direct petroleum inputs.

However, recovery and preparation of rCB requires thermal processing, meaning it will never be "fully carbon neutral".

According to Smithers, further work is still necessary to establish specifications and quality control; and the current generation of rCB technology will need to be improved to produce harder blacks.

A third alternative is ‘renewable carbon black’, made by substituting petroleum feedstocks for biogenic material, typically wood.

The technology uses existing furnaces with minimal modification and can produce a conventional range of harder blacks.

According to Smithers, the commercial supply of the material has now begun with one manufacturer.

However, the approach is highly costly, with prices five to ten times higher than conventional carbon blacks.

The final option, Smithers said, is ‘circular carbon black’, a solution that again capitalises on the availability of ELTs.

Unlike rCB processing, the process requires the intermediate step of having the used tires or polymers rendered down into pyrolysis oils first.

Circular carbon black still produces carbon emissions, but its energy use is considerably lower than conventional carbon black furnace processes.

The technology can produce high-performance reinforcing grades; but the cost will be a major barrier, as it is “at least double those of conventional furnace operations,” the Smithers report concluded.