In Dunkirk, in the largest steel factory in Europe, ArcelorMittal is testing the capture of CO2 emitted by its own industrial activity, responsible for global warming.

Instead of being released into the atmosphere or recovered to heat buildings, the steelmaking gas is routed through the yellow pipes to a brand new metal tower, an "absorption and regeneration column" of about twenty meters high.

Separated from nitrogen, carbon dioxide (CO2) is isolated, and finally captured.

The challenge of this brand new gas plant is to be able to continue to produce steel without emitting carbon dioxide (CO2).

A goal that is all the more imperative as the IPCC scientists who meet from Monday predict that the warming threshold of +1.5°C compared to the pre-industrial era could be reached around 2030.

In the long term, the objective of the world's second steelmaker is to achieve carbon neutrality by 2050. By 2030, it has announced its ambition to reduce its emissions by 25% worldwide, and by 35% in Europe.

In France, it plans to move faster, reducing its emissions by 40% by 2030, thanks to substantial public aid from the post-covid recovery plan.

Employees of the ArcelorMittal steelworks in Dunkirk, February 11, 2022 in the North FRANCOIS LO PRESTI AFP / Archives

A huge task.

Because for each ton of incandescent steel produced, the group emits "1.8 tons of CO2", reminds AFP Emmanuel Deneuville, director of the decarbonization program at ArcelorMittal France.

"90% purified smoke"

The capture of CO2 is only the third way of decarbonization favored by the group.

It will be used to treat residual fumes, "incompressible emissions that we cannot avoid" during the manufacture of steel, explains Florence Delprad-Jannaud, CO2 coordinator at the IFPEN Energies Nouvelles laboratory who developed the process of capture.

To green its production, the steelmaker is betting above all on a drastic increase in the recycling of used steel.

It is also preparing to make a technological leap, abandoning coal, which has been used since the 19th century to reduce (ie remove oxygen) iron ore.

It will be replaced by hydrogen, and the deoxidized ore will be smelted into steel in electric furnaces.

An Arcelor Mittal employee at the Dunkirk site on February 11, 2022 in the North FRANCOIS LO PRESTI AFP

In the immediate future, the experimental sensor should be able to absorb 0.5 tonnes of CO2 per hour, explains Ms. Delprad-Jannaud.

"The smoke that emerges is 90% purified".

Once validated, the industrialized process will have to capture 150 tonnes of CO2 per hour, i.e. 1 million tonnes per year from 2025.

In Dunkirk, the city in France that emits the most greenhouse gases, TotalEnergies plans to agglomerate this CO2 with that emitted by cement manufacturers or chemists who join the project.

And to ship it in liquefied form by boat to Norway to be permanently buried in "deep saline aquifers", former oil or gas cavities.

“40 million tonnes of CO2 were captured and stored in this way in the world in 2021” underlines Philippe Llewellyn, researcher at TotalEnergies who estimates that around twenty the number of projects of this type currently exist on the planet.

"Who's willing to pay?"

"There are solutions to eliminate industrial CO2, but someone will have to pay, who is ready to pay? The consumer? The taxpayer?" asks Michel Jacob, author of a study on the decarbonization of the heavy industry for Roland Berger.

In Dunkirk, another project, called Reuze, is betting on CO2 as a raw material.

It aims to reuse it instead of storing it.

An ArcelorMittal employee at the Dunkirk site, February 11, 2022 in the North FRANCOIS LO PRESTI AFP

Unveiled in February by Engie, it plans to produce carbon-neutral synthetic aeronautical fuels (e-fuels or electro-fuels) with the American group Infinium (e-fuels) from ArcelorMittal fumes.

However, the final investment decision – more than 500 million euros – will not be taken before the end of 2023.

The name Reuze comes from the word "reuse" in English.

But it also comes from the name of the giant who protects the city according to a Dunkirk legend.

It is celebrated every year during Carnival.

© 2022 AFP