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Develops green coal for industry

Published: 19 January 2021

Researchers at Luleå University of Technology are investigating how the production of fossil-free green coal can be adapted for the steel industry. Demand is high. Green coal produced from forest biomass is crucial for the long-term success of fossil-free steel production.

- Fossil-free biochar is not only important for steel production, it is also very important for, for example, battery production and also has many other areas of use, says Kentaro Umeki, professor of energy technology at Luleå University of Technology.

Five or six years ago, researchers in energy technology and process metallurgy at Luleå University of Technology, led by Kentaro Umeki, began to develop processes for producing green coal from biomass, in collaboration with the research institute Swerim and local small and medium-sized companies. The green coal is produced by processing biomass in a pyrolysis reactor at temperatures between about 500 and 600 degrees. It is a similar technology as in the production of biomethanol, which LTU Green Fuels plant is best known for. The current focus for biochar researchers at Luleå University of Technology is to specifically adapt green coal for the steel industry.

- To begin with, we have focused on biochar in blast furnace processes in the manufacture of steel. The HYBRIT project, which with hybrid technology will replace coke coal and make fossil-free steel with fossil-free hydrogen from electricity, is good and exciting, but it will take ten to twenty years before that plant is in production and during the same period we must also do something to reduce carbon dioxide emissions from the blast furnaces, says Kentaro Umeki.

Biochar in several processes

Biochar is also needed in completely different manufacturing processes. In Höganäs, there is a steel process where iron powder is produced, an important product for, for example, car parts, turbines and tools. Direct reduction is called the process for which large amounts of carbon are needed. Other steel companies are also future potential users of biochar.

- All steel companies must use coal. What I mean is that it is not just hydrogen that is needed to produce sustainable steel, you always need solid carbon in almost all processes, and biochar is a fossil-free alternative, says Kentaro Umeki.

A crucial issue for the researchers is to solve how the carbon yield in the pyrolysis process can be increased as much of the biomass is developed into gas and oil.

- One question we are looking at is how to increase the carbon yield, another question is how to adjust and increase the properties of green coal. If we do it correctly, we can also produce hydrogen from the pyrolysis. All this can be used in many different applications, he says.

One such application for green coal is the manufacture of new generation batteries.

- Yes exactly, in a long perspective. If you make batteries, it is an anode with graphite, so if you want to make a durable battery, you need biochar.