In a statement, the company said it injected hydrogen into the No. 9 blast furnace through a single tuyere and gained insights into a number of technical issues, such as how to best position the hydrogen lance in the furnace, flow and pressure conditions, and the interaction between elevated temperatures and plant technology.

Engineers also were able to hit their intended injection rate of 1,000 cubic meters per hour.

“The development of the hydrogen technology at BF9 is an important step in our transformation toward climate-neutral steel production. That way, we are able to reduce the CO₂ emissions of the conventional coal-based blast furnace process significantly,” said thyssenkrupp Steel chief technology officer Arnd Köfler.

In a second round of trials, the company will test injection through all 28 of the furnace tuyeres, paving the way for large-scale industrial use. The second phase is scheduled to start in 2022 and will require construction of a hydrogen pipeline to feed the furnace, thyssenkrupp said.