Sensible CO2 recycling 3 minutes spent reading
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Sensible CO2 recycling

Christopher Eberl
Christopher Eberl is editorially responsible for the topics on the blog as well as for the apprentice website. With his stories he provides deep insights into the diverse world of the voestalpine Group.

Together with a research team from K1-MET, voestalpine is investigating new ways to prevent climate-damaging emissions. In the future, CO2 that is produced during steel production—technologically unavoidable—could be converted into a valuable energy source deep in the earth.

Carbon dioxide from technical processes should no longer impact the climate. That is why a key objective of the voestalpine decarbonization strategy is to avoid its generation. But as long as carbon remains an indispensable component, for example in the production of high-quality steels, researchers are also looking into solutions to prevent or recycle CO2 emissions. In cooperation with a team from the K1-MET metallurgical research competence center, voestalpine is tackling this challenge.

The carbon cycle with geomethanization

Photo: RAG / Karin Lohberger Photography

Storing CO2

The „Carbon Cycle Economy Demonstration“ (C-CED) project is looking into creating a carbon cycle. CO2 generated in voestalpine industrial plants (which is present in the waste gas streams in varying concentrations) will be captured. “The technology used will depend on the composition of the gases,” explains Irmela Kofler from the K1-MET Low Carbon Energy Systems research department. “We can adapt the capture process to the production process for instance to a coking plant, sintering plant, blast furnace, or power plant.” Concentrated, compressed CO2 is pumped together with sustainably produced hydrogen into natural underground storage sites whose original natural gas content has been depleted.

The carbon cycle with geomethanization

Photo: RAG / Karin Lohberger Photography

New energy from the depths

At a depth of about 800 meters, microorganisms indigenous to the site, known as archaea, combine the two gases to produce green methane, the main component of natural gas. This methanation process can take about four weeks. Additional source materials can be pumped in during this process. Like natural gas, the sustainably produced methane is extracted when needed and can be used in industrial processes or to produce electricity. CO2 is again generated and the cycle begins anew.

Twice as sustainable

“This renewable methane can replace some of the fossil carbon and natural gas used in the blast furnace and direct reduction processes as well as in the heating furnaces in the rolling mill area,” explains Nina Kieberger, Project Manager for Carbon-Cycle Economy Demonstration (C-CED) at voestalpine. This would be a further step in decarbonizing steel production. Nina Kieberger and Irmela Kofler point out that: “This process can also be used to store seasonal surpluses of sustainably produced electrical energy in the form of methane to be used when needed within the existing natural gas infrastructure.” In this way, Carbon-Cycle Economy Demonstration helps reduce climate-damaging emissions.

How the carbon cycle works with geomethanization

  1. CO2 from industrial processes is captured.
  2. CO2 is stored together with sustainably produced hydrogen in natural underground storage sites.
  3. Microbiological processes produce green methane gas.
  4. The methane is used for industrial processes or to produce electric power.

Der Kohlenstoffkreislauf mit Geomethanisierung

Christopher Eberl