CO₂ as a raw material

Climate gas to move cars

thyssenkrupp is launching the first cross-industry initiative to utilize carbon dioxide from steel mill gases. Its aim is to exploit steel mill gases as the starting material in the production of chemicals. The PLANCK project is contributing not only to climate protection but also to the success of the switch to sustainable energy.

Carbon dioxide has a terrible image. Discharged into the atmosphere in large volumes, this greenhouse gas is fueling global warming and becoming a climate killer. In Germany alone industrial chimneys, cars, and households emit some 900 million tons of CO₂ every year. Yet carbon dioxide is far from being just something that harms the climate – the gas can also serve as a valuable raw material in the chemical industry.

The idea for the project came to thyssenkrupp’s Chief Technology Officer Reinhold Achatz during a lecture. His colleagues at thyssenkrupp Process Technologies had presented the fundamental possibility of synthesizing ammonia and methanol from steel mill gases – ammonia is used in the production of fertilizers and methanol in fuel production, among other things. The chemical industry currently utilizes natural gas as the raw material. A proportion of the hydrogen required for synthesis is already contained in the steel mill gases. Why not, wondered Achatz, produce the extra hydrogen required from surplus electricity generated from renewable energies? This would reduce the consumption of natural gas, a valuable energy source, cut CO₂ emissions, and stabilize the power grid. The research project aims to develop technologies which make this economically feasible.

From this unconventional idea following preparatory work with the Max Planck Institute for Chemical Energy Conversion (MPI CEC) the content of the PLANCK project was defined. In the “Platform for Sustainable Chemical Conversion” thyssenkrupp started working with partners from industry and research from December 2013, who since then have been promoting the first cross-industry approach aimed at the use of CO₂ in chemicals production. The central idea: A cross-industry solution with utility providers and additional technology companies on board promises better results than the isolated efforts to reduce CO₂ emissions that have been pursued to date. If the technology transfer project, which is scheduled to last ten years, becomes a success, the key steel, chemical, and energy industries will interlink their value chains in future – jointly saving valuable raw materials and reducing CO₂ emissions.

“The prospects for success are good because the basic chemical processes and the required technologies are largely known,” says project manager Markus Oles. Yet the goal is ambitious: Thanks to PLANCK it is hoped that one day almost all CO2 emissions from steel production can be transformed chemically. Until then, however, the researchers and developers still have a few challenges to overcome. For example, the steel mill gases first need to be cleaned and prepared – a research task on which the MPI CEC and the Fraunhofer Institute for Environmental, Safety, and Energy Technology (UMSICHT) are working.

The greatest challenge, however, comes from carbon dioxide itself: chemically CO₂ is extremely inert. The chemists therefore need catalysts if the gas is to react with other substances to form new compounds such as methanol or methane – and large quantities of energy. The catalysts facilitate the chemical reaction by reducing the required activation energy without being consumed themselves. The MPI CEC is developing special catalysts that can respond flexibly to the sharply fluctuating supply of green electricity.

Without electrical energy PLANCK cannot reach its ambitious target. “If the plan is to completely convert the CO₂ contained in steel mill gases, this will not work without additional hydrogen,” explains Ralph Kleinschmidt, technical head of department at thyssenkrupp. This hydrogen is intended to come from water electrolysis using wind and solar power, which is why thyssenkrupp and the Duisburg-based Center for Fuel Cell technology (ZBT) are working on new economical methods for producing the gas. Because the electricity comes from completely renewable sources, PLANCK’s carbon footprint would remain exemplary.

Moreover, the researchers can kill two birds with one stone: Instead of converting green electricity that is no longer needed into hydrogen and producing electricity from it again later on, surplus production from renewable sources could ideally flow directly into the production of base chemicals. That is the aim – and one of the great benefits of the project. If this grid optimization succeeds with the help of the utility providers, PLANCK could through the stabilization of power grids make a substantial contribution to the success of the switch to sustainable energy.

The conversion of steel mill gases into fuels and fertilizers may still seem a distant dream right now – yet the developers intend to gather initial operating experience in a realistic steel mill environment as early as 2015. Tests will then be conducted for two to five years on how the newly developed techniques are proving effective in practice. Initial pilot and test facilities should be put into operation in seven years’ time, and commercial implementation with an investment volume of over €1 billion is planned from 2022. If the project proves a success, PLANCK could usher in a sustainable structural change in Germany’s key industries through an intelligent network of value chains. The project would then not only help reduce CO₂ emissions and save resources but also safeguard jobs and make the Germany more sustainable as an industrial location.