Use of hydrogen in the calciner of rotary kiln plants to reduce CO₂ emissions in the cement industry

In the past decades, the European cement industry has taken various steps to significantly reduce its carbon footprint. Today, the potential of conventional measures to reduce CO₂ emissions in the German cement industry is largely exhausted (e.g. the use of alternative fuels with lower CO₂ emission factors or certain content of biogenic carbon, the increase of energy efficiency and the reduction of clinker contents in cement). In contrast, innovative measures such as CO₂ capture still require time for further development. There is therefore an urgent need to develop and test more advanced CO₂ reduction methods. Since no greenhouse gas emissions are generated from its combustion, green hydrogen is seen as a promising alternative fuel to achieve the ambitioned CO₂ neutrality in the EU by 2050. The working hypothesis of this research project is the expectation that the use of hydrogen in cement production can contribute to a significant reduction of the CO₂ emissions at lower cost compared to other technologies.  Hence, the objective of this research project is to investigate systematically and for the first time the effects of the use of hydrogen in the calciner in the cement production process with regard to process operation, the required plant technology, the product properties and emissions. The intention is to show under which technical and economic boundary conditions hydrogen can be used in the calciner to further reduce CO₂ emissions and energy consumption in the cement industry in the medium term. The methodological approach and the possible solution for this consists of a combination of laboratory and pilot plant trials on the use of H₂ and a simulation of the clinker burning process on an industrial scale.