Thermodynamic analysis of hydrogen utilization as alternative fuel in cement production

Growing attention to the environmental aspect has urged the effort to reduce CO2 emission as one of the greenhouse gases. The cement industry is one of the biggest CO2 emitters in this world. Alternative fuel is one of the challenging issues in cement production due to the limited fossil fuel resources and environmental concerns. Meanwhile, hydrogen (H2) has been reported as a promising non-carbon fuel, with ammonia (NH3) as the main candidate for chemical storage methods. In this work, an integrated system of cement production with an alternative H2-based fuel is proposed, consisting of the dehydrogenation process of NH3 and the H2 combustion to provide the required thermal energy for clinker production. Different catalysts are employed and evaluated to analyze the specific energy input (SEI). The result shows that the conversion rate strongly determines the SEI, with minimum SEI (3829.8 MJ t-clinker−1) achieved by Ni-Pt-based catalyst at a reaction temperature of 600 ºC. Compared to the conventional fuel of coal, the H2-based integrated cement production system shows a significant decrease of 44% in CO2 emission due to carbon-free combustion using H2 as the fuel. The current study on the proposed integrated system of H2-based cement production also provides an initial thermodynamic analysis and basic observation for the adoption of non-carbon-based H2, including the storage system of NH3, in the cement production process.