Chemical engineering solution for carbon neutrality in cement industry: Tailor a pathway from inevitable CO₂ emission into syngas

Cement production is one of the largest industrial sources of CO₂ emissions due to the thermal decomposition of limestone (CaCO₃). We integrate the chemical engineering strategy into the cement production and propose a novel process of “Carbonate Dry Reforming of Methane (CaDRM)” that converts the limestone (CaCO₃) directly into the cement clinker precursor (CaO) and syngas (CO + H₂) through reacting with methane (CH₄). Thermodynamic analysis indicates the reaction temperature of CaDRM is lowered by at least 200 °C compared with CaCO₃ thermal decomposition. Lab-scale experimental studies show a 95 % CaO yield at a 91 % syngas selectivity and 90 % CH₄ conversion in CaDRM using cement raw meal at 700 °C. Process simulation scale-up and economic analysis indicate CaDRM pathway can reduce 37.2 % CO₂ emission in comparison with the conventional CaCO₃ thermal decomposition pathway. More significantly, the net profit of $271.0/t (clinker) can be achieved by the value-added syngas products and the energy saving. The economic and environmental benefits of the proposed CaDRM strategy can help its future commercial deployment.