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.