Thermoneutral coproduction of calcium oxide and syngas by combined decomposition of calcium carbonate and partial oxidation/CO2-reforming of methane

The calcination of limestone to produce lime and cement is characterized by its high-energy consumption and concomitant CO2 emissions to the atmosphere. By combining the calcination reaction with the partial oxidation and CO2-reforming of methane, an overall thermo-neutral process can be designed, with high-quality syngas as a useful byproduct, and a substantial decrease in CO2 release. The thermochemical boundary conditions for such a combined process are established. The thermodynamics are also examined with coal instead of methane as the fuel and carbon source. Adding H2O in the reaction mixture results in the coproduction of CaO and syngas with a H-2/CO molar ratio of 2, suitable for methanol synthesis. A preliminary economic analysis indicates favorable competitiveness, even before the application of credit for CO2 avoidance. The fuel saving of the proposed coproduction vs the separate production may amount up to 70%, and the avoidance Of CO2 emissions may reach 74%.