In the decarbonization process of heavy industries such as steel and building materials, lime kilns, as a core process with high energy consumption and emissions, are ushering in revolutionary changes brought about by oxygen fuel technology.

In traditional air assisted lime kilns, a large amount of nitrogen not only dilutes the combustion reaction, but also takes away nearly 30% of the waste heat from the flue gas. The final emitted CO ₂ concentration in the flue gas is only about 30%, and the carbon capture cost remains high. Oxygen fuel technology replaces air with high-purity oxygen for combustion assistance, removes nitrogen components from the source, and completes the combustion process in an atmosphere of O ₂ and circulating flue gas, completely reconstructing the thermal system of lime kilns.

The advantages of this technology have been verified in practical applications: it can increase the temperature of flue gas and materials in the kiln by about 20%, accelerate the decomposition rate of limestone by 40%, steadily increase the decomposition rate of limestone by 2%, and greatly optimize the control accuracy of raw material combustion. At the same time, the concentration of CO ₂ in the flue gas can jump to over 42%, and some advanced processes even exceed 80%. After being processed by carbon purification equipment, the purity of CO ₂ can reach over 99%, which is directly suitable for geological storage or resource utilization needs.

By relying on flue gas circulation regulation, oxygen fuel combustion can significantly suppress the generation of NO ₓ, shorten the flame length, and enhance radiative heat transfer, resulting in a significant improvement in the thermal efficiency of the kiln. According to the data of domestic landing projects, after applying this technology, the lime kiln can smoothly achieve fuel structure optimization, increase the proportion of white coal, reduce white coal consumption by 2% -3%, and reduce comprehensive carbon consumption by 4%.

Nowadays, the combination of oxygen rich delivery systems and modular carbon capture units in oxygen fuel technology is breaking the decarbonization bottleneck of traditional lime kilns, providing a feasible core path for heavy industry processes to achieve near zero emissions.