Reburning pulverized coal with natural gas/syngas upgrading: NO reducing ability and physicochemical structure evolution of coal char

The lifting gas activates the coal particles, which increases their ability to reduce NO. This technique overcomes the oxygen consumption of large pulverized coal in the early stages of re-firing during air/flue gas transport of pulverized coal. This study conducted experiments on a planar flame burner bench to analyze the physicochemical structure evolution of coal coke after natural gas and syngas activation using FTIR, XPS, and BET. The NO reduction capacity was tested on a micro fluidized bed reaction test bench. The results show that natural gas's upgrading effect is better than syngas. Hydrogen and hydrocarbon radicals generated by the reaction of natural gas with oxygen play a significant role in activation. After upgrading by natural gas, the specific surface area of carbon increased by about 54.2 %, the total pore volume increased by about 51.2 %, the whole oxygen-containing groups decreased by nearly 4.4 %, the total amount of alkyl complexes increased by about 3.6 %, and the nitric oxide reducing ability increased by almost 75 %. The technology minimizes expensive reactive gases while ensuring less reburned coal is used to reduce NOx emissions.