It is important to develop low cost and efficient technique for simultaneous removal of SO2and NOXfrom flue gas. In this paper, ozone oxidation and alkaline wastewater washing process was employed for flue gas desulfurization and denitrification in a 75t/h coal-fired boiler. In order to optimize the operation parameters for SO2and NOXremoval, the influence of several parameters, such as molar ratio of [O3]/[NO] and flue gas temperature on the oxidation rate of NO, oxidation rate of NO, alkaline water level in aeration tank, alkaline water rate and mole ratio of [NaOH/ (SO2+NOx)] on the removal efficiency of SO2and NOXhave been studied. The experimental results showed that molar ratio of [O3]/[NO] had limited effect on the oxidation of SO2, while NO oxidation efficiency improved with the increase of [O3/NO] molar ratio and it reached to ~ 90% at molar ratio of [O3]/[NO] = 1.4. Flue gas temperature performed slight influence on the oxidation of NO in the range of 60 to 120 °C, and had adverse impact on the removal of SO2and NOX. NOXremoval rate was enhanced with increasing NO oxidation rate and achieved to a high level at NO oxidization rate of ~50%. Mole ratio of [NaOH/ (SO2+NOx)] had significant impact on the removal rate of NOX, while it showed limited effects on that of SO2. The increase of alkaline aeration water level and alkaline water rate would definitely lead to a higher removal rate for both SO2and NOX. An optimized removal rate of 93.6% for SO2, 77.6% for NOXand 99.1% for dust were obtained under the water level of 20cm and volume of 74.5t/h.
Intensification of NOx Conversion over Activated Coke by Ozone Oxidation for Sintering Flue Gas at Low Temperatures
