| According to the denitration and desulfurization project from the Ethylene power center in Sinopec Zhenhai Refining&Chemical Company, the treatment of flue gas with low NO concentration was studied. In this paper, ozone oxidation combining with NaOH absorption was used and the studied concentration ranges of NO and SO2were from150to300mg/Nm3and1500to3000mg/Nm3, respectively. The results showed that the decomposition of O3was mainly influenced by temperature and independent of O3initial concentration. When it was lower than or equal to150℃, O3decomposed slowly so that the oxidation of NO wouldn’t influenced greatly. NO oxidation efficiency was proportional to O3dosage, but almost has nothing to do with initial concentration of gas pollutants, air flow and oxygen content of flue gas. The existence of SO2in the flue gas had a slightly negative influence on NO oxidation, but NO oxidation efficiency still could reach93%when O3:NO ratio was1and the corresponding SO2oxidation efficiency was only5%. After absorption, NO removal efficiency was nearly100%and removal of SO2and NO2were greatly influenced by pH value. Solution with low pH value would inhibit absorption of SO2, but improve reaction of NO2. During the absorption process, main reaction products included NO3-, NO2-, SO32-and SO42-. The amount of SO42-accounted for nearly80%of all the products. Both the amounts of NO3-and NO2-were lower than4%, thereinto, the amount of NO3-was a little more.Finally, the comparision of process costs showed that ozone oxidation process was more economic for the flue gas with low NOx concentration because of complication of SCR system. Ozone oxidation process owns rapid reaction and high efficiency. It has great value in industrial application. |
