Simultaneous removal of SO2 and NOx with ammonia combined with gas-phase oxidation of NO using ozone

Abstract

Article Highlights• Simultaneous removal of SO 2 and NO x was achieved by oxidation of NO with O 3 and ammonia absorption • The appearance of SO 2 in fuel gas has little impact on the oxidation of NO • The O 3 /NO molar ratio is the most important factor in the ozone oxidation process • Increasing of O 3 /NO mole ratio and SO 2 concentration are favorable to recycling the byproducts Abstract A process for simultaneous desulfurization and denitrification is proposed, consisting of ozone as the oxidizing agent for NO and ammonia solution as the absorbent. The results showed that the presence of SO 2 and the concentration changes of NO and SO 2 have little impact on the oxidation of NO, the oxidation efficiency of NO can achieve over 90% when the molar ratio of O 3 /NO is 1.0. The presence of NO x had little effect on the absorption of SO 2 , while an appropriate increase of SO 2 concentration favorably affected NO x absorption. The removal efficiency of SO 2 and NO x reached 99.34 and 90.01% at pH 10, flow rate 0.95 Nm 3 /h, n[O 3 ]/n[NO] 1.0, initial SO 2 concentration 2000 mg/Nm 3 , initial NO concentration 200 mg/Nm 3 , ammonia concentration 0.3%, oxygen content of the simulated flue gas 12%, oxidation reaction temperature 423 K and absorption reaction temperature 298 K in the experimental system.

Study on the Key Factors of NO Oxidation Using O3: The Oxidation Product Composition and Oxidation Selectivity

“…In sintering flue gas, other oxidizable pollutants, such as SO 2 , CO, and HCl, also exist, which might influence the oxidation of NO. In a selective oxidation study, the effect of SO 2 on the oxidation of NO by O 3 was studied, , and O 3 exhibited excellent oxidation selectivity on NO. However, the yield of SO 3 was not obtained when trace SO 2 was oxidized by O 3 in the current research.…”

Removal of NOx from Flue Gas Using Yellow Phosphorus and Phosphate Slurry as Adsorbent

“…A large number of strong oxidants, including ozone, − hydrogen peroxide, − potassium permanganate, − and sodium chlorite, − have been added to wet scrubbing systems to enhance the absorption of NO x during the NO x removal process. It is accepted that NO can be oxidized to form more water-soluble NO 2 under the action of oxidants, and high NO x removal efficiency is realized accordingly.…”

Catalytic Oxidation of NO over MnOx–CeO2 and MnOx–TiO2 Catalysts

“…In general, the oxidation of NO to NO 2 can be realized through gas phase oxidation and liquid phase oxidation. The presence of SO 2 is disadvantageous to NO oxidation in the liquid phase because of the high solubility and oxidizability of SO 2 , whereas the oxidation rate of SO 2 is much lower than that of NO in the gas phase [3]. The gas phase oxidation is divided into homogeneous gas phase oxidation and heterogeneous gas-solid catalytic oxidation.…”