Simultaneous desulfurization and denitrification of flue gas by catalytic ozonation over Ce-Ti catalyst

摘要

A novel oxidation-removal process for simultaneous removal of NO_x and SO2 was developed, which utilized the catalytic ozonation over Ce-Ti catalyst and assisted with a glass made ammonia-based washing tower. Compared with conventional flue gas treatment, the present method acquires non-secondary pollution, minimal waste production and low operating costs. The main byproducts, ammonia sulfate and nitrate, are important fertilizers and industrially raw materials. A maximum removal of 95% for NO_x and nearly complete SO2 removal were obtained with the assistance of washing tower under the following experimental conditions: O3 concentration, 8.5 mg·L~(-1); flow of oxidant mixtures, 100 mL·min~(-1); simulated flue gas temperature, 120 °C; H2O flow, 2.4 mL·min~(-1); and total gas flow, 400 mL·min~(-1). The reaction mechanisms are discussed, and the final oxidation products are characterized. The experimental results show that the ~·OH radicals from catalytic ozonation have an oxidation-removal effect of NO_x and SO2. The multipollutant capacity of the washing tower is largely enhanced with the Ce-Ti catalyst. And the present method performs better stability with the assistance of the washing tower.