Study On SO₂ And NO Removal Performance Of Modified Columnar Activated Carbon

Massive emissions of flue gas SO₂, NO_X and other pollution make environmental issues under grievous situation. It's an effective method to use SO₂ and NO removal technology for controlling SO₂ and NO pollution, in which activated carbon?AC?adsorption method has been widely used in industrial flue gas SO₂ and NO removal process. However, industrial columnar AC has some disadvantages such as low adsorption capacity. The cycles and consumption of AC were increased in order to achieve excellent SO₂ and NO removal performance. In this paper, the way to modify columnar AC by oxidization modification and supporting the metal-oxide were studied, besides, the SO₂ and NO removal activities of modified AC was also discussed. The results showed that:?1? The ash and carbon content of columnar AC reduced after modified by oxidation, while the volatile matter and oxygen content increased. And the number of oxygen-containing functional groups on the surface of AC increased when AC was modified by oxidation and loaded metal oxide.?2? The SO₂ and NO removal activities of AC were improved by surface oxidized modification. Compared to other ways of oxidized modification, the AC, after HNO₃ solution oxidized modified?AC-HNO₃?, had the best SO₂ and NO removal activities.At 1500L/?Kg·h? space velocity, 8% O₂ and 150?, the AC-HNO₃ had a NO conversion of 20.0%, a SO₂ conversion of 44.4%.?3? The SO₂ and NO removal activities of catalysts were greatly improved by loading metal oxides. Compared to other catalysts, the AC after hydrogen peroxide modified and loaded with MnO_X?MnO_X/AC-H₂O₂?, had the best NO removal activity,the NO conversion of MnO_X/AC-H₂O₂ catalyst was more than 40.0% at 1500L/?Kg·h?space velocity, 8% O₂, 120 240? and a loading of 1wt% MnO_X. The AC after sulfuric acid modified and loaded V₂O₅?V₂O₅/AC-H₂SO₄? had the best SO₂ removal activity, the SO₂ conversion of the V₂O₅/AC-H₂SO₄ catalyst was more than 79.0% at1500L/?Kg·h? space velocity, 8% O₂, 120²40? and a loading of 1wt% V₂O₅.?4? The SO₂ and NO removal activities of V₂O₅ and MnO_X catalysts were improved by adding CeO₂. The load order had a great impact on SO₂ and NO removal activity of composite catalysts. Compared to the other catalysts, the composite catalyst had excellent SO₂ and NO removal performance when loading V₂O₅ and CeO₂?V₂O₅?f?-CeO₂/AC-H₂SO₄?, respectively. At 1500L/?Kg·h? space velocity, 8%O₂, a loading of 1wt% V₂O₅ and CeO₂, the V₂O₅?f?-CeO₂/AC-H₂SO₄ catalyst had a NO conversion of 59.4% at 240? and SO₂ conversion was more than 85.0% at 120²40?.?5? The oxygen concentration, space velocity and the V₂O₅ loading amount had a great impact on SO₂ and NO removal activities of V₂O₅/AC-H₂SO₄ catalyst. In a certain oxygen concentration range?5% to 9%?, the SO₂ and NO removal activities of catalyst increased with oxygen concentration rising. As the space velocity increasing,the SO₂ and NO removal activities of catalyst decreased. The V₂O₅/AC-H₂SO₄ catalyst had the best SO₂ and NO removal activity at a loading of 5wt% V₂O₅. At1500L/?Kg·h? space velocity, 8% O₂, a loading of 5wt% V₂O₅, the V₂O₅/AC-H₂SO₄ catalyst had a NO conversion of 66.2% at 240? and the SO₂ conversion was more than 90.0% at 120²40?.?6? During the simultaneous SO₂ and NO removal, SO₂ had a strong inhibitory effect on NO removal activity of V₂O₅/AC-H₂SO₄ catalyst. At 1500L/?Kg·h? space velocity, 8% O₂, 240? and a loading of 1wt% V₂O₅, the V₂O₅/AC-H₂SO₄ catalyst had a NO conversion of 55.0% with no SO₂ and had a NO conversion of 24.7% with600 ppm SO₂. NO had promotion on SO₂ removal activity of V₂O₅/AC-H₂SO₄ catalyst.At 1500L/?Kg·h? space velocity, 8% O₂, 120?, a loading of 1wt% V₂O₅, the V₂O₅/AC-H₂SO₄ catalyst had a SO₂ conversion of 85.8% with no NO and had a SO₂ conversion of 86.3% with 600 ppm NO.?7? The regeneration in N₂ decreases the SO₂ and NO removal activities of V₂O₅/AC-H₂SO₄ catalyst. However, the times of regeneration had little effect on SO₂ and NO removal activities of catalyst.