Simultaneous wet desulfurization and denitration by an oxidant absorbent of NaClO2/CaO2
2019
Wang, Zhiping | Lun, Liyong | Tan, Zhongchao | Zhang, Yanguo | Li, Qinghai
The simultaneous wet removal performance of NO and SO₂ was studied using the oxidant absorbent NaClO₂/CaO₂. The factors were studied including NaClO₂ and CaO₂ concentrations, reaction temperature, and gaseous components, such as SO₂, NO, O₂, and CO₂. The products in liquid and solid phases were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and ion chromatography to determine the mechanism of simultaneous desulfurization and denitration by NaClO₂/CaO₂. The results indicated that the removal efficiency of SO₂ was in the range of 98–99.9%, and the removal efficiencies of NO and NOₓ were 99.4% and 95.0%, respectively. The removal efficiencies of NO and NOₓ increased with the increase of NaClO₂ and CaO₂ concentration and reaction temperature. The gaseous components had a stronger effect on NOₓ removal efficiency, followed by NO removal efficiency, and SO₂ removal efficiency. As SO₂ concentration increased, the generation of sulfite species promoted the removal of NO and NOₓ. Competition for NO₂ and SO₂ absorption by absorbent inhibited the removal efficiencies of SO₂ and NOₓ. The presence of O₂ was beneficial for removing SO₂, NO, and NOₓ, while the presence of CO₂ was not. The main products in the liquid and solid phases were NO₃⁻, NO₂⁻, SO₄²⁻, and CaSO₄. The reaction mechanism for simultaneous wet removal of SO₂ and NO by NaClO₂/CaO₂ is proposed and discussed.
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