Study on Simultaneous Removal of NO_x and SO₂ with NaClO₂ in a Novel Swirl Wet System

Abstract

This work attempts to utilize sodium chlorite to clean up NO x and SO 2 gases simultaneously from flue gas in a novel swirl scrubber system. Experiments were carried out to evaluate the effects of various operating parameters such as initial SO 2 concentration, scrubbing medium pH, sodium chlorite concentration, and liquid and gas volumetric flow rates at 35 °C. In addition, reaction mechanisms of simultaneous denitrification and desulfurization using sodium chlorite in acidic and basic solutions are proposed. Complete oxidation of NO into NO 2 occurred using 0.2 M sodium chlorite solution as the scrubbing medium. Complete (100%) SO 2 and 81% NO x removal efficiencies were achieved under optimized conditions. The NO x removal increased with decreasing pH. Input SO 2 enhanced the NO x absorption. The effect of the SO 2 concentration on NO x removal was more intense at higher pH values. Using sodium chlorite as the scrubbing medium in the novel swirl scrubber was found to be quite promising for the simultaneous removal of NO x and SO 2 .

A New Insight into Catalytic Ozonation with Nanosized Ce–Ti Oxides for NOx Removal: Confirmation of Ce–O–Ti for Active Sites

“…However, the experiments as shown in Fig. S13 show that the Am-CeTi prepared by Ce(NH 4 ) 2 (NO 3 ) 6 and Ti(SO 4 ) 2 (Ce(IV)Ti) exhibits higher catalytic activity than that of Am-CeTi prepared by Ce(NO 3 ) 3 and Ti(SO4) 2 (Ce(III)Ti). It indicates that the Ce 4+ has a promotional effect on catalytic activity.…”

“…5 Pourmohammadbagher et al utilized sodium chlorite to clean up NO X in the scrubber system and 81% NO X removal efficiency was achieved at the temperature as low as 35 . 6 Wu et al utilized manganese/titania-based catalysts for low-temperature selective catalytic reduction of NO with NH 3 , and the activity reaches nearly 80% at 80 . 7 However, none of the above technologies has been applied in the industrial applications because of various drawbacks including high investment and operating costs, low NO X removal efficiency and etc.…”

“…9,10 Many papers have reported that the oxidation of NO into HNO 3 by •OH radicals through two steps: (1) the oxidation of NO into HNO 2 or NO 2 and (2) the oxidation of NO 2 or HNO 2 into HNO 3 . [5][6][7]15 The removal of NO X is efficient for •OH radicals due to the stability of HNO 3 . The mechanism of •OH production has been definitely investigated in previous papers.…”

Basic rules of NO oxidation by Fe2+/H2O2/AA directional decomposition system

“…WFGD is the most widely used desulphurization technology in power plants. To achieve NO efficient oxidation and SO 2 /NO x simultaneous absorption in the existing WFGD plants is the direction of efforts . Nevertheless, the characteristics of NO oxidation by a Fe 2+ /H 2 O 2 /AA system still lack experimental study, and its applicability in WFGD conditions remains to be verified.…”

Absorption of NO by using aqueous KMnO4/(NH4)2CO3 solutions

“…During the past years, oxidants such as NaClO 2 , NaClO 3 , ClO 2 , KMnO 4 , H 2 O 2 , and Fenton reagent were used for NO oxidation. Most of the investigations mentioned above were carried out under strongly alkaline conditions, but the strongly alkaline conditions are far from that of a typical wet flue gas desulfurization scrubber.…”