Simultaneous absorption of SO2 and NOx with pyrolusite slurry combined with gas-phase oxidation of NO using ozone: Effect of molar ratio of O2/(SO2+0.5NOx) in flue gas

Sun, Wei; Wang, Hongtao; Ding, Sanglan; Su, Shijun

doi:10.1016/j.cej.2013.05.003

Cited by 49 publications

(24 citation statements)

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“…The rate of Mn leaching reaction was elaborated by shrinking core with an product layer when the reductant agent was aqueous SO 2 , which implicates that the rate-controlled stage is SO 2 diffusion from bulk phase into porous structure of ore particles and the apparent rate constant was estimated 2.5-4.2×10 −2 min −1 (Raisoni and Dixit, 1988). The sphere diffusion controlled without an inert product layer for Mn extraction with Flue gas (this study) is can attributed to the diffusion rate of SO 2 from gas phase into liquid phase (Sun et al, 2013). The fact that rate constant of 3.4×10 −3 min −1 obtained in this study is smaller compered to 2.5-4.2×10 −2 also confirmed the Mn dissolution mechanism.…”

Section: Separation Mechanismmentioning

confidence: 87%

“…Our previous studies show that the high efficiencies of desulphurization and manganese extraction can be attained when low-grade manganese ore was used as absorbent to remove SO 2 in flue gas (Sun et al, 2011;Sun et al, 2013); however, it takes a long time to obtain more than 90% manganese, requiring more than 15 h, which is due to low content of SO 2 in flue gas (below 1% SO 2 ). In this work, simulated flue gas (high concentration of SO 2 contained) was taken to reduce the high-iron pyrolusite ore to simultaneously investigate the leaching behavior of manganese and iron and separation efficiency of manganese from iron.…”

Section: Introductionmentioning

confidence: 99%

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Study on Separation of Manganese from Iron in High-Iron Pyrolusite Ore by Leaching with Simulated Flue Gas

Deng

et al. 2017

J. Chem. Eng. Japan / JCEJ

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Due to the depletion of high-grade manganese ore, much attention has turned to recover manganese from low-grade ores; however, these are usually associated with high-iron content. Moreover, the conventional process of extracting Mn from iron-rich low grade manganese oxide ore focused on recovery of Mn, while ignoring the leaching characteristics of Fe. Hence, simultaneous investigations on leaching behavior and separation e ciency of both manganese and iron were carried out for attaining high recovery of manganese with low iron content from the high-iron low-grade pyrolusite ore using simulated ue gas as the reductant. The e ects of leaching parameters, ue gas components and initial particle size on the leaching e ciency of Mn and Fe were studied, and the results indicated that higher separation e ciency of Mn from iron was achieved at lower SO 2 concentration, O 2 concentration and suitable pulp density. The experimental validation revealed that 93.12% Mn and only 2.57% Fe were extracted under the optimal operating conditions: SO 2 percentage of 5%, O 2 percentage of 1%, reaction temperature of 35°C, solid-to-liquid ratio of 250 g/L, and more than 120 min. Kinetic modelling has indicated that the Mn leaching rate is controlled by the rate of di usion of SO 2 /O 2 from the gas phase to the liquid phase, and the rate of di usion of product or reactants to the ore surface through an inert product layer is the rate-limiting step for Fe dissolution.

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Section: Separation Mechanismmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Study on Separation of Manganese from Iron in High-Iron Pyrolusite Ore by Leaching with Simulated Flue Gas

Deng

et al. 2017

J. Chem. Eng. Japan / JCEJ

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“…In ammonia-based wet flue gas desulfurization process, a great amount of air is needed to oxidize (NH4) 2 SO 3 and NH 4 HSO 3 into (NH 4 ) 2 SO 4 , the byproduct. The possible reason is that an appropriate increase in initial NO concentration promotes the reaction between NO 2 and SO 3 2-, but the increase of desulfurization efficiency is very limited, which indicates the reactions (11)- (12) are the main reactions for SO 2 removal. Figure 4 shows the effect of initial NO concentration on the ozonation process.…”

Section: Influence Of O 3 /No Molar Ratiomentioning

confidence: 99%

“…These pollutants have brought about significant effects on both the environment and human health in China [1,2]. To overcome this problem, many technologies such as nonthermal plasma, electron beam irradiation [3][4][5] and adsorption process [6][7][8][9][10][11][12][13][14][15] have been developed for simultaneous removal of SO 2 and NO x , but only few commercial applications have been reported until now. However, the individual treatment technology may lead to high investment and operating costs.…”

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confidence: 99%

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

Guo

Zhang

et al. 2015

CI&CEQ

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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.

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“…Sun et al . used pyrolusite slurry to remove SO 2 and NO x simultaneously, which could achieve the goal of manganese leaching as well and sulfur reuse. In this technology, however, NO needs to be oxidized by ozone first when the flue gas is injected in the slurry tank, which makes the system complicated and the investment and operating costs are very high.…”

Section: Introductionmentioning

confidence: 99%

Suitability of pyrolusite as additive to activated coke for low‐temperature NO removal

Yang

Jiang

et al. 2017

J of Chemical Tech & Biotech

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BACKGROUND Pyrolusite was used as additive to prepare coal‐based activated coke (AC) for low‐temperature NO removal. The pyrolusite modified AC was prepared by a blending method, and the denitrification performance was evaluated in a lab‐scale simulated fixed‐bed reactor. RESULTS The blending of pyrolusite promoted the specific surface area and pore structure of AC, even though the MnO2 and Fe2O3 showed inhibitory effects when blended separately. Both the basic and acid sites of AC‐Mn(x) increased owing to the participation of the blended MnO2 during the activation, while the blending of Fe2O3 showed an inhibited effect. AC‐P10 showed the highest NO removal efficiency at 74.2%, which was 32.8%, 27.0% and 24.2% higher than that of AC, AC‐Mn4 and AC‐Fe6. The operating temperature adaptability and stability of catalysis activity of AC‐P10 are good. Manganese is the main catalyst of AC‐P(x), and Fe is an accelerant to stimulate the catalytic activity of Mn. The extremely high NO removal activity of AC‐P(x) was due to the synergistic effect of surface functional groups and metals, but the catalysis of metals played a more important role. CONCLUSION Pyrolusite is suitable to prepare the AC‐based denitrification catalyst (AC‐P(x)) for SCR NO removal because the Mn and Fe contained in the pyrolusite showed a synergistic effect. © 2017 Society of Chemical Industry

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Simultaneous absorption of SO2 and NOx with pyrolusite slurry combined with gas-phase oxidation of NO using ozone: Effect of molar ratio of O2/(SO2+0.5NOx) in flue gas

Cited by 49 publications

References 47 publications

Study on Separation of Manganese from Iron in High-Iron Pyrolusite Ore by Leaching with Simulated Flue Gas

Study on Separation of Manganese from Iron in High-Iron Pyrolusite Ore by Leaching with Simulated Flue Gas

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

Suitability of pyrolusite as additive to activated coke for low‐temperature NO removal

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