Influence of mixing, oxygen and residence time on the SNCR process

Liang, Ling; Suo, Hui; Pan, Su; Shang, Tong; Liu, Changchun; Wang, Denghui

doi:10.1016/j.fuel.2013.11.050

Cited by 38 publications

(23 citation statements)

References 26 publications

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“…The same tendencies were obtained under 5% O 2 and 30% O 2 atmosphere, as presented in Figure b. As denoted in overall reactions , more ammonia can be oxidized into NO with the increase of temperature, and NO reduction with ammonia occurs with a narrow temperature window (roughly 800–1000°C) without any additives, which was in agreement with Ling's work . Thus, the chemical equilibrium of oxidization reaction and reduction reaction was reached at 800°C.…”

Section: Resultssupporting

confidence: 87%

Thermal removal of COD and NH₃N from Lurgi coal‐gasification wastewater

Zhang

Wang

et al. 2017

Env Prog and Sustain Energy

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In this article, an alternative approach of wastewater utilization in coal-gasification process was proposed and evaluated. With wastewater being heated and sprayed into the gasifier, water vapor is treated as gasification agent and contaminants are thermally decomposed under specific conditions. The lab-scale experiments were performed using entrained-flow reactor system to investigate thermal removal of COD and NH 3 AN contained in wastewater by changing temperature, reaction atmosphere, oxygen proportion, and residence time. The experimental results show that reaction temperature has a significant effect on COD and NH 3 AN removal, and removal efficiency is obviously increased with temperature increased from 400 to 10008C. The removal efficiency of COD and NH 3 AN in different atmospheres ranks in the order: oxidative > inert > reductive. The thermal decomposition of organic constituents is enhanced by increasing oxygen proportion and residence time. Furthermore, a simplified kinetic study of COD and NH 3 AN removal efficiency was carried out on the hypothesis of pseudo-first order reaction model. The pre-exponential factor and apparent activation energy for COD and NH 3 AN removal were obtained in the range of 3.63 3 10 3 21.62 3 10 6 , 34.39-58.16 kJ mol 21 and 1.58 3 10 4 28.71 3 10 5 s 21 , 41.25-61.75 kJ mol 21 , respectively.

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Section: Resultssupporting

confidence: 87%

Thermal removal of COD and NH₃N from Lurgi coal‐gasification wastewater

Zhang

Wang

et al. 2017

Env Prog and Sustain Energy

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“…Several studies have firmly established that, among various operating conditions, the temperature is the leading one to determine the output of the SNCR process (Liang et al, 2014). Nevertheless, besides the temperature range, the NOx reduction depends also on the concentration of O 2 in the flue gas, the composition of additive (e.g., hydrogen, hydrogen peroxide) and the NH 3 /NO molar ratio (Blejchař and Dolníčková, 2013).…”

Section: Selective Non-catalytic Reduction (Sncr)mentioning

confidence: 99%

Convective recirculation effect on the selective non-catalytic reduction behavior in an industrial furnace

Oliveira

Martignoni

Souza

et al. 2017

Braz. J. Chem. Eng.

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Selective non-catalytic reduction (SNCR) has become an important technique for reducing NOx emissions in industrial furnaces. The occurrence of convective recirculation can cause significant changes in SNCR performance. This paper presents the results of a study performed by Computational Fluid Dynamics (CFD) considering: (i) changes of initial NO X ; (ii) injection plan and (iii) NH 3 /NO molar ratio. The simulations have demonstrated that the convective recirculation (resultant from different injection plans and high temperature gradients) of flue gas assumes a role of vital importance for performance analysis of existing plants and the potential NO X reduction in furnaces during the design phase.

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“…Nitrogen oxide (NO x ) emissions from stationary combustion systems, such as coal‐fired power plants, waste incinerators, and industrial ovens, have become a global concern. To reduce NO x emissions during coal combustion, various NO x reduction technologies, including low‐NO x combustion methods such as air staging combustion, fuel staging combustion, and flue gas recirculation (FGR), as well as NO x removal methods, such as selective catalytic reduction (SCR) and selective non‐catalytic reduction (SNCR), have been widely adopted in both commercial and industrial power plants. A schematic of the combined SCR and low‐NO x combustion methods is illustrated in Figure .…”

Section: Introductionmentioning

confidence: 99%

Performance of Low‐temperature SCR of NO with NH₃ over MnOx/Ti‐based catalysts

Niu

Zhang

et al. 2019

Can J Chem Eng

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The effects of Mn loadings and precursors, catalyst preparation methods, incineration durations and temperatures, and the addition of Co and Ce on NO-reduction efficiency and selectivity (N 2 O formation) during the preparation of MnOx/Ti-based catalysts were studied by micropore-size analysis (XRD, XPS, SEM, and FTIR), while considering changeable parameters. Meanwhile, the performance of low-temperature SCR of NO with NH 3 over the designed catalysts was tested under various gas hourly space velocities (GHSVs), NH 3 /NO molar ratios, and contents of NO, NH 3 , O 2 , H 2 O, and SO 2 in a lab-scale reactor. Overall, the Mn(0.3)Ce(0.1)/Ti catalyst, which had high NO-reduction efficiency and selectivity (low N 2 O formation), was recommended, with the following preparation methods: ultrasonic impregnation; manganese acetate precursor; and incineration at 500 8C. Appropriate textural properties (high surface area and small pore and crystallite sizes), well-dispersed amorphous manganese (rather than crystalline) on the anatase surface (rather than rutile), abundant active sites, and long residence time are essential for high NO-reduction efficiency. In practice, NO-reduction efficiency decreased with increasing GHSV and the NH 3 and NO contents; however, it initially increased and then became saturated with an increasing NH 3 /NO molar ratio and O 2 content. Water deactivated the catalyst to a recoverable state, whereas SO 2 resulted in unrecoverable deactivation.

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Influence of mixing, oxygen and residence time on the SNCR process

Cited by 38 publications

References 26 publications

Thermal removal of COD and NH₃N from Lurgi coal‐gasification wastewater

Thermal removal of COD and NH₃N from Lurgi coal‐gasification wastewater

Convective recirculation effect on the selective non-catalytic reduction behavior in an industrial furnace

Performance of Low‐temperature SCR of NO with NH₃ over MnOx/Ti‐based catalysts

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Influence of mixing, oxygen and residence time on the SNCR process

Cited by 38 publications

References 26 publications

Thermal removal of COD and NH3N from Lurgi coal‐gasification wastewater

Thermal removal of COD and NH3N from Lurgi coal‐gasification wastewater

Convective recirculation effect on the selective non-catalytic reduction behavior in an industrial furnace

Performance of Low‐temperature SCR of NO with NH3 over MnOx/Ti‐based catalysts

Contact Info

Product

Resources

About

Thermal removal of COD and NH₃N from Lurgi coal‐gasification wastewater

Thermal removal of COD and NH₃N from Lurgi coal‐gasification wastewater

Performance of Low‐temperature SCR of NO with NH₃ over MnOx/Ti‐based catalysts