NO  reburning in oxy-fuel combustion: A comparison between solid and gaseous fuels

Normann, Fredrik; Andersson, Klas; Johnsson, Filip; Leckner, Bo G

doi:10.1016/j.ijggc.2011.05.003

Cited by 22 publications

(9 citation statements)

References 13 publications

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“…Temperature has the least influence on NO x formation as mentioned earlier due to relatively low temperature range of typical biomass combustion [26]. Note still that it is proved that reburning during oxy-combustion is more sensitive to temperature [30]. Also, NO x precursors, i.e., ammonia and hydrogen cyanide, are very sensitive to temperature and the HCN/NH 3 ratio increases with increasing temperature [31][32][33].…”

Section: Nox Reduction Pathmentioning

confidence: 81%

Experimental Investigation on NOx Reduction by Primary Measures in Biomass Combustion: Straw, Peat, Sewage Sludge, Forest Residues and Wood Pellets

2012

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An experimental investigation was carried out to study the NO x formation and reduction by primary measures for five types of biomass (straw, peat, sewage sludge, forest residues/Grot, and wood pellets) and their mixtures. To minimize the NO x level in biomass-fired boilers, combustion experiments were performed in a laboratory scale multifuel fixed grate reactor using staged air combustion. Flue gas was extracted to measure final levels of CO, CO 2 , C x H y , O 2 , NO, NO 2 , N 2 O, and other species. The fuel gas compositions between the first and second stage were also monitored. The experiments showed good combustion quality with very low concentrations of unburnt species in the flue gas. Under optimum conditions, a NO x reduction of 50-80% was achieved, where the highest reduction represents the case with the highest fuel-N content. The NO x emission levels were very sensitive to the primary excess air ratio and an optimum value for primary excess air ratio was seen at about 0.9. Conversion of fuel nitrogen to NO x showed great dependency on the initial fuel-N content, where the blend with the highest nitrogen content had lowest conversion rate. Between 1-25% of the fuel-N content is converted to NO x depending on the fuel blend and excess air ratio. Sewage sludge is suggested as a favorable fuel to be blended with straw. It resulted in a higher NO x reduction and low fuel-N conversion to NO x . Tops and branches did not show desirable NO x reduction and made the combustion also more unstable. N 2 O emissions were very low, typically below 5 ppm at 11% O 2 in the dry flue gas, except for mixtures with high nitrogen content, where values up to 20 ppm were observed. The presented results are part of a larger study on OPEN ACCESSEnergies 2012, 5 271 problematic fuels, also considering ash content and corrosive compounds which have been discussed elsewhere.

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Section: Nox Reduction Pathmentioning

confidence: 81%

Experimental Investigation on NOx Reduction by Primary Measures in Biomass Combustion: Straw, Peat, Sewage Sludge, Forest Residues and Wood Pellets

2012

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“…Alongside the sulfur chemistry, nitrogen chemistry in oxy-combustion has also been a focus of several studies (Croiset and Thambimuthu, 2001;Gimenez-Lopez et al, 2010;Glarborg et al, 2003;Kimura et al, 1995;Kuhnemuth et al, 2010;Liu et al, 2005;Tree, 2009, 2012;Mendiara and Glarborg, 2009;Normann et al, 2009Normann et al, , 2010Normann et al, , 2011Obras-Loscertales et al, 2015;Okazaki and Ando, 1997;Watanabe and Okazaki, 2011). Experiments revealed the emission of nitrogen oxides (NO x ) to be significantly lowered in oxy-combustion comparing to that of air-combustion (Croiset and Thambimuthu, 2001;Kimura et al, 1995;Liu et al, 2005).…”

Section: So 3 + H 2 O → H 2 So 4 R(4)mentioning

confidence: 99%

A comprehensive experimental and modeling study of sulfur trioxide formation in oxy-fuel combustion

Choudhury

Padak

2016

International Journal of Greenhouse Gas Control

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This study focuses on the sulfur chemistry occurring within an oxy-combustion system by adopting a combined approach of detailed kinetic modeling and experiments. Influences of variable combustion parameters on SO 3 generation have been investigated computationally by implementing different combustion mechanisms. Results indicated significant influences of the equivalence ratio, inlet SO 2 concentration and presence of NO on SO 3 formation while the inlet O 2 concentration exhibited minimal effect. Presence of NO demonstrated different degrees of direct and indirect interactions between NO x and SO x species for different reaction sets. Sensitivity analysis indicated radicals to be playing a dominant role in SO 3 formation. Collected temporal profiles of SO 3 from the lab-scale combustion setup showed evidence of significant SO 3 formation at temperatures as low as 650K under realistic boiler temperature conditions. The equivalence ratio and the concentrations of SO 2 , O 2 and NO were found to influence the SO 3 formation. Predictions of final SO 3 concentration from different mechanisms were comparable

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“…The combustion mechanism applied in the current study was drawn from the previous studies ,,,,− involving kinetic simulations to elucidate the nitrogen chemistry occurring within the oxy-combustion environment. The mechanism containing 97 species and 779 reactions was applied by Mendiara et al.…”

Section: Methodsmentioning

confidence: 99%

“…Destruction of the recycled NO in the furnace through the reburn mechanism has been reported to be the dominant factor in NO x reduction . Both experimental and kinetic studies have been performed to shed light on the nitrogen chemistry occurring in O 2 /CO 2 environment. ,− Combustion parameters such as, temperature, excess O 2 amount, recycled NO concentration and the stoichiometric ratio in the system have been reported to influence the reduction of NO. ,,, …”

Section: Introductionmentioning

confidence: 99%

An Investigation of the Interaction between NO_x and SO_x in Oxy-Combustion

Choudhury

Padak

2017

Environ. Sci. Technol.

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This study focuses on revealing the interaction of sulfur oxides (SO) and nitrogen oxides (NO) and investigating the application of Fourier transform infrared (FTIR) spectroscopy to quantify SO and NO emissions from gas-phase oxy-combustion systems. The authors aim to contribute to the current state of knowledge by providing speciation data of NO and SO species and it elucidates the influence of nitric oxide (NO) on sulfur trioxide (SO) generation. Detailed kinetic simulations revealed the influence of combustion parameters and the sensitivity analysis confirmed the dominating influence of hydrocarbon fragments on NO reduction. Accompanying experimental analysis exhibited higher reduction of NO to nitrogen (N) comparing to the predictions by the kinetic simulations. Moreover, the presence of NO in the system was observed to influence the SO generation to a variable degree based on the reaction set employed for kinetic simulations. Experimentally, slight decrease in SO concentration was observed in the presence of NO and it can be explained by the radical consumption by NO as SO and NO species share the same radical pool. The oxy-combustion mechanisms available in the literature can be improved further to be able to predict this interaction.

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NO reburning in oxy-fuel combustion: A comparison between solid and gaseous fuels

Cited by 22 publications

References 13 publications

Experimental Investigation on NOx Reduction by Primary Measures in Biomass Combustion: Straw, Peat, Sewage Sludge, Forest Residues and Wood Pellets

Experimental Investigation on NOx Reduction by Primary Measures in Biomass Combustion: Straw, Peat, Sewage Sludge, Forest Residues and Wood Pellets

A comprehensive experimental and modeling study of sulfur trioxide formation in oxy-fuel combustion

An Investigation of the Interaction between NO_x and SO_x in Oxy-Combustion

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NO reburning in oxy-fuel combustion: A comparison between solid and gaseous fuels

Cited by 22 publications

References 13 publications

Experimental Investigation on NOx Reduction by Primary Measures in Biomass Combustion: Straw, Peat, Sewage Sludge, Forest Residues and Wood Pellets

Experimental Investigation on NOx Reduction by Primary Measures in Biomass Combustion: Straw, Peat, Sewage Sludge, Forest Residues and Wood Pellets

A comprehensive experimental and modeling study of sulfur trioxide formation in oxy-fuel combustion

An Investigation of the Interaction between NOx and SOx in Oxy-Combustion

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An Investigation of the Interaction between NO_x and SO_x in Oxy-Combustion