Numerical study on NOx/CO emissions in the diffusion flames of high-temperature off-gas of steelmaking converter

Li, Sen; Wei, Xiaolin; Yu, Linxin

doi:10.1016/j.apenergy.2010.10.030

Cited by 9 publications

(4 citation statements)

References 16 publications

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“…Increasing the temperature is conducive to the forward reactions of reactions R3 and R4, and then NO emission monotonically decreases with temperature (see Figure 4a). However, since reaction R5 is very slow in the absence of H 2 O, 18 it is not conducive to the forward reaction of reaction R4, and then NO reduction slows in the absence of H 2 O when the temperature is <1100 °C (see Figure 4a).…”

Section: Resultsmentioning

confidence: 99%

Effect of H₂O Vapor on NO Reduction by CO: Experimental and Kinetic Modeling Study

Wei

Guo

2012

Energy Fuels

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The experiment and kinetic modeling prediction were conducted to investigate the effect of H 2 O vapor on NO reduction by CO. The experiment was performed in a 36-kW combustion reactor, and modeling prediction was done using the plug-flow reactor model. In the presence of H 2 O, the formation of free-radical H is conducive to NO reduction. H 2 O has a complex effect on NO emission: at T < 1100°C, NO emission decreases with the increase of H 2 O content and temperature, the reaction pathway of NO reduction is NO → HNO → NH → N 2 O → N 2 , and the controlling factors of NO reduction are temperature and H 2 O concentration; at 1100°C < T < 1400°C, NO emission decreases as the H 2 O content increases and remains constant with the change of temperature at [H 2 O] < 1.0%, NO reduction depends on H 2 O concentration rather than temperature, and increasing H 2 O concentration makes free-radical H reach high equilibrium concentration; at T > 1400°C, the effects of H 2 O content and temperature on NO emission at [H 2 O] < 1.0% are similar to that at T < 1100°C, NO emission increases with H 2 O content but decreases with temperature at [H 2 O] >1%, NO reduction depends on the combined effects of H and CO.

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Section: Resultsmentioning

confidence: 99%

Effect of H₂O Vapor on NO Reduction by CO: Experimental and Kinetic Modeling Study

Wei

Guo

2012

Energy Fuels

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“…The high-temperature off-gas is a precious valuable fuel. It is often discharged into the cooling stack to be combusted, and the peak temperature of flame can reach above 2000 °C where CO 2 may decompose and NO x is significantly formed . CO emission concentration can reach above 2000 mg/m 3 which is always over emission standards (300 mg/m 3 in China). , CO is a toxic gas which is dangerous to human health.…”

Section: Introductionmentioning

confidence: 99%

“…A large amount of high-temperature off-gas is produced during oxygen converter steelmaking, the major compositions of off-gas are CO and CO 2 , CO concentration varies from 15 to 70%, and off-gas temperature can reach 1900 K. 1 In the meantime, off-gas entrains a large amount of fine dusts (Fe, FeO, Fe 2 O 3 , etc.) and the amount of the dusts entrained by off-gas is about 80-150 g/m 3 . 2 The high-temperature off-gas is a precious valuable fuel.…”

Section: Introductionmentioning

confidence: 99%

Promotion of CO Oxidization and Inhibition of NO Formation by Gaseous Iron Species during High-Temperature Off-Gas Combustion

Wei

2011

Energy Fuels

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The promotion of CO oxidization and inhibition of NO formation by gaseous iron species were analyzed using the Sandia SENKIN program. It is shown that the relative ratio of CO oxidization dramatically varies with combustion time at early burning stage in the presence of iron species, and all peak values are greater than 2.4. The relative ratio of CO oxidization decreases with the increase of air stoichiometric ratio and CO concentration in off-gas. The circulation reactions of Fe-FeO/FeO 2 -Fe achieve the catalytic effect on CO oxidization. Gaseous iron species can greatly inhibit NO formation, NO reduction ratio can reach above 70% at T = 2073 and 2273 K, and gaseous iron species can effectively inhibit NO formation when combustion temperature is not higher than 2273 K during the off-gas combustion. There are O 2 competitive reactions between thermal NO formation and Fe oxidization, and high chemical activity of iron species inhibits thermal-NO formation. INTRODUCTIONA large amount of high-temperature off-gas is produced during oxygen converter steelmaking, the major compositions of off-gas are CO and CO 2 , CO concentration varies from 15 to 70%, and off-gas temperature can reach 1900 K. 1 In the meantime, off-gas entrains a large amount of fine dusts (Fe, FeO, Fe 2 O 3 , etc.) and the amount of the dusts entrained by off-gas is about 80-150 g/m 3 . 2 The high-temperature off-gas is a precious valuable fuel. It is often discharged into the cooling stack to be combusted, and the peak temperature of flame can reach above 2000°C where CO 2 may decompose and NO x is significantly formed. 3 CO emission concentration can reach above 2000 mg/m 3 which is always over emission standards (300 mg/m 3 in China). 4,5 CO is a toxic gas which is dangerous to human health. High CO emission results in not only atmospheric pollutant but also fuel loss. NO x is a known precursor to the formation of ozone and acid rain, and it can react with volatile organic compounds to form photochemical smog. 6 Iron oxide catalyst is widely used either as single metal oxide or as a mixed oxide in industrial processes, and iron oxide exhibits intermediate activity in the complete oxidation of methane and carbon monoxide. 7-9 NO reduction by iron species has been studied in fluidized bed, and the results indicate that iron or its oxides cause a chemical reduction of NO in the presence of CO. 10 It has been discovered that injection of iron-containing compounds into the combustion and reburning zones of conventional gas-and coal-fired combustors can increase the efficiency of NO x reduction by up to 20% in comparison with that which can be achieved by basic reburning. 11 During the combustion of high-temperature off-gas entraining a large amount of dust containing iron and iron oxides, gaseous iron species is present at T > 2073 K, and it has effects on CO oxidization and NO formation. A detailed chemical kinetic mechanism for gaseous iron-species inhibition of flames, iron pentacarbonyl (Fe(CO) 5 ) mechanism, has been introduced, 12 and modeling ...

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“…Noteworthy are optimization activities implemented in several steel works, which resulted in reduction not only in fuel consumption, but also in emissions as observed by Habashi (2011) and Lukáč et al (2019). An example of such solutions implemented into practice is the use of low-emission burners and the use of the so-called producer gases, especially those rich in hydrogen (Kremer et al 2001;Lee and Jou 2011;Li et al 2011;Kirschen et al 2005) combined with appropriate control of parameters for combustion process. (In particular, the equivalence ratio and temperature of input air are the most important.…”

Section: Innovative Strategies and Technologiesmentioning

confidence: 99%

Integration of waste biomass thermal processing technology with a metallurgical furnace to improve its efficiency and economic benefit

Szwaja

Zajemska

Szwaja

et al. 2021

Clean Techn Environ Policy

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The article presents innovative technology which integrates a metallurgical pusher-type furnace with a waste heat recovery system that consisted of a reactor for torrefaction and pyrolysis of waste biomass. The technology is designed for utilizing both liquefied and gaseous by-products (torgas, pyrolysis gas and condensate denoted as TPC) obtained from torrefaction and pyrolysis of waste biomass. TPC is considered to be applied as an additional fuel for a metallurgical furnace as an example of effective energy management in metallurgical industry. In detail, the technology contains waste heat recovery unit installed on the furnace smoke stack as the heat source for the pyrolysis/torrefaction reactor. The analysis was carried out for a pusher furnace, fed optionally with either natural gas or coke gas. Share of this gaseous/liquid TPC fuel from waste in the total fuel mixture fed to the furnace was varied from 5 to 15% by volume. Practical usefulness of TPC fuel was tested on a specially constructed test stand. Financial analysis in energy consumption and economy of using the obtained TPC fuel for co-combustion with coke gas in the metallurgical pusher furnace was carried out on the basis of data from a steel sheet roller combined with the pusher furnace located in one of large steel works. It was shown that the use of this TPC fuel derived from thermal treatment of waste biomass and other organic substances can be considered an effective method of reducing production costs in the analyzed steel company and can lead to increase in the attractiveness of their products and thus strengthen their competitiveness on the global market. Graphic abstract

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Numerical study on NOx/CO emissions in the diffusion flames of high-temperature off-gas of steelmaking converter

Cited by 9 publications

References 16 publications

Effect of H₂O Vapor on NO Reduction by CO: Experimental and Kinetic Modeling Study

Effect of H₂O Vapor on NO Reduction by CO: Experimental and Kinetic Modeling Study

Promotion of CO Oxidization and Inhibition of NO Formation by Gaseous Iron Species during High-Temperature Off-Gas Combustion

Integration of waste biomass thermal processing technology with a metallurgical furnace to improve its efficiency and economic benefit

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Numerical study on NOx/CO emissions in the diffusion flames of high-temperature off-gas of steelmaking converter

Cited by 9 publications

References 16 publications

Effect of H2O Vapor on NO Reduction by CO: Experimental and Kinetic Modeling Study

Effect of H2O Vapor on NO Reduction by CO: Experimental and Kinetic Modeling Study

Promotion of CO Oxidization and Inhibition of NO Formation by Gaseous Iron Species during High-Temperature Off-Gas Combustion

Integration of waste biomass thermal processing technology with a metallurgical furnace to improve its efficiency and economic benefit

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Effect of H₂O Vapor on NO Reduction by CO: Experimental and Kinetic Modeling Study

Effect of H₂O Vapor on NO Reduction by CO: Experimental and Kinetic Modeling Study