Experimental characterization of the influence of CO on the high-temperature reduction of NO by NH3

Suhlmann, Johannes; Rotzoll, G.

doi:10.1016/0016-2361(93)90394-h

Cited by 28 publications

(16 citation statements)

References 7 publications

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“…Although the oxygen was lean for combustion when CO was held at 6.5%, NH 3 still tended to form NO. These results are consistent with the studies reported by Suhimann and Rotzoll . In their experiments, adding CO to the NH 3 /NO/O 2 system led to more NO release.…”

Section: Resultssupporting

confidence: 93%

Effect of HCl on NO Formation during CO/NH₃ Combustion in an Entrained Flow Reactor at 1023–1223 K

Zhao

Wei

2017

Energy Fuels

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Biomass and coal that contain high amounts of chlorine release HCl during combustion. There is no universal agreement regarding the effect of HCl on NO formation. To investigate the effect of HCl on NO formation, CO/NH3 combustion experiments and simulations were conducted in an entrained flow combustion reactor at 1023–1223 K. The experimental results show that the HCl addition tends to inhibit NO formation at low temperatures and exhibits promotion effects when the temperature is increasing and a temperature enhancement tends to inhibit NO formation. The simulation results provide evidence that the HCl addition inhibits NO formation by reducing the concentrations of the H, O, and OH radicals.

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Section: Resultssupporting

confidence: 93%

Effect of HCl on NO Formation during CO/NH₃ Combustion in an Entrained Flow Reactor at 1023–1223 K

Zhao

Wei

2017

Energy Fuels

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“…The application of the SNCR denitrification process combined with a CFB boiler has certain advantages. 14 The operating temperature of a CFB boiler is consistent with the reaction temperature window of SNCR, which provides a suitable reaction environment for NOx reduction to maintain a high conversion efficiency. Via addition of the reducing agents to the CFB boiler, a proper residence time and mixing condition can be realized for the denitrification reaction.…”

Section: Introductionmentioning

confidence: 86%

“…The circulating fluidized bed (CFB) boiler has developed as a clean coal combustion technology. − Nevertheless, without using flue gas treatment facilities, it fails to satisfy the increasingly stringent emission regulations, especially under the frequent variation of the boiler load. The application of the SNCR denitrification process combined with a CFB boiler has certain advantages . The operating temperature of a CFB boiler is consistent with the reaction temperature window of SNCR, which provides a suitable reaction environment for NOx reduction to maintain a high conversion efficiency.…”

Section: Introductionmentioning

confidence: 88%

Experimental Study of the Enhancement of the Selective Noncatalytic Reduction Denitrification Process with Methane and Propane in a Circulating Fluidized Bed

Liu

Zhao

You

et al. 2019

Ind. Eng. Chem. Res.

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Selective noncatalytic reduction of NO with ammonia (NH 3 ) as a reducing agent and methane (CH 4 ) and propane (C 3 H 8 ) as gaseous additives was studied using benchand pilot-scale experimental setups. The performances of the two additives and their injection pathways were investigated and compared. As indicated by the bench-scale experiments, the NO conversion efficiency was significantly enhanced above 700 °C upon addition of CH 4 and C 3 H 8 . The temperature window for high NOx conversion efficiency was extended downward from 900 to 750 °C and from 900 to 700 °C in the presence of CH 4 (α = 0.5) and C 3 H 8 (α = 0.2), respectively. When the additives and NH 3 were injected simultaneously at the same location, the de-NO efficiency increased as much as 20% due to the formation of a reducing atmosphere, subsequently accelerating the generation of hydroxyl groups after the addition of additives, which induce the dehydrogenation of NH 3 and accelerate the combination of NO with NH 2 to generate N 2 and H 2 O.

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“…The temperature window was also determined to be broadened by the presence of CO which produced the necessary OH radicals needed to initiate NO reduction to N 2 . Subsequent research (Lyon, 1979, Suhlmann, J., Rotzoll, 1993, Pont et al, 1993, and Brauwer, 1996 investigated the effect of CO on DeNOx chemistry and showed the temperature window could be lowered by 100 o C and broadened if the appropriate level of CO (approximately 3800 ppm ) were present. Higher CO levels tend to increase radicals such that NO formation is enhanced over NO reduction.…”

Section: Introductionmentioning

confidence: 99%

Temperature, velocity and species profile measurements for reburning in a pulverized, entrained flow, coal combustor

Tree¹

1999

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Nitrogen oxide emissions from pulverized coal combustion have been and will continue to be a regulated pollutant for electric utility boilers burning pulverized coal. Full scale combustion models can help in the design of new boilers and boiler retrofits which meet emissions standards, but these models require validation before they can be used with confidence. The objective of this work was to obtain detailed combustion measurements of pulverized coal flames which implement two NO reduction strategies, namely reburning and advanced reburning, to provide data for model validation. The data were also compared to an existing comprehensive pulverized coal combustion model with a reduced mechanism for NO reduction under reburning and advanced reburning conditions. The data were obtained in a 0.2 MW, cylindrical, down-fired, variable swirl, pulverized coal reactor. The reactor had a diameter of 0.76 m and a length of 2.4 m with access ports along the axial length. A Wyodak, sub-bituminous coal was used in all of the measurements. The burner had a centrally located primary fuel and air tube surrounded by heated and variably swirled secondary air. Species of NO, NO x , CO, CO 2 and O 2 were measured continuously. Aqueous sampling was used to measure HCN and NH 3 at specific reactor locations. Samples were drawn from the reactor using water quenched suction probes. Velocity measurements were obtained using two component laser doppler anemometry in back-scatter mode. Temperature measurements were obtained using a shielded suction pyrometer. A series of six or more radial measurements at six or more axial locations within the reactor provided a map of species, temperature, and velocity measurements. In total, seven reactor maps were obtained. Three maps were obtained at baseline conditions of 0, 0.5 and 1.5 swirl and 10% excess air. Two maps were obtained under reburning conditions of 0.78 stoichiometric ratio and 1.5 swirl and 0.9 stoichiometric ratio and 0.5 swirl. And finally, two maps were obtained under advanced reburning conditions both at the same operating condition of 1.05 stoichiometric ratio in the reburning zone followed by ammonia injection. Numerous effluent measurements were obtained to study the affect of natural gas injection location, stoichiometric ratio, and injection velocity on effluent NO. For advanced reburning, effluent measurements were obtained for a similar matrix of operating conditions with the additional variable of ammonia nitrogen to nitrogen in NO or nitrogen stoichiometric ratio (NSR). Baseline maps and effluent measurements were useful in establishing the flow patterns of the reactor and determining the effect of swirl on NO. At zero swirl the flame appeared to be lifted and therefore created higher NO. At 0.5 swirl the flame had transitioned to an attached flame with a central recirculation zone and produced lower NO. Detailed velocity measurements of the quarl were obtained which provided boundary conditions for modeling and helped explain why the flame was not attached at zero swirl. ...

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Experimental characterization of the influence of CO on the high-temperature reduction of NO by NH3

Cited by 28 publications

References 7 publications

Effect of HCl on NO Formation during CO/NH₃ Combustion in an Entrained Flow Reactor at 1023–1223 K

Effect of HCl on NO Formation during CO/NH₃ Combustion in an Entrained Flow Reactor at 1023–1223 K

Experimental Study of the Enhancement of the Selective Noncatalytic Reduction Denitrification Process with Methane and Propane in a Circulating Fluidized Bed

Temperature, velocity and species profile measurements for reburning in a pulverized, entrained flow, coal combustor

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Experimental characterization of the influence of CO on the high-temperature reduction of NO by NH3

Cited by 28 publications

References 7 publications

Effect of HCl on NO Formation during CO/NH3 Combustion in an Entrained Flow Reactor at 1023–1223 K

Effect of HCl on NO Formation during CO/NH3 Combustion in an Entrained Flow Reactor at 1023–1223 K

Experimental Study of the Enhancement of the Selective Noncatalytic Reduction Denitrification Process with Methane and Propane in a Circulating Fluidized Bed

Temperature, velocity and species profile measurements for reburning in a pulverized, entrained flow, coal combustor

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Effect of HCl on NO Formation during CO/NH₃ Combustion in an Entrained Flow Reactor at 1023–1223 K

Effect of HCl on NO Formation during CO/NH₃ Combustion in an Entrained Flow Reactor at 1023–1223 K