Modeling N2O Reduction and Decomposition in a Circulating Fluidized bed Boiler

Jan Erik Johnsson, Lars-Erik Åmand, Kim Dam-Johansen, Bo Leckner

Research output: Contribution to journalJournal articleResearch

Abstract

The N2O concentration was measured in a circulating fluidized bed boiler of commercial size. Kinetics for N2O reduction by char and catalytic reduction and decomposition over bed material from the combustor were determined in a laboratory fixed bed reactor. The destruction rate of N2O in the combustion chamber and the cyclone was calculated taking three mechanisms into account: Reduction by char, catalytic decomposition over bed material and thermal decomposition. The calculated destruction rate was in good agreement with the measured destruction of N2O injected at different levels in the boiler. The conclusion is that in the bottom part of the combustor, where the solids concentration is about 1000 kg/m3 and the char content 2 wt%, heterogeneous reactions were the most important N2O destruction mechanisms. Reduction by char accounted for 80% of the N2O destruction, 20 % was due to catalytic decomposition over bed material, and homogeneous thermal decomposition was negligible. However, at higher levels in the combustor the solids concentration is lower: at the top 60% of the N2O destruction was due to thermal decomposition and in the cyclone heterogeneous destruction of N2O was insignificant. It was estimated that more than half of the formation of N2O in the combustion chamber takes place above the secondary air inlet.
Original languageEnglish
JournalEnergy&Fuels
Volume10
Issue number4
Pages (from-to)970-979
Publication statusPublished - 1996

Cite this

Johnsson, J. E., Åmand, L-E., Dam-Johansen, K., & Leckner, B. (1996). Modeling N2O Reduction and Decomposition in a Circulating Fluidized bed Boiler. Energy&Fuels, 10(4), 970-979.
Johnsson, Jan Erik ; Åmand, Lars-Erik ; Dam-Johansen, Kim ; Leckner, Bo. / Modeling N2O Reduction and Decomposition in a Circulating Fluidized bed Boiler. In: Energy&Fuels. 1996 ; Vol. 10, No. 4. pp. 970-979.
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title = "Modeling N2O Reduction and Decomposition in a Circulating Fluidized bed Boiler",
abstract = "The N2O concentration was measured in a circulating fluidized bed boiler of commercial size. Kinetics for N2O reduction by char and catalytic reduction and decomposition over bed material from the combustor were determined in a laboratory fixed bed reactor. The destruction rate of N2O in the combustion chamber and the cyclone was calculated taking three mechanisms into account: Reduction by char, catalytic decomposition over bed material and thermal decomposition. The calculated destruction rate was in good agreement with the measured destruction of N2O injected at different levels in the boiler. The conclusion is that in the bottom part of the combustor, where the solids concentration is about 1000 kg/m3 and the char content 2 wt{\%}, heterogeneous reactions were the most important N2O destruction mechanisms. Reduction by char accounted for 80{\%} of the N2O destruction, 20 {\%} was due to catalytic decomposition over bed material, and homogeneous thermal decomposition was negligible. However, at higher levels in the combustor the solids concentration is lower: at the top 60{\%} of the N2O destruction was due to thermal decomposition and in the cyclone heterogeneous destruction of N2O was insignificant. It was estimated that more than half of the formation of N2O in the combustion chamber takes place above the secondary air inlet.",
author = "Johnsson, {Jan Erik} and Lars-Erik {\AA}mand and Kim Dam-Johansen and Bo Leckner",
year = "1996",
language = "English",
volume = "10",
pages = "970--979",
journal = "Energy & Fuels",
issn = "0887-0624",
publisher = "American Chemical Society",
number = "4",

}

Johnsson, JE, Åmand, L-E, Dam-Johansen, K & Leckner, B 1996, 'Modeling N2O Reduction and Decomposition in a Circulating Fluidized bed Boiler', Energy&Fuels, vol. 10, no. 4, pp. 970-979.

Modeling N2O Reduction and Decomposition in a Circulating Fluidized bed Boiler. / Johnsson, Jan Erik; Åmand, Lars-Erik; Dam-Johansen, Kim; Leckner, Bo.

In: Energy&Fuels, Vol. 10, No. 4, 1996, p. 970-979.

Research output: Contribution to journalJournal articleResearch

TY - JOUR

T1 - Modeling N2O Reduction and Decomposition in a Circulating Fluidized bed Boiler

AU - Johnsson, Jan Erik

AU - Åmand, Lars-Erik

AU - Dam-Johansen, Kim

AU - Leckner, Bo

PY - 1996

Y1 - 1996

N2 - The N2O concentration was measured in a circulating fluidized bed boiler of commercial size. Kinetics for N2O reduction by char and catalytic reduction and decomposition over bed material from the combustor were determined in a laboratory fixed bed reactor. The destruction rate of N2O in the combustion chamber and the cyclone was calculated taking three mechanisms into account: Reduction by char, catalytic decomposition over bed material and thermal decomposition. The calculated destruction rate was in good agreement with the measured destruction of N2O injected at different levels in the boiler. The conclusion is that in the bottom part of the combustor, where the solids concentration is about 1000 kg/m3 and the char content 2 wt%, heterogeneous reactions were the most important N2O destruction mechanisms. Reduction by char accounted for 80% of the N2O destruction, 20 % was due to catalytic decomposition over bed material, and homogeneous thermal decomposition was negligible. However, at higher levels in the combustor the solids concentration is lower: at the top 60% of the N2O destruction was due to thermal decomposition and in the cyclone heterogeneous destruction of N2O was insignificant. It was estimated that more than half of the formation of N2O in the combustion chamber takes place above the secondary air inlet.

AB - The N2O concentration was measured in a circulating fluidized bed boiler of commercial size. Kinetics for N2O reduction by char and catalytic reduction and decomposition over bed material from the combustor were determined in a laboratory fixed bed reactor. The destruction rate of N2O in the combustion chamber and the cyclone was calculated taking three mechanisms into account: Reduction by char, catalytic decomposition over bed material and thermal decomposition. The calculated destruction rate was in good agreement with the measured destruction of N2O injected at different levels in the boiler. The conclusion is that in the bottom part of the combustor, where the solids concentration is about 1000 kg/m3 and the char content 2 wt%, heterogeneous reactions were the most important N2O destruction mechanisms. Reduction by char accounted for 80% of the N2O destruction, 20 % was due to catalytic decomposition over bed material, and homogeneous thermal decomposition was negligible. However, at higher levels in the combustor the solids concentration is lower: at the top 60% of the N2O destruction was due to thermal decomposition and in the cyclone heterogeneous destruction of N2O was insignificant. It was estimated that more than half of the formation of N2O in the combustion chamber takes place above the secondary air inlet.

M3 - Journal article

VL - 10

SP - 970

EP - 979

JO - Energy & Fuels

JF - Energy & Fuels

SN - 0887-0624

IS - 4

ER -