Importance of solid fuel properties to nitrogen oxide formation through HCN and NH3 in small particle combustion

Martti Aho, Jouni Hämäläinen, Jouni Tummavuori

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The formation of nitrogen oxides from fuel-nitrogen through intermediates was studied by measuring first fuel-O/fuel-N ratios and nitrogen functionality in selected solid fuels. Then the ratios of the yields (fuel-N → HCN)/(fuel-N → NH3) in a nearly inert atmosphere at 800ºC in an entrained flow reactor was measured and finally the ratio (fuel-N → N2O)/(fuel-N → NO) in an oxidizing atmosphere at 800ºC The fuels studied were coal, brown coal, S- and C-type peat, fir bark, birch bark and pine bark, all milled to a particle size <63μm. The ratios of O/N in the fuel, measured by elemental analysis, ranged from 7 to 150. Nitrogen functionality (mass percent of the total nitrogen content) was determined by XPS. the (fuel-N → NCN)/(fuel-N → NH3) conversion ratio in the absence of O2, and also the (fuel-N → N2O)/(fuel-N → NO) conversion ratio with O2 present, decreased with increasing ratio of fuel-O/fuel-N, but neither ratio decreased regularly with the increasing ratio of pyrrolic to pyridinic nitrogen in the fuel. Thus, fuel-oxygen plays a more important role than nitrogen functionality in the chemistry of nitrogen oxide formation. The strong effect of (fuel-O/fuel-N) ratio on the (fuel-N → HCN)/(fuel-N → NH3) ratio may be due to the reaction between OH radicals and HCN to form NH3 near the fuel particle. The importance of this reaction is considered. Charring the fuel sample before combustion led to a sharp drop in the conversion of fuel-N to N2O compared with the virgin fuels. Thus, heterogeneous combustion reactions produced much less N2O than homogeneous combustion reactions.

Original languageEnglish
Pages (from-to)22 - 30
Number of pages9
JournalCombustion and Flame
Volume95
Issue number1-2
DOIs
Publication statusPublished - 1993
MoE publication typeA1 Journal article-refereed

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nitrogen oxides
Nitrogen oxides
Nitric Oxide
Nitrogen
nitrogen

Keywords

  • solid fuels
  • proportion
  • nitrogen oxides
  • fortion
  • hydrocyanic acid
  • ammonia
  • coal
  • peat
  • bark
  • brown coal

Cite this

@article{00f9f757827e4c72917c00172e954dc4,
title = "Importance of solid fuel properties to nitrogen oxide formation through HCN and NH3 in small particle combustion",
abstract = "The formation of nitrogen oxides from fuel-nitrogen through intermediates was studied by measuring first fuel-O/fuel-N ratios and nitrogen functionality in selected solid fuels. Then the ratios of the yields (fuel-N → HCN)/(fuel-N → NH3) in a nearly inert atmosphere at 800ºC in an entrained flow reactor was measured and finally the ratio (fuel-N → N2O)/(fuel-N → NO) in an oxidizing atmosphere at 800ºC The fuels studied were coal, brown coal, S- and C-type peat, fir bark, birch bark and pine bark, all milled to a particle size <63μm. The ratios of O/N in the fuel, measured by elemental analysis, ranged from 7 to 150. Nitrogen functionality (mass percent of the total nitrogen content) was determined by XPS. the (fuel-N → NCN)/(fuel-N → NH3) conversion ratio in the absence of O2, and also the (fuel-N → N2O)/(fuel-N → NO) conversion ratio with O2 present, decreased with increasing ratio of fuel-O/fuel-N, but neither ratio decreased regularly with the increasing ratio of pyrrolic to pyridinic nitrogen in the fuel. Thus, fuel-oxygen plays a more important role than nitrogen functionality in the chemistry of nitrogen oxide formation. The strong effect of (fuel-O/fuel-N) ratio on the (fuel-N → HCN)/(fuel-N → NH3) ratio may be due to the reaction between OH radicals and HCN to form NH3 near the fuel particle. The importance of this reaction is considered. Charring the fuel sample before combustion led to a sharp drop in the conversion of fuel-N to N2O compared with the virgin fuels. Thus, heterogeneous combustion reactions produced much less N2O than homogeneous combustion reactions.",
keywords = "solid fuels, proportion, nitrogen oxides, fortion, hydrocyanic acid, ammonia, coal, peat, bark, brown coal",
author = "Martti Aho and Jouni H{\"a}m{\"a}l{\"a}inen and Jouni Tummavuori",
year = "1993",
doi = "10.1016/0010-2180(93)90049-9",
language = "English",
volume = "95",
pages = "22 -- 30",
journal = "Combustion and Flame",
issn = "0010-2180",
publisher = "Elsevier",
number = "1-2",

}

Importance of solid fuel properties to nitrogen oxide formation through HCN and NH3 in small particle combustion. / Aho, Martti; Hämäläinen, Jouni; Tummavuori, Jouni.

In: Combustion and Flame, Vol. 95, No. 1-2, 1993, p. 22 - 30.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Importance of solid fuel properties to nitrogen oxide formation through HCN and NH3 in small particle combustion

AU - Aho, Martti

AU - Hämäläinen, Jouni

AU - Tummavuori, Jouni

PY - 1993

Y1 - 1993

N2 - The formation of nitrogen oxides from fuel-nitrogen through intermediates was studied by measuring first fuel-O/fuel-N ratios and nitrogen functionality in selected solid fuels. Then the ratios of the yields (fuel-N → HCN)/(fuel-N → NH3) in a nearly inert atmosphere at 800ºC in an entrained flow reactor was measured and finally the ratio (fuel-N → N2O)/(fuel-N → NO) in an oxidizing atmosphere at 800ºC The fuels studied were coal, brown coal, S- and C-type peat, fir bark, birch bark and pine bark, all milled to a particle size <63μm. The ratios of O/N in the fuel, measured by elemental analysis, ranged from 7 to 150. Nitrogen functionality (mass percent of the total nitrogen content) was determined by XPS. the (fuel-N → NCN)/(fuel-N → NH3) conversion ratio in the absence of O2, and also the (fuel-N → N2O)/(fuel-N → NO) conversion ratio with O2 present, decreased with increasing ratio of fuel-O/fuel-N, but neither ratio decreased regularly with the increasing ratio of pyrrolic to pyridinic nitrogen in the fuel. Thus, fuel-oxygen plays a more important role than nitrogen functionality in the chemistry of nitrogen oxide formation. The strong effect of (fuel-O/fuel-N) ratio on the (fuel-N → HCN)/(fuel-N → NH3) ratio may be due to the reaction between OH radicals and HCN to form NH3 near the fuel particle. The importance of this reaction is considered. Charring the fuel sample before combustion led to a sharp drop in the conversion of fuel-N to N2O compared with the virgin fuels. Thus, heterogeneous combustion reactions produced much less N2O than homogeneous combustion reactions.

AB - The formation of nitrogen oxides from fuel-nitrogen through intermediates was studied by measuring first fuel-O/fuel-N ratios and nitrogen functionality in selected solid fuels. Then the ratios of the yields (fuel-N → HCN)/(fuel-N → NH3) in a nearly inert atmosphere at 800ºC in an entrained flow reactor was measured and finally the ratio (fuel-N → N2O)/(fuel-N → NO) in an oxidizing atmosphere at 800ºC The fuels studied were coal, brown coal, S- and C-type peat, fir bark, birch bark and pine bark, all milled to a particle size <63μm. The ratios of O/N in the fuel, measured by elemental analysis, ranged from 7 to 150. Nitrogen functionality (mass percent of the total nitrogen content) was determined by XPS. the (fuel-N → NCN)/(fuel-N → NH3) conversion ratio in the absence of O2, and also the (fuel-N → N2O)/(fuel-N → NO) conversion ratio with O2 present, decreased with increasing ratio of fuel-O/fuel-N, but neither ratio decreased regularly with the increasing ratio of pyrrolic to pyridinic nitrogen in the fuel. Thus, fuel-oxygen plays a more important role than nitrogen functionality in the chemistry of nitrogen oxide formation. The strong effect of (fuel-O/fuel-N) ratio on the (fuel-N → HCN)/(fuel-N → NH3) ratio may be due to the reaction between OH radicals and HCN to form NH3 near the fuel particle. The importance of this reaction is considered. Charring the fuel sample before combustion led to a sharp drop in the conversion of fuel-N to N2O compared with the virgin fuels. Thus, heterogeneous combustion reactions produced much less N2O than homogeneous combustion reactions.

KW - solid fuels

KW - proportion

KW - nitrogen oxides

KW - fortion

KW - hydrocyanic acid

KW - ammonia

KW - coal

KW - peat

KW - bark

KW - brown coal

U2 - 10.1016/0010-2180(93)90049-9

DO - 10.1016/0010-2180(93)90049-9

M3 - Article

VL - 95

SP - 22

EP - 30

JO - Combustion and Flame

JF - Combustion and Flame

SN - 0010-2180

IS - 1-2

ER -