Studies of ignition behaviour of biomass particles in a down-fire reactor for improving co-firing performance

Jun Li, Manosh C. Paul, Krzysztof M. Czajka

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

To realize large percentage biomass co-firing with coal in existing coal-fired boilers, the combustion behaviour of biomass is expected to be similar or comparable to that of coal. When co-firing with coal, biomass is not necessarily to be ground as fine as the dedicated coal particles due to its higher reactivity. With aim of achieving promising performance of co-firing with dedicated coal particles, the determination of suitable particle size of biomass becomes important. The paper investigates experimentally the ignition behaviour of three biomass materials in a down-fire reactor associated with thermogravimetric analyser (TGA). TGA results showed that the devolatilization process is accelerated by the presence of oxygen, but failed to identify the impacts of particle size on the ignition behaviour of biomass. However, the ignition testing results based in the down-fire reactor clearly showed that ignition delay time of a large biomass particle is longer than that of smaller one. In addition, being injected into the furnace, the softwood particles take a longer residence time to be ignited than the straw particles at same sizes, which agrees well with their reactivity analysis in TGA. Moreover, the ignition test results suggested that the ignition mechanism of biomass could be alternated from homogeneous to the heterogeneous ignition when the furnace temperature is increasing; at high enough furnace temperatures, the ignition predictably occurs at the particle surface without requiring the start of devolatilization. The results quantitatively demonstrate the effects of particle size on the ignition delay time of biomass , which, together with the transport phenomena and surrounding atmosphere, can contribute to control the biomass combustion profile and co-firing performance.
LanguageEnglish
Pages5870-5877
Number of pages8
JournalEnergy and Fuels
Volume30
Issue number7
Early online date15 Jun 2016
DOIs
Publication statusE-pub ahead of print - 15 Jun 2016

Fingerprint

Ignition
Fires
Biomass
Coal
Furnaces
Particle size
Time delay
Coal fired boilers
Softwoods
Straw
Oxygen
Temperature
Testing

Keywords

  • coal fired boilers
  • biomass
  • down fire reactors
  • ignition behaviour

Cite this

Li, Jun ; Paul, Manosh C. ; Czajka, Krzysztof M. / Studies of ignition behaviour of biomass particles in a down-fire reactor for improving co-firing performance. In: Energy and Fuels. 2016 ; Vol. 30, No. 7. pp. 5870-5877.
@article{dee87cdfc4d343689b7c62a693fb5ce8,
title = "Studies of ignition behaviour of biomass particles in a down-fire reactor for improving co-firing performance",
abstract = "To realize large percentage biomass co-firing with coal in existing coal-fired boilers, the combustion behaviour of biomass is expected to be similar or comparable to that of coal. When co-firing with coal, biomass is not necessarily to be ground as fine as the dedicated coal particles due to its higher reactivity. With aim of achieving promising performance of co-firing with dedicated coal particles, the determination of suitable particle size of biomass becomes important. The paper investigates experimentally the ignition behaviour of three biomass materials in a down-fire reactor associated with thermogravimetric analyser (TGA). TGA results showed that the devolatilization process is accelerated by the presence of oxygen, but failed to identify the impacts of particle size on the ignition behaviour of biomass. However, the ignition testing results based in the down-fire reactor clearly showed that ignition delay time of a large biomass particle is longer than that of smaller one. In addition, being injected into the furnace, the softwood particles take a longer residence time to be ignited than the straw particles at same sizes, which agrees well with their reactivity analysis in TGA. Moreover, the ignition test results suggested that the ignition mechanism of biomass could be alternated from homogeneous to the heterogeneous ignition when the furnace temperature is increasing; at high enough furnace temperatures, the ignition predictably occurs at the particle surface without requiring the start of devolatilization. The results quantitatively demonstrate the effects of particle size on the ignition delay time of biomass , which, together with the transport phenomena and surrounding atmosphere, can contribute to control the biomass combustion profile and co-firing performance.",
keywords = "coal fired boilers, biomass, down fire reactors, ignition behaviour",
author = "Jun Li and Paul, {Manosh C.} and Czajka, {Krzysztof M.}",
year = "2016",
month = "6",
day = "15",
doi = "10.1021/acs.energyfuels.6b01065",
language = "English",
volume = "30",
pages = "5870--5877",
journal = "Energy and Fuels",
issn = "0887-0624",
publisher = "American Chemical Society",
number = "7",

}

Studies of ignition behaviour of biomass particles in a down-fire reactor for improving co-firing performance. / Li, Jun; Paul, Manosh C.; Czajka, Krzysztof M.

In: Energy and Fuels, Vol. 30, No. 7, 15.06.2016, p. 5870-5877.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Studies of ignition behaviour of biomass particles in a down-fire reactor for improving co-firing performance

AU - Li, Jun

AU - Paul, Manosh C.

AU - Czajka, Krzysztof M.

PY - 2016/6/15

Y1 - 2016/6/15

N2 - To realize large percentage biomass co-firing with coal in existing coal-fired boilers, the combustion behaviour of biomass is expected to be similar or comparable to that of coal. When co-firing with coal, biomass is not necessarily to be ground as fine as the dedicated coal particles due to its higher reactivity. With aim of achieving promising performance of co-firing with dedicated coal particles, the determination of suitable particle size of biomass becomes important. The paper investigates experimentally the ignition behaviour of three biomass materials in a down-fire reactor associated with thermogravimetric analyser (TGA). TGA results showed that the devolatilization process is accelerated by the presence of oxygen, but failed to identify the impacts of particle size on the ignition behaviour of biomass. However, the ignition testing results based in the down-fire reactor clearly showed that ignition delay time of a large biomass particle is longer than that of smaller one. In addition, being injected into the furnace, the softwood particles take a longer residence time to be ignited than the straw particles at same sizes, which agrees well with their reactivity analysis in TGA. Moreover, the ignition test results suggested that the ignition mechanism of biomass could be alternated from homogeneous to the heterogeneous ignition when the furnace temperature is increasing; at high enough furnace temperatures, the ignition predictably occurs at the particle surface without requiring the start of devolatilization. The results quantitatively demonstrate the effects of particle size on the ignition delay time of biomass , which, together with the transport phenomena and surrounding atmosphere, can contribute to control the biomass combustion profile and co-firing performance.

AB - To realize large percentage biomass co-firing with coal in existing coal-fired boilers, the combustion behaviour of biomass is expected to be similar or comparable to that of coal. When co-firing with coal, biomass is not necessarily to be ground as fine as the dedicated coal particles due to its higher reactivity. With aim of achieving promising performance of co-firing with dedicated coal particles, the determination of suitable particle size of biomass becomes important. The paper investigates experimentally the ignition behaviour of three biomass materials in a down-fire reactor associated with thermogravimetric analyser (TGA). TGA results showed that the devolatilization process is accelerated by the presence of oxygen, but failed to identify the impacts of particle size on the ignition behaviour of biomass. However, the ignition testing results based in the down-fire reactor clearly showed that ignition delay time of a large biomass particle is longer than that of smaller one. In addition, being injected into the furnace, the softwood particles take a longer residence time to be ignited than the straw particles at same sizes, which agrees well with their reactivity analysis in TGA. Moreover, the ignition test results suggested that the ignition mechanism of biomass could be alternated from homogeneous to the heterogeneous ignition when the furnace temperature is increasing; at high enough furnace temperatures, the ignition predictably occurs at the particle surface without requiring the start of devolatilization. The results quantitatively demonstrate the effects of particle size on the ignition delay time of biomass , which, together with the transport phenomena and surrounding atmosphere, can contribute to control the biomass combustion profile and co-firing performance.

KW - coal fired boilers

KW - biomass

KW - down fire reactors

KW - ignition behaviour

UR - http://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b01065

U2 - 10.1021/acs.energyfuels.6b01065

DO - 10.1021/acs.energyfuels.6b01065

M3 - Article

VL - 30

SP - 5870

EP - 5877

JO - Energy and Fuels

T2 - Energy and Fuels

JF - Energy and Fuels

SN - 0887-0624

IS - 7

ER -