Fly ash formation and deposition during fluidized bed combustion of willow

Tuomas Valmari, Esko I. Kauppinen, Esa Kurkela, Jorma K. Jokiniemi, George Sfiris, Hannu Revitzer

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Fly ash formation and behaviour during combustion of willow (supplemented by 20 wt% of wood pellets) was studied experimentally in a 3–12 MW circulating fluidized bed boiler. Particle size distributions in a size range dae<8 μm were obtained by a Berner low pressure impactor in the convection path at a temperature of 650°C and downstream the convection path (160°C). For particles above 8 μm size analysis was performed from a cyclone sample collected at 160°C. Size distributions contained two distinctive modes. The major inorganic elements in the coarse mode particles (dae>1 μm) formed from the non-volatilised ash residue were Ca, K, P, Mg and S. The fine ash particles (dae<1 μm) formed from vaporised ash forming constituents were composed of alkali (mainly potassium) sulphates, chlorides and, according to chemical equilibrium calculations, carbonates. K2SO4 was condensed prior to our sampling station at 650°C. Condensed KCl and K2CO3 were observed only at the latter sampling station at 160°C. About 50% of the coarse ash particles were deposited on the heat exchanger surfaces between 650°C and 160°C, whereas the concentration of the fine mode sulphate particles was not observed to decrease from 650°C to 160°C.
Original languageEnglish
Pages (from-to)445-459
JournalJournal of Aerosol Science
Volume29
Issue number4
DOIs
Publication statusPublished - 1998
MoE publication typeA1 Journal article-refereed

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Ashes
Salix
Coal Ash
Fluidized bed combustion
Fly ash
fly ash
ash
combustion
Sampling
sulfate
Carbonates
sampling
Alkalies
Particle size analysis
Fluidized beds
range size
Sulfates
Heat exchangers
Boilers
Potassium

Keywords

  • fluidized beds

Cite this

Valmari, T., Kauppinen, E. I., Kurkela, E., Jokiniemi, J. K., Sfiris, G., & Revitzer, H. (1998). Fly ash formation and deposition during fluidized bed combustion of willow. Journal of Aerosol Science, 29(4), 445-459. https://doi.org/10.1016/S0021-8502(97)10021-0
Valmari, Tuomas ; Kauppinen, Esko I. ; Kurkela, Esa ; Jokiniemi, Jorma K. ; Sfiris, George ; Revitzer, Hannu. / Fly ash formation and deposition during fluidized bed combustion of willow. In: Journal of Aerosol Science. 1998 ; Vol. 29, No. 4. pp. 445-459.
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abstract = "Fly ash formation and behaviour during combustion of willow (supplemented by 20 wt{\%} of wood pellets) was studied experimentally in a 3–12 MW circulating fluidized bed boiler. Particle size distributions in a size range dae<8 μm were obtained by a Berner low pressure impactor in the convection path at a temperature of 650°C and downstream the convection path (160°C). For particles above 8 μm size analysis was performed from a cyclone sample collected at 160°C. Size distributions contained two distinctive modes. The major inorganic elements in the coarse mode particles (dae>1 μm) formed from the non-volatilised ash residue were Ca, K, P, Mg and S. The fine ash particles (dae<1 μm) formed from vaporised ash forming constituents were composed of alkali (mainly potassium) sulphates, chlorides and, according to chemical equilibrium calculations, carbonates. K2SO4 was condensed prior to our sampling station at 650°C. Condensed KCl and K2CO3 were observed only at the latter sampling station at 160°C. About 50{\%} of the coarse ash particles were deposited on the heat exchanger surfaces between 650°C and 160°C, whereas the concentration of the fine mode sulphate particles was not observed to decrease from 650°C to 160°C.",
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Valmari, T, Kauppinen, EI, Kurkela, E, Jokiniemi, JK, Sfiris, G & Revitzer, H 1998, 'Fly ash formation and deposition during fluidized bed combustion of willow', Journal of Aerosol Science, vol. 29, no. 4, pp. 445-459. https://doi.org/10.1016/S0021-8502(97)10021-0

Fly ash formation and deposition during fluidized bed combustion of willow. / Valmari, Tuomas; Kauppinen, Esko I.; Kurkela, Esa; Jokiniemi, Jorma K.; Sfiris, George; Revitzer, Hannu.

In: Journal of Aerosol Science, Vol. 29, No. 4, 1998, p. 445-459.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Fly ash formation and deposition during fluidized bed combustion of willow

AU - Valmari, Tuomas

AU - Kauppinen, Esko I.

AU - Kurkela, Esa

AU - Jokiniemi, Jorma K.

AU - Sfiris, George

AU - Revitzer, Hannu

PY - 1998

Y1 - 1998

N2 - Fly ash formation and behaviour during combustion of willow (supplemented by 20 wt% of wood pellets) was studied experimentally in a 3–12 MW circulating fluidized bed boiler. Particle size distributions in a size range dae<8 μm were obtained by a Berner low pressure impactor in the convection path at a temperature of 650°C and downstream the convection path (160°C). For particles above 8 μm size analysis was performed from a cyclone sample collected at 160°C. Size distributions contained two distinctive modes. The major inorganic elements in the coarse mode particles (dae>1 μm) formed from the non-volatilised ash residue were Ca, K, P, Mg and S. The fine ash particles (dae<1 μm) formed from vaporised ash forming constituents were composed of alkali (mainly potassium) sulphates, chlorides and, according to chemical equilibrium calculations, carbonates. K2SO4 was condensed prior to our sampling station at 650°C. Condensed KCl and K2CO3 were observed only at the latter sampling station at 160°C. About 50% of the coarse ash particles were deposited on the heat exchanger surfaces between 650°C and 160°C, whereas the concentration of the fine mode sulphate particles was not observed to decrease from 650°C to 160°C.

AB - Fly ash formation and behaviour during combustion of willow (supplemented by 20 wt% of wood pellets) was studied experimentally in a 3–12 MW circulating fluidized bed boiler. Particle size distributions in a size range dae<8 μm were obtained by a Berner low pressure impactor in the convection path at a temperature of 650°C and downstream the convection path (160°C). For particles above 8 μm size analysis was performed from a cyclone sample collected at 160°C. Size distributions contained two distinctive modes. The major inorganic elements in the coarse mode particles (dae>1 μm) formed from the non-volatilised ash residue were Ca, K, P, Mg and S. The fine ash particles (dae<1 μm) formed from vaporised ash forming constituents were composed of alkali (mainly potassium) sulphates, chlorides and, according to chemical equilibrium calculations, carbonates. K2SO4 was condensed prior to our sampling station at 650°C. Condensed KCl and K2CO3 were observed only at the latter sampling station at 160°C. About 50% of the coarse ash particles were deposited on the heat exchanger surfaces between 650°C and 160°C, whereas the concentration of the fine mode sulphate particles was not observed to decrease from 650°C to 160°C.

KW - fluidized beds

U2 - 10.1016/S0021-8502(97)10021-0

DO - 10.1016/S0021-8502(97)10021-0

M3 - Article

VL - 29

SP - 445

EP - 459

JO - Journal of Aerosol Science

JF - Journal of Aerosol Science

SN - 0021-8502

IS - 4

ER -