A field study on ash behaviour during circulating fluidized-bed combustion of biomass

2. Ash deposition and alkali vapour condensation

Tuomas Valmari, Terttaliisa Lind, George Sfiris, Kristina Nilsson, Willy Maenhaut, E.I. Kauppinen (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

55 Citations (Scopus)

Abstract

Fly ash deposition on heat-exchanger surfaces during fluidized-bed combustion of biomass causes operational problems such as reduced heat transfer and corrosion of superheater tubes. Ash deposition and alkali vapor condensation were studied during circulating fluidized-bed combustion of forest residue in a 35 MW co-generation plant. A 70 ± 10% amount of fly ash was deposited on the heat-exchanger surfaces in the convective back pass between soot-blowing periods. Practically all the largest ash particles (d > 10 μm) but only a small fraction of particles d < 3 μm were deposited. The deposition efficiency of particles with a given size was not correlated with their elemental composition. About 50% of alkali chloride vapors (KCl and NaCl) were condensed in the convective back pass on fine-mode particles (d < 0.6 μm) and the other 50% on the coarse-mode particles. Alkali chlorides were not effectively deposited since they were depleted in the largest (d > 10 μm) ash particles.
Original languageEnglish
Pages (from-to)390-395
Number of pages6
JournalEnergy & Fuels
Volume13
Issue number2
DOIs
Publication statusPublished - 1999
MoE publication typeA1 Journal article-refereed

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Ashes
Fluidized bed combustion
Alkalies
Fly ash
Coal Ash
Heat exchangers
Condensation
Biomass
Superheater tubes
Vapors
Cogeneration plants
Soot
Blow molding
Coal ash
Corrosion
Heat transfer

Keywords

  • fluidized beds

Cite this

Valmari, Tuomas ; Lind, Terttaliisa ; Sfiris, George ; Nilsson, Kristina ; Maenhaut, Willy ; Kauppinen, E.I. / A field study on ash behaviour during circulating fluidized-bed combustion of biomass : 2. Ash deposition and alkali vapour condensation. In: Energy & Fuels. 1999 ; Vol. 13, No. 2. pp. 390-395.
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title = "A field study on ash behaviour during circulating fluidized-bed combustion of biomass: 2. Ash deposition and alkali vapour condensation",
abstract = "Fly ash deposition on heat-exchanger surfaces during fluidized-bed combustion of biomass causes operational problems such as reduced heat transfer and corrosion of superheater tubes. Ash deposition and alkali vapor condensation were studied during circulating fluidized-bed combustion of forest residue in a 35 MW co-generation plant. A 70 ± 10{\%} amount of fly ash was deposited on the heat-exchanger surfaces in the convective back pass between soot-blowing periods. Practically all the largest ash particles (d > 10 μm) but only a small fraction of particles d < 3 μm were deposited. The deposition efficiency of particles with a given size was not correlated with their elemental composition. About 50{\%} of alkali chloride vapors (KCl and NaCl) were condensed in the convective back pass on fine-mode particles (d < 0.6 μm) and the other 50{\%} on the coarse-mode particles. Alkali chlorides were not effectively deposited since they were depleted in the largest (d > 10 μm) ash particles.",
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A field study on ash behaviour during circulating fluidized-bed combustion of biomass : 2. Ash deposition and alkali vapour condensation. / Valmari, Tuomas; Lind, Terttaliisa; Sfiris, George; Nilsson, Kristina; Maenhaut, Willy; Kauppinen, E.I. (Corresponding Author).

In: Energy & Fuels, Vol. 13, No. 2, 1999, p. 390-395.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - A field study on ash behaviour during circulating fluidized-bed combustion of biomass

T2 - 2. Ash deposition and alkali vapour condensation

AU - Valmari, Tuomas

AU - Lind, Terttaliisa

AU - Sfiris, George

AU - Nilsson, Kristina

AU - Maenhaut, Willy

AU - Kauppinen, E.I.

N1 - Project code: K6SU00001

PY - 1999

Y1 - 1999

N2 - Fly ash deposition on heat-exchanger surfaces during fluidized-bed combustion of biomass causes operational problems such as reduced heat transfer and corrosion of superheater tubes. Ash deposition and alkali vapor condensation were studied during circulating fluidized-bed combustion of forest residue in a 35 MW co-generation plant. A 70 ± 10% amount of fly ash was deposited on the heat-exchanger surfaces in the convective back pass between soot-blowing periods. Practically all the largest ash particles (d > 10 μm) but only a small fraction of particles d < 3 μm were deposited. The deposition efficiency of particles with a given size was not correlated with their elemental composition. About 50% of alkali chloride vapors (KCl and NaCl) were condensed in the convective back pass on fine-mode particles (d < 0.6 μm) and the other 50% on the coarse-mode particles. Alkali chlorides were not effectively deposited since they were depleted in the largest (d > 10 μm) ash particles.

AB - Fly ash deposition on heat-exchanger surfaces during fluidized-bed combustion of biomass causes operational problems such as reduced heat transfer and corrosion of superheater tubes. Ash deposition and alkali vapor condensation were studied during circulating fluidized-bed combustion of forest residue in a 35 MW co-generation plant. A 70 ± 10% amount of fly ash was deposited on the heat-exchanger surfaces in the convective back pass between soot-blowing periods. Practically all the largest ash particles (d > 10 μm) but only a small fraction of particles d < 3 μm were deposited. The deposition efficiency of particles with a given size was not correlated with their elemental composition. About 50% of alkali chloride vapors (KCl and NaCl) were condensed in the convective back pass on fine-mode particles (d < 0.6 μm) and the other 50% on the coarse-mode particles. Alkali chlorides were not effectively deposited since they were depleted in the largest (d > 10 μm) ash particles.

KW - fluidized beds

U2 - 10.1021/ef9800866

DO - 10.1021/ef9800866

M3 - Article

VL - 13

SP - 390

EP - 395

JO - Energy & Fuels

JF - Energy & Fuels

SN - 0887-0624

IS - 2

ER -