Performance testing of iron based thermally sprayed HVOF coatings in a biomass-fired fluidised bed boiler

Maria Oksa (Corresponding Author), Tommi Varis, Kimmo Ruusuvuori

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)

Abstract

Managing high temperature corrosion problems in biomass firing boilers has been challenging especially due to high amounts of chemically active compounds, in particular alkali chlorides. Thermally sprayed coatings with high chromium content can offer a solution for protecting low alloyed substrate materials in locations prone to high temperature corrosion. Two thermally sprayed (HVOF - high velocity oxy-fuel) iron based coatings (Fe-27Cr-11Ni-4Mo and Fe-19Cr-9W-7Nb-4Mo) were exposed to biomass boiler conditions for two years. The fluidised bed boiler for district heating used mainly wood-based fuels mixed with small amounts of peat. The coated tubes were located at the hot economiser of the boiler, where the estimated material temperature was about 200 °C maximum. After the exposure the coatings and the carbon steel St35.8 substrate material were analysed with SEM-EDX. It was detected that corrosion due to elements such as chlorine, potassium, zinc, lead and copper had caused severe material wastage in the biomass boiler with relatively low heat exchanger surface temperatures. The low alloyed boiler tubes had suffered severely with a corrosion rate as high as 2 mm/year, whereas dense thermal spray coatings offered excellent protection during the exposure.
Original languageEnglish
Pages (from-to)191-200
Number of pages10
JournalSurface and Coatings Technology
Volume251
DOIs
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed

Fingerprint

boilers
biomass
Boilers
beds
Biomass
Iron
coatings
iron
Coatings
corrosion
Testing
Corrosion
Boiler firing
Temperature
District heating
Sprayed coatings
Peat
tubes
peat
Chlorine

Keywords

  • Biomass
  • chlorine corrion
  • corrosion protection
  • high temperature corrosion
  • HVOF
  • thermal spray coating

Cite this

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title = "Performance testing of iron based thermally sprayed HVOF coatings in a biomass-fired fluidised bed boiler",
abstract = "Managing high temperature corrosion problems in biomass firing boilers has been challenging especially due to high amounts of chemically active compounds, in particular alkali chlorides. Thermally sprayed coatings with high chromium content can offer a solution for protecting low alloyed substrate materials in locations prone to high temperature corrosion. Two thermally sprayed (HVOF - high velocity oxy-fuel) iron based coatings (Fe-27Cr-11Ni-4Mo and Fe-19Cr-9W-7Nb-4Mo) were exposed to biomass boiler conditions for two years. The fluidised bed boiler for district heating used mainly wood-based fuels mixed with small amounts of peat. The coated tubes were located at the hot economiser of the boiler, where the estimated material temperature was about 200 °C maximum. After the exposure the coatings and the carbon steel St35.8 substrate material were analysed with SEM-EDX. It was detected that corrosion due to elements such as chlorine, potassium, zinc, lead and copper had caused severe material wastage in the biomass boiler with relatively low heat exchanger surface temperatures. The low alloyed boiler tubes had suffered severely with a corrosion rate as high as 2 mm/year, whereas dense thermal spray coatings offered excellent protection during the exposure.",
keywords = "Biomass, chlorine corrion, corrosion protection, high temperature corrosion, HVOF, thermal spray coating",
author = "Maria Oksa and Tommi Varis and Kimmo Ruusuvuori",
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language = "English",
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journal = "Surface and Coatings Technology",
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Performance testing of iron based thermally sprayed HVOF coatings in a biomass-fired fluidised bed boiler. / Oksa, Maria (Corresponding Author); Varis, Tommi; Ruusuvuori, Kimmo.

In: Surface and Coatings Technology, Vol. 251, 2014, p. 191-200.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Performance testing of iron based thermally sprayed HVOF coatings in a biomass-fired fluidised bed boiler

AU - Oksa, Maria

AU - Varis, Tommi

AU - Ruusuvuori, Kimmo

PY - 2014

Y1 - 2014

N2 - Managing high temperature corrosion problems in biomass firing boilers has been challenging especially due to high amounts of chemically active compounds, in particular alkali chlorides. Thermally sprayed coatings with high chromium content can offer a solution for protecting low alloyed substrate materials in locations prone to high temperature corrosion. Two thermally sprayed (HVOF - high velocity oxy-fuel) iron based coatings (Fe-27Cr-11Ni-4Mo and Fe-19Cr-9W-7Nb-4Mo) were exposed to biomass boiler conditions for two years. The fluidised bed boiler for district heating used mainly wood-based fuels mixed with small amounts of peat. The coated tubes were located at the hot economiser of the boiler, where the estimated material temperature was about 200 °C maximum. After the exposure the coatings and the carbon steel St35.8 substrate material were analysed with SEM-EDX. It was detected that corrosion due to elements such as chlorine, potassium, zinc, lead and copper had caused severe material wastage in the biomass boiler with relatively low heat exchanger surface temperatures. The low alloyed boiler tubes had suffered severely with a corrosion rate as high as 2 mm/year, whereas dense thermal spray coatings offered excellent protection during the exposure.

AB - Managing high temperature corrosion problems in biomass firing boilers has been challenging especially due to high amounts of chemically active compounds, in particular alkali chlorides. Thermally sprayed coatings with high chromium content can offer a solution for protecting low alloyed substrate materials in locations prone to high temperature corrosion. Two thermally sprayed (HVOF - high velocity oxy-fuel) iron based coatings (Fe-27Cr-11Ni-4Mo and Fe-19Cr-9W-7Nb-4Mo) were exposed to biomass boiler conditions for two years. The fluidised bed boiler for district heating used mainly wood-based fuels mixed with small amounts of peat. The coated tubes were located at the hot economiser of the boiler, where the estimated material temperature was about 200 °C maximum. After the exposure the coatings and the carbon steel St35.8 substrate material were analysed with SEM-EDX. It was detected that corrosion due to elements such as chlorine, potassium, zinc, lead and copper had caused severe material wastage in the biomass boiler with relatively low heat exchanger surface temperatures. The low alloyed boiler tubes had suffered severely with a corrosion rate as high as 2 mm/year, whereas dense thermal spray coatings offered excellent protection during the exposure.

KW - Biomass

KW - chlorine corrion

KW - corrosion protection

KW - high temperature corrosion

KW - HVOF

KW - thermal spray coating

U2 - 10.1016/j.surfcoat.2014.04.025

DO - 10.1016/j.surfcoat.2014.04.025

M3 - Article

VL - 251

SP - 191

EP - 200

JO - Surface and Coatings Technology

JF - Surface and Coatings Technology

SN - 0257-8972

ER -