The influence of flue gas temperature on lead chloride induced high temperature corrosion

Kinnunen, Hanna; Hedman, Merja; Engblom, Markus; Lindberg, Daniel; Uusitalo, Mikko A.; Enestam, Sonja; Yrjas, Patrik

doi:10.1016/j.fuel.2017.01.082

Cited by 28 publications

(24 citation statements)

References 24 publications

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“…The layers of K 2 PbCl 4 on the furnace-facing side of the original salt particles included also some Na, in the cation ratio of 1:8:4 Na–K–Pb. The ratio corresponds well to the SEM/EDXA point analysis results by Kinnunen et al 17 from a deposit collected from a recycled wood firing CFB boiler. Within the original particles it seemed that the KCl of the particle had reacted with the PbCl 2 and the original (K,Na)Cl–(Na,K)Cl matrix was substituted with a K 2 PbCl 4 –(Na,K)Cl matrix ( Figure 6 ).…”

Section: Resultssupporting

confidence: 87%

“… 1 − 3 , 5 , 10 − 17 According to the latest results, Pb forms lead–potassium chlorides in the deposits and these compounds are suggested to cause the corrosion on furnace walls. 1 , 15 − 17 There are two known solid Pb–K–Cl compounds: K 2 PbCl 4 and KPb 2 Cl 5 . The first one was observed in laboratory testing and the latter one has been found from boiler heat transfer surfaces.…”

Section: Introductionmentioning

confidence: 99%

“… 19 , 20 Temperature gradients may play a vital role in PbCl 2 induced corrosion by the means of local melt formation and proximity of a molten phase to the tube surface. 17 …”

Section: Introductionmentioning

confidence: 99%

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Interactions of PbCl₂ with Alkali Salts in Ash Deposits and Effects on Boiler Corrosion

et al. 2018

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A novel temperature gradient laboratory-scale corrosion test method was used to study PbCl2 migration, interactions with SiO2, NaCl, Na2SO4, KCl, K2SO4, or NaCl–KCl (50:50 wt %) and corrosion of carbon steel in waste-fired boilers. Two different steel temperatures (200 and 400 °C) were tested. The temperature in the furnace above the deposits was 700–800 °C. Exposure times of 4 and 24 h were used. The deposit cross sections were analyzed using SEM/EDXA. The results show that PbCl2 vaporized and condensed in the adjacent deposits. PbCl2 did not interact with SiO2 but caused severe corrosion. Deposits containing Na2SO4, K2SO4, and/or KCl reacted with the PbCl2, forming various new compounds (Na3Pb2(SO4)3Cl, K3Pb2(SO4)3Cl, and/or K2PbCl4). In addition, melt formation was observed with all alkali salt deposits. Visibly more Pb was found in deposits where reactions between PbCl2 and alkali salts were possible, i.e., Pb was observed to be bound to the reaction products. No measurable corrosion was observed with steel temperature at 200 °C, while steel temperature of 400 °C resulted in catastrophic corrosion. PbCl2 in contact with the steel surface lead to faster corrosion than K2PbCl4.

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Section: Resultssupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

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Interactions of PbCl₂ with Alkali Salts in Ash Deposits and Effects on Boiler Corrosion

et al. 2018

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“…Pband Zn-containing compounds present in the ash lower the melting points of the sulfates, polysulfates, chlorides, and mixtures thereof that are present in the deposits, and can, therefore, increase the corrosion rates ( Ref 30). Pb forms lead-potassium chlorides in the deposits, which are thought to corrode the furnace walls (Ref [31][32][33]. There are two known solid Pb-K-Cl compounds, K 2 PbCl 4 and KPb 2 Cl 5 .…”

Section: Electrochemical Mechanismmentioning

confidence: 99%

Advances in Corrosion-Resistant Thermal Spray Coatings for Renewable Energy Power Plants: Part II—Effect of Environment and Outlook

2019

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High-temperature corrosion of critical components such as water walls and superheater tubes in biomass/ waste-fired boilers is a major challenge. A dense and defect-free thermal spray coating has been shown to be promising to achieve a high electrical/thermal efficiency in power plants. The field of thermal spraying and quality of coatings have been progressively evolving; therefore, a critical assessment of our understanding of the efficacy of coatings in increasingly aggressive operating environments of the power plants can be highly educative. The effects of composition and microstructure on high-temperature corrosion behavior of the coatings were discussed in the first part of the review. The present paper that is the second part of the review covers the emerging research field of performance assessment of thermal spray coatings in harsh corrosion-prone environments and provides a comprehensive overview of the underlying high-temperature corrosion mechanisms that lead to the damage of exposed coatings. The application of contemporary analytical methods for better understanding of the behavior of corrosion-resistant coatings is also discussed. A discussion based on an exhaustive review of the literature provides an unbiased commentary on the advanced accomplishments and some outstanding issues in the field that warrant further research. An assessment of the current status of the field, the gaps in the scientific understanding, and the research needs for the expansion of thermal spray coatings for high-temperature corrosion applications is also provided.

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“…Several field studies have shown the presence of lead‐containing deposits in the areas where the corrosion is severe. The mechanism is believed to be related to the lowered melting point of the deposit when lead is involved . The first melting point of the mixture between potassium chloride and lead chloride is around 411°C .…”

Section: Introductionmentioning

confidence: 99%

Corrosion of carbon steel underneath a lead/potassium chloride salt mixture

Talus

Kinnunen

Norling

et al. 2019

Materials & Corrosion

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High amounts of lead in waste/recycled wood fuel are known to be a contributing factor to the increased corrosion often related to this type of fuel. In combination with potassium, usually present in the fuel, low‐melting point salt mixtures between lead chloride (PbCl 2) and potassium chloride (KCl) are expected to form. The purpose of this study is to investigate reactions in the mixed salt of PbCl 2 and KCl and its interactions with carbon steel P265GH and its oxide. Laboratory exposures were performed in an isothermal tube furnace with a salt mixture of PbCl 2/KCl (50/50 mol%) put on steel samples. The test duration was 24 hr at either 300°C or 340°C in an atmosphere of 100 ppm HCl and 20 vol% H 2O in synthetic air. After exposure, the salt mixture consists of distinct areas of KCl and PbCl 2 but also the compounds K 2PbCl 4 and KPb 2Cl 5. A general observation is that the oxide thickness increases with temperature and that areas with Pb/K‐mixed salt are frequently found in close connection to more corroded areas. Often the more lead‐rich phase KPb 2Cl 5 is located closest to the corrosion product indicating its importance for the corrosion.

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The influence of flue gas temperature on lead chloride induced high temperature corrosion

Cited by 28 publications

References 24 publications

Interactions of PbCl₂ with Alkali Salts in Ash Deposits and Effects on Boiler Corrosion

Interactions of PbCl₂ with Alkali Salts in Ash Deposits and Effects on Boiler Corrosion

Advances in Corrosion-Resistant Thermal Spray Coatings for Renewable Energy Power Plants: Part II—Effect of Environment and Outlook

Corrosion of carbon steel underneath a lead/potassium chloride salt mixture

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The influence of flue gas temperature on lead chloride induced high temperature corrosion

Cited by 28 publications

References 24 publications

Interactions of PbCl2 with Alkali Salts in Ash Deposits and Effects on Boiler Corrosion

Interactions of PbCl2 with Alkali Salts in Ash Deposits and Effects on Boiler Corrosion

Advances in Corrosion-Resistant Thermal Spray Coatings for Renewable Energy Power Plants: Part II—Effect of Environment and Outlook

Corrosion of carbon steel underneath a lead/potassium chloride salt mixture

Contact Info

Product

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About

Interactions of PbCl₂ with Alkali Salts in Ash Deposits and Effects on Boiler Corrosion

Interactions of PbCl₂ with Alkali Salts in Ash Deposits and Effects on Boiler Corrosion