Interactions of PbCl2 with alkali salts in ash deposits and effects on boiler corrosion

Jonne Niemi, Hanna Kinnunen, Daniel Lindberg, Sonja Enestam

Forskningsoutput: TidskriftsbidragArtikelVetenskapligPeer review

9 Citeringar (Scopus)

Sammanfattning

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 °C and 400 °C) were tested. The temperature in the furnace above the deposits was 700-800 °C. Exposure times of 4 and 24h 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.

OriginalspråkOdefinierat/okänt
Sidor (från-till)8519–8529
TidskriftEnergy and Fuels
Volym32
Utgåva8
DOI
StatusPublicerad - 2018
MoE-publikationstypA1 Tidskriftsartikel-refererad

Nyckelord

  • Superheater corrosion
  • high-temperature corrosion
  • Temperature gradient
  • Corrosion
  • boiler deposits

Citera det här