TY - JOUR
T1 - The influence of flue gas temperature on lead chloride induced high temperature corrosion
AU - Kinnunen, Hanna
AU - Engblom, Markus
AU - Lindberg, Daniel
AU - Uusitalo, Mikko
AU - Enestam, Sonja
AU - Yrjas, Patrik
N1 - ook
PY - 2017
Y1 - 2017
N2 - Firing of waste-based fuels increases the risk for heavy metal-induced corrosion in the furnace walls and in other low-temp. heat transfer surfaces, such as primary superheaters. Lead-contg. compds., esp. alkali lead chlorides, were detected in the boiler water walls, causing severe corrosion. Corrosion rate of chlorine-induced corrosion is known to be dependent on the material temp. and the objective of this work was to study the influence of the flue gas temp. on lead chloride-induced corrosion. The expts. were carried out with full-scale corrosion probe and deposit probe measurements in a recycled wood firing CFB boiler. The material used in the corrosion probe measurements was low alloy steel EN10216-2 16Mo3 and the material temp. was adjusted to 360°. Two corrosion and deposit probes were used in different locations to expose the probes towards hot, 800°, and cooler, 490°, flue gas temps. Changes of the wall thicknesses were measured and the samples were analyzed with SEM/EDS and x-ray diffraction for more detailed deposit characterization. Corrosion was detected in both the hot and the cooler flue gas samples. A low melting (T0 = 368°) alkali-lead-chloride mixt. was identified. Findings from these measurements strongly indicate this mixt. to be the corrosion-causing compd. at both flue gas temps. However, the corrosion rate was higher in the hot flue gas sample compared to the cooler flue gas sample. A much steeper deposit temp. gradient was calcd. for the hot flue gas sample, suggesting that the alkali-lead-chloride mixt. is in the molten form. These findings, together with the higher proportion of the present alkali-lead-chloride mixt., are the potential factors for the higher corrosion rate in the hot flue gas sample compared to the cooler flue gas sample.
AB - Firing of waste-based fuels increases the risk for heavy metal-induced corrosion in the furnace walls and in other low-temp. heat transfer surfaces, such as primary superheaters. Lead-contg. compds., esp. alkali lead chlorides, were detected in the boiler water walls, causing severe corrosion. Corrosion rate of chlorine-induced corrosion is known to be dependent on the material temp. and the objective of this work was to study the influence of the flue gas temp. on lead chloride-induced corrosion. The expts. were carried out with full-scale corrosion probe and deposit probe measurements in a recycled wood firing CFB boiler. The material used in the corrosion probe measurements was low alloy steel EN10216-2 16Mo3 and the material temp. was adjusted to 360°. Two corrosion and deposit probes were used in different locations to expose the probes towards hot, 800°, and cooler, 490°, flue gas temps. Changes of the wall thicknesses were measured and the samples were analyzed with SEM/EDS and x-ray diffraction for more detailed deposit characterization. Corrosion was detected in both the hot and the cooler flue gas samples. A low melting (T0 = 368°) alkali-lead-chloride mixt. was identified. Findings from these measurements strongly indicate this mixt. to be the corrosion-causing compd. at both flue gas temps. However, the corrosion rate was higher in the hot flue gas sample compared to the cooler flue gas sample. A much steeper deposit temp. gradient was calcd. for the hot flue gas sample, suggesting that the alkali-lead-chloride mixt. is in the molten form. These findings, together with the higher proportion of the present alkali-lead-chloride mixt., are the potential factors for the higher corrosion rate in the hot flue gas sample compared to the cooler flue gas sample.
KW - Water wall
KW - High temperature corrosion
KW - Superheater
KW - Lead potassium chloride
KW - Waste wood combustion
KW - Low alloy steel
KW - Water wall
KW - High temperature corrosion
KW - Superheater
KW - Lead potassium chloride
KW - Waste wood combustion
KW - Low alloy steel
KW - Water wall
KW - High temperature corrosion
KW - Superheater
KW - Lead potassium chloride
KW - Waste wood combustion
KW - Low alloy steel
U2 - 10.1016/j.fuel.2017.01.082
DO - 10.1016/j.fuel.2017.01.082
M3 - Artikel
SN - 0016-2361
VL - 196
SP - 241
EP - 251
JO - Fuel
JF - Fuel
ER -