TY - JOUR
T1 - High temperature corrosion of boiler waterwalls induced by chlorides and bromides. Part 2
T2 - Lab-scale corrosion tests and thermodynamic equilibrium modeling of ash and gaseous species
AU - Bankiewicz, D.
AU - Vainikka, Pasi
AU - Lindberg, D.
AU - Frantsi, A.
AU - Silvennoinen, J.
AU - Yrjas, P.
AU - Hupa, M.
PY - 2012
Y1 - 2012
N2 - In Part 1 of the work a measurement campaign was carried out to
determine the occurrence of corrosive ash components in a bubbling
fluidized bed (BFB) boiler combusting solid recovered fuel (SRF). It was
found out that the main ash-forming elements that had been vaporized
and subsequently condensed from the gas phase were Na, K, S and Cl
together with minor amounts of Zn, Pb, Cu, and Br. Both, Cl and Br were
found in the corrosion front of the waterwalls prior to the measurement
campaign. In this work, the forms of ash forming elements in the
combustion gases and in the waterwall deposits of the examined boiler
were predicted by means of thermodynamic equilibrium modeling.
Laboratory tests were also carried out to estimate the degree of
corrosion of boiler steels under bromine containing deposits. A mixture
of ZnBr2 and K2SO4 was selected for
high temperature lab-scale corrosion testing since Zn, Br and K as well
as sulfates were present in the deposit and it was possible to compare
these results to previously published results with ZnCl2–K2SO4 mixtures. The comparison showed that more severe material degradation was caused by the ZnBr2 containing salt than by the corresponding chloride and corrosion was significant already at 400 °C.
AB - In Part 1 of the work a measurement campaign was carried out to
determine the occurrence of corrosive ash components in a bubbling
fluidized bed (BFB) boiler combusting solid recovered fuel (SRF). It was
found out that the main ash-forming elements that had been vaporized
and subsequently condensed from the gas phase were Na, K, S and Cl
together with minor amounts of Zn, Pb, Cu, and Br. Both, Cl and Br were
found in the corrosion front of the waterwalls prior to the measurement
campaign. In this work, the forms of ash forming elements in the
combustion gases and in the waterwall deposits of the examined boiler
were predicted by means of thermodynamic equilibrium modeling.
Laboratory tests were also carried out to estimate the degree of
corrosion of boiler steels under bromine containing deposits. A mixture
of ZnBr2 and K2SO4 was selected for
high temperature lab-scale corrosion testing since Zn, Br and K as well
as sulfates were present in the deposit and it was possible to compare
these results to previously published results with ZnCl2–K2SO4 mixtures. The comparison showed that more severe material degradation was caused by the ZnBr2 containing salt than by the corresponding chloride and corrosion was significant already at 400 °C.
KW - Bromine
KW - chlorine
KW - corrosion
KW - solid recovered fuel
KW - waterwall
U2 - 10.1016/j.fuel.2011.12.023
DO - 10.1016/j.fuel.2011.12.023
M3 - Article
VL - 94
SP - 240
EP - 250
JO - Fuel
JF - Fuel
SN - 0016-2361
ER -