Oxy-fuel combustion(OFC) is one of the most promising technologies for CO_2 capture in coal combustion process

and is attracting more and more attentions. However

under OFC operating conditions

the concentrations of CO_2

H2O

SO_2 and SO3 significantly increase

which might aggravate the corrosion threat. In this study

high temperature corrosion tests for water wall materials(20 G

12 Cr1 Mo V) were conducted in tube furnace with simulated OFC flue gas. The microstructure and composition of the oxide layer were analyzed by SEM-EDS and XRD. The experimental results show that

the high concentration of CO_2 accelerates the high temperature corrosion of water wall materials. In OFC atmosphere(CO_2/O_2/SO_2)

the mass gain rate can be aggravated by 10%~30% compared with that in air combustion atmosphere(N2/O_2/SO_2)

and the component of oxide layer is mainly magnetite. In the OFC reducing atmosphere(CO_2/CO/SO_2/H2 S)

the component of oxide layer is mainly magnetite and Iron(II) sulfide. For both water wall materials tested in this study

the corrosion mass gain curves are parabolic

and the high moisture content in flue gas accelerates the corrosion rate.