Effect of Static Stress on High Temperature Corrosion Behavior of Boiler Tubes in Waste Incineration Environment

Abstract

In superheater tubes of high efficiency waste to energy plants, high temperature corrosion may occur when molten salt containing chlorides or sulfates is formed in the ashes deposited on the fireside tube surface. In addition, if residual stress exists in bent or welded parts, high temperature corrosion may be accelerated or crack like damage may be caused by the presence of the molten salt. In order to investigate the effect of static stress on the high temperature corrosion, crack like damage tests were conducted in actual refuse ash and synthetic refuse ash at 823 K under static stress applied by the constant load method.When buried in synthetic refuse ash containing 20 mass chlorine under a 0.2 proof stress load condition at 823 K, the SUS304 specimen was fractured by intergranular crack like damage after 3.6×10 ks. For SUS310J1 and alloy 625, the specimens exhibited no cracking up to 1.08×10 3 ks. However, the maximum intergranular corrosion depth of SUS310J1 increased as applied stress was increased. Also, as the chlorine concentration in the refuse ash was increased both the maximum intergranular corrosion depth and the maximum corrosion thickness loss tended to increase.

Pengaruh Lingkungan Korosif dan Beban Mekanis Terhadap Perilaku Korosi pada Material Stainless Steel AISI-304

“…[1,2] Dalam industri permesinan, korosi tidak hanya ditinjau dari faktor elektrokimia, tetapi juga faktor mekanisa. Telah diketahui bahwa pembebanan mekanis memberikan pengaruh terhadap proses korosi seperti pengaruh tegangan-regangan, pengaruh panas dan pengelasan pada material tertentu [3][4][5][6]. Lingkungan korosif dengan beban mekanis dibawah tegangan luluh ataupun tegangan threshold untuk material tertentu dapat memicu terjadinya korosi, seperti korosi tegangan retak, korosi fatik dan korosi erosi, yang berujung pada kegagalan dini.…”

An Overview on Corrosion-Resistant Coating Technologies in Biomass/Waste-to-Energy Plants in Recent Decades

“…The chloride concentration in the deposits shows high concentration at locations where ∆T is large, and there is a tendency to form low melting deposits. Additionally, it is known that the amount of Cl, SO 4 , alkalis, and heavy metals affect the corrosiveness and the physical properties of the deposits, such as molten phase amount and permeability [31]. The penetration of corrosive gas components through the deposits and the presence of oxidizing constituents such as O 2 are considered to be necessary for maintaining the corrosion reactions.…”

“…Metal temperatures of WWTs are 250-320 °C depending on water/steam pressure, while surface metal temperatures in SHTs are approximately 300-550 °C. The corrosive environment becomes more severe with the increase in temperature, pressure, and power generation The corrosion attack of materials is commonly general corrosion, although intergranular or localized corrosion [4] occurs under the existence of molten deposits and loading of stress on even highly CRMs.…”