Study on Material Corrosion Resistance of Flue Gas Waste Heat Exchanger

According to the statistics of China Electricity Council, about 97% of China's coal-fired power generating units adopted wet desulfurization process (WFGD), of which the limestone-gypsum wet desulfurization process is the main process, accounting for about 91% of coal generating units. Without GGH, chimney exports can form white smoke plume. To solve the problem of environmental protection of white smoke plume and boiler flue gas waste heat recovery, the heat exchanger will be applied in flue gas condensation. But, the SO2, CO2, HCl and other complex components in flue gas can lead to equipment serious corrosion, so, it is necessary to study the heat exchanger and chimney material's corrosion resistance. In this paper, the natural corrosion experiments in the actual chimney condensate of 2205 duplex stainless steel, 2507 super duplex stainless steel, 316L austenitic stainless steel and TA2 materials were studied by hanging weight loss method and electrochemical method at different temperatures. The results show that: The existence of weld in stainless steel and TA2 will increase the corrosion tendency and corrosion rate of the material. In static immersion, the higher the temperature, the higher the corrosion rate; Corrosion rate is 2507<2205< TA2< 316L; In the presence of SO42- and F-, the oxide film of TA2 is destroyed and its corrosion resistance is reduced, which provides a certain reference for material selection of heat exchangers and chimneys.