Prevention of stack corrosion under wet flue gas desulfurization conditions in a coal-fired power plant: performance analysis and comparative study

Abstract

Background

This study investigated the prevention of stack corrosion under wet flue gas desulfurization conditions in a coal-fired power plant. The performance analysis and comparative studies of six materials for the prevention of stack corrosion were investigated.

Results

The ion chromatography analysis showed the acid condensation contained fluoride, chloride, nitrate, sulphate, and sulphite. The weight loss method showed titanium alloy and foam glass blocks were heat and acid resistant. The scanning electron microscopy indicated the morphologies were pits, cracks, and flakes for sulfuric acid dew corrosion resistant steel, and X-ray diffraction showed the corrosion products mainly consisted of Fe ₂O3, FeSO₄, FeOOH, with some Fe₃O₄ or FeF₃. The comparative study indicated that cyclic wet-dry conditions resulted in more aggressive corrosion to the stack than acid condensation.

Conclusions

Titanium alloy and foam glass blocks had the best performance and could be applied in the stack to prevent corrosion. The effects of cyclic wet-dry conditions should be taken into account to mitigate stack corrosion in coal-fired power plants.