抄録
In flue gas desulfurization plants, which remove sulfur dioxide from the flue gas of oil and coal, chloride coming from the flue gas and makeup fresh water is accumulated in circulating absorbent. When stainless steels are employed as construction materials, pitting corrosion due to Cl- cannot be disregarded.
The Cl- concentration is usually controlled below a certain value to avoid pitting corrosion by discharging part of the absorbent (i.e., plant fluids) from the system. Inhibiting effects of NO3-, which also comes from flue gas, co-existing with Cl- in the absorbent were systematically investigated. As a result, operating instructions for actual plants are successfully established to protect stainless steel from pitting corrosion.
