Question 82Steam Plants - Assistant Engineer
70% to passCarbon dioxide dissolved in boiler water is dangerous in a modern power boiler because the gas _______________.
Aforms carbonic acid which attacks the watersides
Bcombines with sulfates to cause severe waterside pitting
Cbreaks the magnetic iron oxide film inside boiler tubes
Dcombines with oxygen to cause severe waterside scaling
AI Explanation
The correct answer is A) forms carbonic acid which attacks the watersides. When carbon dioxide (CO2) dissolves in boiler water, it forms carbonic acid (H2CO3). This carbonic acid can be corrosive to the internal surfaces (watersides) of the boiler, potentially leading to pitting and other damage over time. This is why the presence of dissolved CO2 in boiler water is considered dangerous in modern power boilers. The other answer options are incorrect because they do not accurately describe the primary risk posed by dissolved CO2 in boiler water. Options B, C, and D describe different boiler water chemistry issues that are not directly caused by the presence of dissolved CO2.
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