Fuels containing 1% sulfur yield combustion flue gases with an acid dew point temperature (ADT) near ____________ °C?
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Answer: B. 130
Explanation
Burning fuel with one percent sulfur produces sulfur dioxide and some sulfur trioxide. Sulfur trioxide combines with water vapor in the flue gas to form sulfuric acid vapor. This chemical reaction elevates the acid dew point temperature of the flue gases to 130 °C. Fossil fuels contain varying amounts of sulfur impurities that oxidize during combustion. Acid dew point represents the temperature where sulfuric acid vapor begins to condense. Condensation of acid leads to severe corrosion on low-temperature metal heat exchangers.
Power plant engineers monitor flue gas temperatures to prevent cold end boiler corrosion. Air preheaters must operate above the acid dew point to extend equipment lifespan. Fuel desulfurization helps lower sulfur trioxide emissions and protects industrial infrastructure. Eighty degrees Celsius is too low and ignores the actual vapor pressure of sulfuric acid. One hundred eighty degrees Celsius overestimates the typical acid dew point for this sulfur level. Two hundred fifty degrees Celsius represents an excessively high thermal margin for standard boilers.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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