The thermal efficiency of recuperators used for preheating air or fuel gas can reach up to _____________ percent?
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Answer: C. 85
Explanation
Modern high-performance recuperators used for preheating combustion air or fuel gas can attain thermal efficiencies up to 85 percent. Advanced recuperator designs maximize heat transfer surface areas to capture large amounts of waste exhaust energy. High thermal effectiveness ensures that a major portion of flue gas sensible heat returns to the combustion zone. Recuperators are continuous heat exchangers that transfer thermal energy from exhaust flue gases to incoming cold streams. Constructing high-efficiency recuperators requires specialized metallic or ceramic alloys capable of withstanding extreme heat. Evaluating recuperator performance involves calculating the ratio of actual heat transferred to maximum possible heat transfer.
Preheating combustion air using high-efficiency recuperators significantly reduces overall plant fuel consumption. Industrial furnace designers select recuperator types based on exhaust gas temperatures and particulate loading levels. Routine maintenance prevents fouling and leaks, ensuring recuperators maintain high thermal efficiencies over time. Option A underestimates the performance capabilities of modern engineered industrial recuperators. Option B represents moderate efficiency levels typical of older or simpler recuperator designs. Option D overestimates recuperator limits, as thermodynamic constraints prevent reaching 99 percent efficiency.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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