BOE MCQs with Explanations Topic: Boiler Drum Level Fluctuation (Shrink & Swell) 1. Boiler drum level fluctuation is mainly due to: A. Feedwater pump failure B. Shrink and swell phenomenon C. Steam separator design D. Economizer choking ✅ Correct Answer: B Explanation: Shrink and swell are dynamic effects caused by pressure changes inside the drum during load variation. They give apparent level change without actual change in water mass . 2. Swell in a boiler drum occurs when: A. Steam demand decreases B. Boiler pressure increases C. Steam demand increases suddenly D. Feedwater temperature decreases ✅ Correct Answer: C Explanation: Sudden increase in steam demand reduces drum pressure. Steam bubbles expand, causing apparent rise in drum level , called swell . 3. Shrink phenomenon is caused by: A. Expansion of steam bubbles B. Collapse of steam bubbles C. Excess feedwater D. Boiler blowdown ✅ Correct Answer: B Explanation: When steam demand decreases, pressure increases. Steam b...
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