【Question 105】Boiler basic questions (April 17)
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This post was last edited by zgj2405 on 2010-4-17 at 17:47. Please hide your replies; think carefully before posting, as edits are invalid! Those with different views on the provided answer keys can post discussions the next day. For multiple accounts under the same IP, only the first response indicating participation is valid. All participants receive 2 points as a reward. This round consists of multiple-choice questions, with 2 points for each question; an additional 5 points are given for getting all answers correct. In principle, answers are graded within 48 hours. For the specific method of hiding, see: http://bbs.hcbbs.com/viewthread.php?tid=492556&highlight=%D2%FE%B2% 1. An excessively high excess air coefficient generally does not lead to ( ). A. Lowering the furnace temperature to reduce heat transfer B. Increased smoke exhaust, resulting in a decrease in the boiler’s thermal efficiency C. Incomplete combustion of fuel, causing the exhaust smoke to be black D. Both A and C above. 2. The ventilation volume for small boilers is usually determined by ( ). A. Adjustment via inlet guide vanes B. Speed regulation method C. Throttling damper method D. Bypass return method 3. The primary air supplied by the boiler air distributor cannot serve the purpose of （ ）。 A. To prevent the formation of carbon black during high-temperature cracking of fuel B. To supply most of the oxygen required C. To maintain flame stability D. To cool the fuel injector 4. The drain pipe in a boiler’s steam and water system is usually located at ( ). A. Main steam distribution header B. Low-pressure steam distribution header C. Low-pressure steam safety valve D. A+B+C 5. The measure that does not prevent excessive water content in the steam is ( ). A. The water level should be low under high load conditions. B. Prevent excessive hardness in the boiler water. C. Prevent too high salt content in the boiler water. D. The steam supply rate should not increase suddenly
Answer key: C, C, B, D, B
1. An excessively high excess air coefficient generally does not cause (D). A. Lowering the furnace temperature reduces heat transfer. B. An increased amount of exhaust gas leads to a decrease in the boiler’s thermal efficiency. C. Incomplete combustion of fuel results in black exhaust gas. D. Options A and C above. 2. The ventilation volume for small boilers is usually set at (C). A. Adjustment via inlet guide vanes B. Speed regulation method C. Throttling damper method D. Bypass return method 3. The primary air supplied by the boiler air distributor cannot serve the purpose of (D). A. Prevent the formation of carbon black during high-temperature cracking of fuel B. Supply most of the required oxygen C. Maintain flame stability D. Cool the injector 4. The drain pipe in a boiler’s steam and water system is usually located at (D). A. Main steam distribution header B. Low-pressure steam distribution header C. Low-pressure steam safety valve D. A+B+C 5. The measure that does not prevent excessive water content in the steam is (B). A. The water level should be low under high load conditions. B. Prevent excessive hardness in the boiler water. C. Prevent too high salt content in the boiler water. D. The steam supply rate should not increase suddenly
1. An excessively high excess air coefficient generally does not cause (C). A. Lowering the furnace temperature reduces heat transfer. B. An increased amount of exhaust gas leads to a decrease in the boiler’s thermal efficiency. C. Incomplete combustion of fuel results in black exhaust gas. D. Options A and C above. 2. The ventilation volume for small boilers is usually set at (C). A. Adjustment via inlet guide vanes B. Speed regulation method C. Throttling damper method D. Bypass return method 3. The primary air supplied by the boiler air distributor cannot serve the purpose of (D). A. To prevent the formation of carbon black during high-temperature cracking of fuel B. To supply most of the oxygen required C. To maintain flame stability D. To cool the injector 4. The drain pipe in a boiler’s steam and water system is usually located at (B). A. Main steam distribution header B. Low-pressure steam distribution header C. Low-pressure steam safety valve D. A+B+C 5. The measure that does not prevent excessive water content in the steam is (A). A. The water level should be low under high load conditions. B. Prevent excessive hardness in the boiler water. C. Prevent too high salt content in the boiler water. D. The steam supply volume should not increase suddenly. 1# zgj2405