【Question 002】Basic boiler questions

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This post was last edited by zgj2405 on 2009-10-28 21:06. 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 responding to participate, only the first response is considered valid. All participants receive 2 points as a reward. For the multiple-choice questions in this round, each question is worth 2 points, with an additional 3 points awarded for getting all questions correct. For specific hiding methods, see: http://bbs.hcbbs.com/viewthread.php?tid=492556&highlight=%D2%FE%B2%D8. 1. Boilers can be classified according to their water circulation method into natural circulation boilers, ( ), compound cycle boilers, and once-through boilers. (A) Layered combustion furnace ； (B) Multiple forced circulation boilers ； (C) Boiling furnace ； (D) Chamber combustion furnace. 2. For the entire boiler unit, the optimal coal powder fineness refers to ( ). (A) Fineness for minimum power consumption of the coal grinder ； (B) Fineness at maximum output of the grinding system ； (C) Fineness at the highest net efficiency of the boiler ； (D) The fineness at which the total power consumption for powder production is minimized. 3. On the water wall tubes of a boiler, scaling inside these tubes can cause ( ). (A) Enhanced heat transfer, increased tube wall temperature ； (B) Heat transfer is reduced, and the tube wall temperature decreases ； (C) Enhanced heat transfer, reduced wall temperature ； (D) Heat transfer decreases, and the tube wall temperature rises. 4. What flows in the boiler’s primary air duct is ( ). (A) Combustion air ； (B) Fuel ； (C) Wind-powder mixture ； (D) Atomized steam. 5. The purpose of dividing the water wall into multiple single-circulation loops is ( ). (A) To prevent all the water inside the boiler from leaking out when the water wall tubes burst, thereby ensuring the safety of the boiler ； (B) Resolve the uneven flow rates in each water wall tube ； (C) Prevent excessive thermal deviation between water wall tubes ； (D) None of them.