Question 123Steam Plants - Assistant Engineer

70% to pass

In most marine boilers, the primary reason the first few rows of generating tubes, called screen or furnace row tubes, are made larger in diameter than the rest of the generating tubes is because _______________.

Atheir main function is to retard combustion gas flow for maximum heat transfer rates

Bthey must screen the superheater from the direct radiant heat of the burners

Cthey require more water flow since they are exposed to the greatest heat

Dthey must act as downcomers to ensure proper circulation

AI Explanation

The correct answer is C) they require more water flow since they are exposed to the greatest heat. The primary reason the first few rows of generating tubes, called screen or furnace row tubes, are made larger in diameter than the rest of the generating tubes is because these tubes are exposed to the greatest heat from the burners. The larger diameter allows for increased water flow through these tubes, which is necessary to prevent overheating and potential tube failure due to the intense heat they experience. The other answer choices do not directly address this key function of the screen or furnace row tubes.