Question 120Steam Plants - Assistant Engineer

The correct answer is D) stack temperature. After routine blowing of tubes on a ship, the stack temperature should decrease. Blowing of tubes helps remove soot and scale buildup inside the boiler tubes, which can improve heat transfer and combustion efficiency. This reduction in insulation and improved airflow through the boiler results in a lower exhaust or stack temperature. The other answer choices are incorrect because: A) CO2 in the stack gas would not necessarily decrease after tube blowing. B) Fuel oil temperature is not directly affected by tube blowing. C) Excess air required for combustion is also not impacted by tube blowing.