Question 378Steam Plants - Assistant Engineer

The correct answer is A) Excessive slag accumulation on the tubes. Laning in a boiler tube bank is caused by the buildup of slag or deposits on the tubes. This uneven accumulation of slag causes some tubes to be more obstructed than others, leading to an uneven flow of gases through the tube bank. This uneven flow, or "laning", can result in localized hot spots and accelerated tube corrosion or failure. The other options are incorrect because they are not the primary causes of laning. Low fuel oil pressure, reduced furnace volume, and insufficient air flow can all contribute to other boiler operational issues, but they do not directly lead to the laning phenomenon in the tube bank.