Exam Question
Describe how the following conditions are prevented in auxiliary boilers:
(a) Feed contamination by oil from heating coil drains;
(b) Internal corrosion;
(c) Furnace blowback;
(d) Uptake fire.
Class 2 (2nd Engineer)
MEP
📅 Dec 2025
Reference Answer
(a) Oil contamination in auxiliary boilers can occur due to leaking fuel tank heating coils. This contamination can lead to higher tube wall temperatures and reduced steam production. To prevent oil contamination, the feed water system includes a hot well where oil is removed before the water enters the boiler. The hot well is equipped with a scum valve to remove any oil that may contaminate the system. If oil contamination is detected, the boiler must be stopped immediately and the source of contamination must be identified and resolved.
(b) Causes of corrosion in Internal Surface:
Water and oxygen in the steam can lead to corrosion through oxidation.
Carbon dioxide (CO2) in the air or steam dissolves to form carbonic acid, a corrosive agent.
(b) Causes of corrosion in Internal Surface:
Water and oxygen in the steam can lead to corrosion through oxidation.
Carbon dioxide (CO2) in the air or steam dissolves to form carbonic acid, a corrosive agent.
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