Exam Question
(a) Describe the effects of fresh water feed on auxiliary boilers. (6)
(b) Describe the measures taken to reduce these effects. (4)
(c) Describe FIVE principle boiler water tests stating the reason for EACH. (6)
Class 4 (4th Engineer)
MEKG
📅 Oct 2023
Reference Answer
### (a) Effects of Fresh Water Feed on Auxiliary Boilers (6 Marks)
Fresh water, although appearing pure, contains dissolved gases and mineral salts that have detrimental effects on boiler systems under high temperature and pressure. These effects primarily manifest as scale formation, corrosion, and carryover.
1. **Scale Formation:**
* **Cause:** Dissolved mineral salts, primarily Calcium ($$Ca^{2+}$$) and Magnesium ($$Mg^{2+}$$), constitute the 'hardness' of water. When heated, temporary hardness salts (bicarbonates) decompose to form insoluble carbonates which deposit on heating surfaces.
Fresh water, although appearing pure, contains dissolved gases and mineral salts that have detrimental effects on boiler systems under high temperature and pressure. These effects primarily manifest as scale formation, corrosion, and carryover.
1. **Scale Formation:**
* **Cause:** Dissolved mineral salts, primarily Calcium ($$Ca^{2+}$$) and Magnesium ($$Mg^{2+}$$), constitute the 'hardness' of water. When heated, temporary hardness salts (bicarbonates) decompose to form insoluble carbonates which deposit on heating surfaces.
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