Exam Question

### (a) Explanation for Frequent Draining of Starting Air Receivers
Starting air receivers must be drained frequently to prevent the accumulation of condensed water and oil, which can lead to a multitude of operational issues, material degradation, and safety hazards. The primary reasons are detailed below:
* **Condensation and Water Accumulation**: Atmospheric air contains a significant amount of water vapour. When this air is drawn into the compressor and compressed to high pressures (e.g., 30 bar), its temperature rises. Subsequent cooling in the intercoolers and aftercoolers, and then within the air receiver itself, causes the water vapour to condense back into liquid water due to the increase in partial pressure and reduction in temperature below its dew point. This liquid water then collects at the bottom of the receiver.
* **Internal Corrosion (Dew Point / Cold Corrosion)**: