Water Drainage from Boiler
What is Wet Steam?
Wet steam is a mixture of saturated steam and liquid water droplets. It is usually caused by carryover of impurities from boiler water due to high water levels or fouling and foaming. Wet steam and carryover are most common when your boiler capacity is below the steam demand of the plant and multiple machines are operating at the same time, called peak draw.
Effects of Moving
The effect of water entrainment is commonly experienced as a reduction in steam quality and heat transfer efficiency. It causes water accumulation and flooding of steam mains, causing water hammer. Wet steam has a lower enthalpy than dry steam and requires more steam (and therefore fuel) to achieve the same level of heat transfer. When the boiler operates for longer periods or at higher capacities, it increases boiler workloads and consumes more fuel.
Fuel Consumption Increase
The amount of fuel increase depends on steam quality and the extent of carryover. However, a common estimate is that every 1% moisture in steam causes a 2-3% increase in fuel consumption due to efficiency losses. Significant water entrainment and associated poorly managed systems can increase fuel consumption by 10-15%.
Preventing Wet Steam and Water Entrainment
Maintain Boiler Water Quality
- Use appropriate water treatment to minimize foaming and scaling.
- Monitor Total Dissolved Solids (TDS) in boiler water regularly.
- Check Boiler Operations:
- Avoid extreme peak drafts and high water levels.
- If necessary, use well-designed steam separators at the azan outlet and/or in the main steam lines.
- Inspect and maintain insulation regularly to minimize condensation.
