The dense phase ash handling system is widely used in boiler ash handling plants because it provides an efficient and reliable method of transporting dry ash, especially fly ash, over short as well as long distances. In coal-fired thermal power plants, it is commonly used to transfer ash from ESP hoppers, bag filters, and other ash collection points to the ash storage silo.

In a dense phase system, ash is conveyed through a pipeline with the help of compressed air. The ash moves in the form of dense plugs or slugs, with a relatively high concentration of ash and lower conveying velocity compared with a dilute phase system.

Main Reasons for Using Dense Phase Ash Handling

1. Low Air Consumption

One of the major advantages of dense phase conveying is its low compressed-air consumption. Since a large quantity of ash is transported using comparatively less air, the system can operate more efficiently and reduce the power required for compressed-air generation.

2. Lower Ash Conveying Velocity

In dense phase conveying, ash travels through the pipeline at a relatively low velocity. This reduces the impact of ash particles on the inner surface of pipelines, bends, and other components.

3. Suitable for Long-Distance Conveying

Dense phase systems are well suited for transporting fly ash over long distances. They can transfer ash from the collection points near the boiler to ash storage silos located at a considerable distance.

4. Reduced Pipeline Wear

The lower conveying velocity helps reduce the erosion and wear of pipelines, bends, and conveying equipment. As a result, the service life of the ash handling system can be improved and maintenance requirements can be reduced.

5. Less Dust Generation

Dense phase ash conveying takes place through a closed pipeline system. This helps minimize the escape of fly ash into the surrounding area and provides a cleaner working environment compared with open ash handling arrangements.

6. Efficient Handling of Dry Fly Ash

The system is particularly suitable for handling dry fly ash collected from ESP hoppers, bag filters, economizer hoppers, and other collection points. It can transport large quantities of ash in a controlled manner.

7. Reliable and Economical Operation

Because of its lower air consumption and reduced wear of conveying components, a dense phase system can provide reliable operation with comparatively lower operating and maintenance requirements.

Conclusion

The dense phase ash handling system is widely used in boiler ash handling plants because it offers several advantages, including low air consumption, low conveying velocity, reduced pipeline wear, long-distance conveying capability, less dust generation, and reliable transportation of dry fly ash.

These advantages make dense phase conveying a suitable choice for fly ash handling in large coal-fired thermal power plants, particularly where ash has to be transported over long distances to storage silos.