Boiler ash conveying system

The boiler ash conveying system is an essential part of waste-to-energy (WtE) plants and industrial boilers. It is designed to handle and transport ash produced from the combustion process. This ash, often referred to as bottom ash or boiler ash, consists of heavier, non-combustible materials that collect at the base of the boiler.

Purpose

The system’s primary functions include:

1. Collecting ash from the boiler grate or combustion chamber.
2. Cooling and conditioning the ash to facilitate safe handling.
3. Transporting ash to a storage or disposal area.

Key Components

1. Ash Hoppers:
   • Located beneath the boiler to collect ash as it falls.
   • Often water-sealed to prevent air leakage into the boiler.
2. Ash Coolers:
   • Use water or air to cool hot ash collected from the boiler to a manageable temperature.
   • Examples:
     • Submerged Scraper Conveyors (SSC): Cool ash in a water bath while transporting it.
     • Dry Ash Coolers: Use air to cool ash, reducing water consumption.
3. Conveying Equipment:
   • Submerged Scraper Conveyors: Transport ash underwater, often used for bottom ash.
   • Belt or Chain Conveyors: For dry ash or after initial cooling.
   • Pneumatic Conveying Systems: Transport ash over long distances using compressed air.
4. Crushers/Grinders:
   • Break down larger clumps of ash to ensure smooth transportation.
5. Storage Silos or Bunkers:
   • Collect ash for temporary storage before final disposal or recycling.
6. Ash Handling Valves:
   • Regulate ash flow and maintain system pressure during transfer.

Types of Boiler Ash Conveying Systems

1. Wet Systems:
   • Use water for cooling and transporting ash (e.g., submerged scraper conveyor).
   • More common in traditional plants but require water treatment.
2. Dry Systems:
   • Eliminate water usage, relying on mechanical or pneumatic systems.
   • Preferred for modern WtE plants to minimize environmental impact and improve efficiency.
3. Pneumatic Systems:
   • Ideal for long-distance ash transport.
   • Use pressurized air to move ash through pipelines.

Environmental Considerations

• Dust Control: Ensure minimal ash escape during transport.
• Ash Utilization: Bottom ash can sometimes be recycled in construction materials.
• Compliance: Systems must meet environmental regulations to prevent leaching of heavy metals or other pollutants.

Would you like guidance on designing such systems or insights into specific technologies like dry ash handling?